Steviol glycoside

chembox new
Name = Steviol
ImageFile = Steviol.svg
ImageSize = 150 px
ImageFile1 = Steviol3d.png ImageSize1 = 150 px
IUPACName = Kaur-16-en-18-oic acid, 13-hydroxy-, (4.alpha.)-
Section1 = Chembox Identifiers
CASNo = 471-80-7
PubChem = 452967
SMILES = CC12CCCC(C1CCC34C2CCC(C3)(C(=C)C4)O)(C)C(=O)O
InChI = 1/C20H30O3/c1-13-11-19-9-5-14-17(2,7-4-8-18(14,3)16(21)22)15(19)6-10-20(13,23)12-19/h14-15,23H,1,4-12H2,2-3H3,(H,21,22)/t14-,15-,17+,18+,19+,20-/m0/s1/f/h21H
Section2 = Chembox Properties
Formula = C₂₀H₃₀O₃
MolarMass = 318.4504 g/mol

The steviol glycosides are responsible for the sweet taste of the leaves of the stevia plant ("Stevia rebaudiana bertoni").These compounds range in sweetness from 40 to 300 times sweeter than sucrose. [ The sweetness multiplier "300 times" comes from [http://www.science.edu.sg/ssc/detailed.jsp?artid=67&type=6&root=3&parent=3&cat=30 subjective evaluations by a panel of test subjects] tasting various dilutions compared to a standard dilution of sucrose. Sources referenced in this article say steviosides have up to 250 times the sweetness of sucrose, but others, including stevioside brands such as SweetLeaf, claim 300 times. 1/3 to 1/2 teaspoon (1.6–2.5 ml) of stevioside powder is claimed to have equivalent sweetening power to 1 cup (240 ml) of sugar.] They are heat stable, pH stable, and do not ferment.cite web
last = Brandle
first = Jim
authorlink =
coauthors =
title = FAQ - Stevia, Nature's Natural Low Calorie Sweetener
work =
publisher = Agriculture and Agri-Food Canada
date = 2004-08-19
url = http://res2.agr.ca/London/faq/stevia_e.htm
format = HTML
doi =
accessdate = 2006-11-08 ] They also do not induce a glycemic response when ingested, making them attractive as natural sweeteners to diabetics and others on carbohydrate-controlled diets.

tructure

The diterpene known as Steviol is the aglycone of stevia's sweet glycosides, which are constructed by replacing steviol's bottom hydrogen atom (see figure above) with glucose (forming an ester), and replacing the top hydrogen atom with combinations of glucose and rhamnose. The two primary compounds, stevioside and rebaudioside A, use only glucose: stevioside has two linked glucose molecules at the top hydrogen site, where rebaudioside A has three, with the middle glucose of the triplet connected to the central steviol structure.

In terms of weight fraction, the four major steviol glycosides found in the stevia plant tissue are:
* 5–10% stevioside (250–300X of sugar)
* 2–4% rebaudioside A — most sweet (350–450X of sugar) and least bitter
* 1–2% rebaudioside C
* ½–1% dulcoside A

Rebaudioside B, D, and E may also be present in minute quantities; however, it is suspected that rebaudioside B is a byproduct of the isolation technique.The two majority compounds stevioside and rebaudioside, primarily responsible for the sweet taste of stevia leaves, were first isolated by two French chemists in 1931. [cite journal
last = Bridel
first = M.
authorlink =
coauthors = Lavielle, R.
title = Sur le principe sucré des feuilles de Kaâ-hê-é (stevia rebaundiana B)
journal = Academie des Sciences Paris Comptes Rendus
volume =
issue = Parts 192
pages = 1123–1125
publisher =
date = 1931
url = http://gallica.bnf.fr/ark:/12148/bpt6k3145g/f1123.table
doi =
id = ]

Availability

Steviol glycosides were first commercialized as a sweetener in 1971 by the Japanese firm Morita Kagaku Kogyo Co., Ltd., a leading stevia extract producer in Japan. In May 2007, The Coca-Cola Company announced plans to obtain approval for Rebiana, a patent-pending stevia-derived sweetener developed jointly by Coca-Cola and Cargill, for use as a food additive within the United States by 2009. Coca-Cola has also announced plans to market rebiana-sweetened products in 12 countries that allow stevia's use as a food additive. The two companies are conducting their own studies in an effort to gain regulatory approval in the United States and the European Union. [cite news |title=Coke and Cargill teaming on new drink sweetener |author=Stanford, Duane D. |publisher=Atlanta Journal-Constitution |date=2007-05-31 |accessdate=2007-05-31 |url=http://www.ajc.com/business/content/business/coke/stories/2007/05/31/0531bizcoke.html] [cite news |title=Coke, Cargill Aim For a Shake-Up In Sweeteners |author=Etter, Lauren and McKay, Betsy |publisher=Wall Street Journal|date=2007-05-31 |accessdate=2007-06-01 |url=http://online.wsj.com/article/SB118058140982419717.html?mod=rss_whats_news_us]

Recently Blue California a US ingredient manufacturer claims to have developed an economical industrial production process for the 'natural sweetener' stevia, which promises lower prices for manufacturers. The ingredient firm said it has completed the isolation of Rebaudioside A, a sweet compound derived from stevia, using a "more economical and proprietary process". The company expects to go into industrial scale production in 2008. The isolation process for Rebaudioside A results in a product that delivers the desired sweetness without the bitter aftertaste. [cite news |title=US firm claims cheap, industrial stevia production |author=Lorraine Heller |publisher=Food Navigator USA|date=2007-11-15 |accessdate=2007-11-01 |url=http://www.foodnavigator-usa.com/news/ng.asp?n=81404-blue-california-stevia-sweetener]

Toxicity

A 1985 study reporting that steviol may be a mutagen [cite journal
last = Pezzuto
first = JM
authorlink =
coauthors = Compadre CM, Swanson SM, Nanayakkara D, Kinghorn AD
title = Metabolically activated steviol, the aglycone of stevioside, is mutagenic
journal = Proc Natl Acad Sci U.S.A.
volume = 82
issue = 8
pages = 2478–82
publisher =
date = April 1985
url = http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&list_uids=3887402
doi =
id =
accessdate = ] has been criticized on procedural grounds that the data were mishandled in such a way that even distilled water would appear mutagenic. [cite journal
last = Procinska
first = E
authorlink =
coauthors = Bridges BA, Hanson JR
title = Interpretation of results with the 8-azaguanine resistance system in Salmonella typhimurium: no evidence for direct acting mutagenesis by 15-oxosteviol, a possible metabolite of steviol
journal = Mutagenesis
volume = 6
issue = 2
pages = 165–7
publisher =
date = March 1991
url = http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&list_uids=2056919
doi =
id =
accessdate = – full article text is reproduced [http://www.cookingwithstevia.com/interpretation.html here] .] More recent studies appear to establish the safety of steviol and its glycosides. In 2006, the World Health Organization (WHO) performed a thorough evaluation of recent experimental studies of stevia extracts conducted on animals and humans, and concluded that "stevioside and rebaudioside A are not genotoxic in vitro or in vivo and that the genotoxicity of steviol and some of its oxidative derivatives in vitro is not expressed in vivo."cite journal
last = Benford
first = D.J.
coauthors = DiNovi, M., Schlatter, J.
title = Safety Evaluation of Certain Food Additives: Steviol Glycosides
journal = WHO Food Additives Series
volume = 54
issue =
pages = 140
publisher = World Health Organization Joint FAO/WHO Expert Committee on Food Additives (JECFA)
date = 2006
url = http://whqlibdoc.who.int/publications/2006/9241660546_eng.pdf
format = PDF – 18 MB ] The report also found no evidence of carcinogenic activity. The report also suggested the possibility of health benefits, in that "stevioside has shown some evidence of pharmacological effects in patients with hypertension or with type-2 diabetes", but concluded that further study was required to determine proper dosage.

ee also

* Stevia
* Glycoside
* Sugar substitute

References

External links

* [http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?sid=598381 PubChem summary of steviol molecule]