INFLUENCE OF ALLIUM SATIVUM OR CINNAMOMUM
VERUM ON FERMENTATION OF MILK AND THEIR
EFFECTS ON THE PHYSICOCHEMICAL,
BIOCHEMICAL, MICROBIOLOGICAL AND
FUNCTIONAL PROPERTIES OF PROBIOTIC YOGURT
SHORI, AMAL BAKR
FACULTY OF SCIENCE
UNIVERSITY OF MALAYA
KUALA LUMPUR
2013
INFLUENCE OF ALLIUM SATIVUM OR CINNAMOMUM
VERUM ON FERMENTATION OF MILK AND THEIR
EFFECTS ON THE PHYSICOCHEMICAL,
BIOCHEMICAL, MICROBIOLOGICAL AND
FUNCTIONAL PROPERTIES OF PROBIOTIC YOGURT
SHORI, AMAL BAKR
THESIS SUBMITTED IN FULFILLMENT OF THE
REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY
INSTITUTE OF BIOLOGICAL SCIENCES
FACULTY OF SCIENCE
UNIVERSITY OF MALAYA
KUALA LUMPUR
2013
ii
DEDICATION
I dedicate this PhD to my mother, father and family for their endless
support
iii
UNIVERSITI MALAYA
ORIGINAL LITERARY WORK DECLARATION Name of Candidate: SHORI, AMAL BAKR I/C/Passport No: G598946
Regisration/Matric No.: SHC090050
Name of Degree: DOCTOR OF PHILOSOPHY
Title of Project Paper/Research Report/Dissertation/Thesis (this Work):
INFLUENCE OF ALLIUM SATIVUM OR CINNAMOMUM VERUM ON FERMENTATION OF MILK AND THEIR EFFECTS ON THE PHYSICOCHEMICAL, BIOCHEMICAL, MICROBIOLOGICAL AND FUNCTIONAL PROPERTIES OF PROBIOTIC YOGURT
Field of Study: FOOD BIOTECHNOLOGY
I do solemnly and sincerely declare that: (1) I am the sole author/writer of this Work, (2) This Work is original, (3) Any use of any work in which copyright exists was done by way of fair dealing and for
permitted purposes and any excerpt or extract from, or reference to or reproduction of any copyright work has been disclosed expressly and sufficiently and the title of the Work and its authorship have been acknowledged in this Work,
(4) I do not have any actual knowledge nor do I ought reasonably to know that the making of this work constitutes an infringement of any copyright work,
(5) I hereby assign all and every rights in the copyright to this Work to the University of Malaya (UM), who henceforth shall be owner of the copyright in this Work and that any reproduction or use in any form or by any means whatsoever is prohibited without the written consent of UM having been first had and obtained,
(6) I am fully aware that if in the course of making this Work I have infringed any copyright whether intentionally or otherwise, I may be subject to legal action or any other action as may be determined by UM.
(Candidate Signature) Date: 28-11-2013 Subscribed and solemnly declared before, Witnesss Signature Date: 28-11-2013
Name: ASSOC. PROF. DR AHMAD SALIHIN HJ BABA
Designation
iv
ABSTRACT
The present study investigated the effects of Allium sativum or Cinnamomum verum
water extract on fermentation of milk and subsequent changes in yogurt bacteria
growth and fermentation products on the organoleptic, nutritional and functional
values of yogurt. Three types of milk (cow, camel and goat) were incubated (41C)
with starter culture in the presence of A. sativum or C. verum water extract until pH of
yogurt was reduced to 4.5. The presence of A. sativum or C. verum water extract in
cow, camel and goat milk did not affect pH reduction during fermentation whereas
titratable acidity (TA) increased only in A. sativum-cow milk yogurt. Both herbal
extracts enhanced proteolytic activity only in cow milk during fermentation but the
viable cell counts (VCC) increased (p
v
sativum reduced the aroma score in the former. The presence of A. sativum or C.
verum in milk during yogurt bacteria fermentation can enhance microbial growth and
metabolism resulting in an increase in VCC, nutrient digestibility, rheological
characteristics and functional properties. The potential stability of yogurt to exposure
to digestive enzymes was also enhanced in the present of A. sativum or C. verum.
vi
ABSTRAK
Kajian ini mengkaji kesan ekstrak air Allium sativum atau Cinnamomum verum ke atas
penapaian susu dan perubahan berikutnya dalam pertumbuhan bakteria yogurt dan
produk penapaian (protein, peptida, oligosaccharides dan asid organik) terhadap
organolepsis, nilai pemakanan dan fungsi yogurt. Tiga jenis susu (susu lembu, unta
dan kambing) telah dieram (41 C) dengan kultur pemula dalam kehadiran ekstrak air
A. sativum atau C. verum sehingga pH yogurt menurun ke 4.5. Kehadiran A. sativum
atau C. verum ekstrak air dalam susu lembu, unta dan kambing tidak menjejaskan
pengurangan pH semasa penapaian manakala keasidan tertitrat (TA) meningkat hanya
dalam yogurt susu lembu-A. sativum. Kehadiran kedua-dua ekstrak herba peningkatan
aktiviti proteolisis hanya dalam susu lembu semasa penapaian tetapi bilangan sel yang
hidup (VCC) meningkat (p
vii
atau C. verum dalam yogurt susu lembu dan unta menunjukkan peningkatan dalam
kapasiti penakungan air (WHC), kecenderungan syneresis (STS) dan kandungan
exopolysaccharides (ESP). Walau bagaimanapun, kedua-dua herba mempengaruhi
sifat reologi yogurt dengan menunjukkan kurangnya kebolehan merintang deformasi
apabila ricihan dikenakan dan tingkah laku penipisan ricih. Penambahan A. sativum
dan C. verum tidak menjejaskan sifat organolepsis yogurt susu lembu dan susu unta
walaupun A. sativum mengurangkan skor aroma dalam susu lembu. Kehadiran A.
sativum atau C. verum dalam susu semasa penapaian oleh bakteria yogurt boleh
meningkatkan pertumbuhan dan metabolisme mikrob yang mengakibatkan
peningkatan dalam VCC, kebolehadaman nutrien, ciri-ciri reologi dan sifat-sifat
berfungsi. Kemungkinan kestabilan yogurt semasa pendedahan kepada enzim
pencernaan telah juga dipertingkatkan dalam kehadiran A. sativum atau C. verum.
viii
ACKNOWLEDGEMENT
I would like to express my gratitude to all those who gave me the possibility to
complete this research work. First of all I want to thank Allah to give me this
opportunity to do my PhD and blessing me with the courage and strength. My special
thanks are also dedicated to my parents, sisters and my brother whose always support
and encouragement. Furthermore, I have very special thanks to my supervisor, Associate
Professor Dr. Ahmad Salihin Baba, who has been big helpful to providing me with the
guidance to completing this work. I would like to express my thanks to Professor Dr.
Saad Tayyab for his grateful advise that gave me the strength to move on forward in my
study, as well as to Professor Dr. Misni Misran for his good cooperation in rheological
study part of research.
I would like to thank all lab assistance for their advice to use the equipments in the
laboratories. I acknowledge the friendly company of my research team-mates who made
my laboratory work more lively.
Last but not least, I would like to express my sincere and heartiest thanks to the
people who helped me during the completion of my research and thesis but are not
mentioned here, I grateful thank you all for your help.
Amal Bakr Shori
ix
Refereed Research Papers
Shori, A.B., & Baba, A.S. (2011). Cinnamomum verum improved the
functional properties of bioyogurts made from camel and cow milks, Journal
of the Saudi Society of Agricultural Sciences,10(2): 101-107.
Shori, A.B., & Baba, A.S. (2011). Antioxidant activity and inhibition of key
enzymes linked to type-2diabetes and hypertension by Azadirachta indica-
yogurt. Journal of Saudi Chemical Society,17(3): 592 -301.
Shori, A.B., & Baba, A.S. (2011). Comparative antioxidant activity,
proteolysis and in vitro -amylase and -glucosidase inhibition of Allium
sativum-yogurts made from cow and camel milk. Journal of Saudi Chemical
Society, DOI: 10.1016/j.jscs.2011.09.014.
Shori, A.B., & Baba, A.S. (2012). Viability of lactic acid bacteria and sensory
evaluation in Cinnamomum verum and Allium sativum-bio-yogurts made from
camel and cow milk. Journal of the Association of Arab Universities for Basic
and Applied Sciences, 12(1), 50-55.
Shori, A.B. (2012). Comparative study of chemical composition, isolation and
identification of micro-flora in traditional fermented camel milk products:
Gariss, Suusac, and Shubat. Journal of the Saudi Society of Agricultural
Sciences,11(2): 7988.
Shori, A.B., Baba, A.S., & Keow, J.N. (2012). Effect of Allium sativum and
fish collagen on the proteolytic and angiotensin-I converting enzyme-inhibitory
activities in cheese and yogurt. Pakistan Journal of Biological Sciences,
15(24): 1160-1167.
x
Shori, A.B. (2012). Changes of hemoglobin content and glucose levels in the
blood of Rattus norvegicus by water extracts of Azadirachta indica. Chinese
Journal of Natural Medicines, 10(2): 135137.
Shori, A.B. & Olorogun, L.A. (2012). Awareness of GM food proliferation in
Saudi Arabia: A case study of Makkah city. Journal of the Association of Arab
Universities for Basic and Applied Sciences, 13(1): 8-13.
Shori, A.B., Baba, A.S., Misran, M. & Tan, H.W. (2013). Enrichment of
yogurt made from camel milk with Allium sativum and Cinnamomum verum:
Influence on syneresis, water holding capacity, exopolysaccharides and
rheological properties. Camel- International Journal of Veterinary Science,
1(1):75-87.
Shori, A.B., Baba, A.S. & Chuah, P.F (2013). The effects of fish collagen on
the proteolysis of milk proteins, ACE inhibitory activity and sensory evaluation
of plain- and Allium sativum-yogurt. Taiwan Institute of Chemical Engineers,
44(5): 701706.
Shori, A.B. (2013). Evaluation of acute toxicity of water extract of Azadirachta
indica leaves and seeds in rats. Pakistan Journal of Biological Sciences,
16(14): 697-700.
Shori, A.B., Baba, A.S., Misran, M. & Tan, H.W. (2013). Influence of Allium
sativum or Cinnamomum verum on physicochemical characteristics of yogurt.
International Journal of Dairy Science, DOI: 10.3923/ijds.2013 (in press).
xi
Shori, A.B., & Baba, A.S. (2014). The influence of Allium sativum or
Cinnamomum verum on cow- and camel- milk yogurts: proteolytic and
angiotensin-I converting enzyme-inhibitory activities. Advanced Materials
Research, 832 (2014) 639-643.
Shori, A.B., & Baba, A.S. (2013). Survival of Bifidobacterium bifidum in cow-
and camel- milk yogurts fortified with Cinnamomum verum and Allium
sativum. Journal of the Association of Arab Universities for Basic and Applied
Sciences. (Accepted)
Shori, A.B., & Baba, A.S. (2013). Effects of inclusion of Allium sativum and
Cinnamomum verum in milk on the growth of lactic acid bacteria during
fermentation. American-Eurasian Journal of Agricultural & Environmental
Sciences (accepted).
Shori, A.B. (2013). Nutritional and therapeutical values of chickpea water
extract enriched yogurt made from cow and camel milk. American Journal of
Drug Discovery and Development, DOI: 10.3923/AJDD.2013 (in press).
Shori, A.B. (2013). Antioxidant activity and viability of lactic acid bacteria in
soybean-yogurt made from cow and camel milk. Journal of Taibah University
for Science, DOI: 10.1016/j.jtusci.2013.06.003.
Baba, A.S., Najarian, A. Shori, A.B., Lit, K.W., & Keng, G.A. In vitro
inhibition of key enzymes related to diabetes and hypertension in Lycium
barbarum-yogurt. The Arabian Journal for Science and Engineering.
(Accepted first round).
xii
Conference Proceedings
Shori, A.B. and Baba, A.S. (2011). Antioxidant activity and inhibition of key
enzymes linked to type-2 diabetes and hypertension by Azadirachta indica-
yogurt. Oral presentation in 3rd IIUM-iCAST, 26-29 November 2010.
Shori, A.B. and Baba, A.S. (2011). Antioxidant activity and inhibition of key
enzymes linked to type-2 diabetes and hypertension by Azadirachta indica-
yogurt. Poster presentation 15th
Biolgical Sciences Graduate Congress. 15-17
December 2010.
Shori, A.B. and Baba, A.S. (2011). Comparative antioxidant activity,
proteolysis and in vitro -amylase and -glucosidase inhibition of Allium
sativum-yogurts made from cow and camel milk. Poster presentation in 7th
Kelantan Health Conference 15 16th June 2011.
Shori, A.B. and Baba, A.S. (2011). Viability of lactic acid bacteria and sensory
evaluation in Cinnamomum verum and Allium sativum- bio-yogurts made from
camel- and cow-milk. Poster presentation in international Congress of
the Malaysian Society for Microbiology 8-11 December 2011.
Shori, A.B. (2012). Changes of hemoglobin content and glucose levels in the
blood of Rattus norvegicus by water extracts of Azadirachta indica. Poster
presentation international conference on natural products (ICNP 2011), 13-16
November.
Shori, A.B. (2011). Determination of acute toxicity, changes of hemoglobin
and sugar level in the blood of Rattus norvegicus by extracts of Azadirachta
indica. Poster presentation 5th
international congress of chemistry and
enviroment, ICCE 2011, 27th
-29th
may.
http://www.iium.edu.my/icast/2010/upload/3rd%20IIUM-iCAST%202010%20Abstract%20Book.pdf
xiii
Shori, A.B (2012). Comparative antioxidant activity and viability of lactic acid
bacteria in soybean-bio-yogurt made from cow and camel milk. Poster
presentation international Conference on Nutrition and Growth. Paris, France,
March 1-3.
Shori, A.B., & Baba, A.S. (2013). The influence of Allium sativum or
Cinnamomum verum on cow- and camel- milk yogurts: proteolytic and
angiotensin-I converting enzyme-inhibitory activities. Oral presentation in
International Conference on Nanoscience and Nanotechnology 2013 (NANO-
SCITECH 2013), March 1-4.
Shori, A.B., & Baba, A.S. (2013). Survival of Bifidobacterium bifidum in cow-
and camel- milk yogurt fortified with Cinnamomum verum and Allium sativum.
Oral presentation in the 8th Asia Pacific Conference on Clinical Nutrition
(APCCN 2013), 9-12 June in Tokyo, Japan.
Awards and Grants
1) King Abdul Allah Grant (Saudi Arabia): scholarship for three years full-time
study in a Doctor of Philosophy program.
2) The post graduate research grand (PPP), University Malaya, Kuala lumpur,
Malaysia. Account No: PS300/2010.
3) Inclusion in the Who's Who in the World 2014 -31th Edition, ISBN: 978-0-
8379-1152-6, Nov. 2013, Marquis Who's Who, USA.
xiv
Table of Contents
Chapter Page
LIST OF TABLES ........................xx
LIST OF FIGURES ..................xxiii
LIST OF ABBREVIATIONS ...........................xxxvii
1.0 Introduction .................................................1
1.1 Background...........2
1.2 Problem statement..............6 1.3 Objectives of study.............7 1.4 Significant of study.............8
1.5 Organization of chapters...........8 2.0 Literature Review ................10
2.1 Aims and scope of the literature review..........11 2.2 What are functional foods?...............11
2.2.1 Functional dairy products .................13
2.2.1.1 Composition of camel, goat and cow milk..........................................14
2.2.2 Yogurt as a functional food..............................17
2.2.2.1 Lactic acid bacteria (LAB).........20
2.2.2.2 Probiotics.........22
2.2.2.2.1 Therapeutic value of probiotic...........24
2.3 Fermentation ........................................................................................29
2.3.1 Lactic acid fermentation....................................................30
2.4 Rheological and physical properties of yogurt.................................31
2.5 Proteolysis of milk protein ...........................................32
2.5.1 Proteolytic agents in yogurt .....................34
2.5.2 Functionality of bioactive peptides ...........35
2.6 Hypertension ..................................................................................................37
2.6.1 Milk-protein-derived peptides with antihypertensive effects....................39
2.6.2 Production of fermented dairy products with ACE inhibitory peptides.................41
2.7 Diabetes .................................................................................. ..........................42
2.7.1 -Amylase inhibitor enzyme ...................47
2.7.2 -Glucosidase inhibitor enzyme .........49
2.8 Gastrointestinal tract (GI)........................................50
2.9 Medicinal plants ...........................................................................................52
2.9.1 Cinnamon (Cinnamomum verum).......................53
2.9.1.1 Botanical description ..............53
2.9.1.2 Chemical composition.............53
2.9.1.3 Therapeutic uses of cinnamon..................................................54 2.9.2 Garlic (Allium sativum)......................56
2.9.2.1 Botanical description ..................56
2.9.2.2 Garlic preparations and their chemical compounds ..............56
2.9.2.3 Therapeutic uses of garlic......58
2.9.3 Phenolic phytochemicals.......................................................59 2.9.4 Natural foods antioxidants and their health benefits.....................61
3.0 Effects of inclusion of Allium sativum and Cinnamomum verum in milk on the
acidification, proteolysis and growth of lactic acid bacteria during fermentation..64
3.1 Introduction.................65
3.2 Materials and methods...................................................66
3.2.1 Substrates and chemicals ..................66
3.2.2 Experimental design .......67
3.2.3 Plant water extraction .....67
xv
3.2.4 Yogurt manufacturing process.............68
3.2.4.1 Preparation of starter culture.............68
3.2.4.2 Yogurt preparation ..............69
3.2.5 Measurement of pH and titratable acidity (TA).........70
3.2.6 Determination of proteolytic activity.....71
3.2.6.1 Sample preparation (yogurt water extract)...........71
3.2.6.2 O-phthaldialdehyde (OPA) assay................................................................72
3.2.7 Microbial viable cell count (VCC) in yogurt......73
3.2.7.1 Sample preparation...............73
3.2.7.2 Enumeration of Lactobacillus spp ..............73
3.2.7.3 Enumeration of Streptococcus thermophilus ......74
3.2.7.4 Enumeration of probiotic bacteria (Bifidobacterium bifidum)...............................74
3.2.8 Statistical analysis............75
3.3 Results................................................................75
3.3.1 Acidity trend during milk fermentation....75
3.3.2 Free amino group in hebal extracts and yogurt .............................................................80 3.3.3 The growth of LAB during fermentation.............83
3.3.3.1 Viable cell count (VCC) of S. thermophilus................83
3.3.3.2 Viable cell count of Lactobacillus spp...................................................86
3.3.3.3 Viable cell count of probiotic (B. bifidum).......................89
3.4 Discussions...............................................................92
3.4.1 Changes in pH and titratable acidity..........92
3.4.2 Proteolytic activity ..............................................................94 3.4.3 Viability of starter culture bacteria.....................95
3.5 Conclusions..........97
4.0 Influence of Allium sativum or Cinnamomum verum water extract on post-
acidification and proximate composition of yogurt made from cow, camel and goat
milk during refrigerated storag.....98
4.1 Introduction.................99
4.2 Materials and methods.............................................................101
4.2.1 Substrates and chemicals ...................101
4.2.2 Experimental design ........101
4.2.3 Plant water extraction procedure..........102
4.2.4 Yogurt manufacturing process..............102
4.2.4.1 Starter culture and yogurt preparation.....102
4.2.5 Measurement of pH and titratable acidity (TA)...............102
4.2.6 Determination of lactose ............102
4.2.7 Determination of total carbohydrate ...................104
4.2.8 Total solid and moisture content...................105
4.2.9 Determination of ash content ............106
4.2.10 Determination of fat content ...........106
4.2.11 Determination of solids-not-fat...........................................................................................107
4.2.12 Statistical analysis...........107
4.3 Results..............................................................107
4.3.1 Changes in pH and titratable acidity (TA) during refrigerated storage..... ..107
4.3.2 Total lactose content ................................................................. ..........112
4.3.3 Total carbohydrate content ..... . 115
4.3.4 Total solids (TS) ................................................. .. ..........118
4.3.5 Total moisture content ..... .120
4.3.6 Ash content of yogurt ...................................................... ...............123
4.3.7 Fat content in yogurt ....................................................125
xvi
4.3.8 Solid-not-fat (SNF) ..................................................................128
4.4 Discussions.............................................................130
4.4.1 Post- acidification in yogurt...............130
4.4.2 Proximate composition................................................................132 4.4.2.1 Lactose and carbohydrates.....................132
4.4.2.2 Total solids, moisture content and ash...............................133
4.4.2.3 Fat and solid-not-fat ................................................134
4.5 Conclusions............135
5.0 Enrichment of yogurt with Allium sativum and Cinnamomum verum: Influence
on water holding capacity, syneresis, exopolysaccharides production and rheological
properties...................136
5.1 Introduction..............137
5.2 Materials and methods.............................................................139
5.2.1 Plant water extraction procedure......139
5.2.2 Yogurt manufacturing process..............139
5.2.2.1 Starter culture and yogurt preparation.........139
5.2.3 Isolation and quantification of exopolysaccharides (EPS)............139
5.2.4 Water holding capacity (WHC) .......140
5.2.5 Susceptibility to syneresis (STS)..........140
5.2.6 Rheological measurements ............140
5.2.7 Sensory evaluation....................................................................................................................141
5.2.8 Statistical analysis.............142
5.3 Results..................................................................143
5.3.1 Exopolysaccharides (EPS) production ..........143
5.3.2 Water holding capacity (WHC) ...........145
5.3.3 Susceptibility to syneresis (STS)......................................................................147
5.3.4 Dynamic rheology ............149
5.3.5 Apparent viscosity ........................................................................157
5.3.6 Sensory evaluation ..............160
5.4 Discussions.............................................................163
5.4.1 Crude EPS content.........163
5.4.2 Water holding capacity and susceptibility to syneresis.................................................163 5.4.3 Dynamic rheology ................164
5.4.4 Apparent viscosity ....................166
5.4.6 Sensory evaluation ...............167
5.5 Conclusions............168
6.0 Viability of lactic acid bacteria and Bifidobacterium bifidum in Cinnamomum
verum- and Allium sativum- yogurt during refrigerated storage...169
6.1 Introduction..........................170
6.2 Materials and methods.............................................................172
6.2.1 Substrates and chemicals ...............172
6.2.2 Plant water extraction procedure......172
6.2.3 Yogurt manufacturing process..............172
6.2.3.1 Starter culture and yogurt preparation....172
6.2.4 Microbial viable cell counts (VCC) in yogurt .............172
6.2.5 Statistical analysis.....................172
6.3 Results..................................................................173
6.3.1 Viable cell counts (VCC) of LAB and B. bifidum......173
6.3.1.1 VCC in milk before fermentation (BF).......173
6.3.1.2 VCC in yogurt during storage (4C)............................................173
xvii
6.4 Discussions..................................................179
6.4.1 Viability of yogurt bacteria.....179
6.4.2 Viability of probiotic (B. bifidum) in yogurt.....................................................................182
6.5 Conclusions..... ..184
7.0 The effect of Cinnamomum verum or Allium sativum on the survival of LAB and
Bifidobacterium bifidum after simulated gastrointestinal digestion of yogurt.185
7.1 Introduction...... ...186
7.2 Materials and methods........................... ..........................187
7.2.1 Substrates and chemicals.....187
7.2.2 Experimental designs ...187
7.2.3 Plant water extraction procedure.......188
7.2.4 Yogurt manufacturing process...........188
7.2.4.1 Starter culture and yogurt preparation......188
7.2.5 In vitro gastrointestinal model ..........188
7.2.5.1 Preparation of gastric and duodenum juices.......188
7.2.5.2 Simulation of gastrointestinal digestion (SGD)........................................................189
7.2.6 Microbial viable cell counts (VCC) in yogurt.......190
7.2.7 Statistical analysis .........190
7.3 Results..................................................190
7.3.1 VCC of Lactobacillus spp. after SGD.....190
7.3.2 VCC of S. thermophilus after SGD .....194
7.3.3 VCC of B. bifidum after SGD .......198
7.4 Discussions..................................................202
7.4.1 Survival of LAB after SGD .........202
7.4.2 Survival of probiotic (B. bifidum) after SGD....................................................................205
7.5 Conclusions........206
8.0 Allium sativum- and Cinnamomum verum- yogurt proteolysis and in vitro
angiotensin-I converting enzyme activity during refrigerated storage ......207
8.1 Introduction...............208
8.2 Materials and methods..................................................210
8.2.1 Substrates and chemicals ............210
8.2.2 Plant water extraction procedure.......210
8.2.3 Yogurt manufacturing process...............210
8.2.3.1 Starter culture and yogurt preparation......210
8.2.4 Sample preparation (yogurt water extract).............210
8.2.5 Determination of proteolytic activity ......210
8.2.5.1 O-phthaldialdehyde (OPA) assay .....211
8.2.5.2 Determination of total soluble protein (TSP).............................................................211
8.2.6 ACE-I inhibition assay ........212
8.2.6.1 O Preparation of yogurt sample .........212 8.2.6.2 Preparation of rabbit lung acetone extract..................................................................212
8.2.6.3 Preparation of ACE reagent ........213
8.2.6.4 Measurement of anti-ACE-I inhibitory activity and IC50.......................................213
8.2.7 Statistical analysis..........214
8.3 Results......................................................214
8.3.1 Proteolytic activity during refrigerated storage........214
8.3.1.1 The extent of proteolysis .........214
8.3.1.2 Total soluble proteins.............................................................................................. ..........217
8.3.2 ACE-I inhibitory activity ........220
8.3.2.1 ACE-I inhibitory activity (IC50).....222
8.4 Discussions......................................................223
8.4.1 Proteolytic activity.....223
xviii
8.4.2 ACE-I inhibitory activity.........................................................................................................225
8.5 Conclusions........227
9.0 Sustainability of ACE inhibitory activity of Allium sativum- and Cinnamomum
verum- yogurt made from cow, camel and goat milk under stimulated
gastrointestinal digestion.........228
9.1 Introduction...............229
9.2 Materials and methods..................................................230
9.2.1 Substrates and chemicals ............230
9.2.2 Experimental designs ...............230
9.2.3 Plant water extraction procedure.......230
9.2.4 Yogurt manufacturing process...........230
9.2.4.1 Starter culture and yogurt preparation......230
9.2.5 In vitro gastrointestinal model ..............231
9.2.5.1 Preparation of gastric and duodenum juices.......231
9.2.5.2 Simulation of gastrointestinal digestion (SGD)........................................................231
9.2.6 Determination of proteolytic activity ..........231
9.2.7 ACE-I inhibition assay ........231
9.2.8 Statistical analysis .........231
9.3 Results..................................................232
9.3.1 The extent of proteolysis after SGD .......232
9.3.2 Total soluble protein (TSP) after SGD .....235
9.3.3 ACE-I inhibitory activity after SGD ......238
9.4 Discussions..................................................242
9.4.1 The extent of proteolysis after SGD ......242
9.4.2 ACE-I inhibitory activity after SGD ..................................................................................244
9.5 Conclusions........246
10.0 Effect of Allium sativum or Cinnamomum verum enriched yogurt on antioxidant
activity and in vitro inhibition of -amylase and -glucosidase enzymes related to
type 2 diabetes .....247
10.1 Introduction................248
10.2 Materials and methods...................................................250
10.2.1 Substrates and chemicals ................250
10.2.2 Experimental design .................250
10.2.3 Plant water extraction procedure.......250
10.2.4 Yogurt manufacturing process...............251
10.2.4.1 Starter culture and yogurt preparation........251
10.2.5 Sample preparation (yogurt water extract).............251
10.2.6 -Amylase inhibition assay .............................. .251
10.2.6.1 Determination of inhibitory concentration (IC50) of yogurt water extracts
toward -amylase activity....252
10.2.7 -Glucosidase inhibition assay and IC50.........252
10.2.8 Total phenolic assay .................................................253
10.2.9 Antioxidant activity by 1, 1-diphenyl-2-picrylhydrazyl radical (DPPH)
inhibition assay ...........254
10.2.10 Statistical analysis........254
10.3 Results....................................................254
10.3.1 In vitro -amylase inhibitory activity .......254
10.3.1.1 -Amylase inhibitory activity (IC50) .......257
10.3.2 In vitro -glucosidase inhibitory activity .......258
10.3.2.1 -Glucosidase inhibitory activity (IC50) ........261
10.3.3 Total phenolic content (TPC) ........262
10.3.4 Antioxidant activity by DPPH Assay ......265
xix
10.4 Discussions.......................................................268
10.4.1 -Amylase inhibitory activity .....268
10.4.2 -Glucosidase inhibitory activity.....................................................................................270
10.4.3 TPC and antioxidant activity.............................................................................................272 10.5 Conclusions..........274
11.0 Sustainability of ACE inhibitory activity of Allium sativum- and Cinnamomum
verum- yogurt made from cow, camel and goat milk under stimulated
gastrointestinal digestion.........275
11.1 Introduction................276
11.2 Materials and methods.......................................................278
11.2.1 Substrates and chemicals ..............278
11.2.2 Experimental designs ................278
11.2.3 Plant water extraction procedure........278
11.2.4 Yogurt manufacturing process.............278
11.2.4.1 Starter culture and yogurt preparation.....278
11.2.5 In vitro gastrointestinal model ............278
11.2.5.1 Preparation of gastric and duodenum juices....278
11.2.5.2 Simulation of gastrointestinal digestion (SGD)......................................................278
11.2.6 -Amylase inhibition assay ........279
11.2.7 -Glucosidase inhibition assay.......279
11.2.8 Total phenolic assay .........279
11.2.9 DPPH inhibition assay .....279
11.2.10 Statistical analysis........279
11.3 Results....................................................279
10.3.1 -Amylase inhibitory activity after SGD .......279
10.3.2 -Glucosidase inhibitory activity after SGD ........284
10.3.3 Total phenolic content after SGD .........288
10.3.4 Antioxidant activity after SGD .....293
11.4 Discussions...................................................298
11.4.1 -Amylase and -glucosidase inhibition activities after SGD .......298
11.4.2 TPC and antioxidant activity in yogurt after SGD ...................................................299
11.5 Conclusions..........302
12.0 Overall conclusions and future research direction........303
12.1 Overall conclusions......304
12.2 Future research directions relating to studies on herbal- yogurt .......305
13.0 List of references.......................................306 Appendix 1.....343
Appendix 2.....344
xx
List of Tables
Table Page
2.1 Different types of functional foods...13
2.2 Dairy components and ingredients in functional foods and their health..14
2.3 Chemical composition of camel, Ggoat and cow milk.....17
2.4 The nutritional value of 100g yogurt.....18
2.5 Contribution of LAB to functionality of fermented products.......22
3.1 Changes of pH, titratable acidity (TA) and bacteria cell counts of starter culture during
1, 3 and 7 days of refrigerated storage....69
3.2. Changes of pH and titratable acidity (TA; lactic acid equivalent %) in A. sativum and
C. verum water extracts...77
3.3 Total free amino groups (g/g) in A. sativum and C. verum water extracts.80
4.1 The pH and titratable acidity (%) in cow, camel and goat milk in presence and absence
of A. sativum and C. verum water extracts....108
4.2 Lactose content (g/100 g) in cow, camel and goat milk in presence and absence of A.
sativum and C. verum water extracts.....113
4.3 Carbohydrate content (g/100 g) in cow, camel and goat milk in presence and absence
of A. sativum and C. verum water extracts....116
4.4 Total solids (%) in cow, camel and goat milk in presence and absence of A. sativum
and C. verum water extracts......118
4.5 Moisture content (%) in cow, camel and goat milk in presence and absence of A.
sativum and C. verum water extracts.....121
4.6 Ash content (%) in cow, camel and goat milk in presence and absence of A. sativum
and C. verum water extracts......123
4.7 Fat content (%) in cow, camel and goat milk in presence and absence of A. sativum
and C. verum water extracts......126
4.8 Solid-not-fat content (%) in cow, camel and goat milk in presence and absence of A.
sativum and C. verum water extracts.....128
5.1 Sensory descriptors and definitions. ...142
5.2 Results of sensory evaluation of A. sativum- and C. verum- yogurt made from cow
milk after 1 and 21 days of refrigerated storage....161
5.3 Results of sensory evaluation of A. sativum- and C. verum- yogurt made from camel
milk after 1 and 21 days of refrigerated storage....162
xxi
6.1 Viability of LAB and B. bifidum in cow and camel milk in the absence or presence of
A. sativum and C. verum water extracts.......173
8.1 Proteolytic activity (g/g) in cow and camel milk in the absence or presence of A.
sativum and C. verum water extracts.....216
8.2 Total soluble proteins (g/g) in cow and camel milk in the absence and presence of A.
sativum and C. verum water extracts.....218
8.3 ACE-I inhibitory activity (%) in A. sativum and C. verum water extracts......221
8.4 ACE-I inhibitory activity (%) in cow and camel milk in the absence or presence of A.
sativum and C. verum water extracts and IC50 values (g/g) for ACE-I inhibition
activity...223
8.5 IC50 values for ACE-I inhibitory activity in A. sativum- and C. verum- yogurt made
from cow or camel milk during 21 days of refrigerated storage...223
9.1 Extent of proteolysis after simulated gastrointestinal digestion (SGD) of A. sativum
and C. verum water extracts......232
9.2 Total soluble protein after simulated gastrointestinal digestion (SGD) of A. sativum
and C. verum water extracts......235
9.3 ACE-I inhibitory activity after simulated gastrointestinal digestion (SGD) of A.
sativum and C. verum water extracts.239
10.1 Inhibition of -amylase and IC50 in A. sativum and C. verum water extracts...256
10.2 Inhibition of -amylase in cow and camel milk in the absence and presence of A.
sativum or C. verum water extract.....256
10.3 IC50 values for -amylase inhibitors in cow and camel milk in the absence and
presence of A. sativum or C. verum water extract.........258
10.4 IC50 values for -amylase inhibitors in A. sativum- and C. verum- yogurt made from
cow or camel milk during 21 days of refrigerated storage258
10.5 Inhibition of -glucosidase and IC50 in A. sativum and C. verum water extracts..259
10.6 Inhibition of - glucosidase by cow and camel milk in the absence and presence of
A. sativum or C. verum water extract....259
10.7 IC50 values for -glucosidase inhibitors in cow and camel milk in the absence and
presence of A. sativum or C. verum water extract.....262
10.8 IC50 values for -glucosidase inhibitors in A. sativum- and C. verum- yogurt made
from cow or camel milk during 21 days of refrigerated storage...262
xxii
10.9 Total phenolic content (TPC) in A. sativum and C. verum water extracts....263
10.10 Total phenolic content (TPC) in cow and camel milk in the absence and presence of
A. sativum or C. verum water extract....263
10.11 DPPH scavenging activity in A. sativum and C. verum water extracts...266
10.12 DPPH inhibition activity in cow and camel milk in the absence and presence of A.
sativum or C. verum water extract.....266
10.13 Regression analysis (correlation) between TPC and DPPH inhibition activity..266
11.1 Effects of in vitro gastrointestinal digestions of A. sativum and C. verum water
extracts on -amylase inhibition activity...279
11.2 Effects of in vitro gastrointestinal digestions of A. sativum and C. verum water
extracts on -Glucosidase inhibition activity....285
11.3 Effects of in vitro gastrointestinal digestions of A. sativum and C. verum water
extracts on total phenolic content..289
11.4 Effects of in vitro gastrointestinal digestions of A. sativum and C. verum water
extracts on antioxidant activity..293
xxiii
List of Figures
Figure page 2.1 Proposed health benefits stemming from probiotic consumption (Saarela et al.,
2002)....25
2.2 Potential means of formation of biologically active peptides from major milk
proteins.37
2.3 Regulation of blood pressure: role of angiontensin-I-converting enzyme in rennin-
angiotensin system and Kallikrein-Kinin system, adapted from Li et al. (2004)39
2.4 Active site of ACE showing the three subsites for interaction (Source: Hong et al.,
2008)....39
2.5 The role of the pancreas in glucose homeostasis (Cheng and Fantus, 2005)....43
2.6 Pathogenesis of type 1 diabetes mellitus (Kumaret al.,1992).......................................44
2.7 Progressive pathogenesis of type 2 diabetes mellitus (DeFronzo, 2004)......................46
2.8 Digestion of Carbohydrate (starch and sucrose) in the body........46
2.9 Human digestive system50
2.10 Cinnamomum verum Bark.......53
2.11 Allium Sativum (Garlic).......56
2.12 Classification of dietary polyphenols with their pharmacological properties.....61
3.1 The flow diagram of traditional production of herbal-yogur....70
3.2 Typical calibration curve for free amino acids concentration...73
3.3 Changes of pH in cow milk in the presence and absence of A. sativum (AS) or C.
verum (CV) water extract during fermentation (41C). Error bars represent a pooled
standard error of the mean (n=3). The level of significance was preset at p = 0.05
compared to control at the same incubation period.77
3.4 Changes of pH in goat milk in the presence and absence of A. sativum (AS) or C.
verum (CV) water extract during fermentation (41C). Error bars represent a pooled
standard error of the mean (n=3). The level of significance was preset at p = 0.05
compared to control at the same incubation period.78
3.5 Changes of pH in camel milk in the presence and absence of A. sativum (AS) or C.
verum (CV) water extract during fermentation (41C). Error bars represent a pooled
standard error of the mean (n=3). The level of significance was preset at p = 0.05
compared to control at the same incubation period.....78
xxiv
3.6 Changes of titratable acidity (TA; lactic acid equivalent %) in cow milk in the
presence and absence of A. sativum (AS) or C. verum (CV) water extract during
fermentation (41C). Error bars represent a pooled standard error of the mean (n=3). The
level of significance was preset at p = 0.05 compared to control at the same incubation
period...79
3.7 Changes of titratable acidity (TA; lactic acid equivalent %) in goat milk in the
presence and absence of A. sativum (AS) or C. verum (CV) water extract during
fermentation (41C). Error bars represent a pooled standard error of the mean (n=3). The
level of significance was preset at p = 0.05 compared to control at the same incubation
period...79
3.8 Changes of titratable acidity (TA; lactic acid equivalent %) in camel milk in the
presence and absence of A. sativum (AS) or C. verum (CV) water extract during
fermentation (41C). Error bars represent a pooled standard error of the mean (n=3). The
level of significance was preset at p = 0.05 compared to control at the same incubation
period...80
3.9 Changes in proteolytic activity (g/g) in cow milk in the presence and absence of A.
sativum (AS) or C. verum (CV) water extract during 4 hours fermentation (41C). Error
bars represent a pooled standard error of the mean (n=3). The level of significance was
preset at p = 0.05 compared to control at the same incubation period....81
3.10 Changes in proteolytic activity (g/g) in goat milk in the presence and absence of A.
sativum (AS) or C. verum (CV) water extract during 4 hours fermentation (41C). Error
bars represent a pooled standard error of the mean (n=3). The level of significance was
preset at p = 0.05 compared to control at the same incubation period....82
3.11 Changes in proteolytic activity (g/g ) in camel milk in the presence and absence of
A. sativum (AS) or C. verum (CV) water extract during 4 hours fermentation (41C) for
milk + A. sativum and 5 hours fermentation for plain milk and milk + C. verum. Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to control at the same incubation period...83
3.12 Changes in viable cell count (VCC) of S. thermophilus (108cfu/ml) in cow milk in the
presence and absence of A. sativum (AS) or C. verum (CV) water extract during 4 hours
fermentation (41C). Error bars represent a pooled standard error of the mean (n=3). The
level of significance was preset at p = 0.05 compared to control at the same incubation
period...84
3.13 Changes in viable cell count (VCC) of S. thermophilus (108cfu/ml) in goat milk in the
presence and absence of A. sativum (AS) or C. verum (CV) water extract during 4 hours
fermentation (41C). Error bars represent a pooled standard error of the mean (n=3). The
level of significance was preset at p = 0.05 compared to control at the same incubation
period...85
3.14 Changes in viable cell count (VCC) of S. thermophilus (108cfu/ml) in camel milk in
the presence and absence of A. sativum (AS) or C. verum (CV) water extract during 4
hours fermentation (41C) for milk + A. sativum and 5 hours fermentation for plain milk
and milk + C. verum. Error bars represent a pooled standard error of the mean (n=3). The
level of significance was preset at p = 0.05 compared to control at the same incubation
period...86
xxv
3.15 Changes in viable cell count (VCC) of Lactobacillus spp. (106cfu/ml) in cow milk in
the presence and absence of A. sativum (AS) or C. verum (CV) water extract during 4
hours fermentation (41C). Error bars represent a pooled standard error of the mean (n=3).
The level of significance was preset at p = 0.05 compared to control at the same
incubation period.....87
3.16 Changes in viable cell count (VCC) of Lactobacillus spp. (106cfu/ml) in goat milk in
the presence and absence of A. sativum (AS) or C. verum (CV) water extract during 4
hours fermentation (41C). Error bars represent a pooled standard error of the mean (n=3).
The level of significance was preset at p = 0.05 compared to control at the same
incubation period.....88
3.17 Changes in viable cell count (VCC) of Lactobacillus spp. (106cfu/ml) in camel milk
in the presence and absence of A. sativum (AS) or C. verum (CV) water extract during 4
hours fermentation (41C) for milk + A. sativum and 5 hours fermentation for plain milk
and milk + C. verum. Error bars represent a pooled standard error of the mean (n=3). The
level of significance was preset at p = 0.05 compared to control at the same incubation
period...89
3.18 Changes in viable cell count (VCC) of B. bifidum (108cfu/ml) in cow milk in the
presence and absence of A. sativum (AS) or C. verum (CV) water extract during 4 hours
fermentation (41C). Error bars represent a pooled standard error of the mean (n=3). The
level of significance was preset at p = 0.05 compared to control at the same incubation
period...90
3.19 Changes in viable cell count (VCC) of B. bifidum (108cfu/sml) in goat milk in the
presence and absence of A. sativum (AS) or C. verum (CV) water extract during 4 hours
fermentation (41C). Error bars represent a pooled standard error of the mean (n=3). The
level of significance was preset at p = 0.05 compared to control at the same incubation
period...91
3.20 Changes in viable cell count (VCC) of B. bifidum (108 cfu/ml) in camel milk in the
presence and absence of A. sativum (AS) or C. verum (CV) water extract during 4 hours
fermentation (41C) for milk + A. sativum and 5 hours fermentation for plain milk and
milk + C. verum. Error bars represent a pooled standard error of the mean (n=3). The level
of significance was preset at p = 0.05 compared to control at the same incubation
period...92
4.1 Typical calibration curve for total lactose concentration....103
4.2 Typical calibration curve for total carbohydrate concentration..105
4.3 Changes of pH in cow milk-yogurt in the presence and absence of A. sativum or C.
verum water extract during 21 days refrigerated storage (4C). Error bars represent a
pooled standard error of the mean (n=3). The level of significance was preset at p = 0.05
compared to plain-yogurt at the same storage period....109
4.4 Changes of pH in camel milk-yogurt in the presence and absence of A. sativum or C.
verum water extract during 21 days refrigerated storage (4C). Error bars represent a
pooled standard error of the mean (n=3). The level of significance was preset at p = 0.05
compared to plain-yogurt at the same storage period....109
xxvi
4.5 Changes of pH in goat milk-yogurt in the presence and absence of A. sativum or C.
verum water extract during 21 days refrigerated storage (4C). Error bars represent a
pooled standard error of the mean (n=3). The level of significance was preset at p = 0.05
compared to plain-yogurt at the same storage period....110
4.6 Changes of titratable acidity (lactic acid equivalent %) in cow milk-yogurt in the
presence and absence of A. sativum or C. verum water extract during 21 days refrigerated
storage (4C). Error bars represent a pooled standard error of the mean (n=3). The level of
significance was preset at p = 0.05 compared to plain-yogurt at the same storage
period.....110
4.7 Changes of titratable acidity (lactic acid equivalent %) in camel milk-yogurt in the
presence and absence of A. sativum or C. verum water extract during 21 days refrigerated
storage (4C). Error bars represent a pooled standard error of the mean (n=3). The level of
significance was preset at p = 0.05 compared to plain-yogurt at the same storage
period.....111
4.8 Changes of titratable acidity (lactic acid equivalent %) in cow milk-yogurt in the
presence and absence of A. sativum or C. verum water extract during 21 days refrigerated
storage (4C). Error bars represent a pooled standard error of the mean (n=3). The level of
significance was preset at p = 0.05 compared to plain-yogurt at the same storage
period.....111
4.9 Changes of total lactose content (g/100 g) in cow milk-yogurt in the presence and
absence of A. sativum or C. verum water extract during 21 days refrigerated storage (4C).
Error bars represent a pooled standard error of the mean (n=3). The level of significance
was preset at p = 0.05 compared to plain-yogurt at the same storage
period.....113
4.10 Changes of total lactose content (g/100 g) in camel milk-yogurt in the presence and
absence of A. sativum or C. verum water extract during 21 days refrigerated storage (4C).
Error bars represent a pooled standard error of the mean (n=3). The level of significance
was preset at p = 0.05 compared to plain-yogurt at the same storage
period.....114
4.11 Changes of total lactose content (g/100 g) in goat milk-yogurt in the presence and
absence of A. sativum or C. verum water extract during 21 days refrigerated storage (4C).
Error bars represent a pooled standard error of the mean (n=3). The level of significance
was preset at p = 0.05 compared to plain-yogurt at the same storage
period.114
4.12 Changes of total carbohydrate content (g/100 g) in cow milk-yogurt in the presence
and absence of A. sativum or C. verum water extract during 21 days refrigerated storage
(4C). Error bars represent a pooled standard error of the mean (n=3). The level of
significance was preset at p = 0.05 compared to plain-yogurt at the same storage
period.....116
4.13 Changes of total carbohydrate content (g/100 g) in camel milk-yogurt in the presence
and absence of A. sativum or C. verum water extract during 21 days refrigerated storage
(4C). Error bars represent a pooled standard error of the mean (n=3). The level of
significance was preset at p = 0.05 compared to plain-yogurt at the same storage
period.....117
xxvii
4.14 Changes of total carbohydrate content (g/100 g) in goat milk-yogurt in the presence
and absence of A. sativum or C. verum water extract during 21 days refrigerated storage
(4C). Error bars represent a pooled standard error of the mean (n=3). The level of
significance was preset at p = 0.05 compared to plain-yogurt at the same storage
period.....117
4.15 Changes of total solids (%) in cow milk-yogurt in the presence and absence of A.
sativum or C. verum water extract during 21 days refrigerated storage (4C). Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to plain-yogurt at the same storage period..119
4.16 Changes of total solids (%) in camel milk-yogurt in the presence and absence of A.
sativum or C. verum water extract during 21 days refrigerated storage (4C). Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to plain-yogurt at the same storage period......119
4.17 Changes of total solids (%) in goat milk-yogurt in the presence and absence of A.
sativum or C. verum water extract during 21 days refrigerated storage (4C). Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to plain-yogurt at the same storage period..120
4.18 Changes of moisture content (%) in cow milk-yogurt in the presence and absence of
A. sativum or C. verum water extract during 21 days refrigerated storage (4C). Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to plain-yogurt at the same storage period..121
4.19 Changes of moisture content (%) in camel milk-yogurt in the presence and absence of
A. sativum or C. verum water extract during 21 days refrigerated storage (4C). Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to plain-yogurt at the same storage period..122
4.20 Changes of moisture content (%) in goat milk yogurt in the presence and absence of
A. sativum or C. verum water extract during 21 days refrigerated storage (4C). Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to plain-yogurt at the same storage period..122
4.21 Changes of ash content (%) in cow milk-yogurt in the presence and absence of A.
sativum or C. verum water extract during 21 days refrigerated storage (4C). Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to plain-yogurt at the same storage period......123
4.22 Changes of ash content (%) in camel milk-yogurt in the presence and absence of A.
sativum or C. verum water extract during 21 days refrigerated storage (4C). Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to plain-yogurt at the same storage period......124
4.23 Changes of ash content (%) in goat milk-yogurt in the presence and absence of A.
sativum or C. verum water extract during 21 days refrigerated storage (4C). Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to plain-yogurt at the same storage period......124
xxviii
4.24 Changes of total fat content (%) in cow milk-yogurt in the presence and absence of A.
sativum or C. verum water extract during 21 days refrigerated storage (4C). Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to plain-yogurt at the same storage period..126
4.25 Changes of total fat content (%) in camel milk-yogurt in the presence and absence of
A. sativum or C. verum water extract during 21 days refrigerated storage (4C). Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to plain-yogurt at the same storage period..127
4.26 Changes of total fat content (%) in goat milk-yogurt in the presence and absence of A.
sativum or C. verum water extract during 21 days refrigerated storage (4C). Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to plain-yogurt at the same storage period..127
4.27 Changes of solid-not-fat content (%) in cow milk-yogurt in the presence and absence
of A. sativum or C. verum water extract during 21 days refrigerated storage (4C). Error
bars represent a pooled standard error of the mean (n=3). The level of significance was
preset at p = 0.05 compared to plain-yogurt at the same storage period...129
4.28 Changes of solid-not-fat content (%) in camel milk-yogurt in the presence and
absence of A. sativum or C. verum water extract during 21 days refrigerated storage (4C).
Error bars represent a pooled standard error of the mean (n=3). The level of significance
was preset at p = 0.05 compared to plain-yogurt at the same storage
period.129
4.29 Changes of solid-not-fat content (%) in goat milk-yogurt in the presence and absence
of A. sativum or C. verum water extract during 21 days refrigerated storage (4C). Error
bars represent a pooled standard error of the mean (n=3). The level of significance was
preset at p = 0.05 compared to plain-yogurt at the same storage period...130
5.1 Exopolysaccharide (EPS) content in cow milk yogurt (mg/l) in the absence and
presence of A. sativum or C. verum water extract during 21 days of refrigerated storage
(4C). Error bars represent a pooled standard error of the mean (n=3). The level of
significance was preset at p = 0.05 compared to plain-yogurt at the same storage
period.....144
5.2 Exopolysaccharide (EPS) content in camel milk yogurt (mg/l) in the absence and
presence of A. sativum or C. verum water extract during 21 days of refrigerated storage
(4C). Error bars represent a pooled standard error of the mean (n=3). The level of
significance was preset at p = 0.05 compared to plain-yogurt at the same storage
period.....144
5.3 Water holding capacity (%) in cow milk-yogurt in the presence and absence of A.
sativum or C. verum water extract during 21 days of refrigerated storage (4C). Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to plain-yogurt at the same storage period..146
5.4 Water holding capacity (%) in camel milk-yogurt in the presence and absence of A.
sativum or C. verum water extract during 21 days of refrigerated storage (4C). Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to plain-yogurt at the same storage period......146
xxix
5.5 Susceptibility to syneresis (%) in cow milk-yogurt in the presence and absence of A.
sativum or C. verum water extract during 21 days of refrigerated storage (4C). Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to plain-yogurt at the same storage period..148
5.6 Susceptibility to syneresis (%) in camel milk-yogurt in the presence and absence of A.
sativum or C. verum water extract during 21 days refrigerated storage (4C). Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to plain-yogurt at the same storage period..148
5.7 Amplitude sweep: elastic modulus (G) and viscous modulus (G) versus strain % in
cow milk-yogurt during 21 days refrigerated storage at 4C. (a) Plain-yogurt, (b) A.
sativum- yogurt , and (c) C. verum- yogurt. Values are presented as mean (n=2)....150
5.8 Amplitude sweep: elastic modulus (G) and viscous modulus (G) versus strain % in
camel milk-yogurt during 21 days refrigerated storage at 4 C. (a) Plain-yogurt, (b) A.
sativum- yogurt , and (c) C. verum- yogurt. Values are presented as mean (n=2)....151
5.9 Frequency sweep: elastic modulus (G) and viscous modulus (G) versus strain % in
cow milk-yogurt during 21 days refrigerated storage at 4C. (a) Plain-yogurt, (b) A.
sativum- yogurt , and (c) C. verum- yogurt. Values are presented as mean (n=2)....153
5.10 Frequency sweep: elastic modulus (G) and viscous modulus (G) versus strain % in
camel milk-yogurt during 21 days refrigerated storage at 4C. (a) Plain-yogurt, (b) A.
sativum- yogurt , and (c) C. verum- yogurt. Values are presented as mean (n=2)....154
5.11 Frequency sweep: tan versus strain % in cow milk-yogurt during 21 days
refrigerated storage at 4C. (a) Plain-yogurt, (b) A. sativum- yogurt, and (c) C. verum-
yogurt. Values are presented as mean (n=2).........155
5.12 Frequency sweep: tan versus strain % in camel milk-yogurt during 21 days
refrigerated storage at 4C. (a) Plain-yogurt, (b) A. sativum- yogurt , and (c) C. verum-
yogurt. Values are presented as mean (n=2).....156
5.13 Apparent viscosity versus shear rate (1-s) in cow milk-yogurt during 21 days
refrigerated storage at 4C. (a) Plain-yogurt, (b) A. sativum- yogurt , and (c) C. verum-
yogurt. Values are presented as mean (n=2).....158
5.14 Apparent viscosity versus shear rate (1-s) in camel milk-yogurt during 21 days
refrigerated storage at 4 C. (a) Plain-yogurt, (b) A. sativum- yogurt , and (c) C. verum-
yogurt. Values are presented as mean (n=2).159
6.1 Changes in viable cell counts of Lactobacillus spp. (x106cfu/ml) in cow milk-yogurt in
the presence and absence of A. sativum or C. verum water extract during 21 days
refrigerated storage (4C). Error bars represent a pooled standard error of the mean (n=3).
The level of significance was preset at p = 0.05 compared to plain-yogurt at the same
storage period........174
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6.2 Changes in viable cell counts of Lactobacillus spp. (x106cfu/ml) in camel milk-yogurt
in the presence and absence of A. sativum or C. verum water extract during 21 days
refrigerated storage (4C). Error bars represent a pooled standard error of the mean (n=3).
The level of significance was preset at p = 0.05 compared to plain-yogurt at the same
storage period....175
6.3 Changes in viable cell counts of Streptococcus thermophilus (x108cfu/ml) in cow
milk-yogurt in the presence and absence of A. sativum or C. verum water extract during 21
days refrigerated storage (4C). Error bars represent a pooled standard error of the mean
(n=3). The level of significance was preset at p = 0.05 compared to plain-yogurt at the
same storage period...176
6.4 Changes in viable cell counts of Streptococcus thermophilus (x108cfu/ml) in camel
milk-yogurt in the presence and absence of A. sativum or C. verum water extract during 21
days refrigerated storage (4C). Error bars represent a pooled standard error of the mean
(n=3). The level of significance was preset at p = 0.05 compared to plain-yogurt at the
same storage period...177
6.5 Changes in viable cell counts of Bifidobacterium bifidum (x109cfu/ml) in cow milk-
yogurt in the presence and absence of A. sativum or C. verum water extract during 21 days
refrigerated storage (4C). Error bars represent a pooled standard error of the mean (n=3).
The level of significance was preset at p = 0.05 compared to plain-yogurt at the same
storage period....178
6.6 Changes in viable cell counts of Bifidobacterium bifidum (x109cfu/ml) in camel milk-
yogurt in the presence and absence of A. sativum or C. verum water extract during 21 days
refrigerated storage (4C). Error bars represent a pooled standard error of the mean (n=3).
The level of significance was preset at p = 0.05 compared to plain-yogurt at the same
storage period179
7.1 The sites of the gastrointestinal tract simulated by the developed in vitro enzymatic
digestion........189
7.2 VCC of Lactobacillus spp. (x106 cfu/ml) in cow milk before and after fermentation
(BF and 0 day respectively) and during refrigerated storage (7 days) under simulated
gastrointestinal condition for 3 hours (1st hour represent gastric digestion, 2nd and 3rd hours
represent 1 and 2 hours in intestinal digestion respectively). Error bars present a pooled
standard error of the mean (n=3). The level of significance was preset at p = 0.05
compared to plain-yogurt at the same storage period....191
7.3 VCC of Lactobacillus spp. (x106 cfu/ml) in camel milk before and after fermentation
(BF and 0 day respectively) and during refrigerated storage (7 days) under simulated
gastrointestinal condition for 3 hours (1st hour represent gastric digestion, 2nd and 3rd hours
represent 1 and 2 hours in intestinal digestion respectively). Error bars present a pooled
standard error of the mean (n=3). The level of significance was preset at p = 0.05
compared to plain-yogurt at the same storage period....192
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7.4 VCC of Lactobacillus spp. (x106 cfu/ml) in goat milk before and after fermentation
(BF and 0 day respectively) and during refrigerated storage (7 days) under simulated
gastrointestinal condition for 3 hours (1st hour represent gastric digestion, 2nd and 3rd hours
represent 1 and 2 hours in intestinal digestion respectively). Error bars present a pooled
standard error of the mean (n=3). The level of significance was preset at p = 0.05
compared to plain-yogurt at the same storage period....194
7.5 VCC of S. thermophilus (x106 cfu/ml) in cow milk before and after fermentation (BF
and 0 day respectively) and during refrigerated storage (7 days) under simulated
gastrointestinal condition for 3 hours (1st hour represent gastric digestion, 2nd and 3rd hours
represent 1 and 2 hours in intestinal digestion respectively). Error bars present a pooled
standard error of the mean (n=3). The level of significance was preset at p = 0.05
compared to plain-yogurt at the same storage period....195
7.6 VCC of S. thermophilus (x106 cfu/ml) in camel milk before and after fermentation (BF
and 0 day respectively) and during refrigerated storage (7 days) under simulated
gastrointestinal condition for 3 hours (1st hour represent gastric digestion, 2nd and 3rd hours
represent 1 and 2 hours in intestinal digestion respectively). Error bars present a pooled
standard error of the mean (n=3). The level of significance was preset at p = 0.05
compared to plain-yogurt at the same storage period....196
7.7 VCC of S. thermophilus (x106 cfu/ml) in goat milk before and after fermentation (BF
and 0 day respectively) and during refrigerated storage (7 days) under simulated
gastrointestinal condition for 3 hours (1st hour represent gastric digestion, 2nd and 3rd hours
represent 1 and 2 hours in intestinal digestion respectively). Error bars present a pooled
standard error of the mean (n=3). The level of significance was preset at p = 0.05
compared to plain-yogurt at the same storage period....198
7.8 VCC of B. bifidum (x109 cfu/ml) in cow milk before and after fermentation (BF and 0
day respectively) and during refrigerated storage (7 days) under simulated gastrointestinal
condition for 3 hours (1st hour represent gastric digestion, 2nd and 3rd hours represent 1 and
2 hours in intestinal digestion respectively). Error bars present a pooled standard error of
the mean (n=3). The level of significance was preset at p = 0.05 compared to plain-yogurt
at the same storage period.199
7.9 VCC of B. bifidum (x109 cfu/ml) in camel milk before and after fermentation (BF and
0 day respectively) and during refrigerated storage (7 days) under simulated
gastrointestinal condition for 3 hours (1st hour represent gastric digestion, 2nd and 3rd hours
represent 1 and 2 hours in intestinal digestion respectively). Error bars present a pooled
standard error of the mean (n=3). The level of significance was preset at p = 0.05
compared to plain-yogurt at the same storage period....200
7.10 VCC of B. bifidum (x109 cfu/ml) in goat milk before and after fermentation (BF and 0
day respectively) and during refrigerated storage (7 days) under simulated gastrointestinal
condition for 3 hours (1st hour represent gastric digestion, 2nd and 3rd hours represent 1 and
2 hours in intestinal digestion respectively). Error bars present a pooled standard error of
the mean (n=3). The level of significance was preset at p = 0.05 compared to plain-yogurt
at the same storage period.....201
8.1 Typical calibration curve for total soluble protein..212
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8.2 Proteolytic activity (g/g) in cow milk-yogurt in the presence and absence of A.
sativum or C. verum water extract during 21 days refrigerated storage (4C). Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to plain-yogurt at the same storage period..216
8.3 Proteolytic activity (g/g) in camel milk-yogurt in the presence and absence of A.
sativum or C. verum water extract during 21 days refrigerated storage (4C). Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to plain-yogurt at the same storage period..217
8.4 Total soluble proteins (g/g) in cow milk-yogurt in the presence and absence of A.
sativum or C. verum water extract during 21 days refrigerated storage (4C). Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to plain-yogurt at the same storage period..219
8.5 Total soluble proteins (g/g) in camel milk-yogurt in the presence and absence of A.
sativum or C. verum water extract during 21 days refrigerated storage (4C). Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to plain-yogurt at the same storage period..219
8.6 ACE-I inhibitory activity (%) in cow milk-yogurt in the presence and absence of A.
sativum or C. verum water extract during 21 days refrigerated storage (4C). Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to plain-yogurt at the same storage period..221
8.7 ACE-I inhibitory activity (%) in camel milk-yogurt in the presence and absence of A.
sativum or C. verum water extract during 21 days refrigerated storage (4C). Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to plain-yogurt at the same storage period..222
9.1 Extent of proteolysis (g/g) of cow milk before and after fermentation (0 day) and
during refrigerated storage (7 days) under simulated gastrointestinal condition for 3 hours
(1st hour represent gastric digestion, 2nd and 3rd hours represent 1 and 2 hours in intestinal
digestion respectively). Error bars represent a pooled standard error of the mean (n=3).
The level of significance was preset at p = 0.05 compared to plain-yogurt at the same storage period....233
9.2 Extent of proteolysis (g/g) of camel milk before and after fermentation (0 day) and
during refrigerated storage (7 days) under simulated gastrointestinal condition for 3 hours
(1st hour represent gastric digestion, 2nd and 3rd hours represent 1 and 2 hours in intestinal
digestion respectively). Error bars represent a pooled standard error of the mean (n=3).
The level of significance was preset at p = 0.05 compared to plain-yogurt at the same storage period....234
9.3 Extent of proteolysis (g/g) of goat milk before and after fermentation (0 day) and
during refrigerated storage (7 days) under simulated gastrointestinal condition for 3 hours
(1st hour represent gastric digestion, 2nd and 3rd hours represent 1 and 2 hours in intestinal
digestion respectively). Error bars represent a pooled standard error of the mean (n=3).
The level of significance was preset at p = 0.05 compared to plain-yogurt at the same storage period....235
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9.4 Total soluble protein (g/g) of cow milk before and after fermentation (0 day) and
during refrigerated storage (7 days) under simulated gastrointestinal condition for 3 hours
(1st hour represent gastric digestion, 2nd and 3rd hours represent 1 and 2 hours in intestinal
digestion respectively). Error bars represent a pooled standard error of the mean (n=3).
The level of significance was preset at p = 0.05 compared to plain-yogurt at the same storage period....236
9.5 Total soluble protein (g/g) of camel milk before and after fermentation (0 day) and
during refrigerated storage (7 days) under simulated gastrointestinal condition for 3 hours
(1st hour represent gastric digestion, 2nd and 3rd hours represent 1 and 2 hours in intestinal
digestion respectively). Error bars represent a pooled standard error of the mean (n=3).
The level of significance was preset at p = 0.05 compared to plain-yogurt at the same storage period....237
9.6 Total soluble protein (g/g) of goat milk before and after fermentation (0 day) and
during refrigerated storage (7 days) under simulated gastrointestinal condition for 3 hours
(1st hour represent gastric digestion, 2nd and 3rd hours represent 1 and 2 hours in intestinal
digestion respectively). Error bars represent a pooled standard error of the mean (n=3).
The level of significance was preset at p = 0.05 compared to plain-yogurt at the same storage period....238
9.7 ACE-I inhibitory activity (inhibition %) of cow milk before and after fermentation (0
day) and during refrigerated storage (7 days) under simulated gastrointestinal condition for
3 hours (1st hour represent gastric digestion, 2nd and 3rd hours represent 1 and 2 hours in
intestinal digestion respectively). Error bars represent a pooled standard error of the mean
(n=3). The level of significance was preset at p = 0.05 compared to plain-yogurt at the same storage period...240
9.8 ACE-I inhibitory activity (inhibition %) of camel milk before and after fermentation (0
day) and during refrigerated storage (7 days) under simulated gastrointestinal condition for
3 hours (1st hour represent gastric digestion, 2nd and 3rd hours represent 1 and 2 hours in
intestinal digestion respectively). Error bars represent a pooled standard error of the mean
(n=3). The level of significance was preset at p = 0.05 compared to plain-yogurt at the same storage period...241
9.9 ACE-I inhibitory activity (inhibition %) of goat milk before and after fermentation (0
day) and during refrigerated storage (7 days) under simulated gastrointestinal condition for
3 hours (1st hour represent gastric digestion, 2nd and 3rd hours represent 1 and 2 hours in
intestinal digestion respectively). Error bars represent a pooled standard error of the mean
(n=3). The level of significance was preset at p = 0.05 compared to plain-yogurt at the same storage period...242
10.1 Typical calibration curve for total phenolic content..253
10.2 -Amylase inhibitory activities (%) in cow milk-yogurt in the presence and absence
of A. sativum or C. verum water extract during 21 days refrigerated storage (4C). Error
bars represent a pooled standard error of the mean (n=3). The level of significance was
preset at p = 0.05 compared to plain-yogurt at the same storage period...256
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10.3 -Amylase inhibitory activities (%) in camel milk-yogurt in the presence and absence
of A. sativum or C. verum water extract during 21 days refrigerated storage (4C). Error
bars represent a pooled standard error of the mean (n=3). The level of significance was
preset at p = 0.05 compared to plain-yogurt at the same storage
period.....257
10.4 -Glucosidase inhibitory activities (%) in cow milk-yogurt in the presence and
absence of A. sativum or C. verum water extract during 21 days refrigerated storage (4C).
Error bars represent a pooled standard error of the mean (n=3). The level of significance
was preset at p = 0.05 compared to plain-yogurt at the same storage
period.....260
10.5 -Glucosidase inhibitory activities (%) in camel milk-yogurt in the presence and
absence of A. sativum or C. verum water extract during 21 days refrigerated storage (4C).
Error bars represent a pooled standard error of the mean (n=3). The level of significance
was preset at p = 0.05 compared to plain-yogurt at the same storage
period.....260
10.6 Total phenolic content (g GAE/ml) in cow milk-yogurt in the presence and absence
of A. sativum or C. verum water extract during 21 days refrigerated storage (4C). Error
bars represent a pooled standard error of the mean (n=3). The level of significance was
preset at p = 0.05 compared to plain-yogurt at the same storage period...264
10.7 Total phenolic content (g GAE/ml) in camel milk-yogurt in the presence and
absence of A. sativum or C. verum water extract during 21 days refrigerated storage (4C).
Error bars represent a pooled standard error of the mean (n=3). The level of significance
was preset at p = 0.05 compared to plain-yogurt at the same storage
period.....264
10.8 DPPH scavenging activity (%) in cow milk-yogurt in the presence and absence of A.
sativum or C. verum water extract during 21 days refrigerated storage (4C). Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to plain-yogurt at the same storage period..267
10.9 DPPH scavenging activity (%) in camel milk-yogurt in the presence and absence of
A. sativum or C. verum water extract during 21 days refrigerated storage (4C). Error bars
represent a pooled standard error of the mean (n=3). The level of significance was preset
at p = 0.05 compared to plain-yogurt at the same storage period..267
11.1 -Amylase inhibitory activities (%) of cow milk before and after fermentation (0 day)
and during refrigerated storage (7 days) under simulated gastrointestinal condition for 3
hours (1st hour represent gastric digestion, 2nd and 3rd hours represent 1 and 2 hours in
intestinal digestion respectively). Error bars represent a pooled standard error of the mean
(n=3). The level of significance was preset at p = 0.05 compared to plain-yogurt at the
same storage period...281
11.2 -Amylase inhibitory activities (%) of camel milk before and after fermentation (0
day) and during refrigerated storage (7 days) under simulated gastrointestinal condition for
3 hours (1st hour represent gastric digestion, 2nd and 3rd hours represent 1 and 2 hours in
intestinal digestion respectively). Error bars represent a pooled standard error of the mean
(n=3). The level of significance was preset at p = 0.05 compared to plain-yogurt at the
same storage period...282
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11.3 -Amylase inhibitory activities (%) of goat milk before and after fermentation (0
day) and during refrigerated storage (7 days) under simulated gastrointestinal condition for
3 hours (1st hour represent gastric digestion, 2nd and 3rd hours represent 1 and 2 hours in
intestinal digestion respectively). Error bars represent a pooled standard error of the mean
(n=3). The level of significance was preset at p = 0.05 compared to plain-yogurt at the
same storage period...284
11.4 -Glucosidase inhibitory activities (%) of cow milk before and after fermentation (0
day) and during refrigerated storage (7 days) under simulated gastrointestinal condition for
3 hours (1st hour represent gastric digestion, 2nd and 3rd hours represent 1 and 2 hours in
intestinal digestion respectively). Error bars represent a pooled standard error of the mean
(n=3). The level of significance was preset at p = 0.05 compared to plain-yogurt at the
same storage period...286
11.5 -Glucosidase inhibitory activities (%) of camel milk before and after fermentation (0
day) and during refrigerated storage (7 days) under simulated gastrointestinal condition for
3 hours (1st hour represent gastric digestion, 2nd and 3rd hours represent 1 and 2 hours in
intestinal digestion respectively). Error bars represent a pooled standard error of the mean
(n=3). The level of significance was preset at p = 0.05 compared to plain-yogurt at the
same storage period...287
11.6 -Glucosidase inhibitory activities (%) of goat milk before and after fermentation (0
day) and during refrigerated storage (7 days) under simulated gastrointestinal condition for
3 hours (1st hour represent gastric digestion, 2nd and 3rd hours represent 1 and 2 hours in
intestinal digestion respectively). Error bars represent a pooled standard error of the mean
(n=3). The level of significance was preset at p = 0.05 compared to plain-yogurt at the
same storage period...288
11.7 Total phenolic content (g GAE/g) of cow milk before and after fermentation (0 day)
and during refrigerated storage (7 days) under simulated gastrointestinal condition for 3
hours (1st hour represent gastric digestion, 2nd and 3rd hours represent 1 and 2 hours in
intestinal digestion respectively). Error bars represent a pooled standard error of the mean
(n=3). The level of significance was preset at p = 0.05 compared to plain-yogurt at the
same storage period...290
11.8 Total phenolic content (g GAE/g) of camel milk before and after fermentation
(0day) and during refrigerated storage (7 days) under simulated gastrointestinal condition
for 3 hours (1st hour represent gastric digestion, 2nd and 3rd hours represent 1 and 2 hours
in intestinal digestion respectively). Error bars represent a pooled standard error of the
mean (n=3). The level of significance was preset at p = 0.05 compared to plain-yogurt at
the same storage period.....291
11.9 Total phenolic content (g GAE/g) of goat milk before and after fermentation (0 day)
and during refrigerated storage (7 days) under simulated gastrointestinal condition for 3
hours (1st hour represent gastric digestion, 2nd and 3rd hours represent 1 and 2 hours in
intestinal digestion respectively). Error bars represent a pooled standard error of the mean
(n=3). The level of significance was preset at p = 0.05 compared to plain-yogurt at the
same storage period...292
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11.10 Antioxidant activities (DPPH inhibition %) of cow milk before and after
fermentation (0 day) and during refrigerated storage (7 days) under simulated
gastrointestinal condition for 3 hours (1st hour represent gastric digestion, 2nd and 3rd hours
represent 1 and 2 hours in intestinal digestion respectively). Error bars represent a pooled
standard error of the mean (n=3). The level of significance was preset at p = 0.05
compared to plain-yogurt at the same storage period....294
11.11 Antioxidant activities (DPPH inhibition %) of camel milk before and after
fermentation (0 day) and during refrigerated storage (7 days) under simulated
gastrointestinal condition for 3 hours (1st hour represent gastric digestion, 2nd and 3rd hours
represent 1 and 2 hours in intestinal digestion respectively). Error bars represent a pooled
standard error of the mean (n=3). The level of significance was preset at p = 0.05
compared to plain-yogurt at the same storage period....296
11.12 Antioxidant activities (DPPH inhibition %) of goat milk before and after
fermentation (0 day) and during refrigerated storage (7 days) under simulated
gastrointestinal condition for 3 hours (1st hour represent gastric digestion, 2nd and 3rd hours
represent 1 and 2 hours in intestinal digestion respectively). Error bars represent a pooled
standard error of the mean (n=3). The level of significance was preset at p = 0.05
compared to plain-yogurt at the same storage period....297
.