1985
DEVELOPMENT AND EVALUATION OF HYPOGLYCAEMIC GUAVA PRODUCTS
WITH ALOE VERA FORTIFICATION
ThesisThesisThesisThesis
by
SILONI SLATHIA
Submitted in partial fulfillment of the requirements for the degree of
DOCTOR OF PHILOSOPHY
(HORTICULTURE)
POST HARVEST TECHNOLOGY
COLLEGE OF HORTICULTURE Dr. Yashwant Singh Parmar University of
Horticulture and Forestry, Nauni, Solan - 173230 (H.P.), INDIA
2013
Dr. P C Sharma
Professor
Department of Food Science and Technology
College of Horticulture
Dr. Y S Parmar University of Horticulture
and Forestry, Nauni, Solan – 173 230 (HP)
CERTIFICATE - I
This is to certify that the thesis entitled “Development and evaluation of
hypoglycaemic guava products with Aloe vera fortification” submitted in partial fulfilment
of the requirements for the award of degree of DOCTOR OF PHILOSOPHY in
HORTICULTURE (Post Harvest Technology) to Dr. Yashwant Singh Parmar University
of Horticulture and Forestry, Nauni, Solan (HP) is a record of bonafide research work carried
out by Ms. Siloni Slathia (H-07-18-D) under my guidance and supervision. No part of this
thesis has been submitted for any other degree or diploma.
The assistance and help received during the course of investigations have been fully
acknowledged.
Place: Nauni, Solan (Dr. P.C. Sharma)
Dated: , 2012 Chairman, Advisory Committee
CERTIFICATE - II
This is to certify that the thesis entitled “Development and evaluation of
hypoglycaemic guava products with Aloe vera fortification”, submitted by Ms. Siloni
Slathia (H-07-18D) to Dr. Yashwant Singh Parmar University of Horticulture and Forestry,
Nauni, Solan (HP) in partial fulfilment of the requirements for the award of degree of
DOCTOR OF PHILOSOPHY in HORTICULTURE (Post Harvest Technology) has
been approved by the student’s advisory committee after an oral examination of the same in
collaboration with the external examiner.
Dr. P C Sharma (Professor) (External Examiner)
Chairman, Advisory Committee
Members of Advisory Committee
(Dr. (Mrs.) Devina Vaidya) (Dr. (Mrs.) Nivedita Sharma)
(Professor) (Professor)
Dr. P K Mahajan Dr. (Mrs) Neerja Rana
(Professor) (Assistant Professor)
Professor and Head
Department of Food Science and Technology
Dean’s Nominee
Dean College of Horticulture
CERTIFICATE - III
This is to certify that all the mistakes and errors pointed out by the external examiner
have been incorporated in the thesis entitled “Development and evaluation of
hypoglycaemic guava products with Aloe vera fortification”, submitted by
Ms. Siloni Slathia (H-07-18-D) to Dr. Yashwant Singh Parmar University of Horticulture
and Forestry, Nauni, Solan (HP) in partial fulfilment of the requirements for the award of
degree of DOCTOR OF PHILOSOPHY in Horticulture (Post Harvest Technology).
Dr. P C Sharma (Professor) Chairman, Advisory Committee
Professor and Head
Department of Food Science and Technology
Dr. YS Parmar UHF, Nauni, Solan (HP)
ACKNOWLEDGEMENTS
I know the world is filled with troubles and many injustices. But the reality is as beautiful as it is
ugly. I think it is just as important to sing about beautiful mornings as it is to talk about slums. I just
could not write anything without slums. I just could not write anything without hope in it.
With limitless humility, I would like to praise and thank the Almighty who bestowed me the
strength and courage to complete this manuscript.
My parents are next only to my god. This flesh, these bones and each drop blood belongs to them.
Any and every good quality to be myself is actually there’s. I thank god for giving me such honest and sacrificial parents to whom I owe all that is mine.
Pride, praise and perfection belong to Almighty alone. So I would like to consecrate myself before the Supreme Being for the mental strength. He bestowed on me to go through the ups and downs of my life.
Indeed, the words of my command are not adequate to pen down my sense of heartfelt gratitude to
the chairman of my advisory committee, Dr. P. C. SharmaDr. P. C. SharmaDr. P. C. SharmaDr. P. C. Sharma, professor, department of Food Science and Technology, for his in constant guidance, deep scientific vision and affectionate attitude during the entire course of my study.
I am immensely indebted to Dr. P.K MahajanDr. P.K MahajanDr. P.K MahajanDr. P.K Mahajan, Dr. Devina Vedya Dr. Devina Vedya Dr. Devina Vedya Dr. Devina Vedya , Dr. Nivedita Sharma and Dr. Dr. Nivedita Sharma and Dr. Dr. Nivedita Sharma and Dr. Dr. Nivedita Sharma and Dr.
Neerja Rana Neerja Rana Neerja Rana Neerja Rana worthy members of my advisory committee, and Dr. V.S BarwalDr. V.S BarwalDr. V.S BarwalDr. V.S Barwal for their kind help, invaluable suggestions, timely help and amiable attitude during the course of investigation.
‘Thanks’ is too small a word to express my deep sense of gratitude to Dr. V.K JoshiDr. V.K JoshiDr. V.K JoshiDr. V.K Joshi for their
sincere, selfless and invaluable help as and when required. I cordially acknowledge the assistance extended by faculty members, office and canning unit staffs
of Department of Food Science and Technology for timely and sincere help during the course of experimentation.
It is Diegratia that I have been blessed with long lasting memorable company of Shweta Sharma
Muzaffar, Jagriti , Navedita, Neha, Vikas Reena and Shavi who made my every moment enjoyable. . All the words in the lexicon will be futile and meaningless if I fail to divulge my extreme sense of regards to my husband and brother.
I would like to express my appreciation to laboratory staff especially Anil Gupta, Anil Verma, Jai Kishan, Harnam and Nariender of the Department of Food Science and Technology.
Satyanand Stokes Library will always remain a luscious remembrance for furnishing my studies
with endless and invaluable information. Needless to say, errors and omissions are mine.
Place: Nauni, Solan Date: , 2013 ( Siloni Slathia )
CONTENTS
CHAPTER TITLE PAGE(S)
1. INTRODUCTION 1-4
2. REVIEW OF LITERATURE 5-38
3. MATERIALS AND METHODS 39-54
4. EXPERIMENTAL RESULTS 55-118
5. DISCUSSION 119-153
6. SUMMARY AND CONCLUSION 154-158
7. REFERENCES 159-178
ABSTRACT 179
ANNEXURES I-III
LIST OF TABLES
Table Title Page
Materials and Methods
3.1 Optimization of method for extraction of pulp from guava fruit cv. Allahabad Safeda
40
3.2 Standardization of recipe for the preparation of guava-Aloe
vera beverage 41
3.3 Relative sweetness of non-nutritive sweeteners (Duo-trio test)
42
3.4
3.5
3.6
Preparation of hypoglycaemic guava-Aloe vera beverage
Preparation of guava-Aloe vera fruit bar
Preparation of hypoglycaemic guava-Aloe vera fruit bar
42
44
51
Experimental Results
4.1 Physico-chemical characteristics of guava fruit (cv. Allahabad Safeda)
54
4.2 Effect of fruit to water ratio and methods of heating on yield (%) of extracted guava pulp
56
4.3 Effect of fruit to water ratio and methods of heating on total solids (%) and total soluble solids (ºB) of extracted guava pulp
58
4.4 Effect of fruit to water ratio and methods of heating on Titratable acidity (%) CA and pH of extracted guava pulp.
59
4.5 Effect of fruit to water ratio and methods of heating on total sugars (%) and ascorbic acid contents (mg/100g) of extracted guava pulp
60
4.6 Effect of fruit to water ratio and methods of heating on pectin (% as calcium pectate) and relative viscosity of extracted guava pulp
61
4.7 Effect of fruit to water ratio and methods of heating on grittiness of extracted guava pulp
62
4.8 Physico-chemical characteristics of raw and Aloe vera gel extract (Aloe vera barbadensis)
63
4.9 Physico-chemical composition of dried stevia leaves 64
4.10 Effect of addition of Aloe vera gel extract on the chemical attributes of guava-Aloe vera beverages.
65
4.11 Effect of addition of Aloe vera gel extract on the sensory characteristics (9 point hedonic scale) of guava-Aloe vera beverage/ nectar
67
4.12 Effect of different proportions of non-nutritive sweeteners (stevia leaves extract and sorbitol) on the chemical attributes of hypoglycaemic guava-Aloe vera beverage
70
Table Title Page
4.13 Effect of different proportions of non-nutritive sweeteners (stevia leaves extract and sorbitol) on the sensory characteristics (9 point hedonic score) of guava-Aloe vera
beverage
72
4.14 Effect of different proportions of non-nutritive sweeteners
(stevia leaves extract and sorbitol) on total soluble solids
(ºB) content of hypoglycaemic guava-Aloe vera beverage
during storage at ambient temperature (12-24ºC)
75
4.15 Effect of different proportions of non-nutritive sweeteners (stevia leaves extract and sorbitol) on titratable acidity (%) CA content of hypoglycaemic guava-Aloe vera beverage during storage at ambient temperature (12-24ºC)
75
4.16 Effect of different proportions of non-nutritive sweeteners (stevia leaves extract and sorbitol) on ascorbic acid (mg/100g) content of hypoglycaemic guava-Aloe vera
beverage during storage at ambient temperature ( 12-24ºC)
76
4.17 Effect of different proportions of non-nutritive sweeteners (stevia leaves extract and sorbitol) on pH content of hypoglycaemic guava-Aloe vera beverage during storage at ambient temperature (12-24ºC)
77
4.18 Effect of different proportions of non-nutritive sweeteners (stevia leaves extract and sorbitol) on total sugars (%) content of hypoglycaemic guava-Aloe vera beverage during storage at ambient temperature (12-24ºC)
78
4.19 Effect of different proportions of non-nutritive sweeteners (stevia leaves extract and sorbitol) on relative viscosity content of hypoglycaemic guava- Aloe vera beverage during storage at ambient temperature (12-24ºC)
79
4.20 Effect of different proportions of non-nutritive sweeteners (stevia leaves extract and sorbitol) on specific gravity content of hypoglycaemic guava-Aloe vera beverage during storage at ambient temperature ( 12-24ºC)
80
4.21 Effect of different proportions of non-nutritive sweeteners (stevia leaves extract and sorbitol) on sensory colour and flavour acceptability score (9 point hedonic scale) of hypoglycaemic guava- Aloe vera beverage during storage at ambient temperature (12-24ºC)
81
4.22 Effect of different proportions of non-nutritive sweeteners (stevia leaves extract and sorbitol) on sensory taste and body score (9 point hedonic score) of hypoglycaemic guava-Aloe vera beverage during storage at ambient temperature (12-24ºC)
82
Table Title Page
4.23 Effect of different proportions of non-nutritive sweeteners (stevia leaves extract and sorbitol) on over all acceptability score (9 point hedonic score) of hypoglycaemic guava- Aloe vera beverage during storage at ambient temperature (12-24ºC)
83
4.24 Effect of different proportions of non-nutritive sweeteners on calculated energy value (K cal /100 g) of hypoglycaemic guava-Aloe vera beverage during storage at ambient temperature (12-24ºC)
84
4.25 Cost of production of hypoglycaemic guava-Aloe vera
beverage 85
4.26 Effect of addition of Aloe vera gel extract on the chemical attributes of guava-Aloe vera fruit bar.
87
4.27 Effect of addition of Aloe vera gel extract on sensory attributes (9 point hedonic scale) of guava-Aloe vera fruit bars.
88
4.28 Effect of addition of non-nutritive sweeteners (stevia leaves extract and saccharin) on chemical attributes of hypoglycaemic guava- Aloe vera fruit bar
92
4.29 Effect of addition of non-nutritive sweeteners (stevia leaves extract and saccharin) on sensory quality (9 point hedonic scale) of hypoglycaemic guava-Aloe vera fruit bar
94
4.30 Effect of different proportions of non-nutritive sweeteners on the total soluble solids (oB) of the hypoglycaemic guava Aloe vera fruit bars during storage at ambient (12-24ºC) and low (4+2ºC) temperature
98
4.31 Effect of different proportions of non-nutritive sweeteners on the titratable acidity (%) of the hypoglycaemic guava -Aloe vera fruit bars during storage at ambient (12-24ºC) and low (4+2ºC) temperature
100
4.32 Effect of different proportions of non-nutritive sweeteners on pH of the hypoglycaemic guava-Aloe vera fruit bars during storage at ambient (12-24ºC) and low (4+2ºC) temperature
101
4.33 Effect of different proportions of non-nutritive sweeteners on the ascorbic acid (mg/100 g) of the hypoglycaemic guava-Aloe vera fruit bars during storage at ambient (12-24ºC) and low (4+2ºC) temperature
102
4.34 Effect of different proportions of non-nutritive sweeteners on the total sugar (%) of the hypoglycaemic guava-Aloe
vera fruit bars during storage at ambient (12-24ºC) and low (4+2ºC) temperature
104
Table Title Page
4.35 Effect of different proportions of non-nutritive sweeteners on the moisture content (%) of the hypoglycaemic guava-Aloe vera fruit bars during storage at ambient (12-24ºC) and low (4+2ºC) temperature.
105
4.36 Effect of different proportions of non-nutritive sweeteners on the total solids (%) of the hypoglycaemic guava Aloe
vera fruit bars during storage at ambient (12-24ºC) and low (4+2ºC) temperature.
106
4.37 Effect of different proportions of non-nutritive sweeteners on the water activity of the hypoglycaemic guava Aloe vera fruit bars during storage at ambient (12-24ºC) and low (4+2ºC) temperature.
108
4.38 Effect of different proportions of non-nutritive sweeteners on sensory colour score (9 point hedonic scale) of the hypoglycaemic guava-Aloe vera fruit bars during storage at ambient (12-24ºC) and low (4+2ºC) temperature
109
4.39 Effect of different proportions of non-nutritive sweeteners on sensory taste score (9 point hedonic scale) of the hypoglycaemic guava-Aloe vera fruit bars during storage at ambient (12-24ºC) and low temperature (4+2ºC).
110
4.40 Effect of different proportions of non-nutritive sweeteners on sensory flavour score (9 point hedonic scale) of the hypoglycaemic guava-Aloe vera fruit bars during storage at ambient (12-240C) and low temperature (4+20C)
113
4.41 Effect of different proportions of non-nutritive sweeteners on sensory texture score (9 point hedonic scale) of the hypoglycaemic guava-Aloe vera fruit bars during storage at ambient (12-24ºC) and low (4+2ºC) temperature.
115
4.42 Effect of different proportions of non-nutritive sweeteners on sensory over all acceptability score (9 point hedonic scale) of the hypoglycaemic guava-Aloe vera fruit bars during storage at ambient (12-24ºC) and low (4+2ºC) temperature.
116
4.43
Effect of different proportions of non-nutritive sweeteners on calculated energy value of hypoglycaemic guava-Aloe
vera fruit bar.
117
4.44 Cost of production of hypoglycaemic guava-Aloe vera fruit bar.
118
LIST OF PLATES
Plate Title BetweenPage(s)
1. Guava fruit (cv. Allahabad Safeda ) used in the study 55-56
2. Guava pulp prepared by using different proportion of guava fruit and water
61-62
3. Preparation of Aloe vera gel extract 63-64
4. Preparation of stevia leaves extract 65-66
5 Guava-Aloe vera nectar/beverages containing varying proportion of guava pulp and Aloe vera extract
67-68
6. Hypoglycaemic guava-Aloe vera nectar/beverages containing different sweeteners
73-74
7. Guava-Aloe vera fruit bars using different proportions of guava and Aloe vera
87-88
8. Hypoglycaemic guava-Aloe vera fruit bars containing different non-nutritive sweeteners and bulking agents
93-94
LIST OF FIGURES
Figure Title BetweenPage(s)
4.1 HPLC chromatograms of stevia leaves extract showing peaks of Steviosides and Rebaudiosides A.
65-66
4.2 Material Flow sheet for the preparation of guava Aloe vera nectar
67-68
4.3 Material flow sheet for preparation of hypoglycaemic guava Aloe vera beverage containing stevia leaves extract as non nutritive sweeteners to replace 50% sugar
69-70
4.4 Material flow sheet for preparation of hypoglycaemic guava Aloe vera beverage containing sorbitol as non nutritive sweeteners to replace 50% sugar
69-70
4.5 Effect of addition of non nutritive sweeteners on calculated energy value (Kcal/100g) of hypoglycaemic guava aloe vera
nectar/beverages during storage
85-86
4.6 Material flow sheet for preparation of guava Aloe vera bar 87-88
4.7 Drying characteristics of guava-aloe vera fruit bar 87-88
4.8 Material flow sheet for preparation of hypoglyceamic guava Aloe vera fruit bar containing stevia leaves extract as non-nutritive sweetener
91-92
4.9 Material flow sheet of hypoglyceamic guava Aloe vera fruit bar containing saccharin as non-nutritive sweetener
91-92
4.10 Drying curve of for preparation hypoglycaemic guava- aloe
vera fruit bars containing 50 per cent substitution of sucrose with stevia leaves extract or saccharin and 10 per cent each of apple pomace or oat bran
91-92
4.11 Effect of different proportions of non-nutritive sweeteners on calculated energy value of hypoglycaemic guava-aloe vera fruit bar during storage
116-117
Chapter-1
INTRODUCTION
Diabetes mellitus is a major world health problem affecting about 2.8 per
cent of the global population (Etuk, 2010). It is usually diagnosed and
characterized by elevated blood sugar level (>120 mg/dl) in the body (Grodner et
al., 1999). According to the World Health Organization (WHO), there are
approximately 160,000 diabetics world-wide. The numbers of diabetics have
doubled in the last few years and are expected to double once again by the year
2025 (Beretta, 2001). Due to its high prevalence and potential deleterious effect
on a patient’s physical and psychological state, diabetes is considered major
health concern (Macedo et al., 2002). Generally, diabetes mellitus has no radical
cure, yet can be managed with the help of restriction in diet and use of certain
drugs like insulin. Oral drugs though, help in lowering the blood glucose level but
also produce many side effects (Parsmore and Eastward, 1986). Thus, use of diet
generally devoid of sugar but rich in other bioactive compounds and free of side
effects appears to be one of the alternatives for the management of this health
problem in human beings.
In India, many herbal remedies have been recommended in various
medical treatments for the management of diabetes. According to Nagarajan et al.
(1978) about 75 Indian plants are known to possess hypoglycaemic properties.
Among them guava, Aloe vera and stevia are reported to exert hypoglycaemic
effect for the diabetic patients (Brusick and Menges, 1997, Rai et al., 2007).
Thus, these plants can be explored for preparation of low calorie products for
use in diabetics.
Guava (Psidium guajava L.) is an important fruit and is considered
superior over other fruits because of its commercial and nutritive values. Guava is
fourth most widely grown fruit in India and the country leads the world in guava
production, accounting for 0.15 million hectare area producing about 1.80 million
tonnes of fruit (Mitra et al., 2008). Guava is a rich source of vitamin C (260
2
mg/100g) (Menzel, 1985), pectin (1.8 %) (Dhingra et al., 1983) and vitamin A
(250IU/100g) (Dhilion et al.,1987). It contains high amount of dietary fibre.
Besides, it also contain appreciable quantities of niacin, thiamine, riboflavin,
carotene, calcium and phosphorus.
Guava generally provides less energy (38-57 Kcal/100kg) as compared to
other fruits like mango, banana etc. and this property makes guava suitable for
diabetes and weight reducing programmes. Peeled guava are known to exert
hypoglycaemic property however guava peel extract has been found to raise the
blood sugar level in rats (Rai et al., 2007). Thus guava pulp after removal of peel
can be utilized for preparation of low calorie products. Besides, guava also
possesses strong flavour due to the presence of several volatile compounds such
as hydrocarbons, alcohol and carbonyls (Steven et al., 1970). It is mostly
consumed fresh but can also be processed into a variety of products like jam,
jelly, toffee, squash and wine (Hernanan et al., 1980; Singh and Dhawan, 1983).
However, the presence of grittiness in guava pulp makes most of the products
unacceptable. Thus, it has become imperative to develop and standardize a
method to remove gritty texture and utilize guava pulp for preparation of
hypoglycaemic products.
Aloe vera (Aloe barbadensis Miller) is an important medicinal plant
belonging to family Lilliaceae. It is used as a source of aloin (4.5 to 25%) and for
flavouring liquids (Rajendran et al., 2007). The ability of Aloe vera to affect body
system depends upon its chemical constituents. Aloe products like aloe drink, gel
powder and creams etc. have long been used in health foods and for medicinal
and cosmetic purposes. Aloe has wide range of medicinal applications such as
wound healing effects, reducing blood sugar in diabetes, smoothening burns,
easing intestinal problems and ulcers (Borrelli and Izzo, 2000). It also possess
anti inflammatory effect (Davis and Mare, 1989). Compounds extracted from
Aloe vera have been used as immunostimulant that have aided in fighting cancer
in cats and dogs (King et al., 1995), however these treatments have not been
scientifically tested on humans.
Annual production of Aloe vera plants is estimated to be 0.1 million
tonnes, out of which 200 tonnes of aloe extract is utilized by the Indian
3
pharmaceutical industries and about 1% of the total products are consumed by
ayurvedic pharmacies (Oudhia, 2003). The aloe contains liquid sources of yellow
latex (exudates) and clear gel (mucilage). Yellow sap consists mainly of
anthraquinones. The therapeutic properties of aloe are ascribed to inner colourless
gel, which consists of about 99 per cent water with an average pH of 4.5. The
remaining solid material consist of more than 45 different ingredients including
vitamins, minerals, enzymes, phenolic compounds, lignin, saponins, sterols,
polysaccharides and salicyclic acid (Chauhan et al., 2007).
The USFDA (United States Food and Drug Administration) refers Aloe
vera as dietary supplement (Anon, 2004). The phytosterol, like lophenol, 24-
methyl lophenol, 24- ethyl lophenol, cyclartanol and methylene-cyclartanol
derived from Aloe vera gel are known to possess specific effect to control blood
glucose level which is useful in the treatment of diabetes mellitus (Tanaka et al.,
2006). Thus, Aloe vera can be explored for development of food product suitable
for diabetics.
Stevia leaves contain steviosides that is high intensity non-nutritive
sweetener (Kumar et al., 2007). It is about 300 times sweeter than sugar and is
stable in light, heat and pH (Shin and Jonner, 1983). The steviosides are used in
different food products like lime juice, tea, coffee etc. for sweetening to replace
sucrose (Kumar et al., 2007). Joint FAO/WHO Expert Committee on Food
Additive (JFECFA) set a temporary ADI of 2mg/kg body weight of stevia which
is known to exert tremendous effect on diabetes and hypertension (JECFA,
2004).
Dietary fibre extracted from plants, is not digested by enzymes in the
intestinal tract, however part of it may be metabolized by bacteria in lower gut.
Tubers, cereals, vegetables, fruits and algae are characterized as the source of
high dietary fibre with low digestibility and low calorific value (Alferdo et al.,
2009). Apple pomace and oat bran are used as a source of carbohydrates,
minerals and dietary fibre (Sun et al., 2007). Thus, both apple pomace and oat
bran can be used as bulking agent to provide mouth feel, flavour and texture to
the low calorie hypoglycaemic fruit bar. Oats provide a vast range of human
4
health benefits such as serum cholesterol lowering (Chen et al., 2006), reducing
coronary disease (Berget et al., 2003) and help in reducing blood pressure (He et
al., 2008). One of the primary components of the oat bran implicated for these
health benefits is dietary fibre. Oat bran also provides flavour, texture and mouth
feel in food products. Specific health benefit of various fibres of food differ
according to the quantity and nature of dietary fibre used in food (Thabaudin et
al., 1997). Hence, suitability of apple pomace and oat bran fibre needs to be
evaluated for development of hypoglycaemic fruit bar.
The objective of treatment for hypoglycaemia is to delay the absorption of
food in the body. Among different approaches, increasing intake of fibre present
in fruits, vegetables, legumes and grains or consuming food with little or no
simple sugars are the approaches for delaying the absorption of food. Guava and
Aloe vera are known to exert hypoglycaemic effect. Similarly, oat bran and apple
pomace being rich source of dietary fibre can be exploited as sources of fibre in
different products. For replacement of simple sugars, the natural plant source of
stevia leaves extract can be used for the development of product rich in
hypoglycaemic properties. The specific information pertaining to development of
fruit product having all the properties of fruit, Aloe vera, fibre and a replacement
of sugar with non-nutritive sweetener is scanty in the literature. Thus, the present
investigation was carried out to meet the following main objectives:-
i) To standardize methods for preparation of guava pulp and Aloe vera gel
extract.
ii) To attempt fortification of guava pulp with Aloe vera gel extract for
preparation of functional guava beverage and fruit bar.
iii) To evaluate suitability of non-nutritive sweeteners and bulking agents for
the development of hypoglycaemic guava products.
iv) To study the effect of storage period on physico-chemical and
organoleptic changes in the developed products.
Chapter-2
REVIEW OF LITERATURE
Diabetes mellitus is a major health problem in both developing countries
and developed countries. It is ranked seventh among the leading causes of death
and third when it’s fatal complications are taken into account (Trivedi et al.,
2004). Diabetes can however be controlled through improved medical care and
monitoring lifestyle changes (Andersons and Chu, 2007). The use of diet
generally devoid of sugar and rich in bioactive compounds appear to be one of
the alternatives for the management of diabetes in human beings. The
compounds that breakdown slowly and releasing glucose gradually into the blood
stream are known to possess lower glycaemic index (Jennie, 2004) and can be
used for management of diet for diabetics.
Guava and Aloe vera having known hypoglycaemic properties can be
utilized for development of product for diabetic while sweetness of stevia leaves
can be explored for replacement of sugar to develop low calories food products.
The detail of research work carried out elsewhere in literature on different aspects
of product development with hypoglycaemic properties have been presented here
under:
2.1 Guava fruits
2.1.1 Physico-chemical composition of guava fruit
2.1.2 Method for extraction of guava pulp
2.2 Aloe vera and its health benefits
2.2.1 Chemical composition
2.2.2 Therapeutical values of Aloe vera barbadensis Miller
2.2.2.1 Hypoglycaemic effect
2.2.2.2 Other therapeutic effects
2.2.2.2.1 Antioxidant effect
6
2.2.2.2.2 Chemeopreventive effect of Aloe vera
2.2.2.2.3 Effect of Aloe vera on skin diseases
2.2.2.2.4 Effect of Aloe vera on digestive troubles
2.2.2.2.5 Effect of Aloe vera on respiratory troubles
2.2.3 Processing of Aloe vera juice
2.2.4 Stabilization of Aloe vera gel
2.2.5 Aloe vera incorporated food products
2.2.6 Physico-chemical composition of gel and juice
2.2.7 Safety studies
2.3 Non-nutritive sweeteners
2.3.1 Saccharin
2.3.2 Sorbitol
2.3.3 Stevia
2.3.4 Safety aspects of non-nutritive sweeteners
2.3.5 Application of non-nutritive sweetener in food products
2.4 Bulking agent
2.4.1 Apple pomace
2.4.2 Oat bran
2.5 Beverages and bars
2.6 Storage studies: Changes in physico-chemical and sensory attributes
2.1 Guava fruits
Guava (Psidium guajava L.), one of the pomiferous fruit of Myrtaceae
family is valued for its characteristic flavour, texture and nutritional qualities
(Tiwari and Dinesh, 2001). The fruit is either eaten fresh or cooked but can also
be processed into several products like jam, jellies, cheese, candies and beverages
(Sammy 1994, Samson 1996, Mercandanate et al., 1999 and Tiwari and Dinesh
2001).
7
According to Phandis (1970),
guava contain water (82.5%), acidity
(2.45%), reducing sugars (4.45%), total sugar (9.73%), ash (0.48 %) and vitamin-
C (260 mg/100g). Bose et al.(1999), reported that through guava fruit is rich
source of ascorbic acid and pectin but it provide low energy value (66 K
cal/100g). The fruit is rich in minerals like phosphorus (23-37mg/100g), calcium
(14-30 mg/100gm), iron (0.6-1.4 mg/100gm) and vitamins like niacin, thiamine,
riboflavin and vitamin A.
Rai et al. (2007) reported that guava controls diabetes and is good for
constipation as it contains high amount of dietary fibre. Also, it contains
reasonable source of potassium which helps in regulating blood pressure.
However, guava consumed with skin is reported to increase blood sugars level in
the body. Similarly, Mitra (2008) reported that peeled guava showed
hypoglycaemic effect on mices. Hence, hyperglycaemic effect of Pisidium
guajava fruit suggests that the use of peeled guava fruit for diabetic patients.
Thus, guava fruits can be explored for the development of hypoglyceamic
products for the diabetic individuals.
2.1.1 Physico-chemical composition of guava fruit
2.1.1.1 Fruit size, shape and weight
Guava is one of the most common fruit in India (Mandhyan et al., 2000).
The guava fruits are mostly round in shape but, some varieties are ovate or pear
shaped (Menzel, 1985). Fruits of Allahabad Safeda cultivar of guava are medium
sized, round and smooth with yellow skin, while the fruit of Sardar cultivar are
large, roundish ovate in shape with yellow skin and soft flesh. Singh et al. (1995)
recorded the length and diameter of guava fruits ranging between 4.27 to 7.94 cm
and 4.22 cm to 7.54 cm respectively, while the weight of rainy season fruits
ranged between 36.67 to 265.67g, whereas the average weight of the Chitaddar,
Allahabad Safeda and Luknow-49 cultivars of guava fruit were 145.3 g, 138.4 g
and 169.7 g respectively with 6.14 cm, 5.76 cm, 6.22 cm length and 6.51cm, 6.49
cm and 5.96 cm diameter, respectively (Murari and Verma, 1989).
8
2.1.1.2 Chemical composition of guava fruit
a) Moisture and Total solids
Guava fruits contain 77.9-86.9 per cent moisture (Singh, 1988 and
Wilson and Burns,1983). The moisture content of unripe and ripe guava fruits
was recorded 82.56 per cent and 85.35 per cent, respectively (Aggarwal et al.,
2002). Similarly Phandis (1970) recorded as 82.50 per cent moisture content in
guava fruits
b) Total soluble solids
Tiwari and Dinesh (2001) recorded the TSS of red fleshed guava fruits
ranging between 8.0ºB to 10.20
ºB. The highest total soluble solids i.e. 18.6
ºB
were recorded in Allahabad Safeda and green varieties of guava, followed by
Nasik (18.4ºB), Sindh (18.2
ºB), Apple Colour (17.8ºB) and Behat Coconut
(17.4ºB) verities of guava during winter season (Singh et al., 1995). Whereas,
Tomuri Gutaniwala had the lowest TSS (10ºB). Winter season fruits are
generally considered superior to those of rainy season (Rathore, 1976 and Singh,
1985).
c) Titratable acidity and pH
Titratable acidity in guava fruit ranged between 0.08-2.2 per cent (Singh
et al., 1988). However, Phandis in 1970 recorded as high as 2.45 per cent
titratable acidity. Similarly, the pH range of 4.1-5.4 is reported by Singh et al.
(1988) in guava fruits. However, the titratable acidity and pH in red fleshed
guava varieties ranged between 0.51 to 2.05 per cent and 2.32 to 3.29,
respectively (Tiwari and Dinesh, 2001).
d) Ascorbic acid
Guava is a rich source of vitamin C (Agnihotri et al., 1962). It ranks third
in vitamin C content after Barbedos cherry and Anola (Phandis, 1970 and
Rathore, 1976). Pandey and Singh (1999) recorded the ascorbic acid contents as
250.0, 233.4, 149.0 and 207.0 mg/100g, respectively in Sardar, Allahabad
9
Safeda, Apple Colour and Sangam varieties of guava. Thus, the product prepared
from guava are also expected to be rich in ascorbic acid.
e) Sugars
The level of starch and sugars vary at different stages of fruit growth.
Starch is stored in capillary tissues and is about 6.50 per cent before maturity
which gets hydrolyzed into sugars as the fruit matures (Okuse et al., 1981). The
main sugars present in fruit are glucose and fructose usually in equal proportions,
which represents about 70-80 per cent of total sugars (Okuse et al., 1981). Shukla
et al. (2009) recorded 5.70 per cent total sugars in guava fruits. The increase in
total sugars may be due to hydrolysis of starch in to sugars and conversion of
organic acids.
f) Specific gravity
Specific gravity of unfermented fruit and vegetable juices with traces of
alcohol or essential oils is always greater than unity. The lower the total soluble
solids, the lesser the specific gravity (Ranganna, 2007). Adsule and Kadam
(1995) reported the specific gravity of guava fruits ranging between 0.94-1.11.
2.1.2 Method for extraction of guava pulp
Jain et al. (1996) suggested cold extraction, instead of hot extraction of
pulp for subsequent use in preparation of various products. Whereas, combined
effect of hot and cold methods were studied by Murari and Verma (1989), they
reported that hot method of pulp extraction increases pulp recovery by 5 to 8 per
cent but developed pink/brown pigments. Therefore, cold extraction method was
more acceptable. Mandhyan et al. (2000) prepared guava pulp by pressure pan
and open pan methods by mixing guava with water at different ratios of 1:2, 1:3,
and 1:4, respectively under laboratory conditions and observed 1:3 as the best
ratio by boiling extract for one hour in open pan. According to Tiwari (2000),
nectars produced with guava and papaya pulps (70:30) had a high sensory score,
mainly due to consistency in flavour and vitamin-C (24.7 mg/100 g).
10
However, guava fruit varieties have also been evaluated for nectar
(Murari and Verma, 1989) and ready to serve drinks (Pandey and Singh 1999).
Singh and Dhawan (1983) have recommended varieties of soft flesh, good
coloured and flavoured guavas for nectar and beverage preparation and Lucknow-
49 was found best for jelly making. Diwan and Shukla (2005) concluded that the
level of pectinase enzyme concentration, incubation time and pH had significant
effect on guava juice yield which varied from 72 to 94 per cent. Maximum juice
(94%) was obtained at 2 per cent enzyme concentration, 20 hrs incubation time,
4.5 pH and 30ºC temp. Moy (2006) made effort to develop high quality juice
powders from four tropical fruits. The dehydrated guava and mango purees,
passion fruit and pineapple juice in a vacuum-puff freeze-drying process.
2.2 Aloe vera barbadensis
Aloe vera ( Aloe vera barbadensis L.) possess medicinal and therapeutic
value, and is known as miracle plant (Akinnyel and Odiyia, 2007). It belongs to
the family “Liliaceae”. It is cactus like plant with green dagger shaped leaves that
are fleshy, tapering and spiny marginated and filled with clear viscous gel. Aloe
vera contains a number of nutrients such as vitamins, minerals, amino acids,
sugar enzymes, fatty acids and saponins which have positive effect on human
body (Paul 2003). According to Gautam and Awasthi (2007), Aloe vera leaf
powder contains many nutrients mainly antioxidant (R-carotene and ascorbic
acid), dietary fiber and iron and possess good water absorption capacity. Aloe
vera is used as a medicinal drug and is a good source of aloin 4.5-25 per cent
(Rajendran et al., 2007).
2.2.1 Chemical constituents present in Aloe vera
Gjerstad (1969) described Aloe as the dried juice of lower portion of
leaves which appeared blackish brown, opaque and smooth. According to
Ghannam et al. (1986), the solid residue of Aloe barbadensis obtained by
evaporating the sap drained from cut leaves contain anthroquinine glycosides,
barbalion and β-barbalion, which yielded Aloe emodin and D-arabinose upon
hydrolysis. Waller et al. (1978) reported that the chemical composition of Aloe
vera barbadensis Miller contained polysaccharide, arginine and other 16
11
common amino acids were also found in free state, with traces of lupeol,
cholesterol, campestrol and β-sitosterol. Various chemical constituents found be
present in Aloe include aloin, Aloe-emodin, Aloetic acid, calcium oxalate,
choline, saponins, uronic acid, sugar, muco polyscaccharide, glucosamines and
hexauronic acid. Further acemannan is the major carbohydrate fraction obtained
from gel of Aloe (Raina, 1982). According to Robson et al.(1982), chemical
characteristics of 99 per cent pure Aloe vera extract was found as glucose
(13mg/dl), uric acid (0.5mg/dl), salicylic acid (3.6mg/dl), creatinine (1.9mg/dl),
alkaline phosphatase (1IU/l), creatinine phosphokinase (10 IU/l), cholesterol
(11mg/dl), triglycerides (374 mg/dl), lactate (14.8 mg/dl) and protein (0.2mg/dl)
as organic constituents and inorganic constituents consisted of sodium (19
meq/l), potassium (21.5 meq/l), inorganic phosphorous (14 mg/dl) and chloride (1
meq/l). Trace metals present in the extract were calcium (23.5 meq/l), magnesium
94.6 mg/dl), copper (0.2 mg/dl) and zinc (0.02 mg/dl). In addition to 10-43 per
cent physiologically active compounds, Aloe also contained inactive ingredients
including large amount (16-63%) of resinous materials plus a volatile oil as
reported by Blitzke et al. (2001).
The mucilaginous gel from the parenchymatous cells in the leaf pulp of
Aloe is used for various curative purposes. Modern clinical use of the gel began
in the 1930’s, for treatment of X-rays and radium burns. Chemical analysis
showed that the gel contained various carbohydrate polymers, either
glucomannans or pectic acid, along with a range of other organic and inorganic
components (Grindlay and Reynolds, 1986).The International Aloe Science
Council (IASC) (1988) maintains a certification program in which whole leaf
Aloe vera gel is expected to adhere to the following specifications: solids
between 0.46-1.31 per cent, pH 3.5-4.7, calcium 98.2-448 mg/l, magnesium 23.5-
118 mg/l and malic acid 0.82-3 g/l. Consistent with these specifications, Rowe
and Parks (1941) determined the pH of fresh Aloe extract to be 4.7. The product
was clear to pale yellow liquid with a characteristic odour and a flash point of
228ºF and boiling point of 225ºF. At 25
ºC, Aloe extract exhibited complete
solubility in water with a specific gravity of 1.02-1.05 and refractive index of
1.3620-1.3700 at pH 4.0-6.5.
12
Femenia et al. (1999) reported that Aloe gel contained 98.5-99.5 per cent
water and approximately 80 per cent of the solids were reported to be water
soluble. The primary compounds in Aloe vera gel were carbohydrates including
free sugars, soluble polysaccharides and fibers. The glucomannans were
particularly abundant. The gel also contained 90 per cent of the essential amino
acids and lipids including fatty acids and sterols. Malic acid (409 micromole/g
dry weights) was the major organic acid present in gel while other organic
compounds included antioxidant (2.6 trolox equivalents), vitamins and trace
amount of anthraquinones (Manna and Mc Analley, 1993).
Pugh et al. (2001) isolated a new immuno stimulatory polysaccharide
called Aloeride from commercial Aloe vera juice. Aloeride was between 4-7
million Daltons and its glycosyl components include glucose (37.2%), mannose
(19.5%) and arbinose (10.3%). Kostalova et al. (2004) identified and analyzed
major protein, mono and polysaccharides from Aloe vera commercial extracts. IR
spectral analysis of carbohydrate fractions showed that main carbohydrate
compound was acetylated beta-D-mannan substituted with D-galactose and D-
glucose. Hu et al. (2003) reported that proteins and polysaccharides were the
necessary components in study of biological activity of Aloe vera leaf extract.
However, the growth stage of Aloe vera plays an important role in the
composition and antioxidant activity of Aloe vera.
2.2.2 Therapeutic effect of Aloe vera barbadensis Miller
Aloe juice was used in various preparations for the treatment of diseases.
In glandular enlargement, gonorrhoea and spleen diseases, the juice of the leaves
was recommended with the addition of powdered turmeric. In case of jaundice
Aloe juice is reported to be beneficial. For dysentery and kidney pain the use of
mucilaginous juice with milk. Neal (2004) reviewed the role of Aloe in the
development of functional foods. He found that the fresh juice obtained from cut
bases of the leaves was cathartic and cooling and can be used to treat liver, spleen
and muscular pain. Nandkrani (1993) found that Aloe had medicinal application
against inflammation, constipation, chronic ulcers, eczematic skin conditions,
internal worms, cancer, bronchial asthma and pharyngitis. Aloe is reported to be
13
used in obstructions of lymphatic system, insect bites, arthritis and mycopathies.
It acted as an analgesic, antifungal antiviral and wound healing agent.
2.2.2.1 Hypoglycaemic effect
Tanaka et al. (2006) evaluated the anti-hyperglycaemic effect of Aloe
vera gel and isolated a number of compounds from the gel. On the basis of
spectroscopic data, five different compounds were identified as lophenol, 24-
methyl lophenol, 24- ethyl lophenol, cyclartanol and methylene-cyclatranol.
Which have been antihyperglycaemic effects on type II diabetic mice. Similarly,
Misawa et al. (2008) reported the effects of lophenol (Lo) and cycloartanol (Cy)
and minor phytosterols of Aloe vera gel, in obese animal model of type II
diabetes and Zucker diabetic fatty (ZDF) rats.
According to Yagi et al. (2009) Aloe vera with High Molecular fractions
(AHM) containing less than 10ppm of barbalion and polysaccharides exhibited
significant hypoglycaemic effect, it can not only lower glucose but also the
triglyceride level which are often high in diabetic patients. Similarly, Ajabnoor
(1990) reported that intraperitoneal administration of bitter principle of Aloe had
a highly significant effect on serum glucose level in alloxon diabetic mice. In
chronic studies in which Aloe vera was given twice a day or once a day for 4
days showed maximum decrease in plasma glucose level on the fifth day in both
the cases. While, Yongchaiyudha et al. (1996) investigated the effect of oral
administration of one table spoonful juice of Aloe vera juice twice a day for 42
days. Blood samples were taken weekly for determination of blood glucose,
which decreased significantly after two week showing decrease in blood glucose.
The hypoglycaemic effect of Aloe and its bitter principal may be mediated
through stimulating synthesis and for release of insulin for β-cells of lingerhans.
Bunyapaphtsara et al. (1996) studied the effect of Aloe vera juice (80%)
in combination with glibenclamide. Treatment consisted of one table spoonful of
Aloe juice twice a day and two tablets of glibenclamide administrated for 42 days
and found no response to glibenclamide alone, but Aloe juice along with
glibenclamide significantly reduced levels of blood glucose within two weeks.
14
These results supported the use of Aloe vera in treatment of diabetes. Similarly,
Arora et al. (2009) studied the effect of Aloe vera juice consumption on type 2
diabetic patients for 3 months and found that Aloe vera juice provides better
glycaemic control along with improvement in lipid profile as well as
anthropometric measurements. Ghannam et al. (1986) reported that the use of
dried sap of the Aloe vera plant is one of the traditional remedies for diabetes in
the Arabian Peninsula. Its ability to lower the blood glucose level was studied in
5 patients with non-insulin dependent diabetes and Swiss albino mice. It was
concluded that Aloe vera contains hypoglycaemic agent which lowers down the
blood glucose levels due to some mechanism unknown as yet. Aloe vera gel
extract slowed hyperglycaemia activity on Non Insulin Dependent Diabetes
Mellitus (NIDDM) rats and could be useful in the treatment of non-insulin
dependent diabetes mellitus. Abdullah et al. (2003) reported that the Aloe vera
has the ability to stimulate gap junctional inter cellular communication (GJIC)
and proliferation of human skin fibroblasts in diabetes mellitus. Aloe vera
contains compounds that neutralize binds with FGF-2 receptor or otherwise alter
signalling pathways for FGF-2. By effecting both GJIC and proliferation of
human skin fibroblasts, Aloe vera may improve wound healing in diabetes
mellitus.
Further, Rajasekaran et al. (2004) reported the presence of hypoglycaemic
activity in alcoholic extract of Aloe vera gel. Effects of oral administration of
Aloe vera extract at a concentration of 200 and 300mg/kg of body weight on;(a)
normal fasted rats (b) oral glucose loaded rats, and (c) streptozotocin-induced
diabetic rats have been studied. Aloe vera maintains the glucose homeostasis by
controlling the carbohydrate metabolizing enzymes. In other study, Rajasekaran
et al. (2005) observed the presence of antioxidant property in alcoholic extract of
Aloe vera leaf gel. The concentration of 300 mg/kg orally fed to diabetic rats
showed significant decrease in the level of blood glucose, glycosylated
haemoglobin and increased haemoglobin. Noor et al. (2007) while studying the
beneficial effects of Aloe vera in streptozotocin induced diabetic rats and
observed that the fasting plasma glucose level was reduced to normal with a
increase in body weight in diabetic rats fed with Aloe vera (300 mg/kg body wt.).
15
Similarly, Rajendran et al. (2007) also reported the therapeutic efficiency of Aloe
vera sap in diabetic rats showed a marked increase in body weight and liver
glycogen while decrease in blood sugar, urine sugar levels and serum lipids.
Chitra et al. (1998) observed the positive influence of Aloe vera on healing of
full thickness wounds in diabetic rats due to hypoglycaemic effect of the Aloe
gel. Bolkent et al. (2004) concluded that the administration of Aloe gel extract
and glibenclamide decreased serum urea and creatine levels showed
improvements in both histological and biochemical parameters thereby
suggesting a protective effect of Aloe vera on mild damage caused by type II
diabetes on kidney tissues.
2.2.2.2 Other therapeutic effects
2.2.2.2.1 Anti-oxidant effect
Umano et al. (1999) identified aroma compound from Aloe leaves out of
which some aroma chemicals possess antioxidant activities. Glutathione
peroxidase activity, superoxide dismutase enzymes and a phenolic anti-oxidant
were found to be present in Aloe vera gel, which may be responsible for these
anti-oxidant effects. On account of its nutritional qualities and anti-oxidant
properties, Aloe vera is reported to firstly help to prevent injury to epithelial
tissues, and when they are damaged, it promotes healing. Antioxidants fight the
destructive ‘free radicals’, the unstable compounds produced during metabolism
or are present in environment pollutants These ‘free radicals’, can cause various
ailments as well as contribute towards the aging process (Paul, 2003). Lim et al.
(2003) reported that life-long dietary Aloe vera supplementation suppresses free
radical induced oxidative damage in hepatic cholesterol rats.
2.2.2.2 Chemopreventive effects of Aloe vera
Winter et al. (1981) studied the effects of Aloe extracts on tumour cells.
The authors found that fresh leaves and commercially stabilised Aloe vera gel
had high levels of lectin like substances measured by immune diffusion and
haemagglutination assay. Fraction from fresh leaf sources were found to
markedly promote attachment and growth of human normal cells, but not tumor
16
cells and to enhance healing of wounded cell monolayer. Winter (1993) isolated
lectins from gel proportion of leaves of Aloe barbadensis by differential
centrifugation and gel filtration which exhibited strong haemagglutination and
mitogenic activities. Anticancer substances were obtained by salting the juice of
Aloe and dissolving the precipitates with alkaline water solution. This solution
had haemagglutinating and lymph juvenating activities and showed 72-84 per
cent inhibition of tumor cell in mices (Suzuki, 1979).
According to Xie et al. (1998) reported that anthracene derivatives
isolated from Aloe were highly effective in killing tumor cells. This cyotoxic rate
was over 50 per cent for human and animal tumor cells. Grimando et al. (1997)
observed that instead of aloin, Aloesin and Aloeresins, Aloemodin showed the
antitumor activities. Aloe-emodin caused cytostasis and accumulation of the cells
in the S and G2-M phase of the cell cycle during the first 48 hours of the
treatment. Similarly, Pecere et al. (2000) showed that Aloe-emodin, a hydroxyl
anthraquinone present in Aloe vera leaves, had a specific in vitro and in vivo
antineuroectodermal tumor activity. The growth of human neuroectodermal
tumors were inhibited in the mice with severe combined immunodeficiency
without any appreciable toxic effects on the animals. The results demonstrated
that Aloe-emodin was an anticancer agent with selective activity against
neuroectodermal tumors.
2.2.2.3 Effects of Aloe vera on skin diseases
Morton (1961) reviewed folk uses and commercial exploitation of Aloe
leaf pulp. The author found that Aloe juice could be used in various preparations
to cure skin diseases. Aloe juice was applied to inflammation and fresh pulp was
soothing and useful in case of burns. Leaf pulp of Aloe washed in cold water
mixed with a little burnt alum then wrapped in muslin cloth are administered to
heal sore eyes. The healing effect of the crude extracts of Aloe vera on cows. In
these studies 100 per cent effectiveness was achieved after 5 days of treatment,
with marked healing during the first 2 days in comparison to 1 per cent
polyvinylpyrrolidone iodine which showed little healing during the first 5 days of
treatment until the treatments regime was changed to Aloe vera gel. Further, the
17
wound healing was found to be faster in rats treated with Aloe gel than with 1 per
cent silver sulfadiazine cream and silver sulfadiazine having Aloe vera (Heggers
et al., 1995).
Syed et al. (1996) evaluated the clinical efficacy and tolerability of topical
Aloe vera extract (0.5%) in a hydraulic cream to cure patients with Psoriasis
vulgaris. The Aloe extract cream had cured 25out of 30 patients (83.3%) and
decreased PASI (Psoriasis Area and Severity Index) score to a mean of 2.2. The
findings indicated that topically applied Aloe vera extract (0.5%) in hydraulic
cream could be considered a safe and an alternate treatment to cure patients
suffering from psoriasis. Similarly Chitra et al. (1998) studied the influence of
Aloe vera on the collagen content and its characteristics in healing wound. The
gel prepared from lyophilized leaf powder was administrated to rats with excision
wounds, either orally or topically, twice a day. The authors reported that Aloe
vera increased the collagen contents of the granulation tissue as well as its degree
of cross-linking of newly synthesized collagen which helped faster healing of
wound.
2.2.2.4 Effects of Aloe vera on digestive troubles
Morton (1961) reviewed the folk uses and commercial use of Aloe leaf
pulp. The author suggested that pulp of Aloe was also used to cure ulcers. Pulp
was diced into a jar, covered with the water and kept in refrigerator. A small dose
of the resulting slimy liquid was taken once or twice a day to cure ulcers.
Similarly, Godding (1976) studied the therapeutics of laxative agents with special
reference to anthraquinones. The author reported that laxative effects of Aloe
were primarily due to 1, 8-dihydroxyanthracene glycosides, aloin A and B
(barbaloin). After oral administration aloin A and B, which were not absorbed in
the upper intestine, were hydrolyzed in the colon by intestinal bacteria and then
reduced to the active metabolites: Aloe-emodin-9 anthrone which acted as a
stimulant and irritant to the gastrointestinal tract. Yagi et al. (2009) studied the
purgative action of Aloe-emodin anthrone, rehin anthrone and mixture of both in
mice and reported that rehin anthrone and the mixture of rehin anthrone and
Aloe-emodin had higher purgative action than Aloe-emodin alone. Synergistic
purgative effect of Aloe-emodin anthrone and rehin anthrone resulted from
18
synergistic stimulation of large intestinal transit and large intestinal water
secretion.
2.2.2.5 Effect of Aloe vera on respiratory troubles
The Aloe pulp with honey was given in cough and cold. Pulp mixed with
syrup of rose water was taken to cure early stages of tuberculosis. Mucilaginous
juice with sugar was said to relieve asthma and various bronchial complaints. A
cough syrup was prepared by cubing and washing the pulp, pressing it in a cloth
to squeeze out all bitter juice and boiling with two parts of sugar. This syrup was
taken alone or added as sweetener to other beverages (Morton 1961). Afzal et al.
(1991) reported that Aloe barbadensis extract used to treat adult bronchial asthma
and pharyngitis contained endogenous arachidonic acid and cyclogenase. The
authors also observed that plant extract contained high proportion of
bronchodilators and bronchi constrictors and low proportion of other
prostaglandin. These were effective in enhancing phagocytosis in adult bronchial
asthma.
2.2.3 Processing of Aloe vera juice
A method of preparation of Aloe vera juice patented by Mc Analley
(1990) isolated the gel fillet of Aloe vera and further isolated the active
ingredients, acemannan. In this method, the leaves cut from the base of the Aloe
plant were washed in a bacteriocidal solution and the end portions of the leaves
were removed to allow the anthraquinone rich sap to drain out, additionally the
rinds were removed. The gel fillets that were left behind were grounded and
homogenized to produce Aloe juice. The juice after filteration mixed with
flavour, colour and preservative for its later use. Meadows (1980) used 2per cent
sodium benzoate and 0.15 per cent ascorbic acid to preserve Aloe gel. Aggarwal
(2002) stated that the most commonly used preservatives were sodium benzoate
and potassium sorbate with pH adjusted to <4.6 with citric acid.
Aloe extract and gel extracts can be freed of anthraquinones by means of
activated charcoal and filleting processes (UNITIS, 2003). Because the Aloe vera
gel activity becomes unstable after removal from the leaves, a number of
19
processes have been developed to overcome this instability. One method used to
stabilize the gel is to expose the gel to high temperatures for a short time (three
minutes). Ultraviolet stabilization, chemical oxidation with hydrogen peroxide,
and preservatives and additives are other methods of retaining the activity of the
gel (Grindlay and Reynolds, 1986).
Mei et al. (2004) studied physico-chemical properties of Aloe vera leaf
and gel as well as processing technology for Aloe beverages. The authors
observed higher content of water and polysaccharides and lower contents of total
sugars, reducing sugar, vitamin C, protein crude fat and aloin in gel as compared
with whole leaf. The authors also standardized optimal processing conditions (the
use of heating and crushing methods for extraction of Aloe juice) for Aloe
beverages which included 8 per cent Aloe juice, 0.18 per cent citric acid, 0.05 per
cent agar and 0.15 per cent CMC-Na. Miranda et al. (2009) studied the effect of
air temperature on the physic-chemical and nutritional properties and antioxidant
capacity of Aloe gel. Analysis of variance revealed that the drying temperature
exerted a clear influence on most of the quality parameters. Drying temperatures
of 80ºC and 90
ºC resulted in significant variation in and /or loss of the physico-
chemical and nutritional properties of the gel, in addition, the antioxidant
capacity of the gel decreased at these temperatures. These effects were also
observed as a result of a lengthy drying period of 810 min at 50ºC. However,
minor alterations in the physico-chemical and nutritional properties of Aloe gel
were produced at drying temperatures of 60-70ºC, resulting in the production of
high quality gel.
2.2.4 Stabilization of Aloe vera gel
Aloe vera like most natural juices, both fruit and vegetables, is an unstable
product when extracted and is subjected to discolouration and spoilage. The great
success of Aloe as commodity in nutritional foods and cosmetics is due to the
proper stabilization procedure that enables processors to store and transport Aloe
vera gel (www.iasc.org.2002). The stabilization of Aloe vera gel using algal
polysaccharides or xanthum gum and proposed that these could serve to stabilize
the network of fresh Aloe vera polysaccharides. According to Paul (2003) the
20
stabilization process included the steps of mixing a heated Aloe vera gel at 30ºC
to 70ºC, addition of an effective antioxidant to prevent oxidation of the gel,
adjustment of the gel pH and cooling the gel for 15-20 minutes.
Chang et al. (2006) studied the effect of heat treatment on the stability of
polysaccharides and barbalion content in gel juice from Aloe vera. The authors
observed that the polysaccharides from Aloe exhibited a maximal stability at 70ºC
decreasing either at higher or lower temperatures. The author also found that
heating promoted a remarkable decrease in barbalion content depending on the
temperature and time as compared to effect on polysaccharides of gel juice from
Aloe vera. Similarly, Ramachandra and Rao (2008) reported the unpasteurized
Aloe gel juice with vitamin C and citric acid to check browning reaction and to
improve flavour of Aloe vera gel and to stabilize the juice. Adjustment of pH of
the Aloe gel and is known to stabilize the gel.
2.2.5 Aloe vera incorporated food products
Takasago Perfumery Company Ltd. (1979) got the patents for the
preparation of Aloe beverage. For the preparation of beverage, Aloe leaves were
treated with amylase, and the resulting liquid was mixed with sugar and
lactobacillus for fermentation. Another beverage was prepared in which amylase
was added to ground Aloe leaves. Angsupanich et al. (1993) prepared Aloe jelly
from Aloe vera powder and fresh Aloe juice was evaluated by sensory panel. It
was found that there was no difference among the odour, flavour, texture and
springiness while transparency of jelly possessed more yellow colour. Eldrige
and Sheehan (1994) studied the use of Aloe vera as food supplement. The use of
Aloe as food supplement and related health benefits were evaluated in 502
community college student from Arizona. Regular user (37%) were students who
reported using supplements daily, while sporadic user (25%) reported taking
supplements less than once per week and the remaining 38 per cent were non-
users. The most popular supplement was Aloe vera along with vitamin C and E,
and minerals. Significantly, more users than non-users believed that food
supplement increased added energy and reduced stress. The findings revealed that
the supplement users perceived more health benefits than non-users. Vinson et al.
21
(2005) reviewed the effect of Aloe vera preparations on human bioavailability of
vitamin C and E. The authors reported that the Aloe improved the absorption of
both vitamins C and E. The absorption was slower and the vitamins lasted longer
in plasma with Aloe. Aloe was the only known supplement to increase the
absorption of these vitamins. Jeakins (2003) reported the use of nutritionally
beneficial additive such as Aloe vera in preparation of chewing gum.
Shin et al. (1995) prepared and compared yoghurt with Aloe vera powder,
fermented with lactic acid bacteria and from dried skimmed milk. Addition of
Aloe vera to yoghurt accelerated acid production. Titratable acidity of Aloe
yoghurt after 24 hours incubation was higher than yoghurt prepared using
skimmed milk powder. Aloe yoghurt fermented with mixed strain had the higher
sensory score. Quality retention of Aloe yoghurt was found to be better 50ºC for
15 days. Umano et al. (1999) identified aroma compounds of Aloe leaves and
also showed its antioxidant activity. The authors found that Aloe leaves have
been used as an aroma ingredient in certain foods and beverages because of their
characteristic aroma. Karg (1969) prepared a bitter brandy with (alcohol 40 per
cent v/v) supplemented with condiments as aromatic substance as bitter
substance. Neal (2004) reviewed role of Aloe in the development of functional
foods and found that the fresh juice obtained from the cut bases of the leaves was
cathartic, cooling and is used in treating liver, spleen and muscular pain. Aloe
gel due to its moisturizing effect can also be used to develop novel surface
coating for fruits and vegetables to extend their shelf life. The gel has been found
to be useful in extending the shelf life of grapes in a study conducted by Valverde
et al. (2005).
Srisukh et al. (2008) developed four formulae of Aloe frozen products (
Aloe ice creams and sherbets). Aloe was incorporated in the form of gel at 25 per
cent by weight along with other ingredients like sweetening, colouring and
flavouring agents. Out of different combinations, the pandan flavoured Aloe ice-
cream was preferred over coconut flavoure Aloe ice-cream, orange flavoured
Aloe ice-cream and pandan flavoured Aloe sherbet. Singh and Singh (2009),
prepared herb bread using 20 per cent Aloe vera gel as a food supplement. The
22
bread was acceptable with golden brown crust, velvety soft and elastic texture,
creamish white colour, pleasant fermentation aroma and wheaty taste. The shelf-
life of bread wrapped in polypropylene (50 gauges) was found satisfactory up to
5 days at ambient condition.
2.2.6 Physico-chemical composition of Aloe gel and juice
2.2.6.1 Total soluble solids
Wang and Strong (1995) reported 0.58 ºB TSS in gel and juice however,
the values of varied with seasonal fluctuation. Agsupanich et al. (1993) observed
the TSS of Aloe juice as 2ºB. While studying the characteristics of fermented
plant beverages in southern Thiland, Kantachote et al. (2005) recorded TSS of
fermented Aloe vera beverage as 11ºB which were attributed to wide variation in
agro-climatic conditions.
2.2.6.2 Total solids
Danhof (1998) reported 0.52 and 1.24 per cent total solids in gel fillet and
mucilage respectively. The author observed varied total solids with leaf
processing methods viz. roller method, leaf splitter method, hand fillet method
and total leaf method which had total solids as 0.39, 0.42, 0.48 and 1.38 per cent
respectively. Boudrean and Beland (2006) noticed that total solids range between
0.5-1.0 per cent in gel which comprised of compounds range including water and
fat soluble vitamins, minerals, enzymes, polysaccharides, phenolic compounds
and organic acid. The IASC (1998) maintained a certification program in which
“whole leaf Aloe gel” was expected to contain solid between 0.46-1.31 per cent.
The total solids of inner gel were recorded as 0.5 per cent by Aggrawal (2002).
Wang and Strong (1995) stated that the average total solids were 0.69 per cent
but season greatly influenced the total solids of the gel. The lower (0.5%) solid
content was observed in winter while, higher solid content in summer (0.8%) was
noticed.
2.2.6.3 Moisture
Gjerstad (1971) found that fresh Aloe vera gel contained 99.52 per cent
water. Consistent with these results, Danhof (1987) reported 99.48 and 98.76 per
23
cent water in gel fillet (juice) and mucilage (gel), respectively. The author also
found that moisture content varied with leaf processing and preservation
methods. Wang and Strong (1995) studied several physical and chemical
properties of Aloe vera barbadensis Miller and reported that the moisture content
varied with leaf processing and preservation methods. Wang and Strong (1995)
recorded 99.5 per cent water in Aloe gel. Rowe and Parks (1941) conducted a
photochemical study of Aloe vera leaf and observed that fresh leaves which were
obtained in August had 96.5 per cent moisture content where as pulp or mucilage
within the Aloe vera leaf had 98.5 per cent water.
2.2.6.4 Acidity and pH
International Aloe Science Council (IASC) (1998) maintains a
certification program in which whole leaf Aloe vera gel was expected to contain
pH between 3.5-4.7. Rowe and Parks (1941) determined the pH of fresh Aloe gel
to be 4.7. Similarly, Wang and Strong (1995) reported that pH consistently varied
in the range 4.4-4.7 in Aloe vera gel. Aggarwal (2002) and Chaisawadi et al.
(2005) recorded average pH value of 4.5 with water content between 97.0-99.5
per cent in fresh Aloe gel. According to Meadows (1980) acidity varied
considerably depending upon the climate, season, variety and soil characteristics.
Danhof (1998) reported pH in Aloe gel as 4.27. The author stated that pH and
acidity were greatly influenced by leaf processing as well as preservation
methods. Kantachote et al. (2005) prepared various fermented plant beverage in
Southern Thailand and recorded total acidity as 2.41g/100ml and pH 3.5 in
fermented Aloe beverage.
2.2.6.5 Ascorbic acid
Pecere (2000) reported that ascorbic acid content of fresh Aloe gel ranged
between 0.5-4.2 mg/100g. Vinson et al. (2005) showed that Aloe fillet gel
enhanced the absorption of vitamin C and E by 304 and 369 per cent respectively.
The vitamins, when taken with Aloe gel were found to last longer in the body by
up to 4 hours, extending their beneficial antioxidant functions.
24
2.2.7.6 Sugars
Several workers have extensively studied Aloe vera sugars. Meadows
(1980) found that glucose and mannose were major sugars present in Aloe with
trace amount of xylose, arabinose, galactose and Rhamnose. Gjerstad (1971)
observed small quantities of free sugars in Aloe vera juice which were mainly
glucose and an aldopentose. Roboz and Haagen-Smith (1984) purified white
water soluble mucilage which on hydrolysis was found to contain equal amounts
of glucose and mannose as the main constituents. The authors also recorded
25.50 per cent sugars on dry basis in mucilage. Earlier, Farkas (1963) also
recorded glucose and mannose 48.8 per cent each in hydrolate gel.
Waller et al. (1978) carried out a detailed analysis of Aloe vera leaves,
including sugar determination of the hydrolyzed lyophilized gel which showed
mannose and glucose in 5:4 ratio and trace amount of xylose, rhamnose,
galactose and either of arabinose or fructose. While mannose and glucose were
present in the ratio of 9-10:1 (Segal et al., 1968). Gowda et al. (1979) separated
the gel polysaccharides from Aloe vera plant into four partially acetylated
glucomannans, the whole having an average glucose/mannose ratio of 1:6,
although the individual ratios varied from 1.5:1 to 1:19 whereas Mandal and Das
(1980) showed glucose and mannose to be present as glucomannan in 1:22 ratio.
Robson et al. (1982) observed that Aloe gel contained 13 mg/dl glucose.
Pecree (2000) recorded 0.3 per cent carbohydrate in Aloe gel. Rowe and
Parks (1941) found 0.1 per cent of simple reducing sugars and small amount of
hydrolysable sugars in gel. Kantachote et al. (2005) recorded total sugars as
2g/100ml in fermented Aloe beverage. According to Wang and Strong (1995) the
concentration of reducing sugars showed a marked fluctuation with season which
ranged from 0.15-0.24 per cent in Aloe. Danhof (1987) observed that the sugar
content of Aloe vera was greatly influenced by the processing methods (heat and
/or cold).
2.2.7 Safety studies
The International Aloe Science Council (Texas) provides certification of
the products as being genuine Aloe. The council does not only certify products
25
that are 100 per cent Aloe but also includes products which contain 10-15 per
cent Aloe. The product which contains 15 per cent Aloe may also contain fruit
juice to make a drink combining the health aspects of Aloe with an attractive and
refreshing flavour (Paul, 2003).
World Health Organization (WHO) prepared monographs of twenty eight
medicinal plants to promote international harmonization in the quality control use
of herbal medicines. According to WHO Aloe vera ( Aloe vera barbedensis) is
safer and healthier plant and can be taken internally as a drink (WHO, 1999).
Thus, Aloe vera can be safely explorated in preparation of different products.
2.3 Non-nutritive sweeteners
Non-nutritive sweeteners are those compounds which sweeten the
products with very small volume and do not import significant energy on
consumption. They are also referred as high intensity sweeteners. Both polyols
and non-nutritive sweetener can replace sugar sweeteners and are thus, termed by
different names like macronutrient substitutes, sugar substitutes, sugar replacers
or alternative sweeteners. Uses of low calorie products include sugar free
beverages and reduced fat food beverages. Production and consumption of non-
nutritive sweeteners has also been increased in European countries (due to
growing interest in health and aging population) as well as in the developing
countries (with the interest in making limited diets more palatable) (Bright,1999).
Various sweeteners have been used in foods with success, for example, the
extract of stevia leaves and a mixture of cyclamate/saccharin (Hanger et al.,
1996).
High intensity sweeteners can offer consumers a way to enjoy the taste of
a sweetener with little or no energy and glycaemia response. Non-nutritive
sweeteners can assist in weight management, control in blood glucose and
prevention of dental caries. Non-nutritive sweeteners are evaluated by various
attributes including sensory qualities (e.g. clean sweet taste, no bitterness,
odourless), safety, compatibility with other food ingredients and the stability in
different food environments. Because non-nutritive sweeteners provide sweet
26
taste with little volume, manufacturers combine the sweeteners with bulking
agents (e.g. polydextrose, maltodextrin, polysaccharides polyol), to replace some
of the functional properties of the nutritive sweeteners. The trend is to blend high
intensity sweeteners with others non-nutritive and nutritive sweeteners to create
new sweet taste profile. Blending can cause sweetness synergy (i.e. the
combination is sweeter than the individual components), which can decrease the
amount of sweetener needed and can improve the overall sweet taste profile.
2.3.1 Saccharin
Saccharin is commercially available as acid saccharin, sodium saccharin
and calcium saccharin. It is used as a substitute for sucrose in soft drinks and
processed foods (Grenby, 1991). The joint committee of FAO/WHO has fixed the
acceptable daily intake of saccharin as 2.5 mg/kg of body weight. Sharma (1999)
prepared dietetic plum appetizer and found considerable decrease in energy value
when sweetened with saccharin (18.16 Kcal/100g) and cyclamate (18.28
Kcal/100g) compared to sucrose (129.7 Kcal/100g).
2.3.2 Sorbitol
Sorbitol is available in crystalline form and as 70 per cent solution.
Sorbitol is generally recognized as safe (GRAS) for use in special dietary foods,
breath mints, cough syrup, hard and soft candies and chewing gums. It is 0.5-0.7
times as sweet as sucrose, depending upon the concentration and temperature
(BeMiller, 1992). Small amount of polyol (Sorbitol) added to beverage causes an
improvement in mouthfeel. Best results are often achieved by a mixture of
sorbitol and sugar. The hydroxyl groups of the sorbitol are less reactive than the
aldehyde and ketone groups of sugars. This makes them stable to heat, and they
melt without decomposition. They do not undergo millard reaction and hence
browning is minimal on heating. Sorbitol is absorbed in the intestine very less.
This represents a calorific value of 2K cal per 100g. Sorbitol does not give rise to
elevated blood sugar levels when eaten (Dias, 1999). According to Kachhi et al.
(1998) sorbitol is included in the list of permitted emulsifying and stabilizing
agents for sugar boiled confectionaries (Rule 60).
27
2.3.3 Stevia rebaudiana Bertoni
The stevia has greatest economical potential as natural alternative
sweeteners over the artificial sweeteners (like aspartame or sodium saccharin).
Steviosides is advantageous over other artificial sweeteners because it is stable at
high temperature (100ºC) and pH range of 3-9, and does not darken with cooking
(Alupuli, 2007). Stevia rebaudiana Bertoni is native of south America .The plant
may reach 1m in height and has leaves up to 2-3cm in length and the flower is
small (7-15mm), arranged in irregular cymes. The cultivation of this plant has
expanded to Singapore, Taiwan, Malaysia, South Korea, China and Israel. It has
also been successfully grown in United States of America (Calofornia) and
Europe. M S Bertoni, a Paraguayan, Botanist first reported the plant as
Eupatorium rebaudianum in 1989. Subsequently, it has been re-defined as stevia
rebaudiana, a member of composite family. For more than a decade South
America, Japan, China, Korea and Taiwan use stevia as natural caloric
sweetening agent and subsequently plant extract has been proved as a food
additive (Genus, 2003).
2.3.3.1 Medicinal properties of stevia
Stevia is characterized as non-nutritive sweetener. It is found to possess
various medicinal properties like antibacterial, antifungal, anti-inflammatory,
antimicrobial, antiviral, anti-yeast, cardiotonic and vasodilator. It is also
recommended in curing diabetes (Panptil and Palasa, 2008), preventing
hypertension, treatment of skin diseases and prevention of tooth decay. Stevia
leaves contain diterpene glycosides that have sweet taste, zero calories and is
carbohydrate free (Kumar et al., 2007). Kumar et al. (2007) concluded that the
use of stevia is popular among Indians due to its zero caloric value and several
other medicinal properties. Stevia is 200 to 300 times sweeter than sugar with a
zero caloric value and is mostly used by diabetic patients. Stevia rebaudiana is a
natural alternative to artificial sweeteners. It is used for the treatment of many
diseases such as diabetes, high blood pressure and obesity various traditional
systems of medicine (Sumathi, et al., 2005, Das and Dang, 2005 and Joshi et al.,
2006).
28
Hsiao et al. (2005) studied the effects of steviosides on the glucose and
insulin metabolism in 2 models of diabetes in rats. Steviosides (0.5 mg/kg) was
reported to lower the blood glucose levels. Stevioside also recorded to reduce the
rise in glucose during glucose tolerance testing in normal rats. Steviosides is
known to have potential therapeutic value as a contraceptive (Planas and Kuae,
1968) and found effective on hypersensitive patients (Chan et al., 2000).
Stevioside has also been proposed to have potential role as hypoglycaemic agent
by stimulating insulin secretion by pancreatic β-cells (Jeppesen et al., 2000).
Further, Steviosides have little or no toxicity in various mammalian species (Xili
et al., 1992 and Toshulkao et al.,1994). Chan et al. (2000) studied the effect of
steviosides on blood pressure and plasma catecholamine in spontaneously
hypersensitive rats (SHR). The hypertensive effects on both systolic and diastolic
blood pressure were 3.14+5.6 per cent, respectively. The hypersensitive effect
was tested for more than 60 minutes with a dose of 200 mg/kg.
2.3.3.2 Composition of Stevia
Stevia leaves contain a complex mixture of sweet diterpene glycoside
including steviosides, steviolbioside, rebaudioside (A, B, C, D, E, F) and
dulcoside A (Kinnely, 2002). Steviosides is isolated and purified from stevia
rebaudiana Bertoni leaves after multiple and selective extractions followed by
crystallization, resulting in a steviosides purity .95 percent and with rebaudioside
A as the main impurity (< 2). Steviosides (3-10 % of dry leaf weight) and
rebaudioside A (1-3%) can be up to 250 times sweeter than sucrose (Duke, 2006).
Major component in stevia leaves (dwb) are protein (6.2%), lipids (5.6%),
stevioside (11%), aluminium (0.072 %), phosphorus (0.328%), potassium
(1.78%) and β-carotene (0.0075%) (Brandle and Starratt,1998). The chemical
structure of steviosides is shown in Fig.2.1
According to Soejarto et al. (1983), sequiterpene lactones are responsible
for the bitter aftertaste. Phillips (1987) described a European patent held by the
stevia company, which attribute bitter aftertaste, even though the contribution of
rebaudioside A is less than that of steviosides. Rebaudiosides E is as sweet as
29
steviosides and rebaudiosides D is as sweet as rebaudiosides A, while other
glycosides are less sweetner than steviosides (Crammer and Ikan, 1986).
Figure 2.1: Structure of Steviosides, Rebaudiosides A and Steviol
(Genus, 2003)
2.3.3.3 Use of stevia
Stevia leaf extracts are used in Japan, Korea and certain countries of
South America to sweeten soft drinks, soup, soya sauce, yoghurt and other foods,
whereas in United State they are used as dietary supplement. Stevia sweetener
extractives have been suggested to exert beneficial effect on human health,
including hypertensive (Chan et al., 2000 and Lee et al., 2001),
antihyperglycaemic (Jeppesen et al., 2002), anticarcinogenic (Das and Das, 1992)
and anti-human rotavirus (Takahashi et al., 2001) activities. The dried leaves
could be mixed within the tea packages to reduce the consumption of sugar. It
could also be used for the production of candies, chocolates, marmalades,
biscuits, ice-creams, sweets, fruit juices and beverages (Uddin et al., 2006). Singh
and Rao (2005) reported that stevia can be used as an alternative source of sugar
for food confectionaries, bakeries, fruit juices, jams, biscuits, chocolates,
vegetables and other food stuffs.
2.3.3.5 Nutritional use
The stevia is used for products like artificial low-calorie (non-sucrose)
sweeteners (Cardello et al., 1999). The primary use as sweeteners is to enhance
the palatability of foods and drinks. Unlike aspartame, stevia sweeteners are heat
stable at 200ºC, acid stable and do not ferment, thereby making them suitable for
use in a wide range of product including baked/cooked foods and drinks (Philips
30
1987 and Parpinello et al., 2001). Joint FAO/WHO Expert Committee on Food
Additive (JECFA) (2004) reported the level of use of stevia in different foods like
beverages (500 mg/kg), deserts (500 mg/kg), breads (160 mg/k) and in biscuits
(300 mg/kg).
Parpinello et al. (2001) studied suitability of steviosides as replacement of
sucrose in peach juice. Comparison between steviosides and sucrose in terms of
sweetness, sweet and bitter after taste were determined both in water and peach
juice. The result demonstrated that 160mg/l of steviosides may replace 34g/l of
sucrose in juice, with 25 per cent decrease in calories without affecting the
sensory characteristics of the products. Barathi (2003) discussed the uses of
steviosides, a sweetening agent found in stevia leaves in bakery, soft drinks
beverage sector and in many household and medicinal properties. Garadana et al.
(2003) reported that the sweeteners were completely hydrolyzed to their a glycon
steviol in 10 and 24 h, respectively. Interestingly, the human intestinal micro
flora was not able to degrade steviol. Furthermore, steviosides and rebaudiosides
A did not significantly influence the composition of faecal cultures among the
selected intestinal micro flora.
2.3.3.6 Steviosides for diabetes
Steviosides, the main component of stevia is about 300 times sweeter than
table sugar. Therefore, only small amount of steviosides is needed for sweetening
purpose and it has no side effects as observed in patients after many years of
continued consumption (Savita et al., 2004). Steviosides helps in insulin
secretion; it acts directly on pancreatic beta cells to secrete insulin (Jeppesen et
al., 2000). It is not absorbed in intestine and is not metabolized by enzymes of
gastrointestinal tract, as sugar bonds in steviosides are beta-glycosidic bonds
(Toskulkao et al., 1997). However, it is degraded to steviol and sugar mioties by
bacteria in the human colon. Genus (2003) concluded that stevia and steviosides
are safe when used as sweeteners. It is suited for both diabetics, and phenyl
ketonuria (PKU) patients, as well as for obese persons intending to lose weight
by avoiding sugar supplements in the diet. No allergic reactions to it seem to
exist. Hsieh et al. (2003) concluded in 2-year study on Chinese patients with
31
mild hypertension, that oral steviosides significantly decreased systolic blood
pressure (SBP) and diastolic blood pressure (DBP) compared with placebo.
Quality of life was improved, and no significant adverse effects were noted.
2.3.5 Application of non nutritive sweeteners for low energy in food
products
Pelgrams (1987) discussed the idea of including a combination of sugars
and artificial sweeteners in low energy foods in the preparation for the total
elimination of sugar component. Kosmark (1992) prepared low-calorie hard
candy with (a) sucrose and corn syrup (b) polydextrose, and (c) combination of
polydextrose and isomalt, which have calorie content of approximately 288,194
and 117 K cal/100 g, respectively. Saccharin is used as a substitute for sucrose in
soft drinks; processed foods like jam, jellies juices, chewing gums and carbonated
drinks (Polosa, 1995).
Barwal (1995) obtained calories reduction in jam up to 28 per cent per
serving by the use of non-nutritive sweeteners viz. saccharin, aspartame and
cyclamate with similar overall quality and sensory attributes. Pastor et al.(1996)
prepared low sugar peach nectar with high fruit content (60%), 0.082 to 0.922 g/l
aspartame and 0 to 4.0 g/l guar gum. They further found that experimental low-
calorie content ranged between 15.1 to 18.9 K cal/ 100 g compared to 55.15 K cal
/100g in control samples. Barwal and Kalia (1997) prepared low sugar apple
jellies by using non-nutritive sweeteners viz. aspartame, cyclamate and saccharin
with sweetness proportion (sucrose equivalent) of 25, 50 and 75 per cent along
with sugar. They attained 23 per cent reduction in calories per serving without
compromising on quality.
Schiffman et al. (1985) evaluated lemon lime and cola flavoured beverage
sweetened with six sweeteners orgnoleptically from forty persons of 18 to 34
years of age on similarity and adjective scale. Sucrose and aspartame were found
statistically equivalent to adjective scale where as, acesuflame and sodium
saccharin were mostly found in orange and cherry beverages when sweetened
with aspartame than with sucrose sweetened strawberry flavoured beverages.
Sharma (1999) prepared dietetic plum appetizer and found considerable decrease
32
in energy value when sweetened with saccharin (18.16 Kcal/100g) and cyclamate
(18.28 Kcal/100g) compared to sucrose (129.7 Kcal/100g).
Barwal et al. (2002) prepared seasoned plum squash using plum pulp,
spices and herbs along with different proportions of 25, 50, 75 and 100 per cent
sweetness for benefit of diabetic, obese and health conscious people. Sugar
content of the product decreased with increased per cent share of sorbitol
sweetness. Moreover, with the increase in proportion of sorbitol sweetness, the
organoleptic score for colour, body and flavour improved. Barwal (2005)
developed diabetic plum squash using non-nutritive sweeteners with proportion
(sugar equivalent) of 25, 50, 75 and 100 per cent along with sorbitol. The calories
reduction could be achieved up to 25 per cent per serving, without any
compromise in quality.
The consumption of stevia for sweetening purpose depends upon the
sweetener’s content of the dried stevia leaves (Savita et al., 2004) which may
vary between 6 and 15per cent of the dry weight. Therefore, the dried leaves are
between 18 to 45 times sweeter than sugar and have zero calories, and zero
cholesterol (Rayaguru and Khan, 2008). Similarly, Manish et al. (2009) reported
60 per cent sugar was replaced in lemon juice, 50 per cent in tea and 75 per cent
in coffee with pure steviosides and stevia leaf extract successfully acceptable
where as with leaf powder 75 per cent and 50 per cent replacement was found to
be acceptable, respectively.
2.4 Bulking agents
2.4.1 Apple Pomace
Apple pomace is by-product of apple processing industries and a
significant source of carbohydrates, acids, vitamin C, minerals and dietary fiber
(Sun et al., 2007). Chemically, apple pomace contains 17.9 per cent crude fibre
16.5 per cent pectin,5.6 per cent minerals (as total ash), 5.1 per cent proteins, 4.2
per cent fat (Smock and Neubert, 1950),17.35 per cent sugars, 14.17 per cent
starch (Sharma et al., 1989) and 241.4 mg/kg phenolic compounds (Scheiber et
al., 2003) on dry weight basis. Apple pomace products have been developed
33
world wide. Innovative attempts have been made to utilize apple pomace in
various applications such as ready-to-serve beverage and squash.
2.4.2 Oat bran
Oat bran is a major by-product obtained during processing of oat products
which provides a vast range of human health benefits such as serum cholesterol
lowering (Chen et al., 2006), reducing coronary heart diseases (Berg and others
2003), reduce symptoms of diabetes (Tapola et al., 2005), reducing blood
pressure (He et al., 2004) and antioxidant activity (Stevenson et al., 2008),and
antioxidant activity (Stevenson et al., 2008). Talukder and Sharma (2010)
concluded that the oat and wheat bran can be in corporated up to 10 per cent and
15 per cent level, respectively for the preparation of baked and steamed chicken
patties.
Physico-chemical properties of the dietary fiber play fundamental roles in
their functionality, which has limited their use as food technological agents. The
emergence of new fiber sources and also new processing methods for improving
their functionality have widened the applications of fibres in the food industry
and opened new possibilities for designing fibre enriched products and generating
new textures in a range of applications ( Rosell et al., 2009).
2.5 Beverages and Bars
2.5.1 Beverages
Kumar et al. (2009) prepared the nectar from pulp of berry fruits
(Zizyphus mauritiana L.) with 20 per cent and 25 per cent pulp, 0.3 per cent
acidity and 15ºBrix TSS. The different treatments of nectar with addition of KMS
(2000 ppm), KMS (1000 ppm) + sodium benzoate (1000 ppm) and sodium
benzoate (1000 ppm) with sugar (equivalent to 70ºB) and citric acid (0.2%) were
prepared and stored for three months. Papaya nectar containing 20 and 23 per
cent pulp, 15ºB TSS and 0.30 per cent acidity was prepared by Saravanan et al.
(2004). Biochemical and sensory evaluation of papaya nectar on 0, 30 and 90
days of storage containing 23 per cent pulp, 15ºB TSS and 0.30 per cent acidity
shows highest acceptability due to better taste and flavour. Doodnath and Badriel
34
(2000) optimized of 20 or 25ºB TSS, 0.20 per cent xanthan gum, 0.15 per cent
citric and 3.75-3.87 pH was for preparation of water melon ready to serve (RTS).
Similarly, Nidhi et al. (2008) prepared ready-to-serve blends of bael-guava
beverage found increase in ascorbic acid content of blended beverage from 0.45
to 12.70 and 1.1 to 17.0 mg/100 ml in 15 and 20 per cent pulp blends,
respectively. Mall and Tondon (2007) studied the blend of guava pulp with anola
to improve flavour and acceptability of the prepared ready-to-serve (RTS)
beverage and found that, the concentration of anola pulp in the beverage
increased with simultaneous decrease in acceptability. Das (2009) prepared the
nectar from jamun fruits and studied it’s storage stability. He observed changes in
physico-chemical characteristics of nectar during storage. The quality of nectar
was found to be acceptable even up to five months of storage. The nectar was
prepared according to Fruit Products Order (FPO) specifications, containing 20
per cent juice, 15 per cent TSS and 0.3 per cent acidity. Similarly, Lavelli et al.
(2009) developed nectarine and peach nectar to evaluate different quality indices.
Mango nectar from pulp of dehydrated ripe mango slices after
reconstitution in equal amounts of water was prepared by Sagar and Khudriya
(1998). They mixed the pulp with sugar in the ratio of 4:3 containing 20 per cent
pulp with sugar and acidity properly adjusted to give 15-16º B total soluble solids
and 0.23 per cent acidity as citric acid. Similar work has also been reported by
Roy et al. (1972) with North Indian varieties and revealed that Dashehari and
Langra varieties of mango in equal proportions produced best nectar.
The quality of commercial nectars (orange, peach, apple, apricot, pear,
Japanese pear and mixed nectars) was studied ,having average values of total
soluble solids between 15-16º B and acid content of 0.38 to 0.47 per cent (Miura
and Takano,1970). Similarly, the quality of nectar depends on ripening stage and
variety of the fruits. On basis of organoleptic evaluation of canned fruit nectars
prepared from different mango varieties concluded that the variety of the fruit
affects the quality of nectars (Roy et al., 1972). The comparison of nectars
prepared from different mango varieties, revealed that the nectar from Baneshan
variety with 20 per cent pulp, 18ºB TSS and 0.3 per cent acidity was satisfactory
35
and refreshing even after extended periods of storage at room temperature (Roy
et al., 1972).
2.5.1 Fruit bar/leather
Processed fruit and vegetable products gained popularity due to their easy
availability throughout the year (Saxsena and Arora, 1997). Fruit leather /bars are
manufactured by the dehydration of fruit purees into leathery mass (Raab and
Ochler, 1976). Ready-to-eat fruit bars are well established product and are being
commercially prepared in our country. Several types of fruit bars have been
developed from mango, papaya, pineapple, guava, jamun, and banana
individually or in combination with different fruits (Mathur et al., 1972; Mir
1990 and Doreyappa Gowda et al., 1995).
According to Rameshwar (1979) mango leather is prepared by spreading
the homogenized pulp along with sugar on bamboo mats and drying to attain
desired thickness. Jagtiani et al. (1988) improved the technology of leather/bar
preparation by drying the mango puree (35ºB) containing 1000ppm SO2
in forced
air electric dehydrator for 2.5 hours. Development of mango bars by dehydrating
fruit pulp in the form of sheets with suitable additives has also been reported by
Mathur et al. (1972). Rao and Roy (1980) found the ideal sugar/acid combination
for the preparation of mango sheet/leather as 25ºB and 0.5 per cent acidity.
However, the addition of sugar increased the drying time. Different combinations
of fruit pulp (apricot, peach and plum) were tried with soya slurry for the
preparation of fruit leather where the product having 85 per cent pulp and 15 per
cent soya slurry recorded high sensory scores in all the types of fruit leathers
(Kaushal and Bhat, 1999). Similarly Rodda and Wei (1981) developed soya
fortified banana fruit bar by using blanched soya fortified in banana fruit bar by
using blanched soya beans and ripe bananas. Likewise Mir (1990) prepared a
fortified mango bar from mango pulp of 30ºB and 45 per cent soya protein
concentration and apricot bar containing apricot pulp supplemented with soya
slurry was prepared by Chauhan et al. (1993).
Krishnaveni et al. (1999) evaluated different packaging materials for
packaging of jack fruit bar and found that Metallised Polyster Polyethylene
36
(MPP) laminate had better nutrient retention with minimum microbial count at
the end of 180 days. Aluminium foil, low density polyethylene of 40, 20 and12
microns, metalized polyster, high density /low density polyethylene and
nylon/ionomers have also been evaluated for packaging mango bar where studies
revealed that aluminum foil based material were excellent for the long term
storage (Nadanasabapthi et al., 1993)
Mir and Nath (1993) reported the changes in chemical, textural and
sensory characteristics of three types of mango bars at -18ºC, 27+3
ºC (65% RH)
and 38+ 1ºC (92 % RH) during 90 days storage and found that moisture, acidity
and reducing sugars of the mango bars increased significantly while non-
enzymatic browning (NEB) reduced. Storage decreased the overall acceptability
and textural characteristics. The deterioration changes were recorded minimum in
mango bars stored at -18ºC.
Gayathri and Uthria (2008) reported that mango and papaya blended fruit
bars in 75:25 and 50:50 enriched with whey protein concentrate @ 5 and 7 per
cent, respectively were highly acceptable. Slight reduction was resulted in pH and
vitamin C with small increase in moisture, acidity and TSS. Similarly, Ashaye et
al. (2005) reported that guava leather higher in protein (2.67%) and fat (1.37%)
and showed better compositional attributes as compared to pawpaw leather. Jain
and Nema (2007) concluded from the study that organoleptic quality of leather
decreased gradually with increase in the quantity of sugar. Organoleptic property
of Allahabad safeda was found best among all cultivars. The ascorbic acid
content of leathers of all cultivars showed decreasing trend with increase in sugar
content.
2.6 Storage Studies: changes in physico- chemical and sensory attributes
2.6.1 Beverages
Mall and Tandon (2007) reported guava-anola blend (80:20) was
acceptable organoleptically after 45 days storage. Slight increase in TSS, total
and reducing sugars and decrease in ascorbic acid was recorded in RTS beverage
during storage. Kalra and Tandon (1984) reported that the pure drink were better
37
than guava and mango blended beverages, whereas Tiwari (2000) observed that
30 per cent papaya could be blended with guava for an acceptable beverage after
6 months of storage. Kumar (2009) developed soya milk-whey based mango RTS
beverage by blending 10 per cent level as per FSSA specification. The increase in
acidity and reducing sugar and a decrease in pH, total sugar and ascorbic acid but
TSS did not change during storage. There was slight increase in microbial load
was observed during storage and acceptable organoleptically after 3 month
storage. Shivkumar et al. (2009) reported the blended tomato and orange juice
squash at different proportions (90:10, 80:20 and 70:30 proportions). The
decrease in pH, total sugars and ascorbic acid while increase in acidity and
reducing sugar content was observed. The TSS did not change during storage of
six month. The squash of 70:30 blended had better nutritional retention and
sensory quality when compared to other two blends after six month storage at
room temperature
Sensory evaluation after 40 weeks storage at different temperatures
revealed non-significant variation in cola beverages sweetened with sucrose,
aspartame and saccharine (Homler, 1984). Ragab (1987) reported increase in
total sugar in apricot jam sweetened with saccharin and xylitol during storage.
The increase was apparently due to hydrolysis of starch and conversion of non-
reducing sugars into reducing sugars. Barwal (1995) observed an increase in
reducing sugars and total solid content and decrease in moisture and total sugars
contents in deictic apple preserves. Despite the change observed in various
attributes, an overview of quality parameters at different storage intervals was
statistically non-significant and the preserve(s) remained quite acceptable.
2.6.2 Fruit leather/bar
Mir and Nath (1993) and Nadanasabathi et al. (1993) observed an
increase in moisture content in fortified mango bars during storage however
Krishnaveni et al. (1999) observed decreased in moisture content during storage
of jackfruit bars. An increase in total soluble solids, acids and sugars were
observed during storage of kiwi, jackfruit, mango and fortified plum bars (Vaidya
et al., 2007; Krishnaveni et al., 1999, Rao and Roy, 1980 and Sharma 1999).
38
However, total sugars decreased in all the products during storage.
Nandansabapthi et al. (1993) found no significant change in total and reducing
sugars of mango bar during storage. Both the vitamins viz. ascorbic acid and
vitamin A decreased during storage in various fruit bars however, their retention
was higher in fruit bars prepared from sulphited pulp which also showed less
intensity of non-enzymatic browning than that of the product made from
sulphited pulp (Rao and Roy 1980, Mir and Nath 1993 and Chan and
Cavalatto,1987).
Further Sharma (1997), Rao and Roy (1980), Mir and Nath (1993)
observed decrease in sensory attributes of fruit leather during storage. However,
date fruit bars fortified with soya protein isolate and dry skimmed milk did not
exhibit any change in their sensory quality up to six months of storage (Sawaya
et al. 1983). The Equilibrium Relative Humidity (ERH) of mango 15-20 per cent
moisture and papaya leather with 12-13 per cent moisture has been reported to
vary between 63.3 to 70 per cent and 50 to 52 per cent respectively (Rao and
Roy, 1980, Chan and Cavalatto, 1978). While, Kumar et al. (2007) found that
guava leather was acceptable up to 9 months when stored in 200g polyethylene
bags at 17-34ºC. While Sandhu et al. (2001) found that guava leather had good
organoleptic property after three months storage and water activity of product
was 0.74. Kumar et al. (2007) reported the guava leather packed in PP sheet was
found to be more economical as compared to other packaging materials.
Although, guava leather can be stored up to three months, at low temperatures it
posses good quality than leather stored at room temperature. Mc Mohan et al.
(2009) reported that the high protein bars made of using protein powder, lipid,
sugar and sorbitol syrup underwent changes during accelerated storage at 32ºC.
The bars become darkened, harder and unacceptable after accelerated storage.
However, product made by using guava, Aloe vera and stevia need to be
developed and evaluated for various health benefits.
Chapter-3
MATERIALS AND METHODS
The present investigations entitled “Development and evaluation of
hypoglycaemic guava products with Aloe vera fortification” were undertaken in
the Department of Food Science and Technology, College of Horticulture, Dr. Y.
S. Parmar University of Horticulture and Forestry, Nauni, Solan (HP) during the
years 2009-2011. The studies were conducted on the following experiments to
achieve different objectives:
1. To standardize methods for preparation of guava pulp and Aloe vera gel
extract.
2. To attempt fortification of guava pulp with Aloe vera gel extract for
preparation of functional guava beverage and fruit bar.
3. To evaluate suitability of non-nutritive sweeteners (stevia leaves extract,
saccharin and sorbitol) for the development of hypoglycaemic guava
products.
4. To study the effect of storage period on physico-chemical and
organoleptic changes in the developed products.
3.1 Procurement of Raw Materials
3.1.1 Guava fruit: Fresh and uniformly mature guava fruits cv. Allahabad
Safeda were procured from local fruit and vegetable market, Solan (Himachal
Pradesh) and brought immediately to the fruit processing unit of the Deptt. Fruits
were sorted, graded and washed thoroughly in water to remove adherent foreign
materials and utilized for extraction of pulp as per experiment 3.2.1.1.
3.1.2 Aloe vera (Aloe vera barbadensis Miller): Mature Aloe vera leaves were
procured from the experimental field of the Deptt. of Forest Products, College of
Forestry, Dr.Yashwant Singh Parmar University of Horticulture and Forestry,
Nauni, Solan (HP) and utilized for extraction of Aloe vera gel extract as per
experiment 3.2.1.2.
40
3.1.3 Non-nutritive sweeteners
Fresh stevia leaves (Stevia rebaudiana) were procured from experimental
field of the Deptt. of Forest Products, College of Forestry, Dr.Yashwant Singh
Parmar University of Horticulture and Forestry, Nauni, Solan. Stevia leaves after
thorough washing were dried in dehydrator at 55+2ºC and ground to a fine
powder in a grinder to pass through 85 size BSS sieve. The powdered leaves
packed in polyethylene pouches (200 gauges) were stored in cool and dry place
until used in product development.
Saccharin sodium (C7H5NO3S) and Sorbitol (C6H14O6) purchased from
M/S Devindra Cottage Industries, Chandigarh were used as a source of non-
nutritive sweeteners for developing different products.
3.2.4 Bulking agent:
Fresh apple pomace was procured from hpmc (Himachal Pradesh
Horticulture Produce Marketing and Processing Corporation plant) Fruit
processing plant Parwanoo, Distt. Solan (Himachal Pradesh) and was dried in a
mechanical drier (55+ 2ºC) to constant weight. The dried pomace was ground in a
grinder (M/S Widsons Electronics ltd New Delhi) and passed through a 30 size
BSS sieve. The powder after packing in polyethylene bags (200 guage) was
stored in a cool and dry place for its later use in product development as bulking
agent. Dried oat bran powder procured locally also was used in the development
of different products.
3.2 Product Development
Experiment 3.2.1: Standardization of extraction methods for guava pulp,
Aloe vera and stevia leaves extract
Experiment.3.2.1.1 Optimization of method for extraction of pulp from
guava fruit cv. Allahabad Safeda
On the basis of preliminary experimentation apart from other factors,
addition of water to the guava fruit s at least 1:1 proportion was found essential
for extraction of pulp. Thus method for preparation of guava pulp was
standardized using different proportions of guava fruit and water (1:1,1:1.5
41
and1:2) and method of heating in open pan and in pressure cooker 0.35Kg/cm2or
0.70 Kg/cm2 steam pressure for variable period of time (Table 3.1.).
After heating the fruit slices along water for predetermined period of time,
the whole mass was passed through the pulper (M/S Bajaj Machineries Pvt. Ltd,
Noida) for extraction of pulp. The extracted pulp was filled hot in presterlized
glass bottle and processed in boiling water for 25 min. On cooling, the bottles
were stored at cool and dry place for later use in product development.
Table 3.1 Optimization of method for extraction of pulp from guava
fruit cv. Allahabad Safeda
Time (min) Fruit :water ratio
Heating methods 1:1 1:1.5 1:2
T1 : Open pan at Atmospheric pressure 30 30 30
T2: Pressure cooker 0.35 Kg/cm2, 10 10 10
T3: Pressure cooker 0.35 Kg/cm2 15 15 15
T4: Autoclave, 0.70 Kg/cm2 2 2 2
T5 : Autoclave, 0.70 Kg/cm2 4 4 4
T6 : Cold extraction without heating - - -
Experiment 3.2.1.2: Extraction and evaluation of Aloe vera gel extract (
Aloe vera barbadensis)
Standard method was followed for the extraction of gel extract from the
Aloe vera. For extraction of Aloe vera gel extract, fresh and mature Aloe vera
leaves after washing were peeled and gel was scrapped with the help of the knife.
The peeled gel was passed through the fruit pulper to extract the gel extract, the
pulp was boiled at 80ºC, followed by addition of 0.3 per cent citric acid to lower
the pH to improve its flow properties according to the method standardized by
Ramchandra and Rao, 2008. The processed gel was packed in presterlized glass
bottles and processed in boiling water for 25 min, followed by storage of bottles
at low temperature (7ºC) for later use in product development.
Experiment 3.2.1.3: Extraction and evaluation of stevia leaves extract
Stevia leaves after thorough washing were dried in dehydrator at 55+2ºC
and ground to a fine powder in a grinder to pass through 85 size BSS sieve. The
42
powdered leaves packed in polyethylene pouches (200 gauges) were stored in
cool and dry place. The stevia leaves extract was prepared by adding 0.5% of
dried stevia leaves powder in boiling water followed by filtration through muslin
cloth. The prepared stevia leaves extract was filled in bottle and stored in
refrigerator for further use in experimentation. The relative sweetness of the non-
nutritive sweeteners was calculated by using duo-trio sensory evaluation test as
shown in Table 3.2. on the basis of equivalent sweetness, the quantity of non-
nutritive sweetener was used to replace the sucrose (cane sugar) in the product.
Table 3.2 Relative sweetness of non-nutritive sweeteners (Duo-trio test)
Sweetener Intensity of sweetness
(Viz-a-viz sucrose)
Stevia leaves extract 300 times
Saccharin 500 times
Sorbitol 0.5 times
Experiment 3.2.2: Preparation of guava-Aloe vera beverage
Experiment 3.2.2.1: Standardization of a method for preparation of guava-
Aloe vera beverage
Different combinations were tried for the preparation of guava-Aloe vera
fruit beverage as shown in Table (3.3). The guava-Aloe vera beverage/nectar was
prepared by using 20 per cent fruit pulp and maintain TSS and the acidity 15ºB
and 0.3 per cent by using cane sugar (sucrose) and citric acid, respectively as per
the standard FSSA, 2006 specification. The proportion of Aloe vera gel extract in
guava pulp was optimized by using varying combination of guava pulp and Aloe
vera gel extract (as shown in Table 3.3). The hot beverage after maintain desired
TSS was then filled into presterlized glass bottles (200ml) and processed for 25
minutes in boiling water. The bottles were cooled, labeled and analyzed for
various physico-chemical and sensory characteristics. The optimized combination
of guava-Aloe vera beverage/nectar was used in development of low calorie
/hypoglycaemic guava-Aloe vera beverage.
43
Table 3.3: Standardization of recipe for the preparation of guava-Aloe
vera beverage
Treatments Guava Aloe vera
T1 20 0
T2 17.5 2.5
T3 15 5
T4 12.5 17.5
T5 10 10
T6 7.5 12.5
T7 5 15
T8 2.5 17.5
T9 0 20
Experiment 3.2.2.2: Standardization of method for preparation
hypoglycaemic/ low calorie guava-Aloe vera beverage
The optimized combination of guava-Aloe vera beverage from experiment
3.2.2.1 was selected for the development of the hypoglycaemic/low calorie
guava-Aloe vera beverage. The proportion of cane sugar (sucrose) was replaced
with equivalent sweetness of stevia leaves extract and sorbitol at different
proportion for the preparation of low calorie/hypoglycaemic guava-Aloe vera
beverage as shown in Table 3.4.
Table 3.4. Preparation of hypoglycaemic guava-Aloe vera beverage
Percent sweetness equivalent used Treatments
Sucrose Non-nutritive sweetener
T1 (control) 100 0
T2 75 25 (stevia leaves extract)
T3 75 25 (sorbitol)
T4 50 50 (stevia leaves extract)
T5 50 50 (sorbitol)
T6 25 75 (stevia leaves extract)
T7 25 75 (sorbitol)
T8 0 100 (stevia leaves extract)
T9 0 100 (sorbitol)
44
Sugar syrup was prepared by boiling the calculated amount of sugar and
water, cooled to room temperature and mixed with the pulp. The non-nutritive
sweeteners viz. stevia leaves extract and sorbitol were added to the
hypoglycaemic beverage to replace sucrose (cane sugar) as shown in Table 3.4in
equivalent level of sweetness. The hot beverage was filled into presterlized glass
bottles (200ml) and processed for 25 minutes in boiling water. The bottles were
cooled, labelled and stored at an ambient temperature (20-34ºC) and were
analyzed for various physico-chemical and sensory characteristics for periodic
interval of 0, 90 and 180 days of storage.
Experiment 3.2.3: Preparation of guava-Aloe vera fruit bars
Experiment 3.2.3.1: Standardization of recipe for the preparation of guava-
Aloe vera fruit bar
Guava-Aloe vera fruit bar was prepared by adding 45 per cent pulp in 55
per cent sugar along with 0.3 per cent and heating the mass to raise TSS to 40ºB.
The prepared mixture was spread on stainless steel trays (30x 20 cm2, with tray
load of 400g per tray) and dried in mechanical dehydrator (55+2ºC) for 8 hours to
a moisture content of 15-20 per cent having a TSS of 68ºB. The dried fruit bars
were cut into strips of suitable dimensions followed by packaging in aluminium
laminates (11 micron) and analyzed for physico-chemical analysis and sensory
attributes. The proportion of Aloe vera in guava-Aloe vera fruit bar was
standardized by using varying proportion of guava pulp and Aloe vera gel extract
i.e. 100:0, 90:10, 80:20, 70:30, 60:40 and 50:50. Maximum proportion of Aloe
vera gel extract with the resultant fruit bar showed maximum acceptability
without bitterness was considered optimum and followed in further
experimentation.
Experiment 3.2.3: Standardization of method for the preparation of
hypoglycaemic guava-Aloe vera fruit bar by using non-nutritive sweeteners.
The optimized combination of guava pulp and Aloe vera gel extract from
above experiment was used for the preparation of low calorie/hypoglycaemic
guava-Aloe vera fruit bar. Sucrose was replaced by using two types of non-
nutritive sweeteners (stevia leaves extract and saccharin) having equivalent
45
sweetness. Apple pomace and oat bran was added concentration of 10per cent.
The detail of different proportion of non-nutritive sweeteners is given in Table
3.5.
Table 3.5. Details of non-nutritive sweeteners and bulking agents used
for preparation of hypoglycaemic guava-Aloe vera fruit bar
Percent sweetness used
Non-nutritive sweetener Bulking agents
Treatments
Sucrose
Stevia leaves
extract
Saccharin Apple
pomace
Oat bran
T1(control) 100 - 0 - -
T2 (control) 100 - - -
T3 (control) - 100 - -
T4 75 25 - 10 -
T5 75 25 - - 10
T6 75 - 25 10 -
T7 75 - 25 10
T8 50 50 - 10 -
T9 50 50 - - 10
T10 50 - 50 10 -
T11 50 - 50 - 10
T12 25 75 - 10 -
T13 25 75 - - 10
T14 25 - 75 10
T15 25 - 75 - 10
The hypoglycaemic guava-Aloe vera fruit bars were prepared by using
different proportion of guava pulp, Aloe vera gel extract, bulking agents and non-
nutritive sweeteners viz. stevia leaves extract and saccharin with sugar in
different proportions. TSS was maintained by adding different proportions of
sugar syrup and non-nutritive sweeteners while acidity of 0.5% was maintained
by adding citric acid. The prepared mixture was heated for 25 min to increase the
concentration (40ºB), and then spread on stainless steel trays (30 x 20 cm
2, with
tray load of 400 g per tray) and dried in mechanical dehydrator (55+2ºC) for 10+2
hours to a moisture content of 15-20 per cent. The dried fruit bar was then cut
into strips of suitable dimensions (10x2 cm2) followed by wrapping in aluminum
laminates (11 microns). After sealing and labelling, the fruit bars were stored at
ambient (12-24ºC) and refrigerated condition (4+2ºC) and were evaluated by
analyzing the product at periodic intervals of 0 day, after 90 days and 180 days
for various physico-chemicals and sensory characteristics.
46
3.3 Physico-chemical characteristics
Fresh guava fruit, Aloe vera, stevia leaves extract and prepared products
were analyzed for various physico-chemical characteristics (as applicable) viz.,
moisture content, total solids, total soluble solids, ash content, fat content,
titratable acidity, sugars, steviosides and Rebaudiosides, pectin, pH, ascorbic
acid, drying rate and specific content as per standard methods given as under:
1. Fruit size
Size parameters comprising of vertical and horizontal diameter of fresh
guava fruit were recorded with the help of Vernier Calliper. Ten fruits were
selected at random and average fruit size (length and diameter) was calculated
and expressed in millimeters (mm).
2. Fruit weight
Average weight (g) of guava fruits was taken by using a digital weighing
balance and expressed in grams.
3. Grittiness
The grittiness in guava pulp was determined by passing the extracted
guava pulp through 35 mesh size. The gritty material remaining on the sieve was
weighed and expressed as per cent.
4. Specific gravity
Specific gravity of beverage was determined by specific gravity bottle.
The specific gravity bottle was first cleaned by shaking with acetone or distilled
water and then dried. Thereafter, tare weight of bottle was noted. Specific gravity
bottle was then filled carefully with the test liquid followed by the insertion of
thermometer stopper, after which Specific gravity bottle was placed in water bath
held at the specified temperature. The specific gravity bottle was removed,
cooled, dried and weighed. The procedure was repeated using distilled water in
place of the sample solutions.
Weight of product held in sp.gr. bottle Specific gravity =
Weight of distilled water held in sp.gr. bottle
47
5. Solids
5.1 Total Soluble Solids (TSS)
The total soluble solids of the sample (pulp, beverage and fruit bar) were
recorded with the help of an Erma Hand Refractometer. A drop of the juice
squeezed from the samples was placed on the prism and viewed through the eye
piece. The readings thus obtained were corrected for temperature variation to
20oC as per International Temperature Correction table (Horwitz, 1980) and
results expressed as oBrix. Total soluble solids of raw material (guava fruit Aloe
vera and stevia leaves extract), beverages and fruit bar (hypoglyceamic guava
Aloe vera) were determined by putting a drop of juice on the prism. Fruit bar
were diluted by addition of water and TSS was calculated by using correction
factor.
5.2 Total Solids and Moisture content
Total solids were estimated by drying weighed sample to constant weight
in a hot air oven at 70+2oC. The dried sample was then cooled to room
temperature in desiccator prior to weighing. The weight after drying was
expressed as percent (w/w), which represented the percent total solids in the
nectar/beverage and bar. The loss in weight of the sample after drying
representing the moisture content was expressed as percent (w/w) (AOAC, 1984).
6. Titratable acidity
A known weight (10g) of the sample (hypoglycaemic guava-Aloe vera
beverage and fruit bar) was crushed and taken in a 250 ml volumetric flask and
the volume was made up by adding distilled water. After filtration, 10 ml of the
filtrate was taken in a separate conical flask and titrated against 0.1 N sodium
hydroxide using phenolphthalein as an indicator to faint pink colour end point.
The value of titratable acidity was calculated from the following expression and
expressed on the basis of predominant acid such as citric acid (beverage and bars)
on fresh as well as on dry weight basis (Ranganna, 2009).
Titre x Normality of alkali x Volume made up x Eq.wt.of
acid x 100 % Titratable acidity =
Volume of aliquot taken for estimation x Wt or vol. of
sample x 1000
48
7. Sugars
Total and reducing sugars different products (pulp in juice and low
calorie/hypoglycaemic guava-Aloe vera beverage and fruit bar) were estimated
by Lane and Eynon (1923) volumetric method as detailed by Ranganna, 1986.
The samples were prepared after using standardized method then titrated against
10 ml of standardized Fehling’s solution using methylene blue as an indicator to a
brick red precipitate for determining the reducing and total sugars respectively.
For estimation of reducing sugars, 25 g of the sample was diluted to 100
ml with distilled water in 250 ml volumetric flask and neutralized with 1 N
NaOH, using phenolphthalein as an indicator. To the neutralized sample, 2 ml of
neutral lead acetate (45%) was added, and whole solution was shaken and kept
for ten minutes. Then 2 ml of potassium oxalate (22%) was added to remove
excess of lead, the volume was made up to 250 ml and filtered. The aliquot was
used for the estimation of sugars. For total sugars, 50 ml of the filtrate was
hydrolyzed by the addition of 10 ml of HCl (1+1) and was left for a period of 24
hours for inversion. The sample after inversion was neutralized with 1 N NaOH
using phenolphthalein as an indicator and the volume was made to 250 ml with
distilled water. The aliquot was used for titration against boiling 10 ml of
Felhings solution using methylene blue as an indicator to a brick red precipitate
for estimating total reducing sugars.
The results were calculated as under and expressed as percent reducing
and total sugars on fresh weight basis.
mg of invert sugar x vol. made x 100
(a) % Reducing sugars = Titre x wt. or vol. of sample x 1000
(b) % Total sugars as invert sugars = calculated as in (a) making use of titre value
as obtained in the determination of total sugars after inversion
8. Ascorbic acid
The titrimetric method using 2, 6 dichlorophenol-indophenol dye was
followed for the determination of ascorbic acid in different products. A known
quantity of sample ( pulp, juice and hypoglycaemic guava-Aloe vera beverage
49
and fruit bar) was ground (fruit bar) and made to 100 ml with 3 %
metaphosphoric acid. Aliquot of the extract was titrated against standardized dye
(2, 6- dichlorophenol-indophenol) to a faint pink colour persisting for at least 15
seconds.
The dye was standardized by titrating against standard ascorbic acid
solution (0.1 mg L-ascorbic acid per ml of 3% HPO3 solution) and dye factor was
calculated from the expression:
0.5 Dye factor =
Titre
Ascorbic acid was calculated from the expression given below and
expressed as mg/100g of the sample (Ranganna, 1986).
Titre x Dye factor x Vol. made up
Ascorbic acid, mg/100 g = Aliquot of extract x Wt. of sample
X 100
9. pH
pH was measured using pH meter (Cyberscan 2100) which was
standardized and calibrated with different buffers of pH 4.0, 7.0 and pH 9.0.
10. Steviosides and Rebaudiosides A
The Steviosides and Rebaudiosides A content from stevia extract was
determined with the help of HPLC analysis. The material was dried in a rotatory
vaccum evaporator at 50ºC. Then lyphilization was done to remove the tiny water
droplets from the dried stevia extract. Known amount of sample was weighed and
dissolved in known amount of mobile phase. The material was kept in sonicator
for some time. The sample was passed through a membrane and put in glass vial.
The HPLC was performed using sample and standard steviosides as per standard
method (AOAC,1980) HPLC chromatograms of stevia leaves extract showing
peaks of Steviosides and Rebaudiosides A. Area against the retention time of
standard were determined and concentration of steviosides and Rebaudiosides A
was determined.
50
11 Drying characteristics
11.1 Drying rate
The rate of dehydration per unit time was calculated by placing a weighed
quantity of pulp (400 gm on stainless steel tray (30x20 cm2) and drying in
mechanical dehydrator (55 + 2ºC) to moisture content of 15-20 per cent (w/w). The
loss in weight during drying was recorded at periodic intervals which were then
calculated by plotting the per cent moisture on dry weight basis against time in
hours (Ranganna, 2009).
11.2 Dehydration ratio
The dehydration ratio between fresh weight of material before drying to that
of dried weight represented the dehydration ratio of given samples (Ranganna,
2009).
12 Ash
Total ash content was determined gravimetrically by taking known weight
of sample (Aloe vera dried stevia leaves) in a tared silica crucible. The sample
was slowly heated over a hot plate until the bulk of organic matter was burnt. The
crucible was then placed in a muffle furnace at 500oC for 4 hours and weighed
for ash content. Total ash in the sample was expressed as percent w/w (AOAC,
1980).
13 Relative viscosity (µr)
It is a synonym of “viscosity ratio”. It is defined as the ratio of the
viscosity of a solution (µ) to the viscosity of the solvent used (µs). It was
determined by using Ostwald viscometer and calculated as under:
µ
µ r = µ s
14 Fat content
The fat content in the dried stevia leaves was determined according to
Roese Gottlieb method (1989). To 10 g of stevia sample, 1.25 ml NH4OH was
added and mixed thoroughly. Ten ml 95 per cent alcohol was then added and
51
mixed properly. To this, 25 ml ethyl ether was added and shaken vigorously for 1
min followed by addition of 25 ml petroleum ether and vigorous shaking.
Centrifugation of the samples was then carried out at 600 rpm for 30 seconds to
obtain clear separation of aqueous and ether phases. The ether solution was
decanted and the extraction of liquid remaining in flask was repeated twice, using
15 ml of each solvent. The fat was dried to a constant weight in oven at 102 ±
2oC. The loss in weight represented the fat content present in the sample.
15 Water activity (aw)
Water activity in fruit bar of different treatments was determined by using
hand held water activity meter (M/S Rotronic Instrument Corporation,
Huntington, USA). The samples were placed in 40 mm deep cups (WP-40) and
the water activity probe was placed on the sample. The Rotronic aw meter was
switched on and after five minutes of equalization, the Rotronic water activity
meter gave the display of aw of the samples. Triplicate determination was made
for each treatment.
16 Pectin
Pectin content was determined by Care and Hayne’s method as described
by Ranganna (2009) and the results were expressed as percent calcium pectate.
Known weight of the sample (15-20g) was heated with 100 ml of water for one
hour, cooled and volume made, filtered, neutralized by adding excess of 1 N
NaOH and kept for overnight. Then 50 ml of 1 N acetic acid and 25 ml of 1 N
CaCl2 was added, kept for one hour and filtered. Residue was washed with hot
water till the filtrate tested negative for chlorides and was dried in an oven at
90oC for overnight. The results were expressed as percent calcium pectate.
Wt. of Calcium pectate x Vol. made
Calcium pectate (%) = Vol. of aliquot x wt/vol. of sample
X 100
17. Energy Value
Energy value of the hypoglycaemic guava and Aloe vera beverage and fruit
bar was calculated by taking into account of total sugars, stevia leaves extract,
saccharin and sorbitol present in guava-Aloe vera beverage and fruit bar. The
52
contents of each nutrient were multiplied by a conversion factor as reported by
Holland (1992) and Kalia and Sood (1996) and expressed in K cal/100g of
hypoglycaemic guava-Aloe vera beverage and fruit bar.
18 Colour
The colour of fruit was determined by visual appearance.
19 Sensory Evaluation
Guava Aloe vera beverage fruit bar and low calorie/Hypoglyceamic
guava-Aloe vera beverages and fruit bars prepared by using non-nutritive
sweeteners viz. stevia leaves extract, sorbitol and saccharin were evaluated for
sensory qualities on the basis of colour (appearance), flavour, body/consistency
and overall acceptability by a panel of semi-trained judges, consisting of teachers,
students and other staff members. The evaluation was done by using the 9 point
Hedonic scale for each attribute as shown in Table 3.6 (Amerine et al., 1965).
Table 3.6. 9 point Hedonic scale used for sensory evaluation of different
products
Score Rating
9 Like extremely
8 Like very much
7 Like moderately
6 Like slightly
5 Neither like nor dislike
4 Dislike slightly
3 Dislike moderately
2 Dislike very much
1 Dislike extremely
20 STATISTICAL ANALYSIS
The data pertaining to physico-chemical evaluation were analyzed
statistically by following the Completely Randomized Design (CRD) according
to Cochron and Cox, 1967, while the data on sensory evaluation were analyzed
according to Randomized Block Design (Mahony, 1985)
53
21 COST OF PRODUCTION
The cost of production was calculated by taking into consideration
various input costs such as cost of raw material, labour, electricity, processing
costs, packaging and other charges.
Chapter-4
EXPERIMENTAL RESULTS
The result obtained in the present investigation on “Development and
evaluation of hypoglycaemic guava products with Aloe vera fortification” are
presented in this chapter. The results obtained during this study are presented in
the following Tables (4.1-4.44) and figures (4.1-4.11) and discussed below under
suitable captions:
4.1 Standardization of extraction method of guava pulp
4.1.1 Physico-chemical characteristics of fresh guava fruit (cv. Allahabad
Safeda)
4.1.1.1 Physical characteristics
The average weight, length and diameter of fresh guava fruit cv.
Allahabad safeda was 82.0 g, 50.0 and 52.66 mm respectively, while the fruit
quotient and volume was recorded
Table 4.1. Physico-chemical characteristics of guava fruit (cv. Allahabad
Safeda)
S.no Parameters Mean 95% Probability
Limits
Physical characteristics
1. Weight,*g 82.0 (81.68, 82.32)
2. Length,*mm 50 .0 (44.37, 55.63)
3. Diameter,*mm 52.66 (18.25, 86.95)
4. Fruit quotient* 1.04 (0.84, 1.24)
5. Fruit volume,*cc 76.3 (58.81, 93.79)
6. Specific gravity 0.92 (0.87, 0.96)
7. Visual skin colour Yellow, Over, 41 B
Ground, 45 A
-
Chemical characteristics
8. TSS ºB 8.30 (7.78, 8.82)
9. Titratable acidity,% 0.76 (0.71, 0.80)
10. pH 4.10 (4.03, 4.17)
11. Ascorbic acid, mg/100g 216.0 (215.05, 216.95)
12. Reducing sugars,% 2.76 (2.42, 3.10)
13. Non-reducing sugars,% 4.83 (4.72, 4.94)
14. Total sugars,% 6.76 (6.62, 7.10)
15. Moisture,% 84.0 (81.40, 86.60)
*n=10
55
as 1.04 and 76.30 cc, respectively (Table 4.1). The specific gravity of fresh fruit
was observed as 0.92 and visual skin colour of fresh guava fruit was found
yellowish while the pulp of the fruit was pale white in colour.
4.1.1.2 Chemical characteristics
The average Total soluble solids (TSS) and titratable acidity in the guava
fruit was recorded as 8.3ºB and 0.76 per cent, respectively with a pH of 4.1
(Table 4.1). As expected, the fresh fruit was found to be good source of vitamin
C with an average ascorbic acid content of 216.0 mg/100g. The total and
reducing sugars in the fresh guava fruits were estimated to be 6.76 and 2.76 per
cent, respectively. The guava fruit had 216 mg/100g ascorbic acid was considered
optimum for development of different fruit products.
4.2 Optimization of method for extraction of pulp from guava fruit cv.
Allahabad Safeda
The method for extraction of guava pulp was standardized by adding
water to the guava pieces with fruit to water ratio 1:1, 1:1.5 and 1:2 prior to
heating either in pressure cooker or in autoclave for varying pressures and
periods of time. The heated mass was then passed through the pulper for
extraction of pulp. The effect of different dilution and heating methods on the
quality of extracted guava pulp are presented in Tables 4.2-4.7 are explained as
under:
4.2.1 Recovery of pulp
The method of heating of guava slices in water exerted significant effect
on the yield of guava pulp extracted through pulper. Heating in pressure cooker at
0.35 Kg/cm2 for 15 min yielded highest pulp (83.3%) while, heating the guava
slices by boiling in open pan resulted in lower pulp yield (67.5%). As expected,
the yield of pulp obtained by using cold extraction (passing guava slices through
the pulper without heating) was the lowest (62.3%). Among the heating methods
heating fruits (1:1) in pressure cooker for 15 min gave the highest pulp yield of
the 78.3 per cent while the fruits (1:1) heat in open kettle for 30 min resulted in
lower pulp yield of 55.2 per cent. Further, the fruit to water ratio brought after
Plate1. Guava fruit (cv. Allahabad Safeda ) used in the study
56
significant effect on the yield of pulp with the increase in water content in the
fruit guava slices the yield of pulp also increased (64.7% to 85.7%). However,
dilution of fruit in water in the ratio of 1:1 gave fruit pulp yield of 64.7 per cent
(Table 4.2).
Similarly, the residue left after extraction by using different heating
methods ranged between 16.6-37.8 per cent. As expected, the combinations as
well as ratio of water in the fruit resulting in higher pulp yield exhibited lowest
residue.
Thus, heating of guava slices along with water in 1:1 ratio in pressure
cooker (0.35 Kg/cm2
) for 15 min prior to passing through the pulper was found
to be most appropriate for extraction of pulp.
Table 4.2 Effect of fruit to water ratio and methods of heating on yield
(%) of extracted guava pulp
Ratio (guava: water dilution)
Yield (%) Residue(%) (peels and seed)
Heating methods
1:1 1:1.5 1:2 Mean 1:1 1:1.5 1:2 Mean
T1 : Atmospheric pressure,
30min
55.2 65.0 82.3 67.5 44.7
(42.0)
35.0
(36.2)
17.7
(24.8)
32.5
(34.4)
T2: Pressure cooker 0.35
Kg/cm2, 10min
76.7 81.5 88.5 82.2 23.3
(28.6)
18.5
(25.5)
11.4
(19.8)
17.7
(24.1)
T3: Pressure cooker 0.35
Kg/cm2, 15min
78.3 82.3 89.3 83.3 21.7
(27.8)
17.6
(24.8)
11.8
(19.2)
16.6
(23.9)
T4: Pressure cooker 0.70
Kg/cm2, 2min
62.9 82.4 88.5 77.9 37.1
(37.5)
17.6
(24.8)
11.5
(19.8)
22.0
(27.4)
T5 : Pressure cooker 0.70
Kg/cm2, 4min
66.4 83.4 89.4 79.7 33.5
(35.4)
16.3
(23.9)
10.5
(18.9)
28.1
(26.1)
T6 : Cold extraction 48.3 62.4 76.1 62.3 51.7
(45.9)
37.6
(37.8)
24.2
(29.4)
37.8
(37.7)
Mean 64.7 76.2 85.7 35.5
(36.2)
23.7
(28.5)
14.4
(22.0)
Figures in parenthesis represents the square root transformed values
CD0.05
T 0.20 0.17
I 0.14 0.12
TxI 0.35 0.30
57
4.2.2 Total solids
Total solids of the pulp extracted after using different methods ranged
between 3.28-3.87 and 2.6 to 4.81 per cent, respectively (Table 4.3). The pulp
extracted after using cold extraction method showed lowest level of total solids
(3.28%), while the pulp obtained after heating in pressure cooker at 0.35 kg/cm2
for 15 min showed total solids of 3.71 per cent. Among heating methods, pulp
extracted after heating fruit along with water in open pan at atmospheric pressure
showed the total solids of 3.48 per cent. Further, the fruit to water ratio brought
about a significant influence on the total solid content of the extracted pulp. With
the increase in proportion of water in fruit, the total solid content of the resultant
pulp exhibited significant decrease. However, the pulp extracted after using 1:1
dilution recorded total solids of 4.81 per cent.
4.2.3 Total soluble solids
TSS of the pulp extracted after using different methods of heating ranged
between 3.28-3.87 and 2.74 to 3.13, respectively (Table 4.3). The pulp extracted
without heating the fruits (cold method) showed lowest level of total soluble
solids (2.74ºB) while the pulp obtained after heating in pressure cooker at 0.35
kg/cm2 for 15 min showed TSS value of 3.04
º B. Among heating methods, pulp
extracted after heating fruit along with water in open pan at atmospheric pressure
showed the TSS 3.13ºB. Further, the fruit to water ratio brought about a
significant influence on the TSS content of the extracted pulp. With the increase
in proportion of water in fruit, the TSS content of the resultant pulp exhibited
significant decrease. However, the pulp extracted after using 1:1 dilution
recorded a significantly higher level of total soluble solid of (4.03ºB) than that of
1:1.56 and 1:2 dilutions.
Generally apart from other attributes, the pulp with higher total solids and
total soluble solids are preferred for product development. Thus, pulp extracted
after heating guava slices along with water in 1:1 ratio dilution exhibited higher
proportion of total solids (4.81%) and total soluble solids (4.03%) and was
considered optimum for extraction of pulp.
58
4.2.4 Titratable acidity
The guava pulp extracted by using different dilutions and methods of
heating ranged between 0.18 to 0.37 and 0.25 to 0.28 per cent, respectively. The
pulp obtained after heating in autoclave at 0.70 Kg/cm2 for 2 min exhibited
titratable acidity of 0.28 per cent. On the other hand, pulp obtained after cold
extraction without heating recorded titratable acidity of 0.26 per cent. With the
increase in water to fruit dilution the acidity of the resultant pulp experienced
significant decrease. However, the pulp obtained after using 1:1 dilution of fruit
and water exhibited significantly highest acidity (0.37%) than that of other two
combinations (Table 4.4).
Table 4.3. Effect of fruit to water ratio and methods of heating on total
solids (%) and total soluble solids (ºB) of extracted guava pulp
Ratio (guava: water dilution)
Total solids (%) Total soluble solids ( ºB)
Heating methods
1:1 1:1.5 1:2 Mean 1:1 1:1.5 1:2 Mean
T1 : Atmospheric pressure,
30min
4.80
(2.2)
3.20
(1.8)
2.43
(1.5)
3.48
(1.8)
4.13
3.0
2.26
3.13
T2: Pressure cooker 0.35
Kg/cm2, 10min
4.76
(2.2)
3.67
(1.8)
2.56
(1.6)
3.56
(1.87)
4.10
2.96
2.16
3.07
T3: Pressure cooker 0.35
Kg/cm2, 15min
4.09
(1.92)
3.70
(1.92)
2.53
(1.59)
3.71
(1.9)
4.13
2.80
2.20
3.04
T4: Pressure cooker 0.70
Kg/cm2, 2min
4.90
(2.21)
3.90
(1.97)
2.80
(1.67)
3.71
(1.9)
4.0
2.86
2.30
3.05
T5 : Pressure cooker 0.70
Kg/cm2, 4min
5.03
(2.24)
3.70
(1.92)
2.90
(1.7)
3.87
(1.96)
4.03
2.86
2.20
3.03
T6 : Cold extraction 4.46
(2.11)
3.03
(1.74)
3.36
(1.79)
3.28
(1.79)
3.80
2.53
1.90
2.74
Mean 4.81
(2.19)
3.48
(1.86)
2.60
(1.61)
4.03
2.83
2.17
Figures in parenthesis represents the square root transformed values
CD0.05
T 0.04 0.19
I 0.03 0.16
TxI 0.08 0.36
4.2.5 pH
Corresponding to titratable acidity, mean value of pH in guava pulp
extracted by using different dilutions and heating methods were recorded as 3.67-
59
4.24 and 3.88 to 3.99, respectively. The pulp obtained after cold extraction
exhibited the lowest pH of 3.88. Further, the water to fruit dilution influenced the
pH of the pulp. With the increase in proportion of water in fruit, there was a
significant increase in pH and decrease in acid content upon dilution.
Table 4.4. Effect of fruit to water ratio and methods of heating on
Titratable acidity (% CA) and pH of extracted guava pulp
Ratio (guava: water dilution)
Titratable acidity (%) CA pH
Heating methods
1:1 1:1.5 1:2 Mean 1:1 1:1.5 1:2 Mean
T1 : Atmospheric pressure,
30min 0.37 0.24 0.16 0.25 3.68 3.90 4.34 3.97
T2: Pressure cooker 0.35
Kg/cm2, 10min
0.39 0.25 0.17 0.27 3.68 3.92 4.38 3.99
T3: Pressure cooker 0.35
Kg/cm2, 15min
0.38 0.23 0.19 0.26 3.67 3.94 4.13 3.90
T4: Pressure cooker 0.70
Kg/cm2, 2min 0.36 0.26 0.20 0.28 3.65 3.92 4.12 3.89
T5 : Pressure cooker 0.70
Kg/cm2, 4min
0.38 0.25 0.19 0.27 3.65 3.93 4.38 3.98
T6 : Cold extraction 0.37 0.23 0.18 0.26 3.64 3.89 4.12 3.88
Mean 0.37 0.25 0.18 3.67 3.90 4.24
CD0.05
T 0.02 0.17
I 0.01 0.12
TxI 0.34 0.28
4.2.6 Total Sugars
The level of total sugars in guava pulp extracted by using different
heating methods ranged between 2.25 to 2.33 per cent (Table 4.5). The pulp
obtained after heating in autoclave for 4 min at 0.70 kg/cm2 exhibited higher
sugar contents (2.33%). On the other hand, pulp extracted after cold extraction
without heating recorded the lowest levels of total sugars (2.25%). The pulp
extracted after heating the 1:1 dilution of fruit and water in pressure cooker at
0.35 kg/cm 2
for 15 min recorded 3.24 per cent total sugars. Further, with the
increase in water total sugar content in the extracted pulp decreased. However,
the pulp obtained using 1:1 dilution of fruit and water resulted in significantly
higher levels of total sugars (Table 4.5) as compared to pulp obtained after 1:1.5
60
and 1:2 dilution. Thus, use 1:1 dilution and heating fruit slices in pressure cooker
at 0.35 kg/cm2 for 15 min was optimized for extraction of guava pulp.
4.2.7 Ascorbic acid content
Ascorbic acid content was present in the extracted pulp obtained after
heating fruits in open pan, pressure cooker as well as in autoclave ranged
between 62.52 to 83.19 mg/100g (Table 4.5). The pulp extracted without heating
(cold extraction) exhibited the highest ascorbic acid contents (83.19 mg/100g)
while, pulp extracted after heating fruit in open pan at atmospheric pressure for
30 min showed lowest level of ascorbic acid (62.52 mg/100g). Heating fruit with
water in increasing proportion (1:1 to 1:2) followed by pulp extraction brought
about significant reduction in the ascorbic acid content of the extracted pulp.
However, cooking fruit in pressure cooker at a pressure of 0.35 kg/cm2 for 10 to
15 min exhibited better retention of ascorbic acid.
Table 4.5. Effect of fruit to water ratio and methods of heating on total
sugars (%) and ascorbic acid contents (mg/100g) of extracted
guava pulp
Ratio (guava: water dilution)
Total sugars (%) Ascorbic acid(mg/100g)
Heating methods
1:1 1:1.5 1:2 Mean 1:1 1:1.5 1:2 Mean
T1 : Atmospheric pressure,
30min
3.25
(1.80)
2.14
(1.46)
1.52
(1.23)
2.30
(1.50) 89.50 58.27 39.80 62.52
T2: Pressure cooker 0.35
Kg/cm2, 10min
3.20
(1.79)
2.15
(1.46)
1.55
(1.24)
2.31
(1.5) 101.5 68.13 42.18 70.60
T3: Pressure cooker 0.35
Kg/cm2, 15min
3.24
(1.80)
2.15
(1.46)
1.55
(1.24)
2.31
(1.5) 101.4 68.13 42.17 70.54
T4: Pressure cooker 0.70
Kg/cm2, 2min
3.25
(1.80)
2.16
(1.46)
1.50
(1.24)
2.32
(1.500 101.3 68.00 41.03 70.45
T5 : Pressure cooker 0.70
Kg/cm2, 4min
3.27
(1.80)
2.15
(1.46)
1.57
(1.25)
2.33
(1.51) 99.67 68.03 42.59 70.20
T6 : Cold extraction 3.14
(1.77)
2.10
(1.144)
1.53
(1.23)
2.25
(1.48) 113.7 78.70 57.13 83.19
Mean 3.22
(1.79)
2.14
(1.46)
1.54
(1.24) 101.2 68.24 44.31
Figures in parenthesis represents the square root transformed values
CD0.05
T 0.007 1.93
I 0.005 1.36
TxI NS 3.34
61
Further, addition of fruit slices in water in different proportions exerted a
significant influence on the ascorbic acid contents of extracted pulp. As expected,
with the increase in dilution, the ascorbic acid content in the extracted pulp
showed a corresponding decrease. However, the pulp extracted after heating
guava fruit slices along with water in 1:1 proportion resulted in significantly
higher proportion of ascorbic acid (101.2 mg/100g). Thus, the method consisting
of heating fruit slices along with water (1:1) in pressure cooker at 0.35 kg/cm2
pressure for 10-15 min retaining about 1/3rd
ascorbic acid from its original value
of 216 mg/100g was found optimum for extraction of pulp.
4.2.8 Pectin and relative viscosity
The pectin content in pulp extracted by using different heating methods
varied between 0.33 to 0.62 and 0.38 to 0.51 per cent as calcium pectate (Table
4.6). The pulp extracted after heating in pressure cooker at a pressure of 0.35
Kg/cm2
for 15 min exhibited highest pectin (0.51%). On the other hand,
pulp extracted after cold extraction (with out heating) recorded the lowest level of
Table 4.6. Effect of fruit to water ratio and methods of heating on pectin (%
as calcium pectate) and relative viscosity of extracted guava pulp
Ratio (guava: water dilution)
Pectin (%) Relative viscosity
Heating methods
1:1 1:1.5 1:2 Mean 1:1 1:1.5 1:2 Mean
T1 : Atmospheric pressure,
30min 0.60 0.43 0.35 0.46 12.33 7.33 2.23 7.30
T2: Pressure cooker 0.35
Kg/cm2, 10min
0.63 0.44 0.33 0.46 15.37 7.50 2.30 6.38
T3: Pressure cooker 0.35
Kg/cm2, 15min 0.70 0.46 0.36 0.51 17.27 7.03 2.30 6.38
T4: Pressure cooker 0.70
Kg/cm2, 2min
0.60 0.42 0.32 0.45 17.37 7.30 2.23 8.84
T5 : Pressure cooker 0.70
Kg/cm2, 4min
0.70 0.45 0.36 0.50 17.43 7.30 2.60 9.11
T6 : Cold extraction 0.53 0.35 0.25 0.38 10.30 6.73 1.86 6.30
Mean 0.62 0.42 0.33 15.01 7.20 2.26
CD0.05
T 0.02 0.18
I 0.02 0.13
TxI 0.04 0.32
Plate 2. Guava pulp prepared by using different proportion of guava
fruit and water
62
pectin. Further, the fruit to water ratio significantly influenced the pectin content
of the extracted pulp as with the increase in dilution, the pectin content of the
pulp showed a decrease. However, the dilution of fruit with water in the ratio of
1:1 resulted in comparatively higher pectin contents (0.62%) of pulp as compared
to pulp obtained after 1:1.5 and 1:2 dilutions.
The relative viscosity of the pulp obtained after heating fruits in the
different combinations of heating methods ranged between 2.26-15.01 and 6.30
to 9.11. The highest relative viscosity (9.11) was found in the pulp extracted
after heating in pressure cooker at 0.70 Kg/cm2 pressure for 4 min. Cold
extraction methods on the other hand, exhibited minimum relative viscosity
(6.30) in the extracted pulp. Further, with the increase in proportion of water in
fruit, relative viscosity of extracted pulp exhibited a decrease and pulp became
watery and free flowing. However, the dilution of water in 1:1 proportion
resulted in pulp of significantly higher relative viscosity.
The grittiness of the pulp obtained after heating fruits in the different
combinations of heating methods ranged between 33.4 to 16.7 and 11.0 to 47.0
per cent. The highest grits (47%) were found in the pulp extracted by cold
extraction methods. On the other hand, pressure cooker at steam pressure of 0.70
Kg/cm2, for 4 minutes exhibited minimum grits (11%) in the pulp. Further, with
the increase in dilution of water in fruit, grits of extracted pulp exhibited decrease
and pulp became watery and free flowing through sieve.
Table 4.7. Effect of fruit to water ratio and methods of heating on grittiness
of extracted guava pulp
Ratio (fruit : water dilution)
(Grits %) Heating methods
1:1 1:1.5 1:2 Mean
T1 : Atmospheric pressure, 30min 40.2 26.6 20.3 29.0
T2:Pressure cooker 0.35 Kg/cm2, 10min 32.4 21.3 16.2 23.3
T3:Pressure cooker 0.35 Kg/cm2, 15min 30.3 20.0 15.3 21.8
T4: Pressure cooker 0.70 Kg/cm2, 2min 17.3 11.3 8.5 12.3
T5 : Pressure cooker 0.70 Kg/cm2, 4min 15.2 10.3 7.5 11.0
T6 : Cold extraction 65.1 43.3 32.5 47.0
Mean 33.4 25.8 16.7
CD0.05 T = 0.20 I = 0.14 TxI=0.35
63
Thus, the pulp extracted by heating guava slices with water in 1:1 ratio
in pressure cooker at a pressure of 0.35 kg/cm2 for 15 min recorded highest pulp
yield (78.3%) with smooth texture and lower residue (21.7%). This pulp
containing 4.13ºB TSS, 0.38 per cent titratable acidity, 3.24 per cent total sugars,
101.4 mg/100g ascorbic acid, 0.70 per cent pectin with a relative viscosity 17.27
was considered optimum for product development.
4.3 Extraction and evaluation of Aloe vera gel extract (Aloe vera
barbadensis)
Aloe vera gel was prepared and stabilized according to the method
optimized by Ramachandra and Rao, 2008. In the preparation, Aloe vera gel
obtained after removing the peel from the Aloe vera stem was passed through
the fruit grater to get a free flowing gel. The gel was stabilized by heating at 80ºC
and adding 0.3 per cent citric acid (Ramachandra and Rao, 2008). The stabilized
gel was filled hot in presterlized glass bottles and heat processed for 25 min and
stored in refrigerator until used for further experimentation. The quality attributes
of raw and processed Aloe vera gel given in Table 4.8 are explained as under:
Physico-chemical attributes of the Aloe vera gel indicate that the raw Aloe
vera gel scrapped from the stem was a colloidal mass, which got stabilized after
Table 4.8. Physico-chemical characteristics of raw and Aloe vera gel
extract (Aloe vera barbadensis)
Sr.
No Parameters Raw gel
Mean + S.E Processed gel Mean + S.E
1. TSS, ºB 2.01 +0.04 2.13+0.08
2. pH 5.21+0.11 3.45+0.02
3. Total sugars,% 0.71+0.02 0.74+0.02
4. Titratable acidity,% CA 0.38+0.01 0.67+0.01
5. Ascorbic acid, mg/100g 124.33+2.31 114.86+2.30
6. Total solids,% 3.1+0.71 2.8+0.20
7. Relative viscosity * 12.51+0.45
8. Pectin,% (as calcium
pectate) 0.52+0.01 0.63+0.02
9. Specific gravity,% 0.97+0.01 1.04+0.04
10. Ash content, % 0.24+0.01 0.26+0.01
n=3
*Too thick to pass through the Ostwald viscometer.
Plate 3. Preparation of Aloe vera gel extract
Aloe vera leaves Washing
Aloe vera gel Peeling
Pulping Aloe vera gel
extract
64
heating at 80ºC and on addition of 0.3 per cent citric acid. Different chemical
attributes in processed Aloe vera gel extract contained 2.13ºB TSS, 0.74 per cent
total sugar, 0.6 per cent titratable acidity, 2.8 per cent total solids, 0.63 per cent
pectin and 0.26 per cent ash. Raw gel possessed almost similar attributes except
titratable acidity. The gel extract was found to be a good source of ascorbic acid
which ranged between 114-124 mg/100g. Stabilization by heating and addition of
citric acid brought about improvement in flow properties of the gel extract. With
respect to flow properties the raw gel extract was difficult to pass through the
viscometer. Thus, on the basis of physico-chemical attributes, the processed gel
extract was found suitable for development of different value added products and
hence optimized for further experimentation.
4.4 Quality attributes of dried stevia leaves
Fresh stevia leaves after washing were dried in mechanical dehydrator
(58+2ºC) to the constant weight and ground to fine powder. The data presented in
Table 4.9 revealed that fresh stevia leaves contained 8.36 + 0.15ºB total soluble
solids (TSS) and dried stevia leaves contained 93.23+ 0.25 per cent total solids.
The leaves powder also showed the presence of 24.5 mg/100g ascorbic acid. The
presence of 13.23 per cent Steviosides and 4.20 per cent Rebaudiosides A
(Fig.4.1) in stevia leaves powder as sweetening compounds indicates its potential
for its use in development of low calorie products.
Table 4.9. Physico-chemical composition of dried stevia leaves
n=3 * on fresh basis
Sr. No Parameters Dried leaves powder Mean + S.E
1 TSS,ºB* 8.36 + 0.15
2 Titratable acidity,% CA 1.45 + 0.01
3 Ascorbic acid, mg/100g 24.5+ 0.50
4 pH 7.10+ 0.10
5 Protein, % 10 +0.02
6 Total solids, % 93.23+ 0.25
7 Moisture,% 6.76+0.25
8 Fat,% 6.07+0.09
9. Total carbohydrate, % 52 +0.03
10. Ash,% 8.13+0.20
11. Steviosides, % 13.23+0.01
12. Rebaudiosides A,% 4.20+ 0.01
65
4.4 Standardization of a method for preparation of guava-Aloe vera
beverage
Suitability of incorporation of Aloe vera gel extract in guava beverage
was evaluated. Guava-Aloe vera beverage was prepared by maintaining 20 per
cent fruit pulp and 15ºB TSS as per FSSA(Food Safety and Standards Act), 2006
specifications. The level of guava pulp was replaced by using Aloe vera gel
extract in the ratios of 20:0, 17.5:2.5, 15:5, 12.5:7.5, 10:10, 7.5:12.5, 5:15,
2.5:17.5 and 0:20. The proportion of Aloe vera gel at which the drink remained
acceptable on the basis of sensory quality was considered optimum. The effect of
addition of Aloe vera gel extract the on the physico-chemical and sensory
attributes of the prepared product presented in Table 4.10-4.11 are explained as
under:-
4.4.1 Physico-chemical attributes of guava-Aloe vera beverage
Data in the Table (4.10) indicate that with the increase in concentration of
Aloe vera gel extract and corresponding decrease in guava pulp the TSS content
in the beverage did not exhibit any appreciable change. The level of total soluble
solids in guava-Aloe vera beverage containing varying proportions of gel extract
ranged between 15.20 and 15.63 ºB. The drink prepared by using 15 per cent
guava pulp and 5 per cent Aloe vera gel extract exhibited total soluble solids of
15.63ºB.
The titratable acidity, pH and ascorbic acid contents in the prepared drink
ranged between 0.30 to 0.34 per cent, 3.15 to 3.45, and 14.21 to 18.86 mg/100g
respectively. The drink prepared by using 15 per cent guava pulp and 5 per cent
Aloe vera gel extract contained acidity of 0.34 per cent and pH of 3.45. Further,
with the decrease in proportion of guava pulp and corresponding increase in Aloe
vera gel extract, the ascorbic acid contents in the drink registered a decrease from
18.86 mg/100g to 14.21mg/100g. However, the beverage prepared by using 15
per cent guava pulp and 5 per cent Aloe vera gel extract showed an ascorbic acid
level of 16.17 mg/100g.
Plate 4. Preparation of stevia leaves extract
Stevia leaves Stevia leaves washed
Dried Stevia leaves Drying in mechanical dehydrator
(55+2oC)
Dried Stevia leaves powder Stevia leaves extract
66
Table 4.10. Effect of addition of Aloe vera gel extract on the chemical
attributes of guava-Aloe vera beverages
Proportion of
guava pulp and
Aloe vera extract
TSS ºB
Titratable
acidity,
% CA
pH Ascorbic
acid
mg/100g
Total
sugars,
%
Specific
gravity
T1: 20:0 15.20 0.32 3.34 18.86 14.64 1.023
T2::17.5:2.5 15.43 0.30 3.22 18.14 14.12 1.030
T3: 15:5 15.63 0.34 3.45 16.17 14.64 1.026
T4:12.5:7.5 15.43 0.31 3.15 16.94 14.38 1.030
T5:10:10 15.43 0.32 3.34 16.12 14.12 1.035
T6:7.5:12.5 15.30 0.34 3.22 16.56 14.48 1.024
T7:5:15 15.40 0.32 3.34 16.48 14.33 1.020
T8:2.5:17.5 15.50 0.33 3.29 15.85 14.23 1.019
T9:0:20 15.25 0.30 3.22 14.21 14.18 1.010
CD0.05 0.32 0.30 0.04 0.32 0.30 0.10
Similar to total soluble solids, total sugar content in beverage did not
experience much change with the addition of Aloe vera gel. The specific gravity
of the prepared beverage having different combinations of guava pulp and Aloe
vera gel extract ranged between 1.010 to 1.035. Thus, the beverage prepared by
using 15 per cent guava pulp and 5 per cent Aloe vera gel extract found to
meet the FSSA specification for the fruit nectar i.e. 20 per cent pulp and
minimum of 15ºB total soluble solids and containing no preservatives. Thus, 5
per cent Aloe vera gel extract can be incorporated in guava beverage without
changing the FSSA specification of fruit nectar.
4.4.2 Sensory evaluation of guava-Aloe vera beverage.
The data pertaining to the effect of addition of varying proportions of
guava pulp and Aloe vera gel extract on the sensory quality of the prepared
guava-Aloe vera beverage presented in Table 4.11 are explained as under:-
4.4.2.1 Colour
The data recorded for colour mean score remained highly significant
within all combinations (Table 4.11).With the increase in proportion of Aloe vera
gel extract and corresponding decrease in guava pulp, the colour acceptability
of the prepared drink exhibited decrease on a 9 point hedonic scale. However, the
67
colour score was recorded as statistically highest for drinks having 20 per cent
guava pulp (7.0) and lowest for 20 per cent Aloe vera gel extract (3.9). The
colour score for the drinks having 20:0, 17.5:2.5 and 12.5:7.5 per cent guava and
Aloe vera were statistically at par and within the acceptable range (more than
6.0). While the drink prepared by using Aloe vera up to 10 per cent or beyond
were not acceptable with respect to colour acceptability.
Table 4.11. Effect of addition of Aloe vera gel extract on the sensory
characteristics (9 point hedonic scale) of guava-Aloe vera
beverage/ nectar
Proportion of guava pulp
and Aloe vera extract
Colour Flavour
/aroma
Taste Body Over all
Acceptability
T1: 20:0 7.0 7.3 6.9 7.2 7.20
T2::17.5:2.5 6.7 7.1 6.3 6.9 6.75
T3: 15:5 6.5 6.8 6.1 6.8 6.55
T4:12.5:7.5 6.4 6.6 6.0 6.8 6.45
T5:10:10 5.9 5.8 5.6 6.4 5.92
T6:7.5:12.5 5.7 4.9 5.4 5.2 5.30
T7:5:15 5.7 4.8 5.0 4.9 5.10
T8:2.5:17.5 5.2 4.6 5.0 4.0 4.70
T9:0:20 3.9 4.3 4.0 2.7 3.72
CD0.05 0.83 0.65 0.80 0.98 0.82
4.4.2.3 Flavour / aroma
The flavour/aroma score of the guava-Aloe vera beverage ranged from 4.3
to 7.3. The highest mean score was obtained in drink having 20 per cent guava
pulp (7.3) which was statistically at par with the drink containing 17.5:2.5,15:5
and 12.5:7.5 guava: Aloe vera extract within the acceptable range (within
acceptable range). The lowest flavour score was awarded to combinations having
20 per cent Aloe vera (4.3) which was statistically at par with drink having 5:15
and 2.5:17.5 per cent guava and Aloe vera, respectively, thus, indicating the
unacceptability beyond 10 per cent or higher Aloe vera gel extract in the drink.
4.4.2.4 Taste
The data recorded for taste acceptability of the beverage remained highly
significant with in all combinations (Table 4.11). As expected, the highest mean
score for taste acceptability were recorded for a drink having 20 per cent guava
Plate 5. Guava-Aloe vera nectar/beverages containing varying proportion of
guava pulp and Aloe vera extract
68
pulp followed by drink having Aloe vera gel in proportion of 17.5:2.5, 15:5
12.5:7.5. Further, addition of Aloe vera beyond 7.5 per cent made the resultant
beverage unacceptable.
4.4.2.5 Body
Sensory evaluation of the beverage indicated that the drink prepared by
using 20 per cent guava pulp alone had highest liking for body. Though, with the
incorporation of Aloe vera gel extract and corresponding decrease in guava pulp
the acceptability of the drink for body of the beverage decreased, yet the drinks
remained acceptable up to the level of 10:10 per cent guava-Aloe vera. Thus, the
drinks having 20:0, 17.5:2.5, 15:5 and 12.5:7.5 per cent guava and Aloe vera gel
extract were statistically at par with pure guava nectar with a mean score more
than 6.0. While, addition of Aloe vera gel extract in the drink beyond 10 per cent
made the body of the drink watery and hence unacceptable.
4.4.2.6 Over all acceptability
As expected the guava beverage having 20 per cent guava pulp alone had
highest acceptability among the panelist with a mean score of 7.20 on a 9 point
hedonic scale. With the addition of Aloe vera gel extract, the sensory score for
overall acceptability decreased. However, the drink containing up to 7.5 per cent
Aloe vera gel extract remained statistically at par with pure guava beverage in
overall acceptability. While, addition of Aloe vera gel extract beyond the level of
7.5 per cent with corresponding decrease in guava pulp which corresponding
decrease in guava pulp made the drink unacceptable. Thus, the addition of 5 per
cent Aloe vera gel extract along with 15 per cent guava pulp was optimized for
preparation the guava-Aloe vera beverage having 20 per cent pulp and 15ºB total
soluble solids.
4.5 Optimization of parameters for preparation of hypoglycaemic guava-
Aloe vera beverage using stevia leaves extract and sorbitol
The suitability of preparing low calorie/hypoglycaemic guava-Aloe vera
drink was evaluated by replacing the sucrose with equivalent level of sweetness
obtained by using sorbitol or stevia leaves extract. The effect of addition of
69
different proportions of stevia leaves extract and sorbitol on the physico-chemical
and sensory attributes of the prepared products presented in Table 4.12 and 4.13
are explained as under:
4.5.1 Changes in biochemical attributes of hypoglycaemic guava-Aloe vera
beverage
As expected, with the increase in level of stevia leaves extract and sorbitol
to replace sucrose, the total soluble solids (TSS) contents in the resultant
beverage exhibited a consistent and significant decrease. The highest total soluble
solids was recorded in the beverage which contained 100 per cent sucrose (15ºB)
while the beverage prepared by using complete substitution with stevia leaves
extract registered the lowest TSS (2.46ºB). The drink prepared by using 50 per
cent replacement of sucrose with equivalent sweetness of stevia leaves extract
showed a TSS of 7.53ºB while the drink having 50 per cent replacement of
sucrose with sorbitol showed a TSS of 11.30ºB (Table 4.12). Thus, the drink
prepared by using stevia leaves extract exhibited lowest TSS than that of drink
containing sorbitol as sweetener. Low TSS in the drink, with corresponding low
total sugars is expected to impart lowest calories to the drink.
The titratable acidity and pH of the drink ranged between 0.31 to 0.33 per
cent and 3.45-3.49, respectively while ascorbic acid in these drinks containing
different proportions of sugar and non-nutritive sweeteners ranged between
16.62-19.65 mg/100g. The guava-Aloe vera drink containing stevia leaves extract
also showed appreciable presence of ascorbic acid. Thus, stevia leaves extract
besides imparting low calories was also capable of providing good amount of
vitamin C to the drink.
Further, with the increase in proportion of non-nutritive sweeteners in the
beverage and corresponding decrease in sucrose, the total sugar content in the
prepared drink registered a consistent decrease. The replacement of total sugars
with corresponding increase in stevia leaves extract are expected to impart
comparatively less calories, which serve the purpose of preparing low calories
(hypoglycaemic) beverage. The relative viscosity and specific gravity of the drink
varied between 1.07 to 1.60 and 1.031 to 1.086. The prepared drink by using
70
100% sucrose exhibited 1.36 relative viscosity and 1.086 specific gravity. The
relative viscosity of sorbitol sweetened beverage increased with increase in the
proportion of sorbitol in beverage and thus, addition of sorbitol in the beverage
caused increase in the relative viscosity of the beverage. The beverage containing
stevia leaves extract and sucrose registered higher specific gravity than that of the
sorbitol sweetened beverage.
Table 4.12. Effect of different proportions of non-nutritive sweeteners
(stevia leaves extract and sorbitol) on the chemical attributes
of hypoglycaemic guava-Aloe vera beverage*
Proportion
Su : St : So
TSS
(ºB )
Titratable
acidity
(%) CA
pH Total
sugars
( % )
Ascorbic
acid
(mg/100g)
Relative
viscosity
Specific
gravity
Energy
value
K cal/100g
T1 : 100 : 0 : 0 15.00 0.32 3.45
14.39
(3.79) 16.85 1.36 1.086 57.56
T2 : 75 : 25 : 0 11.40 0.32 3.47
8.46
(2.90) 16.67 1.25 1.066 33.84
T3 : 75 : 0 : 25 13.40 0.31 3.48
8.17
(2.85) 16.62 1.46 1.062 47.68
T4 : 50: 50 : 0 7.53 0.31 3.45
6.86
(2.61) 17.23 1.17 1.056 27.44
T5 : 50 : 0 : 50 11.30 0.32 3.46
6.02
(2.45) 16.85 1.50 1.054 54.08
T6 : 25 : 75 : 0 4.96 0.33 3.49
3.66
(1.91) 18.87 1.14 1.050 14.64
T7 : 25 : 0 : 75 7.50 0.32 3.47
3.17
(1.78) 16.68 1.54 1.044 57.68
T8 : 0 : 100 : 0 2.46 0.32 3.47
1.64
(1.28) 19.65 1.07 1.032 6.56
T9 : 0 : 0 : 100 5.23 0.33 3.46
1.41
(1.18) 16.68 1.60 1.031 65.64
Mean 8.75 0.32 3.47 5.97
(2.44) 17.35 1.34 1.051 -
CD 0.05 0.30 NS 0.01 0.01 0.03 0.04 0.03 -
Figures in parenthesis represent the square root transformed values.
* Guava-Aloe vera beverage prepared by using guava: Aloe vera in 15:5 proportion
Su-sucrose, St-stevia leaves extract, So-sorbitol
The energy value calculated on the basis of total sugars in the drink
ranged between 6.56 to 65.64 K cal/100g. The drink made by using 100 per cent
sucrose and stevia leaves extract registered lower calorie than sorbitol. Further,
the drink having 50 per cent substitution of stevia leaves extract or sorbitol had
comparatively lesser calories than that of drink having 100 per cent sucrose. Thus
stevia leaves extract sorbitol at 50 per cent can successfully be used for
preparation of low calorie (hypoglycaemic) beverage.
71
4.5.2 Changes in sensory attributes of hypoglycaemic guava-Aloe vera
beverage
The data (Table 4.13) pertaining to the effect on sensory attributes of
guava-Aloe vera beverage prepared by addition of non-nutritive sweetener viz.
stevia leaves extract and sorbitol by replacing equivalent amount of sucrose
presented in Table 4.13 are discussed as under:
4.5.2.1 Colour
The addition of stevia leaves extract as well as sorbitol to replace sucrose
in the guava-Aloe vera beverage brought about significant changes on sensory
colour acceptability score of the resultant beverage. The mean score for colour in
different beverages ranged 5.43 to 8.30 on a 9 point hedonic scale. The beverage
prepared by using 100 per cent sucrose had the maximum acceptability for
colour. With the addition of non-nutritive sweeteners in the drinks to replace
sucrose the colour score registered a consistent decrease. However, the score
remained more than 5.0 indicating that all the drinks were within acceptable
range with respect to appearance.
Further, the drink prepared by replacing 50 per cent sucrose with
equivalent proportions of sorbitol or stevia leaves extract were better than that of
drink containing more than 50 per cent non-nutritive sweeteners. The sensory
score for colour 50 per cent stevia leaves extract or sorbitol were recorded as 7.93
and 8.17 on a 9 point hedonic scale. However, the beverage prepared by
substituting stevia leaves extract beyond 50 per cent level exhibited reduced
liking for colour. Thus stevia leaves extract can be added in the drink only up to
50 per cent replacement level, beyond which it adversely affects the colour
acceptability.
4.5.2.2 Flavour/Aroma
Data presented in Table 4.13 indicate that the drink prepared by using
only sucrose had highest liking for flavour which decreased appreciably with the
increase in proportion of non-nutritive sweeteners. However, all drinks prepared
by substituting sucrose with either stevia leaves extract or sorbitol with up to 50
72
per cent level of substitution were at par with respect to flavour acceptability
score with a mean score ranging between 6.74 to 7.24. Thus all beverages were
within acceptable range.
Further, the drink prepared by replacing 50 per cent sucrose with
equivalent proportion of sorbitol or stevia leaves extract were significantly
superior to drinks which contained more than 50 per cent stevia leaves extract or
sorbitol. Thus, low calorie (hypoglycaemic) guava-Aloe vera beverage can be
prepared by replacing the quantity of sucrose up to 50 per cent by using stevia
leaves extract or sorbitol without affecting the sensory quality of the beverage
with respect to flavour.
Table 4.13. Effect of different proportions of non-nutritive sweeteners
(Stevia leaves extract and Sorbitol) on the sensory
characteristics (9 point hedonic scale) of guava-Aloe vera
beverage*
Proportion
Su : St : So Colour
Flavour
/aroma Taste Body
Over all
acceptability
T1 : 100 : 0 : 0 8.30 7.25 8.30 7.30 7.78
T2 : 75 : 25 : 0 8.18 7.15 7.01 7.15 7.37
T3 : 75 : 0 : 25 8.22 7.24 7.24 7.29 7.49
T4 : 50: 50 : 0 7.93 6.74 6.10 7.05 7.0
T5 : 50 : 0 : 50 8.17 7.24 6.29 7.65 7.33
T6 : 25 : 75 : 0 5.68 5.51 5.47 5.90 5.64
T7 : 25 : 0 : 75 7.10 7.24 6.24 7.13 6.73
T8 : 0 : 100 : 0 5.43 5.32 5.31 5.65 5.42
T9 : 0 : 0 : 100 7.00 7.23 6.25 7.00 6.25
CD 0.05 0.79 0.71 0.55 0.20 0.30
* Guava-Aloe vera beverage prepared by using guava: Aloe vera in 15:5 proportion.
Su-sucrose, St-stevia leaves extract, So-sorbitol
4.5.2.3 Taste
Sensory taste for hypoglycaemic guava-Aloe vera beverage varied from
5.31 to 8.30 on 9 point hedonic scale (Table 4.13). The beverage prepared by
using 100 per cent sucrose had the maximum acceptability for taste with a mean
73
score of 8.30. However, addition of non-nutritive sweetener in the beverage to
replace sucrose, the taste acceptability score registered a decrease. Among stevia
leaves extract sorbitol sweetened drink, the beverage containing stevia leaves
extract exhibited reduced liking due to bitter after taste.
However, the drinks prepared by replacing 50 per cent sucrose with
equivalent proportion of sorbitol were better than drinks containing more than 50
per cent stevia leaves extract in terms of taste. Thus, stevia leaves extract can be
added in the drink up to 50 per cent replacement level, beyond which, it
adversely affects the taste acceptability of the drink.
4.5.2.4 Body
The addition of stevia leaves extract as well as sorbitol to replace sucrose
exhibited significant changes on the sensory score for body of the prepared
beverage. The beverage prepared by using 100 per cent sucrose had maximum
liking with respect to body. With the addition of stevia leaves extract to replace
sucrose at equivalent level of sweetness, the body score of the beverage
registered a consistent decrease and the sorbitol sweetened drinks recorded
increase in body score with corresponding increase in sorbitol proportion.
4.5.2.5 Over all acceptability
The over all acceptability score for drinks prepared by using different
proportion of stevia leaves extract and sorbitol experienced slight decrease with
the increase in proportion of non-nutritive sweeteners. As expected, drink
prepared by using 100 per cent sucrose was ranked significantly superior in over
all acceptability followed by drink prepared by using 25 per cent and 50 per cent
level of substitution with either stevia leaves extract or sorbitol.
Further, guava-Aloe vera beverage containing up to 50 per cent
substitution with stevia leaves extract or sorbitol registered a mean score of 7.0-
7.49 which was significantly and at par with the beverage containing 100 per cent
sucrose. Thus, the proportion of sucrose in the low calorie guava-Aloe vera
beverage can be replaced by up to 50 per cent level of sweetness by stevia leaves
Plate 6. Hypoglycaemic guava-Aloe vera nectar/beverages containing
different sweeteners
74
extract or sorbitol without affecting the over all sensory quality of the prepared
beverage.
4.6 Changes in quality characteristics of hypoglycaemic guava-Aloe vera
beverage during storage
The hypoglycaemic guava-Aloe vera beverage prepared by substituting
the sweetness of sucrose with equivalent proportions of non-nutritive sweeteners
as per earlier experiments (Table 4.12 and 4.13) was packed hot in presterlized
200 ml capacity glass bottle followed by processing in boiling water for 25 min
and stored at ambient temperature (12-24ºC) to evaluate quality at periodic
intervals of 0, 90, and 180 days. The changes in physico-chemical as well as
sensory attributes during storage of the beverages presented in Tables 4.14 to
4.23 are explained as under.
4.6.1 Physico-chemical characteristics of hypoglycaemic guava-Aloe vera beverage during storage.
4.6.1.1 Total soluble solids
The mean total soluble solids (TSS) in different hypoglycaemic guava-
Aloe vera beverages during storage up to six months ranged between 8.75-8.96ºB.
The highest total soluble solids was found in beverage containing 100 per cent
sucrose (15ºB) while the beverage prepared by using complete substitution with
stevia leaves extract recorded minimum TSS (2.46ºB).
With the increase in period of storage, the total soluble solids in all the
beverages registered a consistent increase. Among different combinations the
beverages prepared by substituting with equivalent proportions of stevia leaves
extract exhibited the lowest total soluble solids at all intervals of storage up to
180 days. While the drink prepared by substituting sorbitol showed the total
soluble solids higher as compared to the drink which contained stevia but lower
than the drink which was made by using 100 per cent sucrose (Table 4.14). Thus,
the drink prepared by using 50 per cent substitution with stevia leaves extract
which registered 7.53ºB TSS, was considered optimum for the preparation of low
calorie guava-Aloe vera beverage.
75
Table 4.14. Effect of different proportions of non-nutritive sweeteners
(stevia leaves extract and sorbitol) on total soluble solids (ºB)
content of hypoglycaemic guava-Aloe vera beverage during
storage at ambient temperature (12-24ºC)
Storage intervals Proportion
Su : St : So 0 day 90 days 180 days Mean
T1 : 100 : 0 : 0 15.00 15.10 15.17 15.09
T2 : 75 : 25 : 0 11.40 11.50 11.77 11.56
T3 : 75 : 0 : 25 13.40 13.47 13.60 13.49
T4 : 50: 50 : 0 7.53 7.60 7.73 7.62
T5 : 50 : 0 : 50 11.30 11.43 11.50 11.41
T6 : 25 : 75 : 0 4.96 5.03 5.13 5.04
T7 : 25 : 0 : 75 7.50 7.63 7.76 7.63
T8 : 0 : 100 : 0 2.46 2.60 2.66 2.57
T9 : 0 : 0 : 100 5.23 5.26 5.30 5.26
Mean 8.75 8.83 8.96
CD 0.05 T = 0.16 S = 0.09 TXS = 0.28
Su-sucrose, St-stevia leaves extract, So-sorbitol
4.6.2 Titratable acidity
The presence of mean acid content ranging between 0.29-0.32 per cent
during entire period of storage indicate that level of acidity was appropriate to
have acceptable acid-sugar balance in the prepared beverages (Table 4.15).
Statistically, though the difference in added content of the beverage among
different combinations and storage interval was significant yet, the interaction
among the combinations and storage was not significant.
4.6.3 Ascorbic acid (mg/100g)
With the increase in period of storage, the ascorbic acid content in
hypoglycaemic guava-Aloe vera beverage experienced a slight decrease. The
mean value of ascorbic acid content in different beverages decreased from initial
level of 17.35 mg/100g to 16.60 mg/100g after 180 days of storage (Table 4.16).
However, the beverage prepared by substituting sucrose with varying proportions
of stevia leaves extract registered significantly higher level of ascorbic acid as
compared to the drink which contained sucrose or sorbitol as sweetener. After six
month of storage, the stevia leaves extract sweetened beverage with 50, 75 or 100
per cent substitution also registered higher values of ascorbic acid such as 17.03,
18.62 and 19.21 mg/100g, respectively. Thus, the drinks prepared by using stevia
76
leaves extract as sweetener not only served as low calorie beverage but are also a
good source of ascorbic acid.
Table 4.15. Effect of different proportions of non-nutritive sweeteners
(stevia leaves extract and sorbitol) on titratable acidity (%)
CA of hypoglycaemic guava-Aloe vera beverage during storage at ambient temperature (12-24ºC)
Storage intervals Proportion
Su : St : So 0 day 90 days 180 days Mean
T1 : 100 : 0 : 0 0.32 0.31 0.30 0.31
T2 : 75 : 25 : 0 0.32 0.31 0.31 0.31
T3 : 75 : 0 : 25 0.31 0.30 0.29 0.30
T4 : 50: 50 : 0 0.31 0.29 0.27 0.29
T5 : 50 : 0 : 50 0.32 0.30 0.28 0.30
T6 : 25 : 75 : 0 0.33 0.31 0.29 0.31
T7 : 25 : 0 : 75 0.32 0.31 0.30 0.31
T8 : 0 : 100 : 0 0.33 0.30 0.29 0.31
T9 : 0 : 0 : 100 0.33 0.29 0.28 0.30
Mean 0.32 0.30 0.29
CD 0.05 T = 0.01 S = 0.006 T x S = 0.02
Su-sucrose, St-stevia leaves extract, So-sorbitol
Table 4.16. Effect of different proportions of non-nutritive sweeteners
(stevia leaves extract and sorbitol) on ascorbic acid (mg/100g)
content of hypoglycaemic guava-Aloe vera beverage during storage at ambient temperature ( 12-24ºC)
Storage intervals Proportion Su : St : So 0 day 90 days 180 days Mean T
1 : 100 : 0 : 0 16.85 16.57 15.93 16.45
T2 : 75 : 25 : 0 16.67 16.41 15.85 16.31
T3 : 75 : 0 : 25 16.62 16.38 15.63 16.21
T4 : 50: 50 : 0 17.23 17.18 17.03 17.04
T5 : 50 : 0 : 50 16.68 16.47 15.81 16.38
T6 : 25 : 75 : 0 18.87 18.79 18.62 18.76
T7 : 25 : 0 : 75 16.68 16.46 15.81 16.31
T8 : 0 : 100 : 0 19.65 19.53 19.21 19.46
T9 : 0 : 0 : 100 16.68 16.13 15.82 16.21
Mean 17.35 17.11 16.60
CD 0.05 T = 0.16 S = 0.09 T x S = 0.19
Su-sucrose, St-stevia leaves extract, So-sorbitol
4.6.4 pH
With the increase in period of storage, the pH value of the beverage
registered a marginal but significant increase up to 180 days. The mean pH in low
calorie guava-Aloe vera beverages during storage varied from 3.47 to 3.51. At
77
different intervals of storage, pH of the drinks increased from initial value of
3.45-3.49 to 3.48-3.51 and 3.50-3.53 after 90 and 180 days of storage period,
respectively (Table 4.17). Data further revealed that though, the difference in pH
values in different combinations and storage intervals was significant yet the
interaction among treatments and storage intervals were non-significant.
4.6.5 Total sugars (%)
With the increase in proportion of non-nutritive sweeteners,
corresponding decrease in total sugar was registered. The drink prepared by using
different proportions of stevia leaves extract and sorbitol had total sugars varying
between 1.41 to 14.39 per cent at the start of storage period. The drink prepared
by using 100 per cent substitution with either stevia leaves extract or sorbitol
showed lowest amount of total sugar i.e. 1.64 and 1.41, respectively. After six
months of storage hypoglycaemic drinks caused a slight decrease in total sugar
content ranging between 1.35 to 13.80 per cent.
Table 4.17. Effect of different proportions of non-nutritive sweeteners
(stevia leaves extract and sorbitol) on pH content of
hypoglycaemic guava-Aloe vera beverage during storage at ambient temperature (12-24ºC)
Storage intervals Proportion Su : St : So 0 day 90 days 180 days Mean T
1 : 100 : 0 : 0 3.45 3.48 3.50 3.48
T2 : 75 : 25 : 0 3.47 3.49 3.51 3.49
T3 : 75 : 0 : 25 3.48 3.50 3.51 3.50
T4 : 50: 50 : 0 3.45 3.48 3.53 3.49
T5 : 50 : 0 : 50 3.46 3.49 3.50 3.48
T6 : 25 : 75 : 0 3.49 3.51 3.52 3.50
T7 : 25 : 0 : 75 3.47 3.48 3.52 3.49
T8 : 0 : 100 : 0 3.47 3.50 3.51 3.49
T9 : 0 : 0 : 100 3.46 3.48 3.51 3.48
Mean 3.47 3.49 3.51
CD 0.05 T = 0.01 S = 0.01 T x S = 0.03
Su-sucrose, St-stevia leaves extract, So-sorbitol
Further, the drink prepared by using 50 per cent stevia leaves extract or
50 per cent sorbitol recorded total sugar content of about 6.86 and 6.02 per cent
78
respectively, which decreased to 6.74 to 5.92 per cent after 180 days of storage
interval.
4.6.6 Relative viscosity
The addition of non-nutritive sweeteners affected the relative viscosity of
hypoglycaemic guava-Aloe vera drink, which ranged between 1.07 to 1.60 in
different combinations. The maximum relative viscosity of 1.60 was found in 100
per cent sorbitol sweetened drink, which decreased to 1.52 after 180 days of
storage. Further, the drink prepared by using sorbitol possessed higher viscosity
than stevia leaves extracts sweetened drink. Significant decrease in relative
viscosity was registered during storage up to 180 days.
Table 4.18. Effect of different proportions of non-nutritive sweeteners
(stevia leaves extract and sorbitol) on total sugars (%) content
of hypoglycaemic guava-Aloe vera beverage during storage at ambient temperature (12-24ºC)
Storage intervals Proportion
Su : St : So 0 day 90 days 180 days Mean T
1 : 100 : 0 : 0 14.39
(3.79) 13.85 (3.72)
13.80 (3.71)
14.01 (3.74)
T2 : 75 : 25 : 0 8.46
(2.90) 8.23
(2.86) 8.20
(2.86) 8.29
(2.87) T
3 : 75 : 0 : 25 8.17
(2.85) 8.10
(2.84) 8.02
(2.83) 8.10
(2.84)
T4 : 50: 50 : 0 6.86
(2.61) 6.82
(2.61) 6.74
(2.59) 6.81
(2.60) T
5 : 50 : 0 : 50 6.02
(2.45) 6.00
(2.44) 5. 92 (2.43)
6.01 (2.45)
T6 : 25 : 75 : 0 3.66
(1.91) 3.60
(1.89) 3.55
(1.88) 3.60
(1.89)
T7 : 25 : 0 : 75 3.17
(1.78) 3.11
(1.76) 3.10
( 1.76) 3.13
(1.76)
T8 : 0 : 100 : 0 1.64
(1.28) 1.57
(1.25) 1.48
(1.22) 1.56
(1.25)
T9 : 0 : 0 : 100 1.41
(1.18) 1.39
(1.17) 1.35
(1.16) 1.38
(1.17)
Mean 5.97 (2.44)
5.85 (2.41)
5.78 (2.40)
Figures: Parenthesis represents the arc transformed values
CD 0.05 T = 0.01 S = 0.07 T x S = NS
Su-sucrose, St-stevia leaves extract, So-sorbitol
79
Similarly , the drink prepared by using 50 per cent stevia leaves extract or
sorbitol had 1.17 and 1.50 relative viscosities respectively which decreased to
1.13 and 1.44 after six months of storage. The interaction between combinations
and storage period were found non-significant.
4.6.7 Specific gravity
The data pertaining to specific gravity also reflected slight increase in
specific gravity of hypoglycaemic guava-Aloe vera drink during 180 days of
storage. Mean specific gravity of different combination of drinks increased from
1.031 to 1.068 which increased from 1.044 to 1.082, respectively after 180 days
of storage.
<
Table 4.19. Effect of different proportions of non-nutritive sweeteners
(stevia leaves extract and sorbitol) on relative viscosity of
hypoglycaemic guava- Aloe vera beverage during storage at ambient temperature (12-24ºC)
Storage intervals Proportion Su : St : So 0 day 90 days 180 days Mean T
1 : 100 : 0 : 0 1.36 1.34 1.33 1.34
T2 : 75 : 25 : 0 1.25 1.24 1.23 1.24
T3 : 75 : 0 : 25 1.46 1.45 1.43 1.44
T4 : 50: 50 : 0 1.17 1.15 1.13 1.15
1T5 : 50 : 0 : 50 1.50 1.46 1.44 1.47
T6 : 25 : 75 : 0 1.14 1.08 1.06 1.09
T7 : 25 : 0 : 75 1.54 1.51 1.50 1.52
T8 : 0 : 100 : 0 1.07 1.03 1.02 1.04
T9 : 0 : 0 : 100 1.60 1.54 1.52 1.55
Mean 1.34 1.31 1.30
CD 0.05 T= 0.03 S= 0.02 TXS= 0.06
Su-sucrose, St-stevia leaves extract, So-sorbitol
Further, the drinks prepared by using 100 per cent stevia leaves extract or
sorbitol registered a specific gravity of 1.032 and 1.031 which increased to 1.045
and 1.044 respectively after 180 days of storage interval.
4.6.2 Changes in sensory attributes of hypoglycaemic guava-Aloe vera
beverage during storage
Changes in sensory quality of hypoglycaemic guava-Aloe vera beverage
were evaluated during storage at ambient temperature for 0, 90 and 180 days for
various attributes viz colour, flavour, taste, body and over all acceptability.
80
Table 4.20. Effect of different proportions of non-nutritive sweeteners
(stevia leaves extract and sorbitol) on specific gravity of
hypoglycaemic guava-Aloe vera beverage during storage at
ambient temperature ( 12-24ºC)
Storage intervals Proportion Su : St : So 0 day 90 days 180 days Mean
T1 : 100 : 0 : 0 1.068 1.071 1.082 1.073
T2 : 75 : 25 : 0 1.064 1.068 1.077 1.069
T3 : 75 : 0 : 25 1.062 1.064 1.072 1.066
T4 : 50: 50 : 0 1.056 1.075 1.097 1.076
T5 : 50 : 0 : 50 1.054 1.060 1.072 1.062
T6 : 25 : 75 : 0 1.050 1.055 1.063 1.056
T7 : 25 : 0 : 75 1.044 1.049 1.058 1.050
T8 : 0 : 100 : 0 1.032 1.039 1.045 1.039
T9 : 0 : 0 : 100 1.031 1.036 1.044 1.037
Mean 1.051 1.057 1.068
CD 0.05 T = 0.04 S = 0.02 T x S = 0.06
Su-sucrose, St-stevia leaves extract, So-sorbitol
4.6.2.1 Colour
Sensory evaluation of hypoglycaemic guava-Aloe vera beverage indicated
that the addition of non-nutritive sweeteners significantly influenced the colour
acceptability score of beverage. With the increase in proportion of non-nutritive
sweeteners, the colour acceptability score decreased. The mean score for colour
in different beverages ranged during storage between 6.07 to 8.14 on a 9 point
hedonic scale. The beverage prepared by using 100 per cent sucrose had
maximum acceptability for colour (8.30) which decreased after 180 days of
storage to 7.72 (Table 4.21). The colour acceptability score registered a
consistent decrease after 180 days of storage interval. However, the mean score
remained more than 5.0. Thus, indicating the acceptability of the drink for colour.
Further, the drinks prepared by replacing 50 per cent sucrose with stevia
leaves extract or sorbitol were exhibited higher acceptability than that of which
contained more than 50 non-nutritive sweeteners (stevia leaves extract or
sorbitol).
81
4.6.2.3 Flavour
The data presented in Table 4.21 indicate that the flavour ratings of the
drinks prepared by using non-nutritive sweeteners were almost similar to drinks
prepared by using 100 per cent sucrose, except for drinks prepared by using 75
and 100 per cent stevia leaves extract sweetened beverages. The lower liking for
the drink containing more than 50 per cent stevia leaves extract sweetened
beverages might be attributed to the raw flavour imparted by stevia leaves
extract. Further, with the increase in period of storage, the flavour rating of
beverages made from non-nutritive sweeteners decreased consistently. The
interaction between combinations and storage however, remained non-significant.
Table 4.21. Effect of different proportions of non-nutritive sweeteners
(stevia leaves extract and sorbitol) on sensory colour and
flavour acceptability score (9 point hedonic scale) of
hypoglycaemic guava- Aloe vera beverage during storage at ambient temperature ( 12-24ºC)
Colour Flavour Proportion
Su :St: So 0 day 90
days
180
days
Mean 0 day 90
days
180
days
Mean
T1 : 100 : 0 : 0 8.30 8.25 7.72 8.09 7.25 7.22 7.20 7.22
T2 : 75 : 25 : 0 8.18 8.01 7.11 7.77 7.15 7.12 7.09 7.12
T3 : 75 : 0 : 25 8.22 8.15 8.07 8.14 7.24 7.20 7.19 7.20
T4 : 50: 50 : 0 7.93 7.86 7.78 7.85 6.74 6.70 6.67 6.70
T5 : 50 : 0 : 50 8.17 7.91 7.80 7.96 7.24 7.21 7.17 7.20
T6 : 25 : 75 : 0 5.68 6.59 6.41 6.22 5.51 5.46 5.42 5.46
T7 : 25 : 0 : 75 7.10 7.04 6.93 7.02 6.48 6.42 6.57 6.49
T8 : 0 : 100 : 0 5.43 6.43 6.35 6.07 5.32 5.29 5.24 5.28
T9 : 0 : 0 : 100 7.00 6.93 6.84 6.92 6.23 5.97 5.89 6.03
Mean 7.37 7.53 7.21 6.57 6.51 6.49
CD0.05
T 0.08 0.03
S 0.04 0.01
TxS 0.14 0.04
Su-sucrose, St-stevia leaves extract, So-sorbitol
4.6.2.4 Taste
Sensory evaluation of beverage (Table 4.22) indicated that drinks
prepared by using non-nutritive sweeteners had almost same liking for taste than
that of 100 per cent sucrose sweetened drinks except those prepared by using
more than 50 per cent stevia leaves extract. As such, the drink prepared by using
100 per cent sucrose was ranked higher than the other combinations. However,
82
sensory score of drinks made by using non-nutritive sweeteners increased
consistently during storage upto180 days. The sensory score for taste ranging
between 5.31 to 8.30 at the start of storage which increases to 5.52 to 8.45 after
180 days of storage.
Further, the drinks prepared by using 50 per cent replacement of sucrose
with equivalent sweetness imparted by stevia leaves extract and sorbitol
exhibiting a mean score of 6.23 and 6.37 during six month storage was
considered optimum for preparation of low calorie products. Thus, it can be
concluded that 50 per cent stevia leaves extract can be used for preparation of
hypoglycaemic guava-Aloe vera beverages.
Table 4.22. Effect of different proportions of non-nutritive sweeteners
(stevia leaves extract and sorbitol) on sensory taste and body
score (9 point hedonic scale) of hypoglycaemic guava- Aloe
vera beverage during storage at ambient temperature ( 12-24ºC)
Taste Body Proportion
Su :St : So 0 day 90 days 180 days Mean 0 day 90 days 180 days Mean
T1 : 100 : 0 : 0 8.30 8.39 8.45 8.38 7.30 7.29 7.27 7.62
T2 : 75 : 25 : 0 7.01 7.12 7.19 7.10 7.15 7.12 7.09 7.45
T3 : 75 : 0 : 25 7.24 7.33 7.38 7.31 7.38 7.35 7.29 7.67
T4 : 50: 50 : 0 6.10 6.27 6.34 6.23 7.11 7.06 7.05 7.07
T5 : 50 : 0 : 50 6.29 6.38 6.44 6.37 7.79 7.73 7.65 7.72
T6 : 25 : 75 : 0 5.47 5.52 5.59 5.52 5.99 5.96 5.90 5.95
T7 : 25 : 0 : 75 6.24 6.34 6.37 6.31 7.19 7.15 7.13 7.16
T8 : 0 : 100 : 0 5.31 5.46 5.52 5.43 5.73 5.69 5.65 5.69
T9 : 0 : 0 : 100 6.25 6.32 6.38 6.31 6.18 6.09 6.09 6.09
Mean 6.49 6.60 6.60 6.99 6.70 6.73
CD0.05
T 0.02 0.01
S 0.01 0.01
TxS 0.04 0.02
Su-sucrose, St-stevia leaves extract, So-sorbitol
4.6.2.5 Body
The addition of stevia leaves extract as well as sorbitol to replace sucrose
brought about significant changes on sensory body score during storage. The
beverage containing 100 per cent sucrose and 75 per cent sucrose exhibited
highest body score which decreased during storage. With increase in storage
83
interval a consistent decrease in body score was observed in the combinations.
However, the drink prepared by using 50 per cent stevia leaves extract or sorbitol
exhibited 7.05 and 7.65 body scores, respectively after 180 days on 9 point
hedonic scale. Thus, indicating good liking even after six month of storage.
4.6.2.6 Over all acceptability
The sensory evaluation for overall acceptance of the drinks indicated
that the beverages prepared by using different combinations of non-nutritive
sweeteners remained acceptable which contained up to six month of storage
period except beverage which contained stevia leaves extract more than 50 per
cent.
Table 4.23. Effect of different proportions of non-nutritive sweeteners
(stevia leaves extract and sorbitol) on over all acceptability
score (9 point hedonic scale) of hypoglycaemic guava- Aloe
vera beverage during storage at ambient temperature ( 12-24ºC)
Over all acceptability Proportion
Su: St : So 0 day 90 days 180 days Mean
T1 : 100 : 0 : 0 7.78 7.72 7.68 7.72
T2 : 75 : 25 : 0 7.37 7.33 7.27 7.32
T3 : 75 : 0 : 25 7.49 7.36 7.31 7.38
T4 : 50: 50 : 0 7.00 6.92 6.72 6.88
T5 : 50 : 0 : 50 7.33 7.27 7.26 7.28
T6 : 25 : 75 : 0 5.64 5.60 5.56 5.60
T7 : 25 : 0 : 75 6.73 6.70 6.68 6.70
T8 : 0 : 100 : 0 5.42 5.35 5.31 5.36
T9 : 0 : 0 : 100 6.25 6.19 6.12 6.18
Mean 6.77 6.71 6.65
CD 0.05 T = 0.03 S = 0.02 T x S = 0.04
Su-sucrose, St-stevia leaves extract, So-sorbitol
Although, the over all acceptability of the prepared beverages declined
during storage, yet the beverages sweetened with 50 per cent stevia leaves extract
or sorbitol retained their sensory quality to an appreciable extent. This study
therefore, signifies that 50 per cent level of sucrose can be replaced by non-
nutritive sweeteners to prepare hypoglycaemic guava-Aloe vera beverage.
84
4.7 Energy value of hypoglycaemic guava-Aloe vera fruit beverage.
Energy value of the drink was calculated by taking into account the level
of total sugar present in the drink. Similarly, energy value of the sorbitol
sweetened beverage was calculated on the basis of energy provided by sorbitol.
The figures were expressed as K cal/100g. The data presented in Table 4.24
indicate that energy values of hypoglycaemic guava-Aloe vera beverages ranged
between 6.56 K cal/100g to 65.64 K cal/100g. Maximum energy value of 65.64
K cal/100g was recorded in 100 per cent sorbitol sweetened hypoglycaemic
guava-Aloe vera beverage and minimum in 100 per cent stevia leaves extract
sweetened hypoglycaemic guava-Aloe vera beverage, which decreased to 65.40
K cal/100g and 5.92 K cal/100g, respectively after storage of 180 days. The
decrease in energy value during storage may be attributed to decrease in total
sugars. Substitution of sucrose with 50 per cent stevia leaves extract brought
about substantial reduction in energy value of the drink (27.44 K cal/100g against
57.68 K cal/100g in sucrose sweetened beverage), which is desirable parameter
for development of low calorie beverage. Thus, use of 50 per cent stevia leaves
extract was optimized for the preparation of hypoglycaemic guava-Aloe vera
beverage.
Table 4.24. Effect of different proportions of non-nutritive sweeteners on
calculated energy value (K cal /100 g) of hypoglycaemic guava-
Aloe vera beverage
Calculated energy value (K cal /100 g) Proportion
Su : St : So 0day 90 days 180 days
T1 : 100 : 0 : 0 57.56 55.40 55.20
T2 : 75 : 25 : 0 33.84 32.92 32.80
T3 : 75 : 0 : 25 47.68 47.40 45.96
T4 : 50: 50 : 0 27.44 27.28 26.96
T5 : 50 : 0 : 50 54.08 54.00 53.68
T6 : 25 : 75 : 0 14.64 14.40 14.20
T7 : 25 : 0 : 75 57.68 57.44 57.40
T8 : 0 : 100 : 25 6.56 6.28 5.92
T9 : 0 : 0 : 100 65.64 65.56 65.40
Su-sucrose, St-stevia leaves extract, So-sorbitol
85
4.8 Cost of production of non-nutritive sweeteners on energy value of
hypoglycaemic guava-Aloe vera beverage
Cost incurred in preparation of guava-Aloe vera beverage was calculated
by taking into consideration the cost of all the inputs and the cost involved during
processing. The comparative cost of production of beverage prepared by using
either 100 per cent sucrose or stevia leaves extract and sucrose (50:50) or sorbitol
and sucrose sweetened (50:50) beverage is presented in Table 4.25. The cost was
calculated on the basis of current market prices of ingredients and adding
processing charges as well as profits @ 20 per cent each.
Table 4.25. Cost of production of hypoglycaemic guava-Aloe vera beverage*
Sucrose
(100%)
Stevia leaves
extract (50%)
Sorbitol
(50%) Particulars
Rate
(Rs.) Qty
Amt
(Rs.) Qty
Amt
(Rs.) Qty
Amt
(Rs.)
Guava pulp (Rs/lt.) 30.00 1000 ml 30.00 1000 ml 30.00 1000 ml 30.00
Aloe vera leaves extract
(Rs/lt.) 19.00 500 9.50 500 9.50 500 9.50
Sugar (Rs/Kg.) 40.00 746 29.84 373 15.00 373 15.00
Stevia leaves extract
(Rs/lt.) 3.00 - - 1865 ml 5.59 -
Sorbitol (Rs/lt.) 244.00 - - - - 746 ml 182.00
Citric acid (Rs/kg.) 420 40 16.80 40 16.80 40 16.80
Glass bottle ((Rs/200ml) 3.00 50 150.00 50 150.00 50 150.00
Crown corks (Rs/unit) 1.00 50 50.00 50 50.00 50 50.00
Label (Rs/unit) 0.50 50 25.00 50 25.00 50 25.00
Total Cost of ingredient
(Rs.) 311.14 301.89 478.30
Processing cost@20% 62.22 60.37 95.66
Total 373.36 362.26 573.96
Profit @ 20 % 74.67 72.45 114.79
Total cost of cost product 448.03 434.71 688.75
Total yield (lt.) 10.0 10.0 10.0
Sale Price per lt
(Rs.200 ml bottle )
44.87
(8.97)
43.71
(8.69)
68.87
(13.77)
* Guava-Aloe vera beverage contained either per cent sucrose, stevia leaves extract: sucrose
(50:50) and sorbitol: sucrose (50:50)
The cost per unit of guava-Aloe vera beverage was found lowest (Rs.8.69
/200 ml bottle) when prepared by using 50 per cent sucrose and 50 per cent
stevia leaves extract followed by drink containing 100 per cent sucrose (Rs
8.97/200 ml bottle). While the cost of sorbitol sweetened beverage (50% sucrose
86
and 50% sorbitol) was the highest Rs.13.77/200 ml bottle amongst all other
combination. Thus, the stevia leaves extract sweetened beverage (stevia leaves
extract and sucrose 50:50) was also found to be quite more appreciable and cost
effective.
4.9 Standardization of a method for preparation of guava-Aloe vera
fruits bars
Suitability of incorporation of Aloe vera gel extract in guava-Aloe vera
fruit bar was evaluated. Guava-Aloe vera fruit bar was prepared by mixing 45 per
cent fruit pulp and 55 per cent sucrose and heated till a TSS of 40ºB was attained.
The whole mass was dried in mechanical dehydrator (55+2ºC) to a final moisture
content of 15-20 per cent. The level of guava pulp was replaced by using Aloe
vera gel extract in the ratios of 100:0, 80:20, 70:30, 60:40 and 50:50. The
proportion of Aloe vera gel at which the fruit bar remained acceptable on the
basis of sensory quality was considered optimum. The drying characteristics of
fruit as well as physico-chemical and sensory attributes of the products presented
in Table 4.26 and 4.27 are explained as under:-
4.9.1 Drying characteristics of guava-Aloe vera fruit bar
Observation regarding the dehydration of fruit bars in mechanical
dehydrator (55+2 ºC) revealed that it took 10-12 hrs to attain a moisture content
of 15-20 per cent in different proportions of guava and Aloe vera (Fig.4.7). Rate
of dehydration was very fast within initial period of drying, as 50 per cent of
moisture was lost during 6-7 hrs of drying. Thereafter, rate of drying slowed
down.
4.9.2 Physico-chemical attributes of guava-Aloe vera fruit bars
Data in Table 4.26 indicate that total soluble solids in fruit bar prepared
by using different proportions of guava and aloe vera gel extract ranged between
67.90 to 68.30ºB. The titratable acidity and pH of fruit bars ranged between 1.49
to 1.53 per cent and 2.28 to 2.35. The fruit bar prepared by using 90 per cent
guava and 10 per cent Aloe vera gel extract contained total soluble solids of
68.20ºB, acidity of 1.51 per cent and pH of 2.30, respectively. The total sugars
87
present in fruit bar ranged between 55.7 to 57.4 per cent and the fruit bar
prepared by using 90 per cent guava pulp and 10 per cent Aloe vera gel extract
was recorded 57.5 per cent.
With the decrease in proportion of guava pulp and corresponding increase
in Aloe vera gel extract, the ascorbic acid contents in the fruit bar registered a
decrease from 215.2 mg/100g to 70.2 mg/100g. However, the fruit bar prepared
by using 90 per cent guava and 10 per cent Aloe vera gel extract showed an
ascorbic acid level of 186.0mg/100g, which was significantly higher than that of
fruit bars prepared by using other combinations of guava pulp and Aloe vera gel
extract.
Table 4.26. Effect of addition of Aloe vera gel extract on the chemical
attributes of guava-Aloe vera fruit bar
Proportion of guava
pulp and Aloe vera
gel extract
TSS 0
B
Titratable
acidity %
Ascorbic
acid
mg/100g
Total
sugars
%
pH Total
solids %
Moisture
content %
T1: 100:0 68.00 1.49 215.2 57.4 2.35 82.5 17.5
T2: 90:10 68.20 1.51 186.0 57.5 2.30 82.5 17.5
T3: 80:20 67.90 1.50 167.7 56.4 2.32 82.6 17.4
T4: 70:30 68.30 1.49 147.7 55.8 2.35 82.5 17.5
T5: 60:40 68.20 1.50 113.1 55.7 2.32 82.4 17.6
T6: 50:50 68.30 1.53 70.2 56.4 2.28 82.6 17.4
CD0.05
2.65 0.03 3.16 2.52 0.04 0.03 0.05
The moisture content and total solids of the fruit bar varied between 17.4
per cent to 17.6 per cent and 82.4 per cent to 82.6 per cent respectively. Thus,
addition of Aloe vera gel extract in guava pulp exerted a significant effect on the
ascorbic acid content. While all other parameters were not appreciably altered.
However, to incorporate Aloe vera in fruit bar up to 10 per cent can be
considered.
4.9.3 Sensory evaluation of guava-Aloe vera fruit bars
The data pertaining to the effect of addition of Aloe vera gel extract in
varying proportions on sensory quality of guava-Aloe vera fruit bar presented in
Table 4.27 are explained as under :-
Plate 7. Guava-Aloe vera fruit bars using different
proportion of guava and Aloe vera
Guava-Aloe vera fruit bar
(90:10)
88
Table 4.27. Effect of addition of Aloe vera gel extract on sensory attributes
(9 point hedonic scale) of guava-Aloe vera fruit bars
Proportion of guava
pulp and Aloe vera
extract
Colour Taste Flavour/ Aroma
Texture Over all acceptability
T1: 100:0 8.4 8.6 7.5 7.9 8.0
T2: 90:10 7.9 7.7 7.2 7.5 7.7
T3: 80:20 6.6 6.5 6.3 6.9 6.6
T4: 70:30 5.7 5.7 6.0 6.4 5.9
T5: 60:40 4.9 3.9 5.7 5.6 4.9
T6: 50:50 3.5 3.7 3.6 3.9 3.5
CD 0.05 1.08 1.27 0.72 1.27 0.81
4.9.3.1 Colour
The colour acceptability score in fruit bars prepared by using different
proportions of guava and Aloe vera gel extract ranged between 3.5 to 8.4 with the
highest score recorded in 100 per cent guava fruit bar (8.4). The addition of Aloe
vera to the guava pulp brought about a significant reduction in colour
acceptability of the prepared fruit bar. However, substitution up to 10 per cent
Aloe vera with corresponding reduction in guava pulp was found statistically at
par (mean score 7.9) with the 100 per cent guava fruit bar. Thus, on the basis of
sensory colour score and keeping in view the functional values of Aloe vera, the
proportion of 10 per cent of Aloe vera in guava-Aloe vera fruit bar was optimized
in comparison to other combinations.
4.9.3.2 Taste
The mean acceptability score for taste of guava-Aloe vera fruit bar
prepared by using different proportions of guava-pulp and Aloe vera gel extracted
ranged between 3.7 to 8.6. The fruit bar containing 100 per cent guava pulp had a
highest acceptability for taste (8.6). With the substitution of Aloe vera, the taste
score of the resultant bar experienced a consistent decrease. The fruit bars
prepared by substituting Aloe vera extract up to 40-50 per cent were
characterized as having bitter after taste and were rated unacceptable with mean
taste scores of 3.9 and 3.7, respectively on 9 point hedonic scale. However, the
fruit bars prepared by adding 10 per cent and 20 per cent Aloe gel extract in
89
guava pulp were rated superior in taste and statistically at par with pure guava
pulp based fruit bar. Thus, on the basis of acceptability of the fruit bar for taste,
Aloe vera gel extract can be added to the guava fruit pulp up to the level of 10-20
per cent which was considered appropriate to prepare guava-Aloe vera fruit bars.
4.9.3.3 Flavour /aroma
The flavour score in fruit bar containing different proportions of guava
and Aloe vera gel extract ranged between 3.6-7.5, with the maximum liking
found in fruit bar having 100 per cent guava pulp (7.5). The addition of Aloe
vera gel extract to the guava pulp brought about a significant reduction in flavour
score of prepared fruit bar. However, substitution up to 10-30 per cent Aloe vera
with corresponding reduction in pulp was found within acceptable range with a
mean score of 6.3-7.5 (more than 6.0). Thus, the product having 90 per cent
guava and 10 per cent Aloe vera was found suitable for preparation of guava-Aloe
vera hypoglycaemic fruit bar.
4.9.3.4 Texture
The texture acceptability score in fruit bar containing using different
proportions of guava and Aloe vera gel extract were ranged between 3.9-7.9, with
the maximum liking found in fruit bar having 100 per cent pulp (7.9). The
addition of Aloe vera gel extract to the guava pulp brought about a significant
reduction in texture acceptability score of prepared fruit bar. However,
substitution up to 10-30 per cent Aloe vera with corresponding reduction in pulp
was found within acceptable range with a mean score of 6.4-7.5 (more than 6.0).
Thus, on the basis of sensory texture score and keeping in view the functional
values of Aloe vera, the product having 90:10 and 80:20 guava-Aloe vera
proportions were optimized in comparison to others.
4.9.3.5 Over all acceptability
Sensory score for overall acceptability significantly decreased with
corresponding increase in percentage of Aloe vera in fruit bars. The overall
acceptability score was highest in fruit bar having 100 per cent guava pulp which
was significantly at par with a fruit bar prepared by using 90 per cent guava and
90
10 per cent Aloe vera gel extract. Addition of Aloe vera gel extract beyond 20 per
cent made the resultant product unacceptable with respect to over all
acceptability.
Conclusively, the hypoglycaemic guava-Aloe vera fruit bar was prepared
by taking into account the beneficial effect of Aloe vera and it was found that
the combinations having 90 per cent guava and 10 per cent Aloe vera was
accepted by panelists over other combinations. Thus, the product having 90 per
cent guava and 10 per cent Aloe vera was found suitable for preparation of
guava-Aloe vera hypoglycaemic fruit bar.
4.10 Standardization of formulation for preparation of hypoglycaemic
guava-Aloe vera fruit bar
The recipe of preparation of low calories (hypoglycaemic) guava-Aloe
vera fruit bar was optimized by replacing cane sugar (sucrose) in pre-
standardized guava-Aloe vera fruit bar and was evaluated by substituting the
sweetness of sucrose with equivalent proportions of stevia leaves extract and
saccharin. Optimized proportion of guava and Aloe vera consisted 90 and 10 per
cent, respectively. Further, in order to improve texture and nutritional quality of
the product, the effect of addition of apple pomace as well as oat bran @10 per
cent as bulking agent were also evaluated. The fruit bars prepared by using non-
nutritive sweeteners have been referred to as low calorie as hypoglycaemic fruit
bars. The results of the study presented in Table 4.28 and 4.29 are explained as
under:-
4.10.1 Effect of dehydration on hypoglycaemic guava-Aloe vera fruit bar
Perusal of observations regarding the dehydration of hypoglycaemic fruit
bars (prepared by using non-nutritive sweeteners) revealed that it took around 16-
18 hours to dry it to a moisture content of 15-20 per cent in different non-
nutritive and bulking agents combinations (Fig. 4.10). Similarly, as in case of
different fruit bar combinations, rate of dehydration of fruit bars containing 50
per cent substitution of sucrose with stevia leaves extract or saccharin along with
10 per cent each of apple pomace and oat bran. Rate of dehydration was very fast
91
during initial period of drying, as 50 per cent of moisture was lost during 6-7
hours of drying. Thereafter, rate of drying slowed downed.
4.10.2 Changes in physico-chemical characteristics of hypoglycaemic guava-
Aloe vera fruit bar using non-nutritive sweeteners
With the addition of stevia leaves extract and saccharin and corresponding
decrease in proportion of sucrose, the resultant guava-Aloe vera fruit bar
exhibited a constant and significant reduction in its total soluble solids (TSS).
The fruit bar containing 100 per cent sucrose had TSS of 67.9ºB, which was
significantly reduced to 16.2 and 16.6ºB when fruit bars were prepared by using
100 per cent substitution of either stevia leaves extract or saccharin.
Further, substitution of sucrose with 25, 50 and 75 per cent proportions of
non-nutritive sweeteners viz. stevia leaves extract and saccharin significantly
lowered down the TSS of the fruit bars to 51.1-17.1ºB and 51.4-17.6
ºB
respectively, from its initial value of 67.9ºB when 100 per cent sucrose was used
as a sweetener. Thus, use of stevia leaves extract as well as saccharin were
effective in lowering down the TSS content to prepare a low calorie guava-Aloe
vera fruit bar. Further, addition of apple pomace or oat bran did not bring about
any appreciable effect on the total soluble solids of prepared fruit bars.
The ascorbic acid content in the guava-Aloe vera fruit bar ranged between
176.0-180.6 mg/100g.The addition of non-nutritive sweeteners as well as bulking
agent did not exert any appreciable effect on the ascorbic acid contents of the
hypoglycaemic guava-Aloe vera fruit bars. The titratable acidity and pH of
guava-Aloe vera fruit bars varied between 1.43 to 1.52 per cent and 2.62 to 2.87,
respectively.
With the increase in proportion of non-nutritive sweeteners in the fruit
bars to replace sucrose corresponding decrease in sugar content of the prepared
product was observed (Table 4.28). The total sugar content in the fruit bar
containing different forms of sweetness ranged between 10.5 to 59.8 per cent.
The fruit bar prepared by using 100 per cent sucrose showed highest amount of
total sugars (59.8%), while the product having 100 per cent substitution with
saccharin or stevia leaves extract exhibited the lowest amount of total sugars i.e.
92
10.5 and 10.8 per cent respectively. Further, the fruit bars containing 20, 50 and
75 per cent sucrose substitution with stevia or saccharin registered total sugars of
45.2-45.5 per cent, 24.2-24.4 per cent and 11.5-11.7 per cent respectively. Thus,
the fruit bar registering low amount of total sugars are expected to impart
comparatively lesser calories, to serve the purpose of preparing low calories
(hypoglycaemic) fruit bar.
Table 4.28. Effect of addition of non-nutritive sweeteners (stevia leaves
extract and saccharin) on chemical attributes of
hypoglycaemic guava- Aloe vera fruit bar*
Proportion
Su:St:Sa : Ap : Ot
TSS
0
B
Ascorbic
acid
mg/100g
Titratable
acidity %
pH Total
sugars
%
Total
solid
%
Moisture
content
%
Water
activity
Energy
value
K cal/100g
T1:100 :0: 0:0 67.9
176.0 1.50 2.62 59.8
(50.6)
82.5 17.5
0.54 239.4
T2: 0 :100 : 0:0 16.2
177.5 1.47 2.68 10.8
(10.9)
82.7
17.3
0.54 41.2
T3 :0 : 0 :100:0 16.6
176.5 1.52 2.67 10.5
(19.7)
82.9
17.1
0.51 42.0
T4 : 75 : 25 : 0 :10:0 51.1
177.5 1.43 2.87 45.5
(42.5)
82.9
17.1
0.56 182.0
T5 : 75 : 25: 0 : 0 :10 51.4
177.6 1.50 2.56 45.5
(42.4)
82.9
17.1
0.56 182 .2
T6 : 75 : 0:25 : 10 : 0 51.4
176.7 1.47 2.68 45.2
(44.2)
82.9
17.1
0.57 181.1
T7 : 75 : 0:25 : 0 : 10 51.9
177.9 1.48 2.64 45.2
(42.2)
82.9
17.1
0.61 181.0
T8 : 50: 50 : 0 :10 : 0 34.2
177.7 1.43 2.87 24.2
(29.5)
83.0
17.1
0.56 97.0
T9 : 50: 50 : 0 : 0 : 10 34.5
176.9 1.44 2.76 24.2
(29.5)
82.8
17.2
0.53 97.0
T10
: 50 : 0 : 50 : 10 : 0 34.4
178.9 1.45 2.65 24.3
(29.6)
82.8
17.2
0.59 97.4
T11
: 50: 0 : 50 : 10 : 0 34.8
177.8 1.47 2.66 24.45
(29.6)
82.8
17.2
0.58 97.8
T12
: 25 : 75 : 0: 10:0 17.07
180.6 1.45 2.67 11.5
(19.8)
83.2
16.8
0.47 46.2
T13
: 25 : 75 : 0 : 0 :10 17.5
179.6 1.46 2.67 11.5
(19.8)
83.2
16.8
0.51 47.2
T14
: 25: 0 : 75 : 10 : 0 17.6
178.6 1.43 2.62 11.7
(19.8)
83.3
16.7
0.35 47.1
T15
: 25 : 0 : 75 : 0 : 10 17.9
177.9 1.45 2.72 11.7
(19.8)
82.9
17.1
0.49 47.0
Mean 39.91 177.9 1.47 2.69 32.3
(33.8)
82.9
17.1
0.53 92.5
CD 0.05 0.03 0.36 0.04 0.41 0.72 0.02 0.04 0.04 -
Figures in parenthesis represent the arc transformed values.
*The fruit bars prepared by using 90% guava pulp and 10% Aloe vera gel extract
Su-sucrose, St-stevia leaves extract leaves extract, Sa-saccharin, Ap- Apple pomace, Ot -oat bran
93
The moisture content in fruit bars ranged between 16.7 to 17.5 per cent
with the highest value recorded in the fruit bar prepared by using 100 per cent
sucrose. Similarly the total solid contents in hypoglycaemic guava-Aloe vera fruit
ranged between 82.5 to 83.3 per cent. Addition of apple pomace and oat bran did
not appreciable change in moisture and total solid contents of the fruit bars. The
fruit bars having 50 per cent and 75 per cent replacement of sucrose with
equivalent sweetness of stevia leaves extract or saccharin exhibited moisture
contents of 17.1-17.2 per cent. The water activity in fruit bars containing different
forms of sweetness ranged 0.35 to 0.61.
The energy values calculated on the basis of presence of total sugars in
the drink ranged between 41.2 to 239.4 K cal/100g. This exhibiting about 52 per
cent reduction in energy value for 100 per cent sweetened sucrose beverage. The
fruit bars prepared by using 100 per cent replacement of sucrose with stevia
leaves extract or saccharin registered the lowest amounts of calories. The fruit
bars prepared by replacing 25, 50 and 75 per cent sucrose with stevia or saccharin
had energy values of 181.0-182.2, 97.0-97.8 and 46.2-47.2 K cal/100g,
respectively. Whereas, 100 per cent sucrose sweetened fruit bar had an energy
value of 239.4 K cal/100g. Thus, the replacement of sucrose with stevia or
saccharin brought about 59.8 per cent reductions in calories. Addition of bulking
agents did not exert any appreciable effect on the energy values of the fruit bars.
Thus, low calories fruit bars can successfully be prepared by replacing sucrose
with equivalent proportions of stevia or saccharin. The stevia leaves extract being
a plant source is preferred over saccharin to prepare such products.
4.10.2 Changes in sensory characteristics of hypoglycaemic guava-Aloe vera
fruit bar
The data pertaining to the effect of replacement of sucrose with non-
nutritive sweeteners and addition of bulking agent on sensory attributes of
hypoglycaemic guava-Aloe vera fruit bar presented in Table 4.29 are explained
as under:-
Saccharine (50 %) sweetened fruit bar containing 10% apple pomace and
10% oat bran
Stevia leaves extract (50 %) sweetened fruit bar containing 10% apple
pomace and 10% oat bran
Plate 8. Hypoglycaemic guava-Aloe vera fruit bars containing different
non-nutritive sweeteners and bulking agents
94
4.10.2.1 Colour
The colour acceptability score for hypoglycaemic guava-Aloe vera fruit
bar ranged between 6.50 to 7.50. Maximum sensory, score for colour (7.50) was
recorded in 100 per cent sucrose sweetened fruit bar. With the increase in
addition of non-nutritive sweeteners and bulking agents in fruit bar, colour
acceptability of the resultant fruit bar exhibited a significant decrease. The stevia
leaves extract sweetened fruit bars scored lesser than saccharin sweetened fruit
bars. In most of cases, the fruit bars in which apple pomace was used as bulking
agent with the combination of non-nutritive sweeteners also scored less than that
of the fruit bars prepared by using oat bran. This might be due to the fact that the
dried apple pomace imparted its characteristic colour which altered the colour of
the fruit bar when compared with 100 per cent guava fruit bars. However, in all
the combinations the colour acceptability score remained more than 6.00
indicating good acceptability of the product with respect to its appearance.
Table 4.29. Effect of addition of non-nutritive sweeteners (stevia leaves
extract and saccharin) on sensory quality (9 point hedonic
scale) of hypoglycaemic guava-Aloe vera fruit bar* Proportion
Su:St:Sa : Ap : Ot
Colour
Taste
Flavour/
Aroma
Texture Over all
acceptability
T1:100 :0: 0:0 7.50 7.20 7.30 7.50 7.37
T2: 0 :100 : 0:0 7.30 4.10 4.50 6.5 5.60
T3 :0 : 0 :100:0 7.20 3.50 3.50 5.5 4.92
T4 : 75 : 25 : 0 :10:0 6.95 7.06 7.28 6.95 7.06
T5
: 75 : 25: 0 : 0 :10 7.05 6.90 7.00 7.05 7.00
T6
: 75 : 0:25 : 10 : 0 6.75 5.21 6.95 6.75 6.41
T7
: 75 : 0 : 25 : 0 : 10 6.95 5.20 6.85 6.95 6.48
T8
: 50: 50 : 0 :10 : 0 6.78 7.05 7.05 6.71 6.89
T9
: 50: 50 : 0 : 0 : 10 6.65 6.60 6.93 6.65 6.70
T10
: 50 : 0 : 50 : 10 : 0 6.98 5.07 6.74 6.98 6.44
T11
: 50: 0 : 50 : 10 : 0 6.71 4.98 6.65 6.71 6.26
T12
: 25 : 75 : 0: 10:0 6.60 6.70 6.92 6.60 6.70
T13
: 25 : 75 : 0 : 0 :10 7.05 6.52 6.61 7.05 6.80
T14
: 25: 0 : 75 : 10 : 0 6.50 4.05 6.61 6.50 5.91
T15
: 25 : 0 : 75 : 0 : 10 6.62 3.94 6.32 6.62 5.87
Mean 6.91 5.60 7.30 6.74 6.64
CD 0.05 0.07 0.07 0.02 0.39 0.08
*The fruit bars prepared by using 90% guava pulp and 10% Aloe vera gel extract.
Su-sucrose, St-stevia leaves extract leaves extract, Sa-saccharin, Ap- Apple pomace, Ot -oat bran
95
4.10.2.2 Taste
Sensory score for taste of hypoglycaemic guava-Aloe vera fruit bar was
varied from 3.50 to 7.20 on a 9 point hedonic scale. The highest score (7.20) was
recorded in 100 per cent sucrose sweetened fruit bar and minimum score (3.50)
for fruit bar containing 25 per cent sucrose and 75 per cent saccharin along with
10 per cent oat bran as bulking agent. The acceptability score for taste decreased
significantly with increase in proportion of non-nutritive sweetness to replace
sucrose. The fruit bar containing 100 per cent substitution of stevia or saccharin
were not acceptable. Further, the taste score for fruit bars prepared by using
stevia leaves extract exhibited higher acceptability over saccharin sweetened fruit
bars use of saccharin even up to 25 per cent level was not preferred in the fruit
bars. This might be due to the metallic after taste of the saccharin which becomes
evident with the increase in proportion of saccharin. Further, the addition of 25
per cent and 50 per cent stevia leaves extract to replace sucrose in the fruit bars
did not cause any undesirable effect on the taste acceptability of the fruit bars as
their score remained more than 6.0 on a 9 point hedonic scale. Thus, substitution
of 50 per cent stevia leaves extract with equivalent sweetness of sucrose was
optimized. Similarly, the apple pomace fortified fruit bars got higher score than
oat bran fruit bars. The fruit bars prepared by using oat bran exhibited
comparatively less liking, which might be due to its typical grain taste. As the
proportion of stevia leaves extract and saccharin increased in fruit bar, the taste of
fruit bars got deteriorated. Further, the replacement of sucrose by stevia leaves
extract or saccharin beyond 50 per cent levels significantly lowered the taste
acceptability score of the resultant fruit bars with a mean score registering below
7.0. Thus, the fruit bars prepared by using 25 and 50 per cent stevia leaves extract
with apple pomace as bulking agent preferred over saccharin sweetened fruit
bars.
4.10.2.3 Flavour /aroma
Sensory score for flavour score of the product decreased significantly
with the corresponding increase in proportion of non-nutritive sweeteners in
hypoglycaemic guava-Aloe vera fruit bars. The highest score for flavour (7.30)
96
was obtained by 100 per cent sucrose sweetened fruit bar which was followed by
the fruit bars containing 25 per cent and 50 per cent stevia leaves extract as
replacement for sucrose. The products containing 75 per cent and 100 per cent
non-nutritive sweeteners were least preferred indicating unsuitability of the
prepared products by using non-nutritive sweeteners. However they exhibited
fairly good score for flavour of the product. Among non-nutritive sweeteners the
fruit bars prepared by using stevia leaves extract were preferred over the fruit
bars made by using equivalent proportions of saccharin. Further, the fruity
flavour imparted by apple pomace was effective in improving the resultant fruit
bars as compared to products containing oat bran as bulking agent. Thus,
hypoglycaemic guava-Aloe vera fruit bars can be prepared by using up to 50 per
cent stevia leaves extract along with 10 per cent along apple pomace as bulking
agent.
4.10.2.4 Texture
Additions of non-nutritive sweeteners possess marginal affect on the
texture of the resultant fruit bars. The fruit bar prepared by using 100 per cent
sucrose scored the highest acceptability score for texture (7.50) which was
followed by the product made by using stevia leaves extract as replacement for
equivalent sweetness of sucrose. Further, addition of 10 per cent apple pomace or
oat bran to the fruit bar as bulking agent significantly improved the texture
acceptability score of the hypoglycaemic guava-Aloe vera fruit bars. Thus, stevia
leaves extract sweetened fruit bars up to 50 per cent replacement along with apple
pomace or oat bran as bulking agent exhibited a higher score for acceptability of
the texture, and were optimized. Among the two bulking agents, the product
made by using apple pomace was rated superior in texture as compared to the
product containing oat bran.
4.10.2.5 Over all acceptability
Sensory score for over all acceptability of the product decreased
significantly with the corresponding increase in proportion of non-nutritive
sweeteners in hypoglycaemic guava-Aloe vera fruit bars. The highest score for
over all acceptability (7.37) was obtained by 100 per cent sucrose sweetened fruit
97
bar which was followed by the fruit bars containing 25 per cent and 50 per cent
stevia leaves extract as replacement for sucrose. The products containing 75 per
cent and 100 per cent non-nutritive sweeteners were least preferred indicating
unsuitability of the prepared products by using non-nutritive sweeteners.
However they exhibited fairly good score for over all acceptability of the product.
Among non-nutritive sweeteners the fruit bars prepared by using stevia leaves
extract were preferred over the fruit bars made by using equivalent proportions of
saccharin. Further, the fruity flavour imparted by apple pomace was effective in
improving the overall acceptability of the resultant fruit bars as compared to
products containing oat bran as bulking agent. Thus, hypoglycaemic guava-Aloe
vera fruit bars can be prepared by using up to 50 per cent stevia leaves extract
and 10 per cent apple pomace as bulking agent.
4.11 Storage studies of hypoglycaemic guava-Aloe vera fruit bar
The hypoglycaemic guava-Aloe vera fruit bars prepared by substituting
the sweetness of sucrose with equivalent proportions of non-nutritive sweeteners
as per earlier experiment (Table 4.28 and 4.29) were packed in aluminium
laminates and stored at ambient (12-24ºC) as well as in refrigerated temperature
(4+2ºC) to evaluate their quality at periodic intervals of 0, 90 days and 180 days.
The changes in physico-chemical as well as sensory attributes during storage of
fruit bar presented in Table 4.30-4.42 are explained as follows:
4.11.1 Physico-chemical changes during storage of hypoglycaemic guava-
Aloe vera fruit bar
4.11.1.1 Total soluble solids
With the increase in period of storage, the total soluble solids in the fruit
bars exhibited a marginal increase from mean value of 39.9 to 40.5ºB at ambient
temperature. Storage at low temperature exhibited lesser change in TSS as
compared to the product stored at ambient temperature. Among different
combinations the products prepared by using non-nutritive sweeteners did not
reflect any change during storage. Further, the fruit bars prepared by using stevia
leaves extract or saccharin having initially low total soluble solids also showed
lowest TSS during storage as compared to the products made by using sucrose.
98
Table 4.30. Effect of different proportions of non-nutritive sweeteners on the total soluble solids (oB) of the hypoglycaemic guava Aloe
vera fruit bars during storage at ambient (12-24ºC) and low (4+2ºC) temperature
Treatments
Temperature Days
T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 Mean
Grand
Mean
(I)
Grand
Mean
(C)
0 67.9 16.2 16.6 51.1 51.4 51.4 51.9 34.2 34.5 34.4 34.8 17.0 17.5 17.6 17.9 39.9 39.9 40.2
90 68.5 16.6 16.9 51.6 51.6 51.7 52.2 34.4 34.9 34.5 35.0 17.2 17.7 17.6 18.2 40.3 40.3
180 68.7 16.9 17.2 51.9 51.9 52.7 52.9 34.7 35.2 34.7 35.3 17.5 18.0 18.0 18.5 40.5 40.2
Ambient
temperature
(12-24ºC).
Mean 68.3 16.6 16.9 51.4 51.6 51.9 52.3 35.4 34.9 34.5 34.0 17.2 17.7 17.7 18.2
0 67.9 16.2 16.6 51.1 51.4 51.4 51.9 34.2 34.5 34.4 34.8 17.0 17.5 17.6 17.9 39.9 40.1
90 68.0 16.3 16.7 51.2 51.4 51.5 52.0 34.3 34.7 34.6 34.9 17.1 17.6 17.7 18.0 40.4
180 68.2 16.2 16.7 51.2 51.4 51.5 52.0 34.3 34.7 34.5 34.9 17.1 17.6 17.7 18.0 40.0
Low
temperature
(4+2ºC)
Mean 68.0 16.2 16.6 51.1 51.4 51.4 51.9 34.4 34.6 34.4 34.8 17.0 17.5 17.6 18.0
Grand Mean (T) 68.15 16.4 16.7 52.1 51.7 51.5 51.3 35.4 34.9 34.7 34.5 18.1 17.6 17.6 17.1
CD0.05
Treatment (T) = 0.81 TxI = 1.39 TxIxC =1.99
Intervals (I) =0.36 TxC = 0.80
Temperature (C) =0.29 IxC = 0.51
T1: 100% Sucrose T6: 75 Sucrose + 25% Saccharin + 10% Apple pomace T11: 50 Sucrose + 50% Saccharin + 10% Oat bran
T2: 100% Stevia T7: 75 Sucrose + 25% Saccharin + 10% Oat bran T12: 25 Sucrose + 75% Stevia + 10% Apple pomace
T3: 100% Saccharin T8: 50 Sucrose + 50% Stevia + 10% Apple pomace T13: 25 Sucrose + 75% Stevia + 10% Oat bran
T4: 75 Sucrose + 25% Stevia + 10% Apple pomace T9: 50 Sucrose + 50% Stevia + 10% Oat bran T14: 25 Sucrose + 75% Saccharin + 10% Apple pomace
T5: 75 Sucrose + 25% Stevia + 10% Oat bran T10: 50 Sucrose + 50% Saccharin + 10% Apple pomace T15: 25 Sucrose + 75% Saccharin + 10% Oat bran
99
However, during entire period of storage, these bars also experienced
marginal increase in the TSS.
Further, the fruit bars stored at ambient temperature exhibited higher TSS
as compared to the bars stored at low temperature. Thus, low temperature was
effective in reducing the change in TSS as compared to the bars stored at ambient
temperature.
4.11.1.2 Titratable acidity
During storage of fruit bars up to 180 days, the mean value of titratable
acidity ranged between 1.41-1.48 per cent from its initial level of 1.43 to 1.50 per
cent. This indicating only marginal decrease in acidity during storage. Further,
the effect of storage temperature on the titratable acidity of fruit bars was found
to be non-significant. Thus, the hypoglycaemic fruit bars experienced, not much
of change in their acidity and hence, can be stored successfully for up to 180 days
at both ambient and low temperature.
4.11.1.3 pH
With the increase in period of storage of fruit bars, the pH values
registered a marginal but significant increase for up to 180 days of storage. The
mean pH value of low calorie guava-Aloe vera fruit bars during storage varied
between 2.63 to 2.90. At different intervals of storage, the pH of the fruit bars
from initial mean value of 2.69 increased to 2.79 at ambient temperature and 2.77
at low temperature. The addition of non-nutritive sweeteners to the fruit bars does
not exhibited marginal change in the pH of the hypoglycaemic fruit bars during
storage.
4.11.1.4 Ascorbic acid
With the increase in period of storage, the ascorbic acid content in
hypoglycaemic guava-Aloe vera fruit bars experienced a decrease (Table 4.33).
The mean value of ascorbic acid in different fruit bars at different temperature
decreased from initial level of 178.0 to 176.3 at ambient temperature and 176.5 at
low temperature after 180 days of storage. The fruit bars prepared by substituting
100
Table 4.31. Effect of different proportions of non-nutritive sweeteners on the titratable acidity (%) of the hypoglycaemic guava -Aloe
vera fruit bars during storage at ambient (12-24ºC) and low (4+2ºC) temperature
Treatments
Temperature Days
T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 Mean Grand
Mean
(I)
Grand
Mean
(C)
0 1.50 1.47 1.52 1.43 1.50 1.47 1.48 1.43 1.45 1.44 1.47 1.45 1.46 1.43 1.45 1.47 1.47 1.44
90 1.45 1.44 1.49 1.40 1.47 1.44 1.43 1.41 1.42 1.46 1.44 1.41 1.42 1.40 1.42 1.43 1.44
180 1.43 1.41 1.45 1.48 1.44 1.41 1.40 1.34 1.40 1.42 1.42 1.40 1.41 1.37 1.34 1.41 1.43
Ambient
temperature
(12-24oC)
Mean 1.46 1.44 1.48 1.40 1.47 1.44 1.43 1.41 1.42 1.44 1.44 1.42 1.43 1.40 1.42
0 1.50 1.47 1.52 1.43 1.50 1.47 1.48 1.43 1.45 1.44 1.47 1.45 1.46 1.43 1.45 1.47 1.46
90 1.50 1.47 1.52 1.42 1.46 1.46 1.47 1.43 1.44 1.48 1.47 1.44 1.46 1.43 1.45 1.46
180 1.50 1.46 1.52 1.41 1.50 1.46 1.47 1.40 1.43 1.48 1.46 1.44 1.46 1.43 1.44 1.45
Low
temperature
(4+2ºC)
Mean 1.50 1.46 1.52 1.42 1.48 1.46 1.47 1.42 1.44 1.45 1.46 1.44 1.46 1.43 1.44
Grand Mean
(T) 1.48 1.45 1.50 1.41 1.48 1.45 1.45 1.41 1.43 1.47 1.45 1.43 1.44 1.41 1.43
CD0.05
Treatment (T) = 0.02 TxI = 0.01 TxIxC = 0.04
Intervals (I) = NS TxC = NS
Temperature(C) = NS IxC = NS
T1: 100% Sucrose T6: 75 Sucrose + 25% Saccharin + 10% Apple pomace T11: 50 Sucrose + 50% Saccharin + 10% Oat bran
T2: 100% Stevia T7: 75 Sucrose + 25% Saccharin + 10% Oat bran T12: 25 Sucrose + 75% Stevia + 10% Apple pomace
T3: 100% Saccharin T8: 50 Sucrose + 50% Stevia + 10% Apple pomace T13: 25 Sucrose + 75% Stevia + 10% Oat bran
T4: 75 Sucrose + 25% Stevia + 10% Apple pomace T9: 50 Sucrose + 50% Stevia + 10% Oat bran T14: 25 Sucrose + 75% Saccharin + 10% Apple pomace
T5: 75 Sucrose + 25% Stevia + 10% Oat bran T10: 50 Sucrose + 50% Saccharin + 10% Apple pomace T15: 25 Sucrose + 75% Saccharin + 10% Oat bran
101
Table 4.32. Effect of different proportions of non-nutritive sweeteners on pH of the hypoglycaemic guava-Aloe vera fruit bars during
storage at ambient (12-24ºC) and low (4+2ºC) temperature
Treatments
Temperature Days
T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 Mean Grand
Mean
(I)
Grand
Mean
(C)
0 2.62 2.68 2.67 2.87 2.56 2.68 2.64 2.87 2.76 2.65 2.66 2.67 2.67 2.62 2.72 2.69 2.69 2.75
90 2.66 2.71 2.73 2.89 2.84 2.72 2.70 2.89 2.83 2.85 2.71 2.72 2.71 2.75 2.78 2.76 2.75
180 2.68 2.69 2.79 2.90 2.86 2.74 2.68 2.93 2.84 2.87 2.79 2.77 2.73 2.76 2.81 2.79 2.78
Ambient
temperature
(12-24oC)
Mean 2.64 2.69 2.73 2.89 2.75 2.71 2.67 2.90 2.81 2.79 2.70 2.72 2.71 2.71 2.77
0 2.62 2.68 2.67 2.87 2.56 2.68 2.64 2.87 2.76 2.65 2.66 2.67 2.67 2.62 2.72 2.69 2.73
90 2.62 2.68 2.67 2.87 2.84 2.68 2.66 2.88 2.77 2.74 2.76 2.85 2.70 2.76 2.75 2.74
180 2.64 2.69 2.69 2.88 2.88 2.70 2.67 2.89 2.79 2.78 2.81 2.86 2.74 2.78 2.77 2.77
Low
temperature
(4+2ºC)
Mean 2.62 2.68 2.68 2.85 2.76 2.69 2.67 2.87 2.77 2.72 2.75 2.80 2.70 2.72 2.75
Grand Mean (T) 2.63 2.68 2.70 2.88 2.76 2.70 2.68 2.90 2.80 2.76 2.75 2.76 2.70 2.72 2.76
CD0.05
Treatment (T) = 0.14 TxI = 0.23 TxIxC = 0.35
Intervals (I) = 0.06 TxC = 0.19
Temperature(C) = 0.05 IxC = 0.07
T1: 100% Sucrose T6: 75 Sucrose + 25% Saccharin + 10% Apple pomace T11: 50 Sucrose + 50% Saccharin + 10% Oat bran
T2: 100% Stevia T7: 75 Sucrose + 25% Saccharin + 10% Oat bran T12: 25 Sucrose + 75% Stevia + 10% Apple pomace
T3: 100% Saccharin T8: 50 Sucrose + 50% Stevia + 10% Apple pomace T13: 25 Sucrose + 75% Stevia + 10% Oat bran
T4: 75 Sucrose + 25% Stevia + 10% Apple pomace T9: 50 Sucrose + 50% Stevia + 10% Oat bran T14: 25 Sucrose + 75% Saccharin + 10% Apple pomace
T5: 75 Sucrose + 25% Stevia + 10% Oat bran T10: 50 Sucrose + 50% Saccharin + 10% Apple pomace T15: 25 Sucrose + 75% Saccharin + 10% Oat bran
102
Table 4.33. Effect of different proportions of non-nutritive sweeteners on the ascorbic acid (mg/100 g) of the hypoglycaemic guava -
Aloe vera fruit bars during storage at ambient (12-24ºC) and low (4+2ºC) temperature.
Treatments
Temperature Days
T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 Grand
Mean
Grand
Mean
(I)
Grand
Mean
(C)
0 176.0 179.5 175.5 178.5 177.5 177.6 176.9 177.7 178.9 177.9 177.8 180.6 178.9 178.6 177.9 178.0 178.0 177.0
90 175.5 177.0 175.0 176.4 176.4 176.2 176.4 177.2 175.4 177.5 177.4 178.3 177.4 178.2 177.4 176.8 176.7
180 175.0 176.3 174.5 176.0 175.9 176.5 176.1 176.7 174.5 176.1 177.5 177.6 176.5 178.0 177.0 176.3 176.4
Ambient
temperature
(12-24oC)
Mean 175.5 176.9 175.0 176.3 176.3 176.8 176.5 177.2 176.3 177.2 177.6 178.8 177.6 178.3 177.4
0 176.0 179.5 175.5 178.5 177.5 177.6 176.9 177.7 178.9 177.9 177.8 180.6 178.9 178.6 177.9 178.0 177.0
90 175.9 178.2 175.4 177.6 176.4 176.2 176.6 177.5 175.5 177.6 177.6 178.6 177.8 178.5 171.8 176.7
180 175.7 177.0 175.2 177.4 176.5 176.3 176.3 177.1 175.3 175.3 177.3 178.2 177.7 178.0 171.1 176.5
Low
temperature
(4+2ºC)
Mean 175.9 178.2 175.0 177.0 176.5 176.7 176.6 177.4 175.9 175.9 176.6 178.5 178.1 178.4 173.6
Grand Mean (T) 175.7 178.1 175.2 177.4 176.4 176.7 176.6 177.3 175.8 177.1 177.6 178.3 178.2 178.3 177.6
CD0.05
Treatment (T) = 0.17 TxI = 0.29 TxIxC = 0.41
Intervals (I) = 0.07 TxC = 0.23
Temperature(C) = 0.06 IxC = 0.05
T1: 100% Sucrose T6: 75 Sucrose + 25% Saccharin + 10% Apple pomace T11: 50 Sucrose + 50% Saccharin + 10% Oat bran
T2: 100% Stevia T7: 75 Sucrose + 25% Saccharin + 10% Oat bran T12: 25 Sucrose + 75% Stevia + 10% Apple pomace
T3: 100% Saccharin T8: 50 Sucrose + 50% Stevia + 10% Apple pomace T13: 25 Sucrose + 75% Stevia + 10% Oat bran
T4: 75 Sucrose + 25% Stevia + 10% Apple pomace T9: 50 Sucrose + 50% Stevia + 10% Oat bran T14: 25 Sucrose + 75% Saccharin + 10% Apple pomace
T5: 75 Sucrose + 25% Stevia + 10% Oat bran T10: 50 Sucrose + 50% Saccharin + 10% Apple pomace T15: 25 Sucrose + 75% Saccharin + 10% Oat bran
103
sucrose with stevia leaves extract registered significantly higher levels of
ascorbic acid as compared to the fruit bars which contained sucrose or saccharin
as sweeteners. After six months of storage at different temperature the stevia
leaves extract sweetened beverage also registered decrease in ascorbic acid, but
remained marginally higher than other combinations.
4.11.1.5 Total sugars
With the increase in proportion of non-nutritive sweeteners to replace
sucrose, corresponding decrease in total sugars of resultant fruit bars was
observed. The fruit bars prepared by using different proportions of stevia leaves
extract and saccharin had mean total sugars varying between 10.5 per cent to 59.8
per cent during entire period of storage (Table 4.34). Thus, the fruit bars prepared
by using 100 per cent substitution with either stevia leaves extract or saccharin
showed lowest amounts of total sugars i.e. 10.5 per cent to 10.2 per cent,
respectively during storage. After six months of storage, hypoglycaemic fruit bars
caused a slight decrease in total sugars varying between 10.2 to 59.4 per cent at
ambient temperature and 10.3 to 59.7 at refrigerated temperature. However, the
decrease was comparatively less at low temperature than those stored at ambient
temperature.
4.11.1.5 Moisture content
Data in Table 4.34 reveals that the mean moisture content in
hypoglycaemic guava-Aloe vera fruit bars ranged from 16.8 to 17.6 per cent
during storage up to six months. The moisture present in 100 per cent sucrose
sweetened fruit bar (17.5%) while minimum moisture (16.7%) was found in 75
per cent saccharin sweetened fruit bar with 10 per cent oat bran. Packaging of
fruit bars in aluminium laminates exerted its interference in checking the gain of
moisture during storage. Similarly, the effect of storage intervals and temperature
found non-significant on the moisture content of fruit bars during storage.
4.11.1.6 Total solids
The total solids in the fruit bars marginally decreased with the
corresponding increase in storage period up to six months. The initial mean
104
Table 4.34. Effect of different proportions of non-nutritive sweeteners on the total sugar (%) of the hypoglycaemic guava-Aloe vera
fruit bars during storage at ambient (12-24ºC) and low (4+2ºC) temperature
Treatments
Temperature Days
T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 Mean Grand
Mean (I)
Grand
Mean
(C)
0 59.8
(50.6)
10.8
(10.9)
10.5
(19.7)
45.5
(42.4)
45.4
(42.4)
45.2
(44.5)
45.1
(42.2)
24.2
(29.5)
24.3
(29.5)
24.0
(29.5)
24.4
(29.6)
11.5
(19.8)
11.4
(19.8)
11.9
(20.0)
11.7
(20.0)
32.3
(33.8)
32.3
(33.8)
32.0
(33.6)
90 59.4
(50.4)
10.2
(19.5)
10.2
(19.5)
45.3
(42.4)
45.2
(42.2)
45.0
(42.1)
45.0
(45.1)
24.1
(29.4)
24.0
(29.4)
24.1
(29.4)
24.1
(29.4)
11.1
(19.5)
11.1
(19.5)
11.3
(19.6)
11.3
(19.7)
32.0
(33.6)
32.0
(33.6)
180 59.0
(50.2)
10.1
(19.4)
10.0
(19.4)
44.8
(43.0)
45.0
(42.4)
44.8
(42.0)
44.8
(42.0)
23.9
(29.3)
23.8
(29.2)
23.9
(29.2)
23.8
(29.2)
11.0
(19.3)
10.5
(18.9)
11.3
(19.4)
10.6
(19.0)
31.8
(33.4)
31.9
(33.5)
Ambient
temperature
(12-24oC)
Mean 59.4
(50.4)
10.3
(19.6)
10.2
(19.5)
44.9
(42.6)
45.1
(42.3)
45.0
(42.1)
45.0
(42.1)
24.1
(29.4)
24.0
(29.3)
24.1
(29.4)
24.1
(29.4)
11.2
(19.5)
11.0
(19.4)
11.3
(15.7)
11.2
(19.6)
0 59.8
(50.6)
10.8
(19.9)
10.5
(19.7)
45.5
(45.4)
45.4
(42.4)
45.2
(42.2)
45.1
(42.2)
24.2
(29.5)
24.3
(29.5)
24.0
(29.5)
24.4
(29.6)
11.5
(19.8)
11.5
(19.8)
11.9
(20.0)
11.7
(20.0)
32.3
(33.8)
32.1
(33.7)
90 59.7
(50.6)
10.7
(19.6)
10.4
(19.7)
45.2
(42.2)
45.2
(42.2)
45.1
(42.1)
45.4
(42.3)
24.0
(29.3)
24.1
(29.4)
24.1
(29.4)
24.2
(29.4)
11.1
(19.5)
11.0
(19.6)
11.4
(19.7)
11.4
(19.7)
32.0
(33.6)
180 59.6
(50.5)
10.4
(19.8)
10.3
(19.6)
45.0
(42.3)
45.1
(42.3)
45.0
(42.2)
45.0
(42.1)
24.0
(29.3)
24.1
(29.4)
24.1
(29.4)
24.1
(29.4)
11.3
(19.6)
11.0
(19.6)
11.3
(19.7)
11.3
(19.7)
32.0
(33.6)
Low
temperature
(4+2ºC)
Mean 59.7
(50.6)
10.6
(19.8)
10.3
(19.6)
45.3
(42.3)
45.4
(42.3)
45.1
(42.2)
45.3
(42.2)
24.1
(29.3)
24.1
(29.4)
24.2
(29.4)
24.2
(29.5)
11.3
(19.6)
11.3
(19.6)
11.5
(19.8)
11.5
(19.8)
Grand Mean (T) 59.6
(50.5)
10.5
(19.7)
10.2
(19.6)
45.2
(42.1)
45.3
(42.3)
45.0
(42.1)
45.1
(42.2)
24.1
(29.4)
24.1
(29.4)
24.1
(29.4)
24.2
(29.4)
11.2
(19.6)
11.2
(19.5)
11.4
(19.7)
11.3
(19.7)
Figures in parenthesis represent the arc root transformation
CD0.05
Treatment (T) = 0.20 TxI = 0.35 TxIxC = 0.49
Intervals (I) = 0.09 TxC = 0.27
Temperature(C) = 0.07 IxC = 0.11
T1: 100% Sucrose T6: 75 Sucrose + 25% Saccharin + 10% Apple pomace T11: 50 Sucrose + 50% Saccharin + 10% Oat bran
T2: 100% Stevia T7: 75 Sucrose + 25% Saccharin + 10% Oat bran T12: 25 Sucrose + 75% Stevia + 10% Apple pomace
T3: 100% Saccharin T8: 50 Sucrose + 50% Stevia + 10% Apple pomace T13: 25 Sucrose + 75% Stevia + 10% Oat bran
T4: 75 Sucrose + 25% Stevia + 10% Apple pomace T9: 50 Sucrose + 50% Stevia + 10% Oat bran T14: 25 Sucrose + 75% Saccharin + 10% Apple pomace
T5: 75 Sucrose + 25% Stevia + 10% Oat bran T10: 50 Sucrose + 50% Saccharin + 10% Apple pomace T15: 25 Sucrose + 75% Saccharin + 10% Oat bran
105
Table 4.35. Effect of different proportions of non-nutritive sweeteners on the moisture content (%) of the hypoglycaemic guava-Aloe
vera fruit bars during storage at ambient (12-24ºC) and low (4+2ºC) temperature.
Treatments
Temperature Days
T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 Mean Grand
Mean
(I)
Grand
Mean
(C)
0 17.5 17.3 17.1 17.1 17.6 17.1 17.1 17.0 17.2 17.2 17.2 16.8 16.8 16.7 16.7 17.1 17.1 17.3
90 17.3 17.2 17.4 17.3 17.3 17.3 17.3 17.5 17.5 17.5 17.5 17.2 17.0 16.9 16.9 17.3 17.2
180 17.6 17.8 17.6 17.5 17.5 17.3 17.2 17.6 17.8 17.8 17.6 17.2 17.2 17.1 17.1 17.5 17.4
Ambient
temperature
(12-24oC)
Mean 17.8 17.5 17.3 17.2 17.4 17.2 17.2 17.4 17.5 17.5 17.4 17.1 17.0 16.9 16.9
0 17.5 17.3 17.1 17.1 17.1 17.1 17.1 17.0 17.2 17.2 17.2 16.8 16.8 16.7 16.7 17.1 17.2
90 17.6 17.4 17.2 17.2 17.3 17.2 17.2 17.2 17.3 17.3 17.3 16.8 16.9 16.9 16.8 17.2
180 17.6 17.4 17.3 17.3 17.5 17.3 17.1 17.2 17.4 17.4 17.5 17.2 17.2 16.9 16.9 17.3
Low
temperature
(4+2ºC)
Mean 17.6 17.4 17.2 17.3 17.3 17.2 17.1 17.1 17.3 17.3 17.3 16.9 16.9 16.8 16.8
Grand Mean (T) 17.7 17.5 17.3 17.2 17.2 17.2 17.1 17.3 17.4 17.4 17.3 17.0 16.9 16.9 16.8
Figures in parenthesis represent the square root transformation
CD0.05
Treatment (T) = 0.01 TxI = NS TxIxC = 0.02
Intervals (I) = NS TxC = NS
Temperature(C) = NS IxC = NS
T1: 100% Sucrose T6: 75 Sucrose + 25% Saccharin + 10% Apple pomace T11: 50 Sucrose + 50% Saccharin + 10% Oat bran
T2: 100% Stevia T7: 75 Sucrose + 25% Saccharin + 10% Oat bran T12: 25 Sucrose + 75% Stevia + 10% Apple pomace
T3: 100% Saccharin T8: 50 Sucrose + 50% Stevia + 10% Apple pomace T13: 25 Sucrose + 75% Stevia + 10% Oat bran
T4: 75 Sucrose + 25% Stevia + 10% Apple pomace T9: 50 Sucrose + 50% Stevia + 10% Oat bran T14: 25 Sucrose + 75% Saccharin + 10% Apple pomace
T5: 75 Sucrose + 25% Stevia + 10% Oat bran T10: 50 Sucrose + 50% Saccharin + 10% Apple pomace T15: 25 Sucrose + 75% Saccharin + 10% Oat bran
106
Table 4.36. Effect of different proportions of non-nutritive sweeteners on the total solids (%) of the hypoglycaemic guava Aloe vera
fruit bars during storage at ambient (12-24ºC) and low (4+2ºC) temperature.
Treatments
Temperature Days
T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 Mean Grand
Mean
(I)
Grand
Mean
(C)
0 82.5 82.7 82.9 82.9 82.4 82.9 82.9 83.0 82.8 82.8 82.8 82.2 83.2 82.3 83.3 82.8 82.8 82.7
90 82.07 82.5 82.6 82.7 82.7 82.7 82.7 82.5 82.5 82.5 82.5 83.6 83.0 83.1 83.0 82.7 82.2
180 82.4 82.2 82.4 82.5 82.5 82.7 82.8 82.4 82.2 82.2 82.4 82.8 82.8 82.9 82.8 82.5 82.6
Ambient
temperature
(12-24oC)
Mean 82.2 82.5 82.67 82.8 82.8 82.8 82.8 82.7 82.5 82.5 82.6 83.0 83.0 83.1 83.0
0 82.5 82.7 82.9 82.9 82.9 82.9 82.9 83.0 82.8 82.8 82.8 83.2 83.2 83.3 83.3 82.8 82.4
90 82.4 82.6 82.8 82.8 82.7 82.8 82.8 82.8 82.7 82.7 82.7 83.2 83.1 83.1 83.2 81.7
180 82.4 82.6 82.7 82.8 82.5 82.7 82.9 82.8 82.6 82.6 82.5 82.9 82.8 83.1 83.1 82.8
Low temperature
(4+2ºC)
Mean 82.4 82.6 82.8 82.7 82.8 82.9 82.5 82.8 82.7 82.7 82.6 83.1 83.1 83.2 83.2
Grand Mean (T) 82.3 82.5 82.7 82.8 82.8 82.8 82.8 82.7 82.6 82.6 82.6 83.0 83.1 83.1 83.1
CD0.05
Treatment (T) = 2.01 TxI = 3.47 TxIxC = 4.91
Intervals (I) = 0.18 TxC = 2.88
Temperature(C) = 0.73 IxC = 1.26
T1: 100% Sucrose T6: 75 Sucrose + 25% Saccharin + 10% Apple pomace T11: 50 Sucrose + 50% Saccharin + 10% Oat bran
T2: 100% Stevia T7: 75 Sucrose + 25% Saccharin + 10% Oat bran T12: 25 Sucrose + 75% Stevia + 10% Apple pomace
T3: 100% Saccharin T8: 50 Sucrose + 50% Stevia + 10% Apple pomace T13: 25 Sucrose + 75% Stevia + 10% Oat bran
T4: 75 Sucrose + 25% Stevia + 10% Apple pomace T9: 50 Sucrose + 50% Stevia + 10% Oat bran T14: 25 Sucrose + 75% Saccharin + 10% Apple pomace
T5: 75 Sucrose + 25% Stevia + 10% Oat bran T10: 50 Sucrose + 50% Saccharin + 10% Apple pomace T15: 25 Sucrose + 75% Saccharin + 10% Oat bran
107
value of total solids ranged between 82.3 to 83.3 per cent at ambient condition
and 82.2-83.1 per cent at low temperature during storage up to 180 days from
initial value of 82.4 to 83.2 per cent (Table 3.36). Corresponding with the
increase in moisture content, there was marginal decrease in total solids during
storage of hypoglycaemic fruit bars. The fruit bars stored at low temperature
registered lesser decrease in total solids than those stored at ambient condition.
4.11.1.7 Water activity
The data pertaining to change in water activity of hypoglycaemic guava-
Aloe vera fruit bar are presented in Table 4.37. The average mean value of water
activity ranged 0.50 to 0.62 drying entire period of storage. The maximum water
activity (0.62) was found in fruit bars which contained 75 per cent sucrose and 25
per cent saccharin along with 10 per cent oat bran as bulking agent while
minimum water activity was recorded in fruit bar formulated with 25 per cent
sucrose and 75 per cent saccharin along with 10 per cent oat bran as bulking
agent. However, the effect of storage temperature on the water activity of fruit
bars found significant. Thus, the fruit bars with water activity ranging between
0.50 to 0.62 are expected to have better storage life.
4.11.2 Changes in sensory attributes of hypoglycaemic guava-Aloe vera fruit
bars during storage
Changes in sensory quality of the low calories fruit bar evaluated during
storage at ambient as well as temperature up to 180 days. Data in different
attributes such as colour, taste, flavour and over all acceptability presented in
Tables 4.38-4.41 are explained as under.
4.11.2.1 Colour
Sensory evaluation of hypoglycaemic guava-Aloe vera fruit bars indicated
that the addition of non-nutritive sweeteners significantly influenced the colour
acceptability score of the bar. With the increase in proportion of non-nutritive
sweeteners, the colour acceptability score decreased. The colour score for
hypoglycaemic guava Aloe vera fruit bar ranged between 6.05 to 7.50. Maximum
score (7.50) was recorded in 100 per cent sucrose sweetened fruit bar. With the
108
Table 4.37. Effect of different proportions of non-nutritive sweeteners on the water activity of the hypoglycaemic guava Aloe vera
fruit bars during storage at ambient (12-24ºC) and low (4+2ºC) temperature
Treatments
Temperature Days
T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 Mean
Grand
Mean
(I)
Grand
Mean
(C)
0 0.54 0.54 0.51 0.56 0.55 0.57 0.61 0.56 0.53 0.59 0.58 0.47 0.51 0.55 0.49 0.53 0.53 0.54
90 0.54 0.54 0.59 0.58 0.58 0.58 0.63 0.57 0.54 0.60 0.59 0.59 0.52 0.57 0.50 0.54 0.54
180 0.55 0.55 0.52 0.59 0.60 0.62 0.65 0.58 0.55 0.61 0.63 0.51 0.54 0.56 0.51 0.55 0.54
Ambient
temperature
(12-24oC)
Mean 0.54 0.54 0.54 0.53 0.58 0.59 0.63 0.57 0.54 0.60 0.60 0.52 0.52 0.56 0.50
0 0.54 0.54 0.51 0.56 0.55 0.57 0.61 0.56 0.53 0.59 0.58 0.47 0.51 0.55 0.49 0.53 0.53
90 0.53 0.54 0.52 0.57 0.57 0.57 0.62 0.58 0.54 0.60 0.50 0.49 0.51 0.55 0.49 0.54
180 0.55 0.54 0.52 0.57 0.58 0.58 0.62 0.58 0.56 0.60 0.59 0.52 0.55 0.55 0.50 0.54
Low temperature
(4+2ºC)
Mean 0.54 0.54 0.52 0.57 0.57 0.51 0.62 0.57 0.54 0.60 0.58 0.50 0.53 0.55 0.59
Grand Mean (T) 0.54 0.54 0.53 0.58 0.58 0.58 0.62 0.57 0.54 0.60 0.59 0.51 0.53 0.56 0.54
CD0.05
TxI = 0.02
TxC = 0.02
TxIxC = 0.04
Treatment (T) = 0.01
Intervals (I) = NS
Temperature(C) = NS IxC = NS
T1: 100% Sucrose T6: 75 Sucrose + 25% Saccharin + 10% Apple pomace T11: 50 Sucrose + 50% Saccharin + 10% Oat bran
T2: 100% Stevia T7: 75 Sucrose + 25% Saccharin + 10% Oat bran T12: 25 Sucrose + 75% Stevia + 10% Apple pomace
T3: 100% Saccharin T8: 50 Sucrose + 50% Stevia + 10% Apple pomace T13: 25 Sucrose + 75% Stevia + 10% Oat bran
T4: 75 Sucrose + 25% Stevia + 10% Apple pomace T9: 50 Sucrose + 50% Stevia + 10% Oat bran T14: 25 Sucrose + 75% Saccharin + 10% Apple pomace
T5: 75 Sucrose + 25% Stevia + 10% Oat bran T10: 50 Sucrose + 50% Saccharin + 10% Apple pomace T15: 25 Sucrose + 75% Saccharin + 10% Oat bran
109
Table 4.38 Effect of different proportions of non-nutritive sweeteners on sensory colour score (9 point hedonic scale) of the
hypoglycaemic guava-Aloe vera fruit bars during storage at ambient (12-24ºC) and low (4+2
ºC) temperature
Treatments
Temperature Days
T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 Mean Grand
Mean
(I)
Grand
Mean
(C)
0 7.50 7.30 7.20 6.95 7.05 6.75 6.95 6.78 6.65 6.98 6.71 6.60 6.05 6.50 6.62 6.90 6.91 6.82
90 7.42 7.22 7.12 6.88 6.95 6.66 6.85 6.70 6.55 6.89 6.63 6.52 5.98 6.40 6.58 6.82 6.83
180 7.38 7.15 7.02 6.80 6.86 6.55 6.78 6.62 6.47 6.80 6.55 6.46 5.90 6.32 6.50 6.74 6.75
Ambient
temperature
(12-24oC)
Mean 7.43 7.22 7.11 6.87 6.95 6.65 6.86 6.70 6.55 6.89 6.63 6.52 5.97 6.40 6.56
0 7.50 7.30 7.20 6.95 7.05 6.75 6.95 6.78 6.65 6.98 6.71 6.60 6.05 6.50 6.62 6.92 6.84
90 7.44 7.29 7.17 6.88 6.98 6.68 6.89 6.72 6.59 6.91 6.66 6.54 5.99 6.47 6.59 6.84
180 7.40 7.20 7.12 6.80 6.90 6.60 6.79 6.65 6.50 6.87 6.50 6.48 5.94 6.38 6.54 6.77
Low
temperature
(4+2ºC)
Mean 7.45 7.26 7.18 6.77 6.97 6.68 6.88 6.72 6.58 6.92 6.62 6.54 5.99 6.45 6.58
Grand Mean (T) 7.44 7.24 7.14 6.87 6.96 6.66 6.87 6.71 6.56 6.90 6.62 6.53 5.99 6.42 6.57
CD0.05
Treatment (T) = 0.13 TxI = 0.22
Intervals (I) = 0.05 TxC = 0.18
TxIxC = 0.32
Temperature(C) = 0.05 IxC = 0.83
T1: 100% Sucrose T6: 75 Sucrose + 25% Saccharin + 10% Apple pomace T11: 50 Sucrose + 50% Saccharin + 10% Oat bran
T2: 100% Stevia T7: 75 Sucrose + 25% Saccharin + 10% Oat bran T12: 25 Sucrose + 75% Stevia + 10% Apple pomace
T3: 100% Saccharin T8: 50 Sucrose + 50% Stevia + 10% Apple pomace T13: 25 Sucrose + 75% Stevia + 10% Oat bran
T4: 75 Sucrose + 25% Stevia + 10% Apple pomace T9: 50 Sucrose + 50% Stevia + 10% Oat bran T14: 25 Sucrose + 75% Saccharin + 10% Apple pomace
T5: 75 Sucrose + 25% Stevia + 10% Oat bran T10: 50 Sucrose + 50% Saccharin + 10% Apple pomace T15: 25 Sucrose + 75% Saccharin + 10% Oat bran
110
increase in addition of non-nutritive sweeteners and bulking agents in fruit bar,
colour acceptability of the resultant fruit bar exhibited a significant decrease. The
fruit bars in which apple pomace was used as bulking agent with the combination
of non-nutritive sweetener also scored less than that of the fruit bar prepared by
using oat bran. This might be due to the fact that the dried apple pomace imparted
its characteristic colour which decreased the colour of the fruit bar when
compared with sucrose sweetened and oat bran fortified fruit bar. The fruit bar
prepared by using 100 per cent sucrose had maximum acceptability for colour
which decreased after 180 days of storage interval at both the temperature. The
colour acceptability score registered a consistent decrease, after 180 days of
storage interval, however, the score remained more than 6.0, thereby indicating
good acceptability of fruit bars during storage.
4.11.2.2 Taste
Sensory score for taste of hypoglycaemic guava-Aloe vera fruit bars
varied from 3.50 to 7.20 on a 9 point hedonic scale which decreased to 3.24-7.11
during storage up to six months. The highest score (7.20) was recorded in 100 per
cent sucrose sweetened a fruit bar and minimum score (3.50) for a fruit bar 100
per cent saccharin sweetened bars. The acceptability score for taste of fruit bars
decreased during storage intervals. Further, the taste score for fruit bars
containing stevia leaves extract exhibited higher acceptability over saccharin
sweetened fruit bar. This might be due to the metallic after taste of the saccharin
which becomes evident with the increase in proportion of saccharin. Further, the
addition of 25 per cent and 50 per cent stevia leaves extract exhibit to replace
sucrose in the fruit bar did not cause any appreciable adverse effect on the taste
acceptability of the fruit bar as their score remained more than 7.0 on a 9 point
hedonic scale. Similarly, the apple pomace fortified fruit bar got higher score
than oat bran fruit bar. Addition of apple pomace along with stevia leaves extract
exhibited better liking for taste of fruit bars than of oat bran fortified fruit bar.
With the increase in period of storage, the sensory liking for taste of the fruit bars
got decreased.
111
Table 4.39 Effect of different proportions of non-nutritive sweeteners on sensory taste score (9 point hedonic scale) of the
hypoglycaemic guava-Aloe vera fruit bars during storage at ambient (12-24ºC) and low temperature (4+2
ºC)
Treatments
Temperature Days T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 Mean
Grand Mean
(I)
Grand Mean
(C)
0 7.20 4.10 3.50 7.06 6.90 5.21 5.20 7.03 6.60 5.07 4.98 6.70 6.52 4.05 3.94 5.60 5.60 5.37
90 7.12 4.00 3.17 6.95 6.82 5.12 5.12 6.95 6.49 4.62 3.75 6.58 6.48 3.78 3.68 5.37 5.38
180 7.02 3.91 3.03 6.85 6.72 5.07 5.02 6.81 6.38 4.02 3.33 6.45 6.36 3.28 3.08 5.15 5.18
Ambient
temperature
(12-24oC)
Mean 7.11 4.00 3.23 6.95 6.81 5.13 5.11 6.93 6.49 4.57 4.02 6.52 6.45 3.70 3.56
0 7.20 4.10 3.50 7.06 6.90 5.21 5.20 7.03 6.60 5.07 4.98 6.70 6.52 4.05 3.94 5.60 5.40
90 7.12 4.01 3.20 7.00 6.88 5.14 5.14 6.98 5.52 4.68 3.79 6.60 6.48 3.79 3.69 5.40
180 7.03 3.92 3.05 6.95 6.88 5.09 5.07 6.88 6.43 4.09 3.43 6.52 6.38 3.38 3.09 5.21
Low
temperature
(4+2ºC)
Mean 7.12 4.01 3.25 7.00 6.85 5.15 5.13 6.97 6.51 4.61 4.06 6.60 6.46 3.74 3.56
Grand Mean (T) 7.11 4.00 3.24 6.97 6.83 5.14 5.12 6.95 6.50 4.59 4.04 6.58 6.45 3.72 3.56
CD0.05
Treatment (T) = 0.13 TxI = 0.22
Intervals (I) = 0.06 TxC = 0.18 TxIxC = 0.33
Temperature (C) = 0.05 IxC = 0.08
T1: 100% Sucrose T6: 75 Sucrose + 25% Saccharin + 10% Apple pomace T11: 50 Sucrose + 50% Saccharin + 10% Oat bran
T2: 100% Stevia T7: 75 Sucrose + 25% Saccharin + 10% Oat bran T12: 25 Sucrose + 75% Stevia + 10% Apple pomace
T3: 100% Saccharin T8: 50 Sucrose + 50% Stevia + 10% Apple pomace T13: 25 Sucrose + 75% Stevia + 10% Oat bran
T4: 75 Sucrose + 25% Stevia + 10% Apple pomace T9: 50 Sucrose + 50% Stevia + 10% Oat bran T14: 25 Sucrose + 75% Saccharin + 10% Apple pomace
T5: 75 Sucrose + 25% Stevia + 10% Oat bran T10: 50 Sucrose + 50% Saccharin + 10% Apple pomace T15: 25 Sucrose + 75% Saccharin + 10% Oat bran
112
Further, the replacement of stevia leaves extract or saccharin beyond 50
per cent level significantly lowered the taste acceptability score of the resultant
fruit bars with a mean score registering below 7.0. Thus, the fruit bar prepared by
using 25 and 50 per cent stevia leaves extract with apple pomace as bulking agent
exhibited higher acceptability score than that of saccharin sweetened fruit bar.
Further, fruit bars containing apple pomace had better liking than fruit bar having
oat bran. However, sensory score of fruit bars made by using non-nutritive
sweeteners decreased consistently during storage up to 180 days. The mean score
for taste the star of storage period ranged between 3.50 to7.20 which decreased to
3.23 - 7.11 at ambient temperature and 3.25 -7.12 at low temperature after storage
of 180 days.
4.11.2.3 Flavour
Sensory score for flavour score of the product decreased significantly
with the corresponding increase in proportion of non-nutritive sweeteners in
hypoglycaemic guava-Aloe vera fruit bars. The highest score for flavour (7.30)
was obtained by 100 per cent sucrose sweetened fruit bar which was followed by
the fruit bars containing 25 per cent and 50 per cent stevia leaves extract as
replacement for sucrose. The products containing 75 per cent and 100 per cent
non-nutritive sweeteners were least preferred indicating unsuitability of the
prepared products by using non-nutritive sweeteners. However they exhibited
fairly good score for flavour of the product. Among non-nutritive sweeteners the
fruit bars prepared by using stevia leaves extract were preferred over the fruit
bars made by using equivalent proportions of saccharin. Further, the fruity
flavour imparted by apple pomace was effective in improving the resultant fruit
bars as compared to products containing oat bran as bulking agent. Thus,
hypoglycaemic guava-Aloe vera fruit bars can be prepared by using up to 50 per
cent stevia leaves extract along with 10 per cent along apple pomace as bulking
agent. Further, sensory score of fruit bars made by using non-nutritive sweeteners
decreased consistently during storage up to 180 days. The mean score for flavour
during storage period ranged 3.50 to7.30 to which decreased to 3.05-7.25 at
ambient temperature and 3.06-7.28 at low temperature after storage up to 180
days.
113
Table 4.40 Effect of different proportions of non-nutritive sweeteners on sensory flavour score (9 point hedonic scale) of the
hypoglycaemic guava-Aloe vera fruit bars during storage at ambient (12-24ºC) and low temperature (4+2
ºC)
Treatments
Temperature Days
T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 Mean Grand
Mean
(I)
Grand
Mean
(C)
0 7.30 4.50 3.50 7.28 7.00 6.95 6.85 7.05 6.93 6.74 6.65 6.92 6.61 6.61 6.32 6.48 6.48 6.36
90 7.26 4.11 2.85 7.22 6.92 6.92 6.73 6.92 6.88 6.68 6.58 6.84 6.58 6.43 6.32 6.35 6.36
180 7.20 4.02 6.80 7.18 6.85 6.80 6.67 6.83 6.80 6.50 6.47 6.77 6.54 6.33 6.13 6.26 6.27
Ambient
temperature
(12-24oC)
Mean 7.25 4.21 3.05 7.22 6.92 6.89 6.75 6.93 6.87 6.64 6.56 6.84 6.57 6.45 6.32
0 7.30 4.50 3.50 7.28 7.00 6.95 6.85 7.05 6.93 6.74 6.65 6.92 6.61 6.61 6.32 6.48 6.38
90 7.26 4.12 2.88 7.24 6.94 6.94 6.75 6.94 6.89 6.70 6.59 6.87 6.58 6.49 6.32 6.37
180 7.20 4.07 2.82 7.20 6.88 6.84 6.69 6.85 6.82 6.56 6.49 6.80 6.54 6.38 6.13 6.28
Low
temperature
(4+2ºC)
Mean 7.28 4.25 3.06 7.24 6.94 6.91 6.76 6.95 6.88 6.67 6.57 6.86 6.57 6.49 6.26
Grand Mean (T) 7.26 4.23 3.05 7.23 6.93 6.90 6.75 6.94 6.87 6.65 6.56 6.85 6.57 6.47 6.29
CD0.05
Treatment (T) = 0.13 TxI = 0.22
Intervals (I) = 0.06 TxC = 0.18
TxIxC = 0.32
Temperature(C) = 0.05 IxC = 0.08
T1: 100% Sucrose T6: 75 Sucrose + 25% Saccharin + 10% Apple pomace T11: 50 Sucrose + 50% Saccharin + 10% Oat bran
T2: 100% Stevia T7: 75 Sucrose + 25% Saccharin + 10% Oat bran T12: 25 Sucrose + 75% Stevia + 10% Apple pomace
T3: 100% Saccharin T8: 50 Sucrose + 50% Stevia + 10% Apple pomace T13: 25 Sucrose + 75% Stevia + 10% Oat bran
T4: 75 Sucrose + 25% Stevia + 10% Apple pomace T9: 50 Sucrose + 50% Stevia + 10% Oat bran T14: 25 Sucrose + 75% Saccharin + 10% Apple pomace
T5: 75 Sucrose + 25% Stevia + 10% Oat bran T10: 50 Sucrose + 50% Saccharin + 10% Apple pomace T15: 25 Sucrose + 75% Saccharin + 10% Oat bran
114
4.11.2.4 Texture
Addition of non-nutritive sweetener did not affect the texture of the
resultant fruit bars. The fruit bar prepared by using 100 per cent sucrose scored
having the highest acceptability for texture (7.50). Further, addition of 10 per cent
apple pomace to the fruit bar as bulking agent significantly improved the texture
acceptability score of the hypoglycaemic guava-Aloe vera fruit bars. Thus, stevia
leaves extract sweetened fruit bars up to 50 per cent replacement containing apple
pomace or oat bran as bulking agent exhibited a higher score for acceptability of
the texture and were optimized. Similarly, the product made by using apple
pomace was rated superior in texture as compared to the product containing oat
bran as bulking agent.
However, the mean score decreasing from 5.50-7.50 on 0 day to 5.12-
7.43 after six month was considered optimum and quite within acceptable range.
Further, sensory score of fruit bars made by using non-nutritive sweeteners
decreased consistently during storage up to 180 days.
4.11.2.5 Over all acceptability
The overall acceptability of the fruit bars prepared experienced slight
decrease with the increase of the storage period. However, the fruit bars prepared
by 100 per cent sucrose ranked significantly superior in over all acceptability.
Conclusively, it emerges that 50 per cent stevia or saccharin was at par to 100 per
cent sucrose sweetened fruit bars during storage. Although, the quality of the
prepared fruit bars declined during storage, yet the fruit bars sweetened with 50
per cent stevia leaves extract or saccharin retained their sensory quality to an
appreciable extent. This study signifies that 50 per cent level of sucrose can be
replaced by non-nutritive sweeteners to prepare hypoglycaemic fruit bars.
4.12 Energy value of of hypoglycaemic guava-Aloe vera fruit bar.
The data presented in Table 4.42 and fig 4.11 indicated that 59.2 per cent
reduction in energy value of guava-Aloe vera fruit bars. The mean value of
hypoglyceamic guava Aloe vera fruit bar ranged between 41.2 K cal/100g to
239.4 K cal/100g. On the 0 day, maximum energy value of 239.4 K cal/100g was
115
Table 4.41 Effect of different proportions of non-nutritive sweeteners on sensory texture score (9 point hedonic scale) of the
hypoglycaemic guava-Aloe vera fruit bars during storage at ambient (12-24ºC) and low (4+2
ºC) temperature
Treatments
Temperature Days
T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 Mean Grand
Mean
(I)
Grand
Mean
(C)
0 7.50 6.50 5.50 6.95 7.05 6.75 6.95 6.78 6.65 6.98 6.71 5.60 6.05 5.50 5.62 6.47 6.47 6.36
90 7.42 6.22 5.12 6.88 6.95 6.66 6.85 6.70 6.55 6.89 6.63 5.52 5.98 5.40 5.58 6.35 6.36
180 7.38 6.15 5.02 6.80 6.86 6.55 6.78 6.62 6.47 6.80 6.55 5.46 5.90 5.32 5.50 6.26 6.26
Ambient
temperature
(12-24oC)
Mean 7.43 6.29 5.21 6.87 6.95 6.65 6.86 6.70 6.55 6.89 6.63 5.52 5.98 5.41 5.56
0 7.50 6.50 5.50 6.95 7.05 6.75 6.95 6.78 6.65 6.98 6.71 5.60 6.05 5.50 5.62 6.47 6.38
90 7.44 6.25 5.15 6.89 6.88 6.69 6.87 6.70 6.72 6.54 6.89 5.54 6.00 5.43 5.60 6.37
180 7.39 6.18 5.07 6.85 6.88 5.59 5.80 6.64 6.50 6.83 6.59 5.50 5.95 5.37 5.59 6.30
Low
temperature
(4+2ºC)
Mean 7.44 6.31 5.24 6.90 6.94 6.67 6.87 6.71 6.62 6.78 6.73 5.55 6.00 5.43 5.60
Grand Mean (T) 7.43 6.30 5.12 6.88 6.94 6.66 6.86 6.70 6.58 6.83 6.68 5.53 5.99 5.42 5.58
CD0.05
TxI = 0.22
TxC = 0.18
TxIxC = 0.32
Treatment (T) = 0.13
Intervals (I) = 0.06
Temperature(C) = 0.05 IxC = 0.08
T1: 100% Sucrose T6: 75 Sucrose + 25% Saccharin + 10% Apple pomace T11: 50 Sucrose + 50% Saccharin + 10% Oat bran
T2: 100% Stevia T7: 75 Sucrose + 25% Saccharin + 10% Oat bran T12: 25 Sucrose + 75% Stevia + 10% Apple pomace
T3: 100% Saccharin T8: 50 Sucrose + 50% Stevia + 10% Apple pomace T13: 25 Sucrose + 75% Stevia + 10% Oat bran
T4: 75 Sucrose + 25% Stevia + 10% Apple pomace T9: 50 Sucrose + 50% Stevia + 10% Oat bran T14: 25 Sucrose + 75% Saccharin + 10% Apple pomace
T5: 75 Sucrose + 25% Stevia + 10% Oat bran T10: 50 Sucrose + 50% Saccharin + 10% Apple pomace T15: 25 Sucrose + 75% Saccharin + 10% Oat bran
116
Table 4.42 Effect of different proportions of non-nutritive sweeteners on sensory over all acceptability score (9 point hedonic scale) of
the hypoglycaemic guava-Aloe vera fruit bars during storage at ambient (12-24ºC) and low (4+2
ºC) temperature
Treatments
Temperature Days
T1 T2
T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 Mean Grand
Mean
(I)
Grand
Mean
(C)
0 7.37 5.60 4.92 7.06 7.00 6.41 6.49 6.89 6.70 6.44 6.26 5.70 5.80 5.91 5.87 6.29 6.29 6.09
90 7.42 5.40 3.12 6.88 6.95 6.66 6.85 6.7 6.55 6.89 6.63 5.52 5.78 6.64 6.58 6.10 6.12
180 7.24 5.31 2.47 6.91 6.82 6.24 6.31 6.72 6.53 6.03 5.72 5.53 5.42 5.56 5.55 5.89 5.94
Ambient
temperature
(12-24oC)
Mean 7.34 5.43 3.50 6.95 6.92 6.44 6.55 6.77 6.59 6.45 6.20 5.58 5.40 5.96 6.00
0 7.37 5.60 4.92 7.06 7.00 6.41 6.49 6.89 6.70 6.44 6.26 5.70 5.80 5.91 5.87 6.29 6.16
90 7.31 5.41 4.60 7.00 6.92 6.43 6.36 6.83 6.43 6.20 5.98 5.66 5.40 5.79 5.80 6.14
180 7.25 5.34 4.51 6.95 6.88 5.90 5.90 6.75 6.56 6.08 5.75 5.57 5.42 5.62 5.58 6.00
Low temperature
(4+2ºC)
Mean 7.31 5.45 4.67 7.00 6.93 6.25 6.25 6.82 6.56 6.24 6.00 5.64 5.54 5.77 5.75
Grand Mean (T) 7.32 5.44 4.08 6.97 6.92 6.34 6.40 6.79 6.57 6.34 6.10 5.61 5.47 5.86 5.87
CD0.05
TxI = 0.22
TxC = 0.18
TxIxC = 0.32
Treatment (T) = 0.13
Intervals (I) = 0.06
Temperature(C) = 0.04 IxC = 0.08
T1: 100% Sucrose T6: 75 Sucrose + 25% Saccharin + 10% Apple pomace T11: 50 Sucrose + 50% Saccharin + 10% Oat bran
T2: 100% Stevia T7: 75 Sucrose + 25% Saccharin + 10% Oat bran T12: 25 Sucrose + 75% Stevia + 10% Apple pomace
T3: 100% Saccharin T8: 50 Sucrose + 50% Stevia + 10% Apple pomace T13: 25 Sucrose + 75% Stevia + 10% Oat bran
T4: 75 Sucrose + 25% Stevia + 10% Apple pomace T9: 50 Sucrose + 50% Stevia + 10% Oat bran T14: 25 Sucrose + 75% Saccharin + 10% Apple pomace
T5: 75 Sucrose + 25% Stevia + 10% Oat bran T10: 50 Sucrose + 50% Saccharin + 10% Apple pomace T15: 25 Sucrose + 75% Saccharin + 10% Oat bran
117
recorded in 100 per cent sucrose sweetened hypoglycaemic guava-Aloe vera bar
and minimum in 100 per cent stevia leaves extract sweetened hypoglycaemic
guava-Aloe vera fruit bar. Further, during storage of the products, the calculated
energy values exhibited a constituent decrease which was attributable to the
constituent decrease in resolved sugar contents of the fruit bars. The fruit bars
containing 50 per cent proportion of stevia leaf extract or saccharin which were
adjudged acceptable in sensory quality exhibited the energy value of 96-96.7
Kcal/100g after six month of storage period. In comparison to 100 per cent
sucrose sweetened fruit bars, the reduction in energy value was calculated to be
59.8 per cent in stevia or saccharin sweetened fruit bars. The decrease in energy
value during storage may be attributed to decrease in total sugars.
4.13 Cost of production of hypoglycaemic guava-Aloe vera fruit bar
Cost incurred in preparation of guava-Aloe vera fruit bar was calculated
by taking into consideration the cost of all the inputs and the cost involved during
processing. The comparative cost of production of fruit bar prepared by using 100
per cent sucrose as presented in Table 4.43. The cost was calculated on the basis
of current market prices of ingredients, and adding processing changes as well as
profit @20 per cent of each.
Table 4.43. Effect of different proportions of of non-nutritive sweeteners on
calculated energy value of hypoglycaemic guava-Aloe vera
fruit bar
Calculated energy value (Kcal/100g) Proportion Su :St : Sa : Ap : Ot 0 day 90 days 180 days
T1:100 :0: 0:0 239.4 237.6 236.9 T2: 0 :100 : 0:0 41.2 40.8 40.4 T3 :0 : 0 :100:0 42.0 40.8 40.0 T4 : 75 : 25 : 0 :10:0 182 178.6 178.2
T5 : 75 : 25: 0 : 0 :10 182 180.3 179.5
T6 : 75 : 0:25 : 10 : 0 181.1 180.8 179.2
T7 : 75 : 0 : 25 : 0 : 10 181.0 180.5 179.7
T8 : 50: 50 : 0 :10 : 0 97.0 96.3 96.0
T9 : 50: 50 : 0 : 0 : 10 97.0 96.5 96.3
T10: 50 : 0 : 50 : 10 : 0 97.4 96.8 96.4 T11: 50: 0 : 50 : 10 : 0 97.8 97.1 96.7 T12: 25 : 75 : 0: 10:0 46.2 45.8 45.9
T13 : 25 : 75 : 0 : 0 :10 47.20 45.5 45.8
T14 : 25: 0 : 75 : 10 : 0 47.1 46.8 46.5
T15: 25 : 0 : 75 : 0 : 10 47.00 46.8 46.3 Su-sucrose, St-stevia leaves extract leaves extract, Sa-saccharin, Ap- Apple pomace, Ot -oat bran
118
The cost per unit of guava-Aloe vera fruit bar was found lowest
(Rs.11.66/10g) when prepared using 50 per cent sucrose and 50 per cent stevia
leaves extract followed by 100 per cent sucrose sweetened guava-Aloe vera fruit
bar i.e. Rs.13.18/100g. While the cost of saccharin sweetened fruit bar (50%
sucrose and 50% saccharin) was Rs.16.26/100g bar. The cost of saccharin
sweetened fruit bar was higher than 100 per cent sucrose and stevia leaves extract
sweetened fruit bar. Thus, the stevia leaves extract sweetened fruit bar was more
appreciable and cost effective than saccharin sweetened fruit bar.
Table 4.44 Cost of production of hypoglycaemic guava-Aloe vera fruit bar
Standard 100 %
sucrose
Stevia leaves
extract (50%) Saccharine (50%)
Particulars Rate (Rs.)
Qty Amt
(Rs.) Qty
Amt
(Rs.) Qty Amt (Rs.)
Guava pulp 30.00/lt 4050 ml 120.00 4050 ml 120.00 4050 ml 120.00
Aloe vera leaves
extract 19.00/lt 450 9.00 450 9.00 450 9.00
Sugar 40.00/kg 5500 220.00 2750 110.00 2750 110.00
Stevia leaves
extract 3.00/lt - - 2000 6.00 -
Saccharin 2500.0/100g - - - - 3g 337.50
Citric acid 42.00/100g 40 16.80 40 16.80 40 16.80
Bulking agents 300/kg 1 300.00 1 300.00 1 300.00
Laminates 2.00 100 200.00 100 200.00 100 200.00
Label 0.50 100 50.00 100 50.00 100 50.00
Total Cost of
ingredient (Rs.) 915.80 809.80 1143.3
Processing
cost@20% 183.16 161.96 228.60
Total 1098.96 971.76 1371.90
Profit @ 20 % 219.77 194.35 274.38
Total cost of
product 1318.7
1166.1
1 1646.28
Total yield (lt.) 10kg /100 pcs (100 g )
Sale Price for
100 g fruit bar Rs.13.18
Rs.11.66
Rs.16.46
Chapter-5
DISSCUSION
The present investigation entitled “Development and evaluation of
hypoglycaemic guava product with Aloe vera fortification” was conducted in the
department of Food Science and Technology, Dr. Y.S. Parmar University of
Horticulture and Forestry, Nauni, Solan (HP) during the years 2009-2011. The
results of this study presented in tables 4.41-4.44 and figures 4.1- 4.5 are
discussed as under:
5.1 Physico-chemical composition of guava fruits
5.1.1 Physical characteristics
Guava (Psidium guajava L.) one of the pomiferous fruit of Myrtaceae
family is valued for characteristic flavour, texture and nutritional qualities
(Tiwari and Dinesh, 2001). The average weight, length and diameter of fresh fruit
were found to be 82.0 g, 50.0 mm and 52.66 mm, respectively (Table 4.1).
Similar, characteristics of guava fruits have been reported by Singh et al. (1995).
The specific gravity of fresh fruits was observed as 0.92 which was found to be
slightly lower than the observation of Murari and Verma (1989) in guava fruits.
5.1.2 Chemical characteristics
The average total soluble solids (8.3oB) and titratable acidity (0.76 %) in
guava fruit cv. Allahabad Safeda was found to be lower than observation of
Murari and Verma (1989). Guava was found to be a rich source of vitamin C and
average ascorbic acid content was recorded as 216.0 mg/100g (Table 4.1).
However, Murari and Verma (1989) reported 272.0 mg/100g of ascorbic acid
present in Allahabad Safeda cultivar of guava fruit. The total sugar present in
fruit was 6.67 per cent with reducing sugars as 4.83 per cent which were similar
to the values recorded by Murari and Verma (1989) and Sandhu et al. (2001).
While the moisture content of 84 per cent in guava fruits was found similar to
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the findings of Phandis (1970) and Sandhu et al. (2001) for moisture content in
guava fruits.
5.2 Optimization of method for extraction of pulp from guava fruit cv.
Allahabad Safeda
The method for extraction of guava pulp was standardized by diluting the
guava slices in water in different ratio (1:1, 1:1.5 and 1:2) followed by heating
either in open pan (atmospheric pressure) or in pressure cooker for varying steam
pressure and period of time. After treatment the pulp was extracted by passing the
fruit mass through a pulper. The method of heating guava slices exerted a
significant effect on the yield of guava pulp. Heating in pressure cooker at 0.35
Kg/cm2 for 15 min yielded 83.3 per cent pulp while heating in open pan gave a
pulp yield of 67.5%. Further, the increase in proportion of water in fruit caused
increase in the yield of the pulp with consequent decrease in amount of residue
(Table 4.2). Earlier, Mandhyan et al. (2000) and Sandhu et al. (2001) also
recorded increase in yield of pulp within increase in proportion of water in guava
pulp. Thus heating guava slices with water (1:1 ratio) in pressure cooker at 0.35
Kg/cm2 for 15 min with maximum pulp yield was found most appropriate for
guava pulp extraction. Earlier Mandhyan et al. (2000) also recommended boiling
in pressure cooker for 1 hour for extraction of guava pulp. Sandhu et al. (2001)
also recorded increase in recovery of pulp through hot extraction methods than
cold extraction method.
The total solids and total soluble solids in pulp extracted by using
different heating methods ranged between 3.28 to 3.87 per cent and 2.74 to
3.13ºB, respectively (Table 4.3). The pulp obtained after heating fruits in pressure
cooker at 0.70 Kg/cm2
steam pressure for 4 min exhibited highest mean total
solids (3.87%) followed by pulp obtained after heating for 15 min at 0.35 Kg/cm2
in pressure cooker. Further, with the increase in proportion of water in the fruit
slices, the total solids of the resultant pulp exhibited a decrease. Accordingly, the
pulp obtained by using 1:1 dilution of fruit and water resulted in highest solid
content of 4.81 per cent (Table 4.3) as compared to pulp obtained after using
1:1.5 and 1:2 dilution. Similarly the pulp obtained after using 1:1 proportion of
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fruit and water exhibited higher TSS (4.03 ºB) as compared to other
combinations. The dilution caused by using higher proportion of water was
attributed to this decrease in total solids of the extracted pulp. Further, the total
soluble solids in the pulp extracted after using different methods ranged between
2.74 to 3.13ºB (Table 4.3). The pulp extracted by using cold extraction exhibited
lowest level of total soluble solids (2.74ºB) while pulp obtained after heating in
pressure cooker at 0.35 Kg/cm2 for 15 min showed mean TSS value of 4.13
ºB.
Thus, dilution of guava slices along with water at 1:1 proportion followed by
heating in pressure cooker at 0.35 Kg/cm2 steam pressure for 15 min was
optimized for extraction of guava pulp. However, Mandhyan et al. (2000) found
1:4 as optimum method for extraction of guava pulp. The difference in method of
heating (open cooking in contrast to cooking under pressure) might be attributed
to this observation.
The dilution of fruit slices in water in different proportions brought about
significant difference in titratable acidity and pH of the extracted pulp. The pulp
extracted after using 1:1 dilution had highest titratable acidity and lowest pH
(3.67). The titratable acidity of the pulp extracted after heating fruits in different
method ranged between 0.25-0.28 per cent with a mean pH value of 3.88-3.99
(Table 4.4). Similarly, total sugars content in extracted pulp decreased with the
increase in proportion of water. The pulp extracted after using 1:1 dilution had
the highest total sugar contents (3.2%) followed by pulp obtained after using
1:1.5 dilution. Further, heating of fruit slices brought about significant
improvement in total sugars content as the pulp obtained after cold extraction had
the lowest total sugars (2.25%). Sandhu et al. (2001) recorded similar values of
total sugars in the guava pulp.
Persual of data in Table 4.5 indicate that method of heating fruit slices
exerted its significant influence on the ascorbic acid content of extracted pulp.
The guava pulp obtained after cold extraction had the highest mean ascorbic acid
(83.19 mg /100g), which decreased to 62.52 mg/100g when fruits were heated in
open pan. However, heating under controlled conditions in pressure cooker
brought about significant improvement in retention of ascorbic acid in the
extracted pulp. Similarly, use of water for dilution brought about significant
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reduction in ascorbic acid contents of extracted pulp. However, the pulp obtained
after using 1:1 dilution exhibited highest ascorbic acid (101.2 mg/100g) than that
of higher dilution our results were in conformation to the findings of Sandhu et
al. (2001) and Murari and Verma (1989) for ascorbic acid values in guava pulp.
As expected, heating of fruit brought about significant improvement in pectin in
guava pulp obtained after cold extraction had the lowest pectin content (0.38%).
Boiling of fruits at varying steam pressure is attributable to this increase in pectin
content. However, use of higher dilutions caused reduction in pectin content of
the resultant pulp (Table 4.6). The effect of dilution was found to be very
significant in the relative viscosity of the pulp. The pulp obtained from the fruits
after using 1:1 dilution exhibited the highest relative viscosity. Similarly, the
heating of the fruits causing better extraction of pectin also showed increase in
relative viscosity of the extracted pulp. The effect of heating to disintegrate
tissues was quiet apparent from the grittiness of the extracted pulp. The pulp
obtained after cold extraction exhibited highest grits (47%) in the pulp which
were reduced to a 29 per cent in open pan heating, 21.8-23.3 per cent in pressure
cooker (0.35 Kg/cm2) steam pressure and just 11-12.3 per cent in pressure cooker
at 0.70 Kg/cm2 steam pressure. Thus, on the basis of chemical attributes
including pectin, relative viscosity and less grittiness, the method consisting of
heating guava fruits along with water in 1:1 proportion in a pressure cooker at
0.35 Kg/cm2 pressure for 15 min was optimized for extraction of guava pulp.
5.3 Extraction and evaluation of Aloe vera gel extract (Aloe vera
barbadensis) and dried stevia leaves powder
5.3.1 Aloe vera gel extract
Physico-chemical attributes of raw Aloe vera gel (Table 4.8) indicate that
raw gel obtained after scrapping of Aloe vera stem after peeling was a colloidal
mass and difficult to handle. As per method optimized by Ramachandra and Rao
(2008) the gel got stabilized to a free flowing gel after heating the mass at 80ºC
and adding 0.3 per cent citric acid. Earlier Ramachandra and Rao (2008) found
that stabilization by heating and addition of citric acid was also capable to check
browning and improve flavour of Aloe vera juice. Chemically, the processed gel
contained almost similar attributes as that of raw gel except titratable acidity.
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Processed gel contained higher titratable acidity (0.67%) which was attributable
to the exogenous addition of 0.3 per cent citric acid during stabilization. Though,
heating of gel for stabilization brought about reduction in ascorbic acid content of
the processed gel, yet the Aloe vera gel extract was found to be a good source of
ascorbic acid and suitable for product development. The ascorbic acid values
found in present investigation were in conformity with the values of ascorbic acid
reported by Pierce (1983) in Aloe gel extract. Processing of gel exhibited a
substantial improvement on the flow properties as the raw gel was found to be
too thick to pass through the orifice of the viscometer. Improvement in flow
properties of the gel extract after heating has also been reported by Feminia et al.
(1999) and Wang and Strong (1995). Thus, heating of raw gel and stabilization
with exogenous addition of citric acid was considered optimum for extraction of
Aloe vera gel extract.
5.3.2 Quality attributes of dried stevia leaves
Fresh stevia leaves after drying in dehydrator were ground to a fine
powder and evaluated for various quality attributes. Data in Table 4.9 indicate
that the total soluble solids in fresh stevia leaves had a TSS of 8.36+0.15ºB,
which was slightly higher than the observations reported by Savita et al. (2004)
and Rolly Kanchan et al. (2009). The quantity of steviosides was recorded as
13.23+0.01 per cent was found similar to the observation of Lima and Malavolta
(1999) who recorded steviosides varying between 5 to 15 per cent in dried stevia
leaves. The protein and fat content in dried leaves was recorded to be 10.0 per
cent and 6.07 per cent, respectively was found to be lower than the values
observed earlier by Savita et al. (2004) and Rolly Kanchan et al. (2009) but
within the same range as recorded by Brandle and Starratt,1998 in dried stevia
leaves. The rebaudiosides A recorded as 4.20+0.10 per cent were within range of
2 to 4 per cent reported by Tateo et al. (1999) while Kolb et al. (2001) found
rebaudiosides A in stevia leaves between 1.62 to 7.27 per cent on dry weight
basis. It is apparent from the result that besides a source of steviosides, stevia
leaves are also a potential source of these constituent like proteins, fibres, and
minerals etc. which are significant from nutrition point of view.
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5.4 Standardization of method for preparation of guava-Aloe vera
beverage
The method for preparation of guava-Aloe vera beverage was
standardized by maintaining 20 per cent pulp and 15ºB TSS in the prepared drink
as per FSSA (2006) specifications. The preparation of Aloe vera gel extract was
incorporated by replacing the corresponding proportion of guava pulp in the
resultant guava-Aloe vera beverage. The level of Aloe vera gel at which the
beverage remained acceptable in both chemical and sensory characteristics were
optimized. The results of the study are discussed as under:-
5.4.1 Physico-chemical attributes of guava-Aloe vera beverage
Out of different combination, the guava- Aloe vera nectar prepared by
using 15 per cent guava pulp and 5 per cent Aloe vera gel extract containing
15.63ºB TSS, 0.34 per cent titratable acidity, 16.17 mg/100g ascorbic acid and
with a specific gravity of 1.026 was optimized. Similar blends of guava-anola and
guava-bael were prepared by Mall and Tondon (2007) and Nidhi et al. (2008).
With the increase in proportion of Aloe vera gel in beverage, total soluble solids
and total sugar did not exhibit much variation, which was attributed to the use of
cane sugar (sucrose) for maintaining the desired TSS as Aloe vera gel contributes
little to the total soluble solids. Further, with the decrease in guava pulp and
corresponding increased in Aloe vera gel exhibit to maintain 20 per cent pulp in
the beverage, the ascorbic acid content in the beverage did not experience much
change in ascorbic acid. Contribution of ascorbic acid from Aloe vera might be
attributed to this observation as Aloe vera also contained appreciable proportion
of ascorbic acid.
Accordingly, Aloe vera gel can be incorporated in guava pulp for
preparation of guava-Aloe vera beverage containing bioactive compounds.
Earlier, many workers have reported that two or more fruit pulp/juices may be
blended in various proportions for preparation of more palatable and nutritious
beverages (Kalra et al., 2001, Saxena et al., 1997, Attri et al., 1998 and Tiwari,
2000).Thus, guava Aloe vera beverage prepared by using 15 per cent guava pulp
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and 5 per cent Aloe vera gel extract was found to meet the FSSA specifications of
fruit beverage.
5.4.2 Sensory quality of hypoglycaemic guava-Aloe vera beverage
Comparison of physico-chemical and sensory attributes (Table 4.10 and
4.11) of guava-Aloe vera beverage reveals that though the chemical attributes
were not affected yet there was a significant effect on the sensory quality of
prepared beverages.
With the increase in Aloe vera content in the beverage sensory colour
scores decreased. Similar, Joshi et al. (2006) observed decrease in colour score
with the increase in juice content while working on the preparation of plum
beverages. The guava-Aloe vera having 15 per cent guava and 5 per cent Aloe
vera was chosen by panelist. Flavour/aroma score was decrease with the increase
in Aloe vera and decrease in guava pulp. It might be due to characteristic of Aloe
vera and resulting proportionally lower sensory flavour/aroma score. Singh
(2002) observed a similar decrease while working on bitter gourd diabetic
beverages.
With respect to taste, beverage having 15 per cent guava and 5 per cent
Aloe vera scored 6.1 score among other treatment. The taste score decreased as
the concentration of Aloe vera was increased. It can be concluded from these
results that product with high concentration of Aloe vera exhibited higher
astringency that lowered the acceptability score for taste. Similar observations
were also recorded by Schiffman et al. (1985), Sharma (1999), Barwal et al.
(2000), Roy (2001) and Singh (2002), Barwal et al. (2005).
The body score of guava-Aloe vera beverage decreased with increased of
Aloe vera (Table 4.11). Earlier, the decrease in body score was also reported by
Tiwari (2000) and Singh (2002). The over all acceptability showed in Table
4.11 that the highest score 20 per cent guava pulp which was followed by 17.5
per cent guava 17.5 per cent guava and 2.5 per cent Aloe vera by taking an
account the beneficial effect of the Aloe vera 15 per cent guava and 5 per cent
Aloe vera was more acceptable after 17.5 per cent guava and 2.5 per cent Aloe
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vera beverage. The OAA of guava-Aloe vera beverage decreased with the
increase in Aloe vera per cent in pulp. Similar, results were reported by Mall and
Tondon (2007).
Considering all aspect, guava-Aloe vera beverage 15 per cent guava and 5
percent Aloe vera was adjudged best by the panellist due to its acceptable sugar
pulp blend according to FSSA (2006). Hence, beverage having 15 per cent guava
and 5 per cent Aloe vera was used for the preparation of hypoglycaemic guava-
Aloe vera beverage.
5.5 Optimization of parameters for preparation of hypoglycaemic guava-
Aloe vera beverage using stevia leaves extract and sorbitol.
The guava-Aloe vera beverage containing 15 per cent guava pulp and 5
per cent Aloe vera gel extract was evaluated for preparation of low
calorie/hypoglycaemic guava-Aloe vera drink prepared by replacing the sucrose
with equivalent level of sweetness obtained by using sorbitol or stevia leaves
extract. The type and level of non-nutritive sweetener at which the beverage
exhibited maximum acceptability for sensory quality were optimized. The results
of the study presented in Table 4.12 and 4.13 are discussed as under.
5.5.1 Physico-chemical characteristics of hypoglycaemic guava-Aloe vera
beverage
The total soluble solids in beverage containing different proportion of
sweeteners (sucrose, stevia leaves extract and sorbitol) ranged between 2.46-
15.0ºB. As expected, with the increase in level of stevia leaves extract and
sorbitol to replace sucrose, the total soluble solids (TSS) contents in the resultant
beverage exhibited a consistent decrease. The highest total soluble solids was
recorded in the beverage which contained 100 per cent sucrose (15ºB) while the
beverage prepared by using complete substitution with stevia leaves extract
registered the lowest TSS (2.46ºB). Sharma (1999), Barwal et al. (2005) and
Singh (2002) also recorded change in TSS with the addition of non-nutritive
sweeteners in low calorie plum beverage and diabetic bitter gourd ready-to-serve
drinks also registered. The titratable acidity of different beverage ranging
between 0.31-0.33 per cent did not exhibit significant change by addition of non-
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nutritive sweeteners. The guava-Aloe vera drink containing stevia leaves extract
also showed appreciable presence of ascorbic acid. Thus, stevia leaves extract
besides imparting low calories was also capable of providing good amount of
vitamin C to the drink.
Further, with the increase in proportion of non-nutritive sweeteners and
corresponding decrease in sucrose, the total sugar content in the prepared drink
registered a consistent and significant decrease (Table 4.12). The replacement of
total sugars with corresponding increase in stevia leaves extract are expected to
impart comparatively less calories, which serve the purpose of preparing low
calories (hypoglycaemic) beverage. Sharma (1999) Barwal et al. (2005) and
Singh (2002) prepared low calorie plum beverage and diabetic bitter gourd ready-
to-serve drinks (RTS) by using no-nutritive sweeteners. The relative viscosity of
sorbitol sweetened beverage increased with increase in the proportion of sorbitol
in beverage while stevia leaves extract sweetened drink exhibited lowest relative
viscosity. Further, the beverage containing 100 per cent sucrose showed
maximum specific gravity which decreased with decrease in proportion of
sucrose in the drink. Since, there is direct relationship between total sugars and
specific gravity. Therefore beverage containing no-nutritive sweeteners had lower
specific gravity. The energy value calculated on the basis of total sugars in the
drink ranged between 6.56 to 65.64 K cal/100g. The drink made by using 100 per
cent stevia leaves extract registered lowest calorie than 100 per cent sorbitol or
sucrose sweetened beverage. Further, the drink having 50 per cent substitution of
stevia leaves extract or sorbitol had comparatively lesser calories than that of
drink having 100 per cent sucrose. Thus stevia leaves extract and sorbitol at 50
per cent level of substitution can successfully be used for preparation of low
calorie (hypoglycaemic) beverages. Sharma (1999), Barwal et al. (2002) and
(2005) also reported reduction in calorie in plum beverages and diabetic bitter
gourd ready-to-serve drinks (RTS).
5.5.2 Changes in sensory quality of hypoglycaemic guava-Aloe vera
beverage
Sensory attributes of hypoglycaemic guava-Aloe vera beverage prepared
by replacing sugar with equivalent proportion of stevia leaves extract and sorbitol
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presented in Table 4.13 are discussed as under:-
5.5.2.1 Colour
The colour acceptability score of different beverage containing varying
proportion of sweeteners ranged between 5.43-8.30 on a 9 point hedonic scale.
The addition of stevia leaves extract as well as sorbitol to replace sucrose brought
about significant changes on sensory colour acceptability score of the resultant
beverage. The beverage prepared by using 100 per cent sucrose had the
maximum acceptability for colour. With the addition of non-nutritive sweeteners
in the drinks to replace sucrose the colour score registered a consistent decrease.
Further, in comparison to stevia leaves extract for sweetening caused significant
reduction in colour acceptability score of the beverage. However, the beverage
containing stevia leaves extract up to 50 per cent level of replacement registered a
mean score of 7.93. While use of stevia leaves extract beyond 50 per cent level
(i.e. 75% and 100%) made the beverage unacceptable in colour/appearance. The
colour imparted by stevia leaves might be attributed to this decrease in colour
acceptability of the beverage.
5.5.2.2 Flavour/Aroma
Flavour acceptability score of beverage prepared by different sweeteners
ranged between 5.32-7.25 (Table 4.13). The drink prepared by using only sucrose
had highest liking for flavour which decreased appreciably with the increase in
proportion of non-nutritive sweeteners. However, all drinks prepared by
substituting sucrose with sorbitol at all levels (25, 50, 75 and 100) of substitution
were acceptable in flavour with a mean score ranging between 6.74 to 7.24.
Earlier, Barwal et al. (2002) did not found any effect on the flavour acceptability
score of sorbitol sweetened beverage. The flavour acceptability for drinks
containing stevia leaves extract significantly decreased with increase in
proportion of stevia leaves extract. Typical flour/aroma imparted by the stevia
leaves extract was attributable for decrease in flour acceptability of beverage.
However, the hypoglycaemic guava Aloe vera beverage containing up to 50 per
cent level of stevia leaves remained acceptable.
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5.5.2.3 Taste
Data in Table 4.13 reveals that all beverage containing either sucrose or
sorbitol as sweeteners were acceptable for its taste attributes. However, guava-
Aloe vera beverage sweetened by using stevia leaves extract remained acceptable
only when stevia leaves extract was added up to 50 per cent level of sweetness.
Addition of stevia leaves extract beyond 50 per cent (i.e. 75% and 50%) made
beverage unacceptable in taste. This change was attributable to the bitter after
taste imparted by stevia leaves. The unpleasant taste associated with stevia
(Pinherio, 2005) with the increase in the quantity of stevia extract is increased.
Thus, the drinks prepared by replacing 50 per cent sucrose with equivalent
proportion of stevia leaves extract was optimized for preparation of low calorie
guava-Aloe vera beverage.
5.5.2.4 Body
Evaluation of the beverage for body (Table 4.13) revealed that stevia
leaves extract exhibited significant reduction in its sensory score. The drink
prepared by using 100 per cent sucrose had maximum liking with respect to body
followed by beverages containing sorbitol as non-nutritive sweeteners. With the
addition of stevia leaves extract to replace sucrose at equivalent level of
sweetness, the body score of the beverage registered a consistent decrease while
sorbitol sweetened drinks did not experience much changes in the acceptability
score for body. Improvement in body score with corresponding increase in
sorbitol proportion has also reported by Barwal et al. (2002). Watery nature of
the stevia leaves extract might have resulted in decrease in body of the resulted
beverage. However, the drinks containing up to 50 per cent stevia leaves extract
showing a mean body score more than 7.0 were considered optimum for the
preparation of low calorie guava-Aloe vera beverage.
5.5.2.5 Over all acceptability
Data presented in Table 4.13 indicate that the over all acceptability score
of beverage containing stevia leaves extract or sorbitol experienced slight
decrease with the increase in proportion of non-nutritive sweeteners. Among non-
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nutritive sweeteners, the sorbitol beverages did not exhibit much change in over
all acceptability with increase in level of sorbitol our results were in conformity
with the observations of Barwal et al. (2002) for sorbitol sweetened beverage. As
expected, drink prepared by using 100 per cent sucrose were ranked significantly
superior in over all acceptability followed by drink prepared by using 25 per cent
and 50 per cent level of substitution with either stevia leaves extract. Addition of
stevia leaves extract beyond 50 per cent made beverage unacceptable. Leafy
bitter after taste might have led to reduction in the score of over all acceptability
as reported by Thandhani and Subash (2009) also recorded reduction in
acceptability of beverage prepared by replacing sucrose with stevia leaves. Thus,
low calorie guava-Aloe vera beverage can successfully prepared by replacing
sucrose.
5.6 Storage studies of hypoglyceamic guava-Aloe vera beverages.
Low calorie guava-Aloe vera beverage containing different non-nutritive
sweeteners were packed hot in presterlized 200 ml glass bottles and processed in
boiling water for 25 min followed by storage at ambient temperature. The
changes in physic-chemical and sensory attributes of the beverages were
evaluated at periodic interval of 0, 90 and 180 days. The changes in physico-
chemical as well as sensory attributes during storage of the beverages are
presented in tables 4.14 to 4.22 are explained as under
5.6.1 Physico-chemical characteristics of hypoglycaemic guava-Aloe vera
beverage during storage
5.6.1.1 Total soluble solids
The total soluble solids in beverage containing different of non-nutritive
sweeteners ranged between 2.46-15ºB, which increased to 2.66-15.17ºB after six
month of storage at ambient temperature. Among different combinations, the
beverages prepared by substituting with equivalent proportions of stevia leaves
extract exhibited the lowest total soluble solids at all intervals of storage up to
180 days. While the drink prepared by substituting sorbitol showed higher total
soluble solids as compared to the drink which contained stevia but lower than the
drink which was made by using 100 per cent sucrose (Table 4.14). Thus, the
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drink prepared by using 50 per cent substitution with stevia leaves extract which
registered 7.53ºB TSS, was considered optimum for the preparation of low calorie
guava-Aloe vera beverage. The increase in total soluble solids in all beverages
during storage might be due to solubilisation of pulp constituents and hydrolysis
of starch into simpler sugar as has been observed by Jawanda et al., 1978. A
slight increase in total soluble solid of fruit beverage i.e. papaya, guava and bael
was also recorded by Saravanan et al. (2004), Nagpal (2002) and Verma (2004)
during storage.
5.6.1.2 Titratable acidity
The titratable acidity of the beverage showed slight decline during 180
days of storage. The presence of mean acid content ranging between 0.29-0.32
per cent during entire period of storage indicate that level of acidity was
appropriate to have acceptable acid-sugar balance in the prepared beverages
(Table 4.15). Changes occurring during storage showed a slight decline in
titratable acidity. The decrease in acidity might be due to chemical interaction
taking place between organic acids and pigments by action of enzymes and
temperature (Khanna and Thirumaran, 2001). Khurdiya and Lotha (1984) noticed
a slight decrease in acidity in jamun juice and nectar during storage. Similarly,
Sarvanan et al. (2004) and Ahire et al. (2010) also recorded reduction in acidity
of papaya beverage and pomegranate juice during storage.
5.6.1.3 Ascorbic acid
A slight decrease in ascorbic acid content in beverage with the increase in
period of storage was observed in all types of combinations (Table 4.16). The
mean value of ascorbic acid in different beverages decreased from initial level of
17.35 mg/100g to 16.60 mg/100g after 180 days of storage (Table 4.16).
However, the beverage prepared by using stevia leaves extract registered higher
level of ascorbic acid than sorbitol sweetened beverage. Further, drink
containing 50 per cent stevia leaves extract exhibited higher level of ascorbic acid
after six month of storage. This might be due to presence of ascorbic acid in
stevia leaves extract. Das (2009) recorded a continuous decrease in ascorbic acid
content in jamun RTS, beverage, squash and syrup during six month of storage.
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The reduction might be due to oxidation of ascorbic acid into dehydro-ascorbic
acid during storage at ambient condition. Similar observations were recorded by
Sethi et al. (1980) in lime-guava cocktail, Gosh et al. (1982) reported in
preservation of the fruit juice and pulp in flexible pouches; Ram (1984) in anola
beverages. The decline in ascorbic acid content may also be due to the thermal
oxidation during processing and storage. According to Aruna et al. (1997) the
reason for loss of ascorbic acid during storage might be due to its oxidation to
furfural and hydroxymethyl furfural. Similar results were observed by Nagpal
(2002) in guava beverage. Ahire et al. (2000) recorded higher decrease in
ascorbic acid content in juices during storage at ambient condition. Thus, the
beverage prepared by using stevia leaves extract as sweetener to replace sucrose
were considered optimum for preparation of low calorie beverages, which also
contained slightly higher ascorbic acid.
5.6.1.4 pH
The pH value of the beverage registered a marginal but significant
increase up to 180 days. The mean pH in low calorie guava-Aloe vera beverages
during storage varied from 3.47 to 3.51 (Table 4.17). The pH was found to be
increased during storage, which was in conformity with the results of Hassan and
Ahmed (1998).
5.6.1.5 Total Sugars
The incorporation of non-nutritive sweeteners brought about significant
reduction in total sugars contents of the beverages at time of preparation. During
storage the total sugars in different beverage experienced about 3.2 per cent
decrease from mean value of 5.97 to 5.78 per cent (Table 4.18). The drink
prepared by using different proportions of sweetness had total sugars varying
between 1.41 to 14.39 per cent on 0 day and 1.35 to 13.80 per cent after 180 days
of storage (Table 4.18). The decrease in total sugars during storage might be
attributed to the involvement of sugars in browning reaction and formation of
hydroxymethyl furfural (HMF). According to Shaw et al. (1997) hexose sugars in
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lemon juice break down to produce carboxylic intermediates leading to the
formation of brown pigments.
5.6.1.6 Relative viscosity
The presence of sucrose or sorbitol in the drink exhibited higher relative
viscosity in the resultant beverage while products made by using stevia leaves
extract had comparatively low relative viscosity (Table 4.19). During storage, the
beverage experienced reduction in relative viscosity. The maximum relative
viscosity of 1.60 was found in 100 per cent sorbitol sweetened drink, which
decreased to 1.52 after 180 days of storage. Further, the drink prepared by using
sorbitol possessed higher viscosity than stevia leaves extracts sweetened drink.
The decrease in relative viscosity of fruit beverages observed during storage
could probably be the result of the breakdown of insoluble solids
(polysaccharides) into soluble compounds (Gould, 1983).
5.6.17 Specific gravity
Specific gravity of hypoglycaemic beverages ranging between 1.031-
1.068 experienced a slight increase during storage up to 180 days. Changes in
chemical constituents of beverage during storage at ambient temperature might
be attributed to this change in specific gravity after six month of storage.
Conclusively, the beverage prepared by using stevia leaves extract or
sorbitol as substitution for sucrose did not exhibit any adverse change in chemical
constituents and were therefore optimized for preparation of low calorie products.
5.6.2 Changes in sensory quality of hypoglycaemic guava-Aloe vera
beverage during storage
Sensory quality of hypoglycaemic guava-Aloe vera beverages evaluated
during storage at ambient temperature at periodic interval of 0,90 and 180 days.
The results of study for each sensory attributes viz. colour, taste, flavour and over
all acceptability presented in table 4.21-4.23 are discussed as under:
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5.6.2.1 Colour
Sensory evaluation for colour acceptability indicated the increase in
period of storage, the colour acceptability of the beverage decreased (Table 4.21).
The decrease in colour score during storage might attributed to the formation of
brown pigments which made the appearance of the drink unacceptable. Earlier,
Cornwell and Wrolstad (1981) also recorded decrease in colour score of pear
juice during storage due to browning data further revealed that though the colour
score of the beverage decreased during storage yet the mean score remained more
than 6.0, thus indicating the acceptability of drink even after 180 days of storage.
5.6.2.2 Flavour
With the increase in period of storage, the flavour rating of beverages
made from non-nutritive sweeteners decreased consistently (Table 4.21).
Decrease in flavour score might be attributed to the possible loss of volatile
aromatic substances during storage at ambient condition as has been reported by
Thakur and Barwal (1998) and Krishnaveni et al. (2001). However, the drink
containing up to 50 per cent stevia leaves extract exhibiting a mean score more
than 6.00 remained within acceptable range even after 180 days of storage. Thus,
low calorie guava-Aloe vera drinks can be prepared by using stevia leaves extract
up to 50 per cent level of substitution.
5.6.2.3 Taste
Sensory evaluation of beverage (Table 4.22) indicated that drinks
prepared by using non-nutritive sweeteners had almost same liking for taste as
that of 100 per cent sucrose sweetened drinks except those prepared by using
more than 50 per cent stevia leaves extract. Taste score decreased significantly as
the proportion of stevia leaf extract increased. It might be due to bitterness
accompanied by sweet taste of stevia as reported by Soejarto et al. (1983) and
Philips (1987). The unpleasant taste associated with stevia has also been reported
by Pinherio (2005). During storage, a slight increase in sensory taste scores has
been observed that could be due to mellowing/smoothening of taste during
storage. Thus, all types of beverages were within the acceptable taste up to
except for beverage that contained stevia beyond 50 per cent level of substitution.
135
Thus, addition of stevia leaves extract up to 50 per cent level of substitution was
optimized for the preparation of low calorie guava-Aloe vera beverage. Our
findings are in conformity with the observation recorded by Tandhani and Subash
(2009) while evaluating replacement of sucrose with stevia leaf extract in lemon
juice.
5.6.2.4 Body
The guava Aloe vera beverage containing sucrose or sorbitol as
sweeteners exhibited higher sensory score for body which decreased during
storage up to 180 days. As expected, stevia sweetened drinks showed lower
acceptability for body which was attributable to the use of watery extract of
stevia which did not impart any body to the resultant drink. With increase in
storage interval a consistent decrease in body score was observed in all the
combinations (Table 4.22). During storage decrease in body score might be due
to the fact that degradation of colloidal particle resulting in lower consistency in
the drink. Similar decrease of body score in finished products was reported by
Krishanveni et al. (2001); Sharma (1999) and Barwal et al. (2005) in different
beverages during storage. However, the drink containing up to 50 per cent stevia
leaves extract remained acceptable with respect to body during the entire period
of the storage.
5.6.2.5 Over all acceptability
Evaluation of beverages for over all acceptance revealed that all the
beverages prepared containing different proportions of non-nutritive sweeteners
remained acceptable up to six month of storage period except beverage which
contained stevia leaves extract more than 50 per cent. Leafy bitter after taste
might have led to reduction in the score of over all acceptability as reported by
Tadhani and Subash (2009) in replacement of sucrose in common beverages. But
after taste is reported associated with the use of concentration of stevia
(Anonymous, 2006). A similar observation has been reported by Manimegalai
and Ramah (1998), Sharma et al. (2002) and Singh et al. (2002) while working
on spiced plum beverage and diabetic bitter gourd ready to serve drink. Thus, the
136
use of stevia leaves extract up to 50 per cent level of substitution has been found
to be appropriate for the preparation of low calorie guava-Aloe vera beverage.
5.7 Energy value
Energy value of the drink was calculated on the basis of presence of total
sugar present in the drink at different period of storage and expressed as K
cal/100g.The data presented in Table 4.24 reveals that calculated energy values of
different beverages ranging between 6.56 K cal/100g to 65.64 K cal/100g
reduced to 5.92-65.40 Kcal/100g after six month storage. Maximum energy value
of 65.64 K cal/100g was recorded in 100 per cent sorbitol sweetened
hypoglycaemic guava-Aloe vera beverage and minimum in 100 per cent stevia
leaves extract sweetened beverage, which decreased to 65.40 K cal/100g and 5.92
K cal/100g, respectively after storage of 180 days. Further, the beverage
containing 50 per cent stevia leaves extract and remained acceptable exhibited a
calculated energy value of 26.96 Kcal/100g. The decrease in energy value during
storage might be attributed to decrease in residual total sugars. Though, sorbitol
has high energy value but it does not raise the elevated blood sugar levels in the
system. According to Dias (1999) very little sorbitol is absorbed by small
intestine and whatever reaches the colon is fermented by micro flora to give
volatile fatty acids and hence sorbitol can be used for formation of diet for
diabetics. Earlier, Barwal (1995) recorded 25 per cent reduction in low calorie
jam by using non-nutritive sweeteners. Sharma (1999), Barwal et al. (2002) and
Singh (2002) also observed reduction in calories by addition of non–nutritive
sweeteners in low calorie plum appetizer, squash and diabetic bitter gourd ready
to serve drink (RTS).
Thus, stevia leaves extract up to 50 per cent level of sucrose substitution
at which drinks remained acceptable in sensory quality, can be used for
preparation of hypoglycaemic guava-Aloe vera beverages. At 50 per cent level of
sucrose substitution with stevia leaves extract, the product provide about 51.1 per
cent reduction in calories and hence optimized.
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5.8 Cost of production
The production of low calorie guava-Aloe vera beverages was calculated
by taking into consideration the cost of all the inputs and adding 20 per cent in
the processing cost. The sale price per 200 ml glass bottle was calculated after
adding 20 per cent profit margin. The beverage prepared by using 50 per cent
level of sucrose substitution with stevia leaf extract was found to be lowest in
cost (Rs.8.97/200ml bottle) followed by drink containing 100 per cent sucrose
(Rs.8.69/200ml bottle). Among all other combinations, drink containing 50 per
cent sorbitol sand 50 per cent sucrose was the costliest (Rs 13.77/200ml bottle).
High cost of raw material i.e. sorbitol was attributed to this increase in cost of
sorbitol sweetened beverage. Thus, use of stevia leaves extract up to 50 per cent
level besides bringing significant reduction in calories also costing low was
optimized for preparation of low calories guava-Aloe vera beverage.
5.9 Standardization of method for preparation of guava –Aloe vera fruit
bar
The pulp of guava fruit was blended in different ratio with Aloe vera to
prepare guava–Aloe vera fruit bar. The fruit bar having different ratio of guava
and Aloe vera are blended together to standardize a method of preparation for
hypoglycaemic guava-Aloe vera fruit bar. The different proportion of guava (90,
80, 70, 60 and 50) and Aloe vera (10, 20, 30, 40 and 50) were taken for blend.
Similar, blends of mango-papaya and mango-guava with whey, soya, peas and
carrot were done by Gayathri and Uthria (2008) and Sarojini et al. (2009).
Suitability of utilization of Aloe vera gel extract for preparation of guava-
Aloe vera fruit bar was evaluated by replacing the proportion of guava pulp with
equivalent proportion of Aloe vera gel extract. The fruit bars were prepared by
using 45 per cent fruit pulp and 55 per cent sugar and heating the mass to 40ºB
TSS followed by drying to a moisture content of 15-20 per cent. The level of
Aloe vera gel extract at which the resultant bar remained acceptable optimized.
The levels of the study presented in Tables 4.26-4.27 and figure 4.7 are discussed
as under:-
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5.9.1 Drying curve of guava-Aloe vera fruit bar
After heating of guava-Aloe vera mass to 45ºB, the whole mass in the
form of thin layer was dried in the dehydrator. The drying curve of the fruit bars
revealed that it took 10-12 hrs to attain a moisture content of 15-20 per cent in
different proportions of guava and Aloe vera (Fig.4.7). Rate of dehydration was
very fast within initial period of drying, as 50 per cent of moisture was lost
during 6-7 hrs of drying. Thereafter, rate of drying slowed down. Similar, results
have been reported by Sagar and Kumar (2007) in dehydrated guava slices and
leather. Thus, guava-Aloe vera fruit bars can be prepared by drying the whole
mass having (40ºB TSS) in mechanical drier within 10-12 hrs at 55+2ºC.
5.9.2 Changes in physico-chemical attributes of guava-Aloe vera fruit bar.
The total soluble solids in fruit bar prepared by using different proportions
of guava and Aloe vera gel extract ranged between 67.9-68.3ºB (Table 4.26).
With the increase in concentration of Aloe vera extract and corresponding
decrease in proportion of guava pulp, the TSS contents of the prepared fruit bar
did not exhibit any appreciable change. The fruit bar prepared by using 90 per
cent guava pulp and 10 per cent Aloe vera gel had a TSS value of 68.2 ºB. The
titratable acidity and pH of fruit bars ranged between 1.49 to 1.53 per cent and
2.28 to 2.35, respectively. The fruit bar prepared by using 90 per cent guava pulp
and 10 per cent Aloe vera gel extract contained acidity of 1.51 per cent and pH
of 2.30, respectively. The fruit bar prepared by using 90 per cent guava pulp and
10 per cent Aloe vera gel extract exhibit 57.5 per cent total sugars. Sarojini et al.
(2009) obtained similar results of chemical constituents while preparing fortified
guava and mango bars.
With the decrease in proportion of guava pulp corresponding increase in
Aloe vera gel extract, the ascorbic acid contents in the fruit bar registered a
decrease from 215.2 mg/100g to 70.2 mg/100g. However, the fruit bar prepared
by using 90 per cent guava and 10 per cent Aloe vera gel extract showed an
ascorbic acid level of 186.0 mg/100g, which was significantly higher than that of
fruit bars prepared by using other combinations of guava pulp and Aloe vera gel
139
extract. Our results were confirmation to the findings of Jain and Nema (2007)
who found decrease in ascorbic acid with the addition of sugars in guava leather.
The moisture content of the fruit bar prepared by using 90 per cent guava
pulp and 10 per cent Aloe vera gel extract was 17.5 per cent with a resultant total
solids 82.5 per cent, respectively. Ashaye et al. (2005) and Jain and Nema (2007)
found similar values for moisture content and total solids in pawpaw and guava
leather. Thus, among different combinations of guava and Aloe vera, the fruit bar
prepared by using 90 per cent guava and 10 per cent Aloe vera gel extract was
optimized for the preparation of hypoglyceamic guava-Aloe vera fruit bar.
5.9.3 Changes in sensory quality of hypoglycaemic guava-Aloe vera fruit
bar
The data pertaining to sensory quality of guava-Aloe vera fruit bar
presented in Table 4.27 is discussed as under :-
5.9.3.1 Colour
The decrease in colour acceptability score in fruit bars was registered with
the incorporation of Aloe vera gel extract. The fruit bar prepared by using
different proportions of guava and Aloe vera gel extract ranged between 3.5 to
8.4 with the highest score recorded in 100 per cent guava fruit bar (8.4) (Table
4.27). The addition of Aloe vera to the guava pulp brought about a significant
reduction in colour acceptability of the prepared fruit bar. This might be due to
the increase in Aloe vera gel extract which does not in unpleasant parts colour to
the fruit bar. Earlier, Gayatthri and Uthira (2008) reported decrease of colour
acceptability in protein enriched mango-papaya blended fruit bar. However,
fruit bars containig upto 20 per cent Aloe vera gel extract remained within the
acceptable range with a mean colour score more than 6.0 on a 9 point hedonic
scale.
5.9.3.2 Taste
With the substitution of Aloe vera, the taste score of the resultant fruit bar
experienced a consistent decrease. The mean acceptability score for taste of
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guava-Aloe vera fruit bar prepared by using different proportions of guava-pulp
and Aloe vera gel extracted ranged between 3.7 to 8.6 (Table 4.27). The fruit bar
containing 100 per cent guava pulp had a highest acceptability for taste (8.6)
followed by the fruit bar having 90 per cent guava and 10 per cent Aloe vera. The
sensory score for taste decreased with the increase in concentration of Aloe vera
in the fruit bar. Decrease in acceptability score of fruit bars containing Aloe vera
beyond 20 per cent was attributable to the presence of bitter principles leading to
astergency of the product. Thus, incorporation of Aloe vera up to 20 per cent
level of substitution was optimized for preparation of guava-Aloe vera fruit bar.
5.9.3.3 Flavour/aroma
Decrease in flavour/aroma score was observed due to increase in Aloe
vera and decrease in guava pulp. The flavour score in fruit bar containing
different proportions of guava and Aloe vera gel extract ranged between 3.6-7.5,
with the maximum liking found in fruit bar having 100 per cent guava pulp
(7.5). The addition of Aloe vera gel extract to the guava pulp brought about a
significant reduction in flavour score of prepared fruit bar. It might be due to
increase in inherent bitter characteristics of Aloe vera thus resulting in
proportionally lower sensory aromas score. Similar, decrease in flavour score was
also reported by Chauhan et al.(1993) in apricot soya bar and Sharma (1997) in
plum soya bar. Thus, addition of Aloe vera up to 10-20 per cent level was
considered for preparation of guava-Aloe vera fruit bar.
5.9.3.4 Texture
The texture acceptability score in fruit bar containing using different
proportions of guava and Aloe vera gel extract ranged between 3.9-7.9 on 9 point
hedonic scale the fruit bar containing 100 per cent guava pulp had highest liking
followed by fruit bar containing 10 per cent Aloe vera gel extract and 90 per cent
guava pulp (Table 4.27). The addition of Aloe vera gel extract to the guava pulp
brought about a significant reduction in texture acceptability score of prepared
fruit bar. Thus, addition of 10-20 per cent Aloe vera level with corresponding
decrease in guava pulp was considered for preparation of guava-Aloe vera fruit
bar.
141
5.9.3.5 Over all acceptability
The over all acceptability score guava-Aloe vera fruit bars decreased with
corresponding increase in percentage of Aloe vera in finished products. The
highest over all acceptability score was registered in fruit bar having 100 per cent
guava pulp which was followed by fruit bar prepared by using 90 per cent guava
pulp and 10 per cent Aloe vera gel extract. Further, among all the combinations
of Aloe vera, the fruit bar having 90 per cent guava pulp and 10 per cent Aloe
vera scored highest (7.7) for over all acceptability followed by the fruit bar
having 80 per cent guava pulp and 20 per cent Aloe vera. Addition of Aloe vera
beyond 20 per cent level made the fruit bars bitter, astringent and unpleasant in
over all acceptance, which was attributable to the inherent character of Aloe vera.
Thus, on basis of sensory score for all attributes, the fruit bar prepared by
using 90 per cent guava and 10 per cent Aloe vera gel extract was optimized for
the preparation of hypoglyceamic guava-Aloe vera fruit bar.
5.10 Standardization of formulation for preparation of hypoglycaemic
guava-Aloe vera fruit bar using non-nutritive sweeteners.
Guava Aloe vera fruit bar containing guava pulp and Aloe vera gel extract
in 90:10 proportions was further modified to prepare low calorie fruit bar. The
proportion of sucrose used in preparation of fruit bar was replaced by using
equivalent sweetness level of stevia leaves extract and saccharine. Further, in
order to improve texture and nutritional quality of the product, the effect of
addition of apple pomace as well as oat bran @ 10 per cent as bulking agent was
also evaluated. The fruit bars prepared by using non-nutritive sweeteners have
been referred to as low calorie or hypoglycaemic fruit bars. The results of the
study on different attributes presented in Table 4.28-4.29 and Fig 4.2 are
discussed as under:-
5.10.1 Drying of hypoglycaemic guava-Aloe vera fruit bar
The drying curve of hypoglycaemic fruit bars (containing non-nutritive
sweeteners and bulking agents) revealed that it took around 16-18 hours to dry it
to a moisture content of 15-20 per cent (Fig. 4.11). Rate of dehydration was very
142
fast during initial period of drying as 50 per cent of moisture was lost during 6-7
hours of drying. Thereafter, rate of drying slowed downed. Rapid dehydration
rate in the initial stages might be attributed to the presence of free water which
converted into vapour at a faster rate and thereafter the drying rate slowed down.
The results were also in conformity with the findings of Sagar and Kumar (2007)
during drying of guava slices and leather.
5.10.2 Changes in physico-chemical characteristics of hypoglycaemic guava-
Aloe vera fruit bar using non-nutritive sweeteners
Addition of stevia leaves extract and saccharin to replace sucrose, brought
about significant reduction in total solids of the resultant guava-Aloe vera fruit
bar. The fruit bar containing 100 per cent sucrose had TSS of 67.9ºB, which was
reduced to 16.2 and 16.6ºB when fruit bars were prepared by using 100 per cent
substitution of either stevia leaves extract or saccharin. Similarly, Barwal and
Kalia (1997) and Barwal (1995) reported reduction in TSS with the addition of
non-nutritive sweeteners in low sugar apple jellies and jam. However, by using
50 per cent substitution of sucrose with either stevia or saccharin along with
apple pomace or oat bran, the fruit bars showed a TSS of 34.2-34.8 ºB.
As the sweetening agents do not contribute to ascorbic acid the addition
of non-nutritive sweeteners as well as bulking agent did not exert any appreciable
effect on the ascorbic acid contents of the resultant fruit bars. Thus, the mean
ascorbic acid in fruit bars was found to be 177.9 mg/100g. Similarly, titratable
acidity and pH in the prepared fruit bars ranged between 1.43-1.52 per cent and
2.62-2.87, respectively. While moisture content in the fruit bars was estimated to
range between 16.7-17.8 per cent with a corresponding total sugars of 82.2-83.3
per cent. The increase in proportion of non-nutritive sweeteners in fruit bars to
replace sucrose. Further with corresponding decrease in total sugar of the
prepared product was observed (Table 4.28). The total sugar content in the fruit
bar containing different forms of sweeteners ranged between 10.5 to 59.8 per
cent. The fruit bar prepared by using 100 per cent sucrose showed highest amount
of total sugars (59.8%), while the product having 100 per cent substitution with
saccharin or stevia leaves extract exhibited the lowest amount of total sugars i.e.
143
10.5 and 10.8 per cent, respectively. The energy values calculated on the basis of
presence of total sugars in the drink ranged between 47.0 to 239.4 K cal/100g.
Fruit bars containing 50 per cent stevia leaves extract or saccharine showed a
calculated energy value of 97.0-97.8 K cal/100g. This registering about 59.8 per
cent reduction in calories as compared to 100 per cent sucrose sweetened. The
fruit bars prepared by using 100 per cent replacement of sucrose with stevia
leaves extract or saccharin registered the lowest amounts of calories. Thus, the
replacement of sucrose with stevia or saccharin brought about significant ction in
calories. Earlier, Barwal and Kalia (1997) and Barwal (1995) recorded 28 per
cent reduction of calories in low sugar apple jellies and jam prepared by replacing
sugar with non-nutritive sweeteners. Thus, low calories guava-Aloe vera fruit
bars can be prepared by replacing 50 per cent sweetness of sucrose with either
stevia leaves extract as saccharine as non-nutritive sweetener.
5.10.3 Changes in sensory quality of hypoglycaemic guava-Aloe vera fruit
bar
The results of the study pertaining to changes in sensory quality of low
calorie fruit bars presented in Table 4.29 are discussed as under:-
5.10.3.1 Colour
With the increase in proportion of non-nutritive sweeteners and bulking
agents, the colour acceptability of the resultant fruit bar decreases (Table 4.29).
Among non-nutritive sweeteners the stevia leaves extract sweetened fruit bars
scored less than that of saccharin sweetened fruit bars. In most of the cases, the
fruit bars in which apple pomace was used as bulking agent with the combination
of non-nutritive sweeteners also scored less than that of the fruit bars prepared by
using oat bran. This might be due to the fact that the dried apple pomace imparted
its characteristic colour which altered the colour of the fruit bar when compared
with standard and oat bran fortified fruit bars. However, in all fruit bars
containing varying proportion of non-nutritive sweeteners, the mean acceptability
score remained more, this indicating good acceptability for colour. Earlier,
Gayathri and Uthira (2008) found similar colour acceptability in protein enriched
144
mango-papaya blended fruit bar and Mir and Nath (1993) in mango fortified fruit
bar.
5.10.3.2 Taste
The acceptability score for taste decreased significantly with the increase
in proportion of non-nutritive sweeteners to replace sucrose. The fruit bar
containing 100 per cent substitution of stevia or saccharin were not at all
acceptable. Further, the taste score for fruit bars prepared by using stevia leaves
extract exhibited higher acceptability over saccharin sweetened fruit bars. Use of
saccharin even up to 25 per cent level was not preferred in the fruit bars (Table
4.29). This might be due to the metallic after taste of the saccharin which
becomes evident with the increase in proportion of saccharin. Thus, stevia leaf
extract appears to be more preferable over saccharin for preparation of low
calorie guava-Aloe vera fruit bars.
5.10.3.3 Flavour /aroma
Sensory score for flavour acceptability of the product decreased with the
corresponding increase in proportion of non-nutritive sweeteners in
hypoglycaemic guava-Aloe vera fruit bars. The highest score for flavour (7.30)
was obtained by 100 per cent sucrose sweetened fruit bar which was followed by
the fruit bars containing 25 per cent and 50 per cent stevia leaves extract as
replacement for sucrose. Among non-nutritive sweeteners, the fruit bars prepared
by using stevia leaves extract were preferred over the fruit bars made by using
equivalent proportions of saccharin. Further, the fruity flavour imparted by apple
pomace was effective in improving the acceptability of resultant fruit bars as
compared to products containing oat bran as bulking agent. Thus, the fruit bars
containing 25 per cent and 50 per cent stevia leaves extract as replacement for
sucrose and 10 per cent apple pomace was more acceptable than other
combination and hence optimized.
5.10.3.4 Texture
The addition of stevia leaves extract and saccharin to replace sucrose in
fruit bars imparted marginal effect on the texture quality guava Aloe vera fruit
145
bars. The fruit bar prepared by using 100 per cent sucrose scored the highest
acceptability for texture (7.50). Further, addition of 10 per cent apple pomace or
oat bran to the fruit bar as bulking agent significantly improved the texture
acceptability score of the hypoglycaemic guava-Aloe vera fruit bars. However,
use of 75 per cent substitution with saccharin brought about significant reduction
in texture acceptability of the fruit bar. Li et al. (2008) and Mc Mohan et al.
(2009) also recorded change in texture acceptability score in high protein
nutrition bars. Thus, stevia leaves extract or saccharin up to 50 per cent level of
substitution can be used for preparation of low calorie guava Aloe vera fruit bar.
However, stevia being a plant source is preferred over saccharin for such
products.
5.10.3.5 Over all acceptability
Over all acceptability score of the product decreased with the
corresponding increase in proportion of non-nutritive sweeteners in
hypoglycaemic guava-Aloe vera fruit bars. The highest score for over all
acceptability (7.37) was obtained by 100 per cent sucrose sweetened fruit bar
which was followed by the fruit bars containing 25 per cent and 50 per cent stevia
leaves extract as replacement for sucrose (Table 4.29). Among non-nutritive
sweeteners, the fruit bars prepared by using stevia leaves extract were preferred
over the fruit bars made by using equivalent proportions of saccharin. Further, the
fruity flavour imparted by apple pomace was effective in improving the over all
acceptability of the resultant fruit bars as compared to products containing oat
bran as bulking agent. Thus, fruit bars prepared by using 50 per cent replacement
of sucrose with either stevia leaves extract or saccharin along with 10 per cent
apple pomace as bulking agent were found acceptable over other combinations
and hence optimized.
5.11 Storage studies of hypoglyceamic guava Aloe vera fruit bars
The changes in different quality characteristics of hypoglycaemic guava-
Aloe vera fruit bar sweetened with different sweetening agent (sucrose, stevia
leaf extract and saccharin) were studied by packing in aluminium laminates and
146
storing under ambient (12-24ºC) and low (4+2
ºC) temperature. The results of
study presented in tables 4.30-4.42 are discussed as under:-
5.11.1 Physico-chemical characteristics of hypoglycaemic guava-Aloe vera
fruit bars during storage
The changes in physico-chemical of hypoglycaemic guava-Aloe vera fruit
bar sweetened with different sweetening agent (stevia leaf extract and Saccharin)
during storage are discussed below:
5.11.1.1 Total soluble solids
Data (Table 4.30) pertaining to TSS of hypoglycaemic guava-Aloe vera
fruit bar indicated slight increase in total soluble solids during storage. However,
corresponding less changes in TSS were recorded in products packed at
aluminium laminates stored in low temperature while fruit bars changes stored
at ambient temperature exhibited more increase TSS which was in accordance
with the findings of Manimegalai et al. (2001). Slight increase in TSS of fruit
bars was attributable to the loss of moisture during storage. However, contrary to
these observations Thakur (1997), found increase in TSS of apricot soy bar
during storage.
5.11.1.2 Titratable Acidity
Titratable acidity of guava-Aloe vera fruit bars decreased with increase in
storage period but this decrease was greater magnitude at ambient temperature
than at low temperature condition. The loss of acids might be due to utilization
of acids for conversion of non-reducing sugars and their involvement in non-
enzymatic browning reactions. Similar, decrease in titratable acidity has been
reported by Gayathri and Uthria (2008) in protein enriched mango-papayas
blended fruit bar.
5.11.1.3 pH
pH value of hypoglycaemic guava-Aloe vera fruit bar increase during
storage at both the conditions. Increase in pH of fruit bars might be attributed to
corresponding decrease in acidity during storage. A similar result was observed
147
by Dabhade and Khedkar (1980) and Roy (1988) in mango powder and slices and
Gayathri and Uthria (2008) also observed increase in pH mango-papaya blended
fruit bar during storage.
5.11.1.4 Ascorbic acid
A considerable reduction in ascorbic acid content of low calorie guava-
Aloe vera fruit bars was observed during storage under both the condition (Table
4.33). The loss of ascorbic acid during storage could be due to degradation of
ascorbic acid during storage. Comparatively less reduction was recorded in fruit
bars stored at low temperature which was attributable to protective effect of low
temperature to slow down the rate of oxidation of ascorbic acid. Gahilod et al.
(1982) and Alkesh (2001) have recorded similar pattern of ascorbic acid in
mango leather and apple rings, respectively. The decrease in ascorbic acid in fruit
bars is in close conformity the findings of Kumar et al. (2007), who recorded
decrease in ascorbic acid during the storage of guava leather in different
packaging materials. However, the fruit bars containing appreciable amount of
ascorbic acid even after six month of storage.
5.11.1.5 Total sugars
Total sugars contents in guava-Aloe vera fruit bars containing different
sweeteners ranged between 10.5-59.8 per cent which experienced marginal
decrease after during storage. After six month of storage period the total sugars
were recorded as 10.2-59.4 per cent at ambient temperature and 10.3-59.7 at low
temperature in different fruit bars. Difference in total sugars in fruit bars was
attributable to use of different non-nutritive sweeteners viz. Stevia leaves extract
and saccharin while decline in total sugars in fruit bars during storage was
attributed to their involvement in no-enzymatic reaction. Almost similar result
were observed by Barwal and Kalia (1997), Ragab (1987) and Barwal (1995)
who reported reduction in total sugars during storage in low sugar apple jellies
and jam prepared by replacing sugar with non-nutritive sweeteners.
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5.11.1.6 Moisture content
The change in moisture content during storage of guava-Aloe vera leather
are presented in Table 4.35. The increase in moisture content during storage,
might be due to the absorption of moisture by the product from the environment
or the change might be attributed to the chemical changes such as browning
reaction during storage (Doreyappagowda et al., 1995). Mir (1990) while
studying storage changes in coconut powder and soya protein fortified mango
bars observed increase moisture content during 90 days of storage. Similar,
results have been reported by Gayathri and Uthria (2008) in protein enriched
mango-papayas blended fruit bar and Kumar et al. (2007) in guava leather packed
in different packaging materials. However, the change in moisture content of fruit
bars during storage was only marginal, which is not expected to affect the quality
of the product.
5.11.1.7 Total solids
The decrease in total solids of hypoglycaemic fruit bar was observed
(Table 4.36). The maximum decrease was in ambient conditions than refrigerated
conditions. Increase in moisture content could be the reason for decrease in total
solids as has also been reported by Kumar et al. (2007) in guava leather packed in
different packaging materials.
5.11.1.8 Water activity
The water activity of the stored hypoglycaemic guava-Aloe vera fruit bar
increase during storage up to six months (Table 4.37). However, during the entire
period of storage the water activity of fruit bars ranging between 0.50-0.62 was
considered to be appreciable for storage of the products. The increase in water
activity was also observed by Li et al. (2008) and Mc Mohan et al. (2009) in high
protein nutrition bars.
Conclusively, the low calorie fruit bars did not exhibit any appreciable
change in the physico-chemical attributes during storage up to six months. Thus,
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such products can successfully be stored at both ambient and low temperature for
at least up to six months.
5.11.2 Sensory quality of hypoglycaemic guava-Aloe vera fruit bar.
Sensory evaluation of hypoglycaemic guava-Aloe vera fruit bars was
conducted on a 9 point hedonic scale at periodic interval of 0, 90 and 180 days.
The results of the study for different parameters presented in Table 4.38-42 are
discussed as under:-
5.11.2.1 Colour
With the increase in storage period, the colour acceptability score of fruit
bars experienced a marginal decrease. The fruit bar prepared by using 100 per
cent sucrose exhibited maximum acceptability for colour which decreased after
180 days of storage interval at both the temperature. The colour acceptability
score registered a consistent decrease, up to 180 days of storage. The decrease in
sensory colour of fruit bars during storage interval, this might be attributed to the
non-oxidative changes (cis-trans isomerisation, epoxide formation or thermal
degradation or oxidative changes) in the products as has been reported by Mir
and Nath (1993). However, all type of fruit bars exhibiting mean score more
than 6.0 were considered well within the acceptable range Thus all fruit bars were
within acceptable range. Further, the fruit bars prepared by replacing 50 per cent
sucrose with stevia leaf extract or saccharin were better in appearance than that
of fruit bars containing more than 50 per cent non-nutritive sweetener. Gayathri
and Uthira (2008) found decrease in colour acceptability during storage in protein
enriched mango-papayas blended fruit bar while Barbaste and Badrie (2000)
recorded similar observation in in papaya cheese. Thus, packing of fruit bars in
aluminium laminates was considered optimum for storage of low calorie guava-
Aloe vera fruit bars up to six months.
5.11.2.2 Taste
Sensory score for taste of hypoglycaemic guava Aloe vera fruit bars
varied from 3.50 to 7.20 on a 9 point hedonic scale. The highest score (7.20) was
recorded in 100 per cent sucrose sweetened fruit bar while fruit bars prepared by
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using 100 per cent stevia or saccharin scored the least for taste attribute indicating
unsuitability for complete substitution with stevia or saccharin for preparation of
fruit bars. The addition of 25 per cent and 50 per cent stevia leaves extract to
replace sucrose in the fruit bar did not cause any appreciable adverse effect on the
taste acceptability of the fruit bar as their score remained more than 6.0 on a 9
point hedonic scale (Table 4.39). Similarly, the apple pomace fortified fruit bar
got higher score than that of oat bran fortified fruit bar. Addition of apple pomace
along with stevia leaves extract exhibited better liking for taste of fruit bars than
of oat bran fortified fruit bar. With the increase in period of storage, the sensory
liking for taste of the fruit bars exhibited slight decrease. Similar decrease in taste
acceptability during storage was observed by Mir and Nath (1993) and Sarojini et
al. (2009) in fortified mango bars and fruit bars, respectively. However, the fruit
bars containing 50 per cent stevia leaves extract along with bulking agent
exhibiting these mean taste score more than 6.0 remained acceptable even after
six month of storage. Thus, the mean score more than 6.0 remained acceptable
even after six month of storage. Thus, the fruit bars containing stevia leaf exhibit
up to 50 per cent level of sucrose substitution along with 10 per cent apple
pomace were considered optimum for preparation of low calorie guava-Aloe vera
bars/leather.
5.10.2.3 Flavour/aroma
With the increase in storage period decrease in flavour score was
registered on 9 point hedonic score. The products containing 75 per cent and 100
per cent non-nutritive sweeteners were least preferred indicating unsuitability
than 25 per cent and 50 per cent of the prepared fruit bars by using non-nutritive
sweeteners. However they exhibited fairly good score for flavour of the product.
Further, the fruity flavour imparted by apple pomace was effective in improving
the resultant fruit bars as compared to products containing oat bran as bulking
agent. Thus, hypoglycaemic guava-Aloe vera fruit bars can be prepared by using
up to 50 per cent stevia leaves extract along with 10 per cent along apple pomace
as bulking agent. Further, sensory score of fruit bars made by using non-nutritive
sweeteners decreased consistently during storage up to 180 days. Sagar and
Kumar (2007) and Gayathri and Uthira (2008) found similar decrease in flavour
151
score was observed in dehydrated guava leather and protein enriched mango-
papaya blended fruit bar.
5.11.2.4 Texture
The increase in proportion of non-nutritive sweetener did not affect the
texture of the resultant fruit bars. The fruit bar prepared by using 100 per cent
sucrose score the highest texture score (7.50) which was closely followed by the
product made by using stevia leaf extract as replacement for equivalent sweetness
of sucrose. Further, addition of 10 per cent apple pomace as oat bran to the fruit
bar as bulking agent improved the texture acceptability score of the
hypoglycaemic guava Aloe vera fruit bars. Thus, stevia leaf extract sweetened
fruit bars up to 50 per cent replacement containing apple pomace or oat bran as
bulking agent exhibited a highest texture score. However, texture score of fruit
bars made by using non-nutritive sweeteners decreased consistently during
storage of 180 days. Barbaste and Badrie (2000) and Mir and Nath (1993) found
similar trend for textural changes in papaya cheese and fortified mango bar
during storage.
5.10.2.4 Over all acceptability
Sensory evaluation for over all acceptance of the fruit bars revealed that
the fruit bars containing 100 per cent sucrose had the highest liking among taste
while the fruit bars prepared by 100 per cent stevia leaves extract and saccharin
were not at all preferred. Further addition of apple pomace and oat bran as
bulking agents improved over all acceptability of the products. In comparison to
saccharin sweetened products, the stevia leaves extract sweetened had highest
liking for sensory evaluation. Further, with the increase in proportion of non-
nutritive sweeteners the sensory quality of the resultant fruit bar decreased.
Decrease in sensory quality with the increase in proportion of non-nutritive
sweeteners was attributed to bitter after taste imparted by stevia and metallic after
taste by saccharin. Thus, the product containing up to 50 per cent stevia and
saccharin exhibited highest liking as compared to the products which contained
non-nutritive sweeteners beyond 50 per cent level (Table 4.41). Further, the over
all acceptability of the fruit bars containing different sweeteners experienced
152
slight decrease with the increase in the period storage. Decrease in over all
acceptance has also been recorded by various workers during storage of fruit bars
like guava leather, fortified mango bar, dehydrated guava slices and leather and
protein enriched mango-papaya blended fruit bar; (Mir and Nath 1993; Sagar and
Kumar 2007, Kumar et al. 2007 and Gayathri and Uthira, 2008).
Thus, on basis of sensory score the fruit bar prepared by using 50 per cent
non-nutritive sweeteners and 10 per cent apple pomace as bulking agent was
optimized for the preparation of hypoglyceamic guava-Aloe vera fruit bar.
5.11 Energy value
Energy value of different fruit bars were calculated from the residual total
sugars presented in the product at different interval of storage. The calculated
energy value was found highest (239.4 K cal/100g) in fruit bars prepared by
using sucrose as sweetening agents which decreased in all combination of the
fruit bars prepared by using 100 per cent stevia leaves extract or saccharin
exhibited the lowest energy values (Table 4.43). Further, during storage of the
products, the calculated energy values exhibited a constituent decrease which was
attributable to the constituent decrease in resolved sugar contents of the fruit bars.
The fruit bars containing 50 per cent proportion of stevia leaf extract or saccharin
which were adjudged acceptable in sensory quality exhibited the energy value of
96-96.7 Kcal/100g after six month of storage period. In comparison to 100 per
cent sucrose sweetened fruit bars, the reduction in energy value was calculated to
be 59.2 per cent in stevia or saccharin sweetened fruit bars. Similar to these
observation Barwal and Kalia (1997) and Barwal (1995) recorded about 28 per
cent reduction in calories in low sugar apple jellies and in jam. Thus, use of stevia
leaves extract was or saccharin up to 50 per cent level of substitution was
optimized for preparation of low calorie guava-Aloe vera fruit bars. Further,
stevia leaves extract being a plant source was considered appropriate for
preparation of such products.
5.12 Cost of production of hypoglycaemic guava-Aloe vera fruit bar
Cost incurred in preparation of guava-Aloe vera fruit bar was calculated
by taking into consideration the cost of all the inputs and the cost involved during
153
processing. Earlier, Kaushal (2004) used the same methodology for calculation
of cost of production of sea buckthorn fruit leather. The comparative cost of
production of 100 per cent sucrose sweetened fruit bar, 50 per cent stevia leaf
extract and 50 per cent saccharin sweetened fruit bar is shown in Table 4.43. The
cost per unit of guava-Aloe vera fruit bar was found lowest (Rs.11.66 /100g)
when prepared by using 50 per cent sucrose and 50 per cent stevia leaf extract
followed by a product that contained 100 per cent sucrose as sweetener
(Rs.13.18/100g). While the cost of saccharin sweetened bar (50% sucrose and
50% saccharin) was Rs.16.46/100g which was found higher than that of 50 per
cent stevia leaves extract sweetened product. Thus, fruit bar containing 50 per
cent the stevia leaf extract besides being acceptable in sensory quality was also
found cost effective.
Conclusively, an acceptable quality of guava-Aloe vera fruit bars can be
prepared by using 50 per cent stevia leaves extract as non-nutritive sweeteners to
replace up to 50 per cent of sucrose. The product besides being low in calories
also contained appreciable quantity of ascorbic acid and health promoting
benefits of Aloe vera.
Chapter-6
SUMMARY AND CONCLUSION
The present investigation entitled “Development and evaluation of
hypoglycaemic guava products with Aloe vera fortification” was carried out in
Department of Food Science and Technology, Dr. Yashwant Singh Parmar University
of Horticulture and Forestry, Nauni, Solan during the years 2009-2011. Guava fruits
cv. Allahabad safeda procured from local market were utilized for optimization of
method for extraction of pulp using different combinations of heating method and
fruit to water. Aloe vera and stevia leaves were procured from experimental fields of
Department of Forest Products, College of Forestry. Aloe vera gel was stabilized by
heating and addition of citric acid while stevia leaves extract was prepared by using
fine powder of dried stevia leaves in water. Trial was laid down for the development
of palatable guava-Aloe vera beverages and fruit bars by using different combination
of guava pulp and Aloe vera gel extract. The best rated combinations of guava pulp
and Aloe vera gel extract were further used for the preparation of hypoglycaemic
guava-Aloe vera beverage and fruit bars. Sucrose present in optimized products was
replaced with non-nutritive sweeteners viz. stevia leaves extract, saccharin and
sorbitol with equivalent sweetness proportion (Sucrose equivalent) of 25, 50, 75 and
100 per cent. The beverages were packed in presterlized glass bottle and processed in
boiling water while fruit bars were packed in aluminum laminated pouches and stored
until used for quality analysis. The storage stability of optimized products was
evaluated at periodic interval of 0, 90 and 180 days at ambient temperature (12-24oC)
and low temperature (4+2ºC). However, the beverages were evaluated only at
ambient temperature (12-24ºC). The results of this study on various aspects of product
preparation and storage are summarized briefly as under:
6.1 Physico-chemical characteristics of guava fruit, Aloe vera and stevia
1. The guava fruits of cv. Allahabad Safeda used in this study weighed 82.0 g
with a mean volume of 76.3 cc per fruit and size parameter of 50 mm length
and 52.6 mm diameter, respectively. The specific gravity of fresh fruits was
recorded as 0.9. The visual skin colour of guava fruit was yellowish while
155
pulp of fruit was pale white in colour. The average total soluble solids (TSS),
ascorbic acid and titratable acidity of guava fruits were recorded as 8.3ºB, 216
mg/100g and 0.76 per cent, respectively.
2. Heating guava slices with water in 1:1 in pressure cooker at 0.35 kg/cm2 for
15 min gave pulp with highest yield (78.3%), lowest waste residue (21.6%)
and smooth in texture. The resultant pulp containing 4.13ºB total soluble
solids, 0.38 per cent titratable acidity and ascorbic acid content 101.4mg/100g
was considered optimum for product development.
3. Processed Aloe vera gel possessed almost similar attributes as that of raw gel
except titratable acidity and flow behavior. The gel extract was found to be a
good source of ascorbic acid which ranged between 114-124 mg/100g.
Stabilization of Aloe vera gel extract by heating and addition of citric acid
brought about improvement in its flow characteristics. Different chemical
attributes in processed Aloe vera gel extract were recorded as 2.13ºB TSS, 0.74
per cent total sugar, 0.67 per cent titratable acidity and 2.8 per cent total solids.
Thus, on the basis of physico-chemical attributes, the processed gel extract
was found suitable for development of different value added products.
4. The dried stevia leaves powder contained 8.35 + 0.15ºB total soluble solids
(TSS), also showed 24.5 mg/100g ascorbic acid. The presence of 13.23 per
cent steviosides and 4.20 per cent rebaudiosides A in stevia leaves powder as
sweetening compounds indicated its good potential for use in development of
low calorie products.
Hypoglycaemic guava-Aloe vera beverage.
5. Acceptable and palatable guava-Aloe vera beverage developed by using 15 per
cent guava and 5 per cent Aloe vera gel extract with a minimum TSS of 15ºB
without any preservative was found appropriate to meet the FSSA, 2006
specification for the fruit nectar.
6. The beverages prepared by using 15 per cent guava and 5 per cent Aloe vera
gel extract contained 15.63ºB total soluble solids, 16.17 mg/100g ascorbic
acid and 14.64 per cent total sugar. The sensory acceptability score of the
prepared beverages decrease with the increase in addition of Aloe vera gel
extract.
156
7. Hypoglycaemic guava-Aloe vera beverage was developed by replacing sugars
with non-nutritive sweetener viz. stevia leaves extract and sorbitol.
Replacement of sucrose up to 50 per cent sweetness level with equivalent
proportion of stevia leaves extract or sorbitol was optimum without affecting
the overall sensory quality of prepared low calorie beverages.
8. The beverages prepared by using 50 per cent replacement of sucrose with
equivalent sweetness of stevia leaves extract exhibited TSS (7.53ºB), ascorbic
acid (17.23 mg/100g) and energy value (27.44 Kcal/100g) while the drink
having 50 per cent replacement of sucrose with sorbitol showed a TSS
(11.30ºB), ascorbic acid (16.85 mg/100g) and energy value 54.08 (K
cal/100g). However, addition of non-nutritive sweetener beyond 50 per cent
level of sucrose substitution brought about adverse effect on the sensory
quality of prepared guava-Aloe vera beverages.
9. The beverages prepared by using 50 per cent substitution of sucrose with
stevia leaves extract or sorbitol were found comparable to 100 per cent sucrose
sweetened beverage during storage in sensory quality. The guava-Aloe vera
beverages experienced slight increase in total solid, pH and specific gravity
and decrease in titratable acidity, ascorbic acid, total sugars and relative
viscosity up to 180 days storage. Although the sensory quality of the prepared
beverages sweetened by using different sweeteners decreased during storage,
yet the beverage sweetened with 50 per cent stevia leaves extract or sorbitol
had their sensory score within the acceptable range. Thus, this study signifies
that 50 per cent level of sucrose can be replaced by using non-nutritive
sweeteners to prepare hypoglycaemic drink.
10. The energy value of different hypoglycaemic guava-Aloe vera beverages
ranged between 6.56 K cal/100g to 65.64 K cal/100g. Maximum energy value
of 65.64 K cal/100g was recorded in 100 per cent sorbitol sweetened
hypoglycaemic guava-Aloe vera beverage. The beverage containing 50 per
cent substitution of sucrose with stevia leaves extract had an energy value of
27.4 K cal/100g thus exhibiting about 52 per cent reduction in energy value
for 100 per cent sweetened sucrose beverage.
11. Cost of production of guava-Aloe vera beverage containing stevia leaves
extract (50%) was found to be lowest (Rs.8.69/200 ml bottle) when compared
with 100 per cent guava-Aloe vera beverages i.e. Rs.8.97/200ml bottle.
157
However, the cost of sorbitol sweetened beverages (50% sucrose and 50%
sorbitol) was recorded to be highest (Rs.13.77/200ml bottle). Thus, the stevia
leaves extract sweetened beverage containing natural plant extract was also
found cost effective than sorbitol sweetened beverage.
Hypoglycaemic guava-Aloe vera fruit bar
12. Guava-Aloe vera fruit bar was prepared by heating 45 per cent fruit pulp along
with 55 per cent sugar to a TSS of 40ºB followed by drying in dehydrator to a
final moisture content of 15-20 per cent . Among different combinations of
guava and Aloe vera gel extract, the fruit bar prepared by using 90 per cent
guava and 10 per cent Aloe vera gel extract was optimum for preparation of
hypoglycaemic guava-Aloe vera fruit bar.
13. The fruit bar prepared by using 90 per cent guava pulp and 10 per cent Aloe
vera gel extract contained 68.20ºB TSS, 1.5 per cent titratable acidity, 57.5 per
cent total sugars, 17.45 per cent moisture and 186.0mg/100g of ascorbic acid.
The sensory score for colour, taste, texture and over all acceptability score was
more than 7.0 on a 9 points hedonic scale. Thereby, indicating its superiority
over other combination of guava pulp and Aloe vera gel extract.
14. Hypoglycaemic guava-Aloe vera fruit bar was developed by replacing sugars
with non-nutritive sweetener viz. stevia leaves extract and saccharin. Out of
different combinations, replacement of sucrose with equivalent sweetness up
to 50 per cent level of stevia leaves extract or saccharine along with 10 per
cent apple pomace was found optimum for preparation of low calorie guava-
Aloe vera fruit bars with respect to over all sensory quality. Further, the stevia
leaves extract being a plant source was preferred over saccharin to prepare
such products.
15. The hypoglyceamic fruit bar prepared by using 50 per cent stevia leaves
extract or saccharin contained 10 per cent apple pomace having 34.2 and
34.4ºB TSS, 17.0 and 17.2 per cent moisture, 24.2 and 24.3 per cent total
sugars and 177.7 and 178.9 100mg/g ascorbic acid, respectively. During
storage, of all fruit bars after wrapping in aluminum laminates exhibited
marginal changes in physico-chemical characteristics. Although, the sensory
quality of the prepared fruit bars declined during storage, yet the bar
sweetened with 50 per cent stevia leaves extract or saccharin retained their
158
sensory quality to an appreciable extent. Storage at low temperature exhibited
comparatively less changes in quality as compared to ambient temperature.
This signifies that 50 per cent level of sucrose can be replaced by non-nutritive
sweeteners like stevia leaves extract or saccharine to prepare hypoglyceamic
fruit bars.
16. The calculated energy value of different hypoglyceamic guava-Aloe vera fruit
bars ranged between 47.00 K cal/100g to 239.4 K cal/100g. Fruit bar having
50 per cent substitution of stevia leaves extract or saccharine had 96-97
Kcal/100g as compared to 239.4 Kcal/100g calories found in 100 per cent
sucrose sweetened fruit bars. Thus, hypoglyceamic guava-Aloe vera fruit bars
exhibited about 59.2 per cent reduction in the energy value over 100 per cent
sucrose sweetened fruit bars.
17. The cost of hypoglyceamic guava-Aloe vera fruit bar sweetened by using 50
per cent stevia leaves extract was found lowest (Rs.11.66/100g) than 100 per
cent sucrose sweetened guava-Aloe vera fruit bar ( Rs.13.18/100g). While the
cost of saccharin sweetened fruit bar (50% sucrose and 50% saccharin)
worked out to Rs.16.46/100 g which was found to be even higher than 100 per
cent sucrose or stevia leaves extract sweetened fruit bar. Thus, the stevia
leaves extract sweetened fruit bar was also regarded as more cost effective
than saccharin sweetened fruit bar.
From the present investigation, it emerges that low calorie fruit beverage and
bars (leather) can be developed by using appropriate combination of guava pulp, Aloe
vera gel extract and stevia leaves. Functional properties of the Aloe vera gel can be
incorporated by using 15 per cent guava and 5 per cent Aloe vera for preparation of
beverage and 90 per cent guava and 10 per cent Aloe vera for preparation of bars.
Hypoglycaemic guava-Aloe vera beverages and fruit bar with substantial reduction in
calories can be prepared by replacing 50 per cent sugars with equivalent sweetness of
stevia leaves extract. Thus, plant based sources like Aloe vera and stevia leaves can
be successfully be utilized for development of hypoglyceamic products for the obese
and diabetic people.
Chapter-7
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179
Dr. Y. S. Parmar University of Horticulture and Forestry,
Nauni, Solan (HP)
Department of Food Science and Technology
Title of Thesis : “Development and evaluation of hypoglycaemic
guava products with Aloe vera fortification”
Name of the Student : Siloni Slathia
Admission Number : H-2007-18-D
Major Advisor : Dr. P.C. Sharma
Major Field : Post Harvest Technology
Minor Field (s) i) Biochemistry
ii) Microbiology
Degree Awarded : Ph. D (Post Harvest Technology)
Year of award of Degree : 2012
No. of pages in Thesis : 179+III
No. of words in Abstract : 604
ABSTRACT
The suitability of guava, Aloe vera gel extract and non-nutritive sweeteners (stevia, sorbitol and saccharine) were
evaluated for the preparation of hypoglycaemic products like beverage and bars. The method for preparation of guava pulp
consisting of heating of guava slices with water in 1:1 ratio at 0.35 Kg/cm2 pressure for 15 min followed by passing through
the pulper was optimized to yield about 78.3 per cent pulp with good physic-chemical attributes. Aloe vera gel extracted by
peeling Aloe vera leaves and passing through fruit mill was observed as good source of various nutrients including ascorbic
acid. Further, the stabilization of the Aloe vera gel extract by heating at 80ºC and addition of 0.3 per cent citric acid resulted
in improvement of its flow characteristics. On the basis of physico-chemical attributes, Aloe vera gel extract was found
suitable for development of different products. Stevia leaves extract prepared by boiling the dried stevia leaves powder in
water contained appreciable amount of Steviosides and Rebaudiosides and was found optimum for the preparation of low
calorie food products. Out of different combination guava-Aloe vera beverage prepared by using 15 per cent guava pulp and
5 per cent Aloe vera gel extract with a minimum TSS of 15ºB followed by heating was found most appropriate on the basis
of sensory acceptability. With the increase in proportion of Aloe vera gel extract, the sensory score decreased beyond 5 per
cent level. Among non-nutritive sweeteners, use of stevia leaves extract at 50 per cent level of sucrose substitution was
optimized increase to prepare guava-Aloe vera beverage. With the increase in proportion of stevia leaves extract beyond 50
per cent level of sucrose substitution, the acceptability of the drink decreased. The optimized beverage containing 7.53ºB
TSS, 17.23 mg/100g ascorbic acid and 27.44 Kcal/100g energy value provided about 52 per cent reduction in calories over
100 per cent sucrose sweetened beverage. During storage the beverages though experienced marginal changes in various
physico-chemical and sensory attributes yet remained shelf stable up to 180 days of storage. Guava-Aloe vera fruit bar
prepared by heating 45 per cent fruit pulp along with 55 per cent sugar to a TSS of 40ºB followed by drying in dehydrator to
a final moisture content of 15-20 per cent. Among different combinations, the fruit bar prepared by using 90 per cent guava
and 10 per cent Aloe vera gel extract was found optimum for preparation of guava-Aloe vera fruit bar. Hypoglycaemic
guava-Aloe vera fruit bar was developed by replacing sugars with non-nutritive sweetener viz. stevia leaves extract and
saccharin. Out of different combinations replacement of sucrose with equivalent sweetness up to 50 per cent level of stevia
leaves extract or saccharine along with 10 per cent apple pomace was found optimum for preparation of low calorie guava-
Aloe vera fruit bars with respect to over all physico-chemical and sensory quality. Among non-nutritive sweeteners, the fruit
bar prepared by using 50 per cent stevia leaves extract along with 10 per cent apple pomace having 34.2ºB TSS, 17.0 per
cent moisture, 24.2 per cent total sugars and 177.7 mg/100g ascorbic acid was optimized for the preparation of low calorie
fruit bars. Storage of fruit bars at low temperature exhibited comparatively less changes in quality attributes as compared to
ambient temperature. Fruit bar having 50 per cent substitution of stevia leaves extract had energy value of 97.0 K cal/100g
and as such brought about 59.8 per cent reduction in the energy value over 100 per cent sucrose sweetened fruit bars. Thus,
plant based sources like Aloe vera and stevia leaves can successfully be utilized for development of hypoglycaemic products
for the obese and diabetic people.
Signature of the Major Advisor Signature of Student
Countersigned
Professor and Head
Department of Food Science and Technology
Dr. Y. S. Parmar University of Horticulture and Forestry
Nauni, Solan- 173230 (HP)
i
APPENDIX - I
AGRO-METEOROLOGICAL DATA
Month
Temperature (°C)
Maximum Minimum
Relative
Humidity (%)
Rainfall
(mm)
Year 2010
June 33.30 18.50 48 37.30
July 29.00 19.50 70 90.30
august 28.40 18.80 84 54.10
September 26.9 17.3 79 346.6
October 27.1 10.5 62 41.7
November 24.4 6.1 55 21.8
December 19.9 1.2 58 70.2
Year 2011
January 18.1 0.4 54 23.2
February 19.0 0.3 60 61.5
ii
APPENDIX - II
DUO-TRIO TEST
EVALUATION FOR RELATIVE SWEETNESS OF NON-NUTRITIVE
SWEETENERS
NAME: Date:
PRODUCT:
The first sample ‘R’ given is the reference sample.
Taste it carefully.
From the pair of coded samples next given, judge which sample is the same as ‘R’.
A positive answer is to be made even if it is a guess.
Set no. Code no. of pairs Same as ‘R’
I --------------------- ------------------
II --------------------- ------------------
III --------------------- ------------------
IV --------------------- ------------------
Signature of Evaluator
iii
HEDONIC RATING TEST
EVALUATION FOR SENSORY QUALITY OF GUAVA-ALOE VERA BEVERAGE.
NAME: Date:
PRODUCT:
Please evaluate the following samples as per the standard scale.
Sample Colour Flavour /aroma
Taste Body Over all acceptability
1 2 3
4 5 6 7 8 9
Nine point hedonic scale
9 like extremely 4 Dislike slightly
8 Like very much 3 Dislike moderately
7 Like moderately 2 Dislike very much
6 Like slightly 1 Dislike extremely
5 Neither like nor dislike
Signature of Evaluator
iv
HEDONIC RATING TEST
EVALUATION FOR SENSORY QUALITY OF HYPOGLYCAEMIC GUAVA -
ALOE VERA BEVERAGE.
NAME: Date:
PRODUCT:
Please evaluate the following samples as per the standard scale.
Sample Colour Flavour /aroma
Taste Body Over all acceptability
1 2 3 4 5 6 7
8 9
Nine point hedonic scale
9 like extremely 4 Dislike slightly
8 Like very much 3 Dislike moderately
7 Like moderately 2 Dislike very much
6 Like slightly 1 Dislike extremely
5 Neither like nor dislike
Signature of Evaluator
v
HEDONIC RATING TEST
EVALUATION FOR SENSORY QUALITY OF GUAVA ALOE VERA FRUIT BAR
NAME: Date:
PRODUCT:
Please evaluate the following samples as per the standard scale.
Sample Colour Taste Flavour
Texture Over all acceptability
1
2
3
4
5
6
Nine point hedonic scale
9 like extremely 4 Dislike slightly
8 Like very much 3 Dislike moderately
7 Like moderately 2 Dislike very much
6 Like slightly 1 Dislike extremely
5 Neither like nor dislike
Signature of Evaluator
vi
HEDONIC RATING TEST
EVALUATION FOR SENSORY QUALITY OF HYPOGLYCAEMIC GUAVA ALOE
VERA FRUIT BAR.
NAME: Date:
PRODUCT:
Please evaluate the following samples as per the standard scale.
Sample Colour Taste Flavour Texture Over all acceptability
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Nine point hedonic scale
9 like extremely 4 Dislike slightly
8 Like very much 3 Dislike moderately
7 Like moderately 2 Dislike very much
6 Like slightly 1 Dislike extremely
5 Neither like nor dislike
Signature of Evaluator
APPENDIX-III
ANOVA for physico-chemical attributes of guava fruit (cv.Allahabad Safeda)
Mean sum of squares (MSS) Sources of
variation
Degree of
freedom Weight Length diameter Fruit volume Fruit quotient Specific gravity
Treatments (T) 9 1122.7 56.356 21.041 9.0394x 10-2
539.25 1.4088 x104
Methods 2 414.3 39.433 26.233 3.4233x 10-3
322.08 1.3227
TxM 18 10355 55.656 22.530 1.9975x10-2
620.88 1.7532
Error 18 26.276 6.0913 3.8755 1.1534x10-1
20.345
ANOVA for storage of extracted guava pulp
Mean sum of squares (MSS) Sources of
variation
df
Yield Residue Total
solids
Total soluble
solids
Titratable
acidity
pH Total
sugars
Ascorbic
acid
Pectin Relative
viscosity
Grits
Treatments (T) 5 664.22 669.79 4.8152 x
10-1
1.6919 x 10-1 9.1296 x 10-4 2.1922 x
10-2
5.7811 x
10-3
398.51 2.0297 x
10-2
11.428 664.22
Methods (I) 2 1996.7 1987.1 22.297 16.005 1.8095 x 10-1
1.5285 13.077 1.4684 x
104
4.1312 x
10-1
743.32 1996.7
TxI 10 61.239 61.312 4.9519 x
10-2
1.1296 x 10-2
1.9074 x 10-4
1.6491 x
10-2
1.5900 x
10-3
13.083 1.0300 x
10-1
8.2816 61.239
Error 36 4.509 x
10-2
6.9352 x
10-2
3.2222 x
10-2
4.2222 x 10-2
4.7222 x 10-4
3.1678x
10-2
5.7222 x
10-4
4.0851 8.9074 x
10-4
3.8889 x 10-2
4.509 x
10-2
viii
ANOVA for guava-Aloe vera beverages
Mean sum of squares (MSS) Sources of variation Degree
of
freedom
TSS Titratable
acidity
Ascorbic
acid
Total sugars pH Specific gravity
Treatment (T) 8 3.8667 x 10-1 5.3333 x 10-3 10.575 4.2383 2.5617 x 10-2 3.5259 x 10-2
Error 18 7.4000 x 10-1
6.1333 x 10-3
3.8884 3.7389 6.7407 x 10-4
4.5306 x 10-3
ANOVA for guava-Aloe vera beverages
Mean sum of squares (MSS) Sources of
variation
Degree
of
freedom Colour Flavour/aroma Taste Body Over all Acceptability
Treatment (T) 8 8.5194 13.758 7.381 24.203 8.5194
Replicarion 9 1.8630 1.1472 1.3099 1.9617 1.8630
Error 72 8.713x10-1
5.3634 x10-1
8.1821x10-1
1.2090 8.713x10-1
ix
ANOVA for hypoglyceamic guava-Aloe vera beverages
Mean sum of squares (MSS) Sources of
variation
Degree
of
freedom TSS Titratable
acidity
Ascorbic
acid
Total sugars pH Relative viscosity Specific gravity
Treatment (T) 8 54.208 1.3704 x 10-4
3.7504 55.197 3.1667
x 10-4
1.0645x 10-1
7.9675 x 10-4
Error 18 2.1852 x
10-2
1.9630 x 10-4
4.9270 x
10-2
2.8356 x 10-2
4.2963
x 10-4
5.2222x 10-4
5.6667 x 10-6
ANOVA for hypoglyceamic guava-Aloe vera beverages
Mean sum of squares (MSS) Sources of
variation
Degree
of
freedom Colour Flavour/aroma Taste Body Over all Acceptability
Treatment (T) 8 18.500 13.82 15.819 1.993 1.992
Replication (R) 9 8.4741 10.767 6.100 1.0179 1.0178
Error 72 8.4741 1.6306 1.4306 5.1063x10-1
5.1063x10-1
x
ANOVA for physico-chemical attributes for hypoglyceamic guava-Aloe vera beverages during storage
Mean sum of squares (MSS) Sources of
variation
Degree
of
freedom TSS Titratable
acidity
pH Total sugars Ascorbic acid Relative
viscosity
Specific gravity
Treatment (T) 8 162.39 4.7778 x10-4 5.5864 x10-4 148.17 13.528 2.9294 x10-1 8.8587 x10-3
Storage(S) 2 2.7605 x10-1 6.5444 x10-3 1.3130 x10-2 8.1751 x10-1 3.9326 1.0468 x10-2 9.6850 x10-3
TxS 16 7.8549 x10-3
1.2639 x10-4
1.9336 x10-4
1.8729 6.9684 x10-2
2.5373 x10-3
9.1074 x10-3
error 54 2.9383 x10-2
1.6420 x10-4
3.6296 x10-4
1.9809 x10-2
2.8967 x10-2
1.7605 x10-3
2.2167 x10-3
ANOVA for sensory attributes for hypoglyceamic guava-Aloe vera beverages during storage
Mean sum of squares (MSS) Sources of variation Df
Colour Flavour/aroma Taste Body Over all Acceptability
Treatment (T) 8 5.8106 5.3211 7.6462 4.8816 6.2579
Storage(S) 2 3.9042 x10
-1 5.0033 x10
-2 1.8072 x10
-1 4.2790 x10
-2 1.068 x10
-1
TxS 16 3.3865 x10-1 1.1371x10-2 1.5642x10-3 5.6366 x10-3 6.4958 x10-3
Replication (R) 2 2.1605 x10-4
1.2248 x10-2
8.0235 x10-1
1.3493 x10-2
1.9370 x10-3
Error 52 7.8276 x10-3
1.2020 x10-1
6.0294 x10-4
2.8463 x10-4
1.1396 x10-3
xi
ANOVA for guava-Aloe vera fruit bar
Mean sum of squares (MSS) Sources of
variation
Degree
of
freedom TSS Titratable
acidity
Ascorbic
acid
Total sugars pH Total solids Moisture content
Treatment (T) 5 2.6810 7.1222 x10-4
8164.6 1.5396 9.7889 x10-4
1.6846 x10-2
1.7729 x10-2
Error 12 2.2300 2.7222 x10-4
3.1733 2.0133 4.3889 x10-4
3.3889 x10-4
7.2222 x10-4
ANOVA for guava-Aloe vera fruit bar
Mean sum of squares (MSS) Sources of
variation
Degree
of
freedom Colour Taste Flavour/aroma Texture Over all Acceptability
Treatment (T) 8 26.960 8.3735 4.4568 22.417 13.177
Replication (R) 8 5.2963 3.2068 6.2346 8.8167 1.9796
Error 64 1.4563 1.4221 1.0228 2.0167 8.2852
xii
ANOVA for physico-chemical characteristics of hypoglyceamic hypoglycaemic guava-Aloe vera fruit bar
Mean sum of squares (MSS) Sources of
variation
Degree
of
freedom TSS Titratable
acidity
Ascorbic
acid
Total sugars pH Total solids Moisture content
Treatment (T) 14 884.67 2.3857 x10-3
2.6185 859.20 2.2361 x10-2
3.9931 x10-
4
2.1756 x10-1
Error 30 5.4444
x10-2
6.4000 x10-4
4.7336
x10-2
3.91324 x10-1
6.1371 x10-2
2.5910 x10-
4
4.3516 x10-2
ANOVA for sensory quality of hypoglyceamic hypoglycaemic guava-Aloe vera fruit bar
Mean sum of squares (MSS) Sources of
variation
Degree
of
freedom Colour Taste Flavour/aroma Texture Over all Acceptability
Treatment (T) 14 2.4543 x10-1
5.0914 1.2283 2.1496 x10-1
2.4543 x10-1
Replication (R) 2 9.8429 x10-2
6.9995 x10-1
1.8611 x10-3
1.1100 x10-1
9.8429 x10-2
Error 28 1.8127 x10-4
5.4947 x10-2
1.9043 x10-3
1.9741 x10-3
1.8127 x10-4
xiii
ANOVA for physico-chemical attributes of hypoglyceamic hypoglycaemic guava-Aloe vera fruit bar during storage
Mean sum of squares (MSS) Sources of variation Degree of
freedom TSS Ascorbic acid Titratable
acidity
pH Total sugars Total solid Moisture
content
Water
activity
Treatment (T) 14 5318.6 15.916 1.2837 x10-2
8.4309 x10-2
2161.7 8.6808 7.8693 7.1793 x10-2
Storage interval (I) 2 4.5410 16.265 2.4280 x10-2
1.9442 x10-1
1.6932 11.506 1.1859 8.1323 x10-3
Storage condition (C) 1 7.2593 x10-1
1.7763 4.1317 x10-2
8.6700 x10-3
4.3662 x10-1
3.8473 1.2649 3.0941 x10-3
TxI 28 1.5718 7.6260 x10-1
1.4825 x10-4
1.2413 x10-2
8.7591 x10-2
8.8535 1.6911 x10-1
4.2404 x10-4
TxC 14 1.6190 1.5533 x10-1
3.0672 x10-4
5.9168 x10-3
6.8584 x10-2
9.5509 2.1277 x10-2
3.8233 x10-4
IxC 2 3.7019 4.4424 x10-1
1.3219 x10-2
2.2900 x10-3
2.6467 x10-1
8.1387 3.4055 x10-1
1.3664 x10-3
TxIxC 28 1.4998 1.4813 x10-1
1.6608 x10-4
1.9190 x10-3
4.9514 x10-2
9.3297 1.4126 x10-2
3.3680 x10-4
ERROR 180 1.5336 6.9917 x10-2
7.0407 x10-4
4.8815 x10-2
9.9534 x10-2
9.3326 4.4213 x10-2
6.7034 x10-4
ANOVA for sensory quality of hypoglyceamic hypoglycaemic guava-Aloe vera fruit bar during storage
Mean sum of squares (MSS) Sources of variation Degree of freedom
Colour Taste Flavour Texture Overall acceptability
Treatment 14 2.4543 x10-1
5.0914 1.2283 2.1496 x10-1
2.4543 x10-1
Replication 2 9.8429 x10-2
6.9995 x10-1
1.8611 x10-3
1.1100 x10-1
9.8429 x10-2
Error 28 1.8127 x10-4
5.4947 x10-2
1.9043 x10-3
1.9741 x10-3
1.8127 x10-4
CURRICULUM VITAE
Name : Siloni Slathia
Father’s Name : Sh. Babu Singh Slathia
Date of Birth : 4 July, 1984
Sex : Female
Marital Status : Married
Nationality : Indian
Educational Qualifications:
Certificate/ degree Class/ grade Board/ University Year
Metric
First JKBOSE 1999
10+2 Second JKBOSE 2001
B.Sc.
M.Sc
First
First
University of Jammu
University of Jammu
2004
2006
Whether sponsored by some state/ : NA
Central Govt./Univ./SAARC
Scholarship/ Stipend/ Fellowship, any : NA
other financial assistance received
during the study period
(Siloni Slathia)
