Plant-Based Sweeteners

Ph. D. StudentAtheer Jasim Mohammed

Master of Dairy Science and Technology/Iraq

May, 2015

Facts

Most of high-potency sweeteners of diverse chemical structures are known to occur naturally.

Consumer interest in natural high-potency sweeteners has grown dramatically in last decade, fuelled by concerns about the use of artificial additives in foods.

The level of development activity is high, as is the activity involved in a continuing search for other natural sweeteners through the use of various screening techniques.

Natural sweeteners show many similarities to their synthetic counterparts in terms of their overall taste properties.

Examples of high-potency sweeteners of plant originSweetener Structural class Plant source Country of origin

Brazzein Protein Pentadiplandra brazzeana West AfricaCurculin Protein Curculigo latifolia MalaysiaMabinlin Protein Capparis masakai ChinaMonellin Protein Discoreophyllum cumminsii West AfricaPentadin Protein Pentadiplandra brazzeana West Africa

Thaumatin Protein Thaumatococcus daniellii West AfricaMonatin Amino acid Schlerochiton ilicifolius South Africa

Abrusoside Glycoside Abrus precatorius ThailandAlbiziasaponins Glycoside Albizia myriophylla Thailand

Baiyunoside Glycoside Phlomis betonicoides ChinaBryoside Glycoside Bryonia dioica Italy

Cussoracosides Glycoside Cussonia racemosa MadagascarCyclocarioside Glycoside Cyclocarya paliurus ChinaGlycyrrhizin Glycoside Glycyrrhiza glabra ChinaLo han guo Glycoside Siratia grosvenorii China

Mukurozioside Glycoside Sapindus mukurossi ChinaOsladin Glycoside Polypodium vulgare USA, Eur.

Periandrin Glycoside Periandra dulcis BrazilPhlomisoside Glycoside Phlomis younghusbandii ChinaPolypodoside Glycoside Polypodium glycyrrhiza USA

Pterocaryoside Glycoside Pterocarya paliurus ChinaRubusoside Glycoside Rubus suavissimus China

Steviol Glycoside Stevia rebaudiana ParaguayTelosmosides Glycoside Telosma procumbens PhilippinesSelligueain A Proanthocyanidin Selliguea feei IndonesiaHernandulcin Bisabolane sesquiterpene Lippia dulcis Mexico

Phlorizin Dihydrochalcone Lithocarpus litseifolius ChinaTrilobatin Dihydrochalcone Lithocarpus litseifolius China

Phyllodulcin Flavonoid Hydrangea macrophylla Japan

Adapted from (Helen Mitchell, 2006)

It is origin of Paraguay and Brazil. Stevia is cultivated primarily in USA, Canada, Korea, Japan, Taiwan, china, and United Kingdom.

In September 1995 the USA FDA allowed Stevia and it is extracted to be imported as a food supplement but not as a sweetener. Major food companies like coca cola and beatrice foods used Stevia extracts to sweeten the foods for sale in Japan, Brazil and other countries.

The plant grows up to range 65-180 centimeters when cultivated or growing naturally in fertile soil. It is a short day plant and flowering from January to March in the southern hemisphere. The suitable natural climate is semi humid subtropical with temperature extremes from 21 to 43°C.

The steviol glycoside sweeteners share a common aglycone, steviol. Linked to steviol are carbohydrate moieties and it is the number and linkages of these that differentiate the steviol glycoside sweeteners

Stevioside (Stevia rebaudiana)

leafs considered the most parts of plant which is rich with stevia rebaudiana A, and can be used these techniques to preparation of sweetener from the leaves typically involves some or all of the following unit operations: aqueous extraction reached by selective extraction into a polar organic solvent, decolourisation, removal of impurities through flocculation and filtration, ion exchange and finally crystallization.

Stevioside (Stevia rebaudiana)

A research report suggests rebaudioside A is less sweet than stevioside that may be a significant of the methodologies employed or due to the actual materials evaluated being mixtures of steviol glycosides rather than the pure glycoside.

Sweetness potencies of steviol glycosides.

Sensory properties

Compound Relative sweetnessa

Stevioside 300

Rebaudioside A 250-450

Rebaudioside B 300-350

Rebaudioside C 50-120

Rebaudioside D 250-450

Rebaudioside E 150-300

Dulcoside A 50-120

Steviolbioside 100-125

aSweetness potency measured relative to 0.4% (w/v) sucrose.* Adapted from (Kim and DuBois, 1991)

Both stevioside and rebaudioside A appear to be stable sweeteners. One study was observed in carbonated beverages buffered with either phosphoric

acid or citric acid. After 2 months storage at 37◦C, some degradation was reported, but no significant changes were seen when formulated beverage products were stored at room temperature and below for 5 months. Some shakiness (20% loss) of rebaudioside A on exposure to UV light was mentioned following 1 week of exposure to sunshine, but stevioside be completely stable under the same conditions.

The authors conclude that these sweeteners are viable as commercial products in that they show adequate hydrolytic stability. The solubility of stevioside in water has been measured and found to be just less than 1% (w/v).

Physical and chemical properties

Physiological properties rebaudiana A leaves contain ent-kaurene diterpene glycosides (stevioside and

the rebaudiosides) 300 times sweeter than sucrose with superior solubility in water and a positive taste profile that are safely metabolized by the body without any side effect.

Rebaudioside A in the digestive tract is first metabolized by microbes in the colon to stevioside which is further converted into glucose molecule and steviol. The released glucose molecule is used by the bacteria in the colon and is not absorbed into the blood stream.

Steviol glycosides are not readily absorbed from the upper small intestine of the rat or human following oral administration. As human digestive enzymes do not hydrolyse β-glycosidic linkages, digestion in the small intestine is limited. Microbial fermentation occurs in the large intestine of both rat and human, releasing the aglycone steviol. Steviol is then absorbed, conjugated with glucuronic acid and excreted as steviol glucuronide, the primary route being in feces for the rat and urine for humans.

The study also showed that the majority of steviol glycosides are absorbed and glucuronidated in the liver. The newly bonded glucuronidate is released in the blood and filtered by the kidneys into the urine. Small amounts of glucuronide that remain in the colon are excreted through fecal matter.

Applications

In Korea, stevioside is an accepted sweetener in baked products, table-top sweeteners, beverages and seasonings.

steviol glycoside sweeteners have acceptance across the range of food and beverage applications normally associated with the use of high-potency sweeteners.

particularly in Japan where it is considered a 'food’ because of its natural origin.

It is now accepted that whenever safety studies have been carried out using purified and fully characterised steviol glycosides, the reproductive safety of these sweetener materials has been fully demonstrated.

A number of sub-chronic (13-week) toxicity studies have been completed in recent years, these studies have all reported no statistically significant effects in the great majority of cases; although some impact on body-weight gains for groups receiving the highest doses tested .

Matsui(1996). examined the genetic toxicity of stevioside and steviol in a range of mutagenicity tests with metabolic activation. Stevioside was not found to be mutagenic in any of the assays examined. Steviol, however, produced dose-related positive responses in some mutagenicity tests.

Other workers reported no compound-related alterations of blood, clinical chemistry or urinalysis parameters. Although stevioside is not mutagenic, its aglycone, steviol (13-hydroxy-ent-kaurenoic acid) has been shown to be mutagenic in some tests with S. typhimurium strains.

Safety

In July 2008, JECFA found steviol glycosides safe for use in food and beverages.

Also, the US Food and Drug Administration (FDA) announced in December 2008 that it had no objection to the use of rebiana in food and beverages in the United States.

In 2009, the French government was the first in the EU to approve the use of rebausioside A in food and beverages in France.

In 2010, the European Food Safety Authority published a Scientific Opinion confirming that steviol glycosides are safe for use in foods and beverages. Approval throughout the EU is anticipated, although the precise timing is currently uncertain.

Regulatory status

Thaumatin is normally described as being approx. 2000 times the sweetness of sucrose.

The temporal taste profile of Thaumatin is characterised by a delay in perceiving sweetness, a lengthy sweetness growth phase until maximum sweetness is perceived, followed by a lingering sweet/liquorice after taste.

Thaumatin (Thaumatococcus daniellii)

Sensory properties

Thaumatin is the common name for a mixture of potently sweet proteins that can be extracted from the West African plant Thaumatococcus daniellii (Bennett), known locally as the katemfe berry.

The plant divided in two kinds, Thaumatins I and II being the major constituents, each with almost identical molecular weight of 22,000 Daltons. Thaumatins I and II have very similar amino acid sequences, differing only in five residues.

The protein is stabilized by eight disulphide bridges, thus conferring a greater stability to heat and pH denaturation to the molecule than might be expected for a protein.

Thaumatin was used as a tool in early studies that sought to understand the structure of the mammalian receptor for sweetness .

Physical and chemical properties Thaumatin is stabilized by the eight disulphide bridges that result in a cross-

linked network of amino acid chains. This confers a measure of stability to heat and extremes of pH.

These disulphide bridges are also responsible for holding the protein chain in the correct conformation to elicit sweetness, as has been confirmed by demonstrating that cleavage of a single disulphide bridge results in loss of sweetness.

Physiological properties Thaumatin is a natural plant protein of known structure containing normal amino

acids.

Applications The main commercial applications for Thaumatin its claimed flavor modifying

and enhancing functionalities. Thaumatin has found application in liquid medicines. The oral care products and in the nutraceutical/fortified foods industries. increasing concentrations of Thaumatin appear to have increasing effects on the

bitterness associated with vitamin B complex preparations, caffeine and soybean peptides.

Thaumatin was studied for its sub-acute toxicity in rats and dogs and its ability to produce anaphylactic antibodies following oral administration to rats and normal human subjects. It was found to be readily digested prior to absorption in rats and no adverse effects resulted from its continuous administration to rats and dogs at dietary concentrations of 0%, 0.3%, 1.0% and 3.0% for 13 weeks.

Also, it was shown to be non-teratogenic when administered orally to rats at 0, 200, 600 and 2000 mg/kg body weight/day from day 6 to 15 of gestation and was without effect on the incidence of dominant lethal mutations when administered on five consecutive days to male mice at 200 and 2000 mg/kg per day.

The results indicate that Thaumatin when used as a flavor modifier and extender, and partial sweetener, is unlikely to be hazardous at the expected level of consumption.

Safety

Thaumatin was originally permitted as a natural food additive in Japan in 1979.

It was approved as a sweetener in the United Kingdom and Australia. In the United States, Thaumatin was accorded GRAS status as a flavor

adjunct for chewing gum in 1984 and this has since been extended by FEMA to general use across all food categories.

Regulatory status

Sweetener Product category Maximum usable dose

Thaumatin (E957)

Confectionery Confectionery with no added sugar Cocoa or dried fruit based Confectionery; energy reduced or with

no added sugar Chewing gum with no added sugar  Food supplements Edible ices, energy reduced or with no added sugar

 50 mg/kg50 mg/kg50 mg/kg  

400 mg/kg50 mg/kg

Table shows regulatory approval of Thaumatin in the EU

The Chinese plant Siraitia grosvenorii family that grows mainly in Guangxi Province, with most of the product from the mountains of Guilin. Siraitia fruits are used both inside and outside the People’s Republic of China as a food, beverage, and traditional medicine.

The sweet constituents of the plant are triterpene glycosides, known as mogrosides. Common names for the plant include: lo han guo, lo han kuo, Arhat fruit, Monk

Fruit, Fructus momordicae and Momordicae grosvenori fructus. Subsequent isolation of two sweet components (named mogrosides IV and V) was

completed successfully and their sensory properties described. Mogroside V is the most abundant component, occurring at around 1% in the dried fruits.

Lo Han Guo (morgroside)

Structure of morgroside V

In study was described the sweetness of mogroside as being 150 times as potent as sucrose. In other report estimated the potency of mogroside V as approximately 250 times as sweet as sucrose at a 5% sucrose equivalent concentration.

the sweetener is known to deliver a taste profile that contains taste elements commonly seen in natural potent sweeteners, such as a slight delay to reaching maximum sweetness intensity and an aftertaste that contains liquorice and cooling elements.

Sensory properties

Physical and chemical properties There are no study reports detailing the stability of mogroside. In addition, the indigenous use of the lo han guo fruit involves drying the

fruit and then preparing an aqueous decoction that also indicates that the sweet principle is likely to be a relatively stable molecule.

Aqueous solutions containing mogroside V are reported to be stable, even under boiling conditions.

the β-linkages of the carbohydrate moieties are intrinsically resistant to hydrolysis.

Extracts of lo han guo fruit have long been used indigenously to treat colds, sore throats and minor stomach and intestinal complaints.

Recent studies suggest that the mogrosides may exhibit anti-cancer properties, possibly based on their researches anti-oxidant characteristics.

Physiological properties

Applications The traditional use of the lo han guo fruit has been to prepare an aqueous

extract that is then consumed as a tea or tonic drink. There have been some minor beverage products on the market in USA that have

contained (lo han fruit extract) as a part of the overall sweetening system. In addition, can be used as table-top sweeteners will be a target.

In safety studies that have been completed, it has been shown to be non-mutagenic in short-term predictive tests and to produce no mortalities when administered to mice at doses up to 2 g/kg body weight.

Safety

Regulatory status

Lo han guo fruits and extracts are considered to be foods in China. A GRAS petition has been reviewed by FDA which issued a ‘no

objection’ letter, thus confirming its GRAS status within the US market.

Thanks for your attention …