All About Sweeteners
by D. Eric Walters, Ph.D.

Artice of the week:

Sweetener article of the week

Stevia

 

Stevia is a general term referring to a plant, Stevia rebaudiana (Bertoni), native to Paraguay.  The plant has been used as a sweetener for centuries by the Guaraní people of this region.  The plant contains a number of diterpene glycosides that taste sweet; the main ones are stevioside and rebaudioside A.

   

Other names:
Stevioside
Rebaudioside
Rebaudioside A
Rebiana
Truvia®

Taste:

The leaves of stevia can be used directly for sweetening, but the taste quality is not as good as the purified glycosides.

Stevioside is about 200 times as sweet as sucrose, with significant bitter taste and licorice-like taste at higher concentrations.  Its onset is slower than sucrose, and its sweetness lingers.

Rebaudioside A is about 300 times as sweet as sucrose, with less bitter and licorice off-tastes than stevioside.

Calories:
Stevioside and rebaudioside A are non-caloric.

Safety:
As noted above, the stevia plant has been used as a sweetener for centuries in parts of South America.  The Coca-Cola Company and Cargill have undertaken or sponsored a wide array of safety studies in conjunction with their development of rebaudioside A as a commercial sweetener.  Eleven of these are scheduled for publication in Food and Chemical Toxicology and are already available in the on-line edition[1-11].  Bacteria in the colon remove the sugars from stevioside and rebaudioside, and the remaining steviol molecule is absorbed by the body.  It is conjugated in the liver (glucuronic acid is attached to make it more water-soluble) and then excreted in the urine[6].

Chemistry:
Stevioside and rebaudioside A are diterpene glycosides--the plant product steviol, with 3 or 4 glucose molecules attaced.
Structures of steviol, stevioside, and rebaudioside A

Properties:
Stevioside and rebaudioside A are quite stable to heat and pH, except in acid at pH less than 2[3].

References:
1.  Renwick, A.G.; Tarka, S.M.  Microbial hydrolysis of steviol glycosides.  Food Chem. Toxicol.  (in press, 2008).  PubMed link
2.  Curry, L.L.; Roberts, A.; Brown, N.  Rebaudioside A: two-generation reproductive toxicity study in rats   Food Chem. Toxicol.  (in press, 2008).  PubMed link
3.  Prakash, I.; DuBois, G.E.; Clos, J.F.; Wilkens, K.L.; Fosdick, L.E.  Development of rebiana, a natural, non-caloric sweetener.  Food Chem. Toxicol.  (in press, 2008).  PubMed link
4.  Maki, K.C.; Curry, L.L. ; Reeves, M.S.; Toth, P.D.; McKenney, J.M.; Farmer, M.V.;
Schwartz, S.L.; Lubin, B.C.; Boileau, A.C.; Dicklin, M.R.; Carakostas, M.C.;
Tarka, S.M.  Chronic consumption of rebaudioside A, a steviol glycoside, in men and women
with type 2 diabetes mellitus.  Food Chem. Toxicol.  (in press, 2008).  PubMed link
5.  Carakostas, M.C.; Curry, L.L.; Boileau, A.C.; Brusick, D.J.  Overview: the history, technical function and safety of rebaudioside A, a naturally occurring steviol glycoside, for use in food and beverages.  Food Chem. Toxicol.  (in press, 2008).  PubMed link
6.  Wheeler, A.; Boileau, A.C.; Winkler, P.C.; Compton, J.C.; Prakash, I.; Jiang, X.;. Mandarino, D.A Pharmacokinetics of rebaudioside A and stevioside after single oral doses in healthy men. Food Chem. Toxicol.  (in press, 2008).  PubMed link
7.  Roberts, A.; Renwick, A.G.  Comparative toxicokinetics and metabolism of rebaudioside A, stevioside, and steviol in rats.   Food Chem. Toxicol.  (in press, 2008).  PubMed link
8.  Renwick, A.G.  The use of a sweetener substitution method to predict dietary exposures for the
intense sweetener rebaudioside A.   Food Chem. Toxicol.  (in press, 2008).  PubMed link
9.  Maki, K.C.; Curry, L.L.; Carakostas, M.C.; Tarka, S.M.; Reeves, M.S.; Farmer, M.V.; McKenney, J.M.; Toth, P.D.; Schwartz, S.L.; Lubin, B.C.; Dicklin, M.R.; Boileau, A.C.; Bisognano, J.D.  The hemodynamic effects of rebaudioside A in healthy adults with normal and low-normal blood pressure.   Food Chem. Toxicol.  (in press, 2008).  PubMed link
10.  Curry. L.L.; Roberts, A.  Subchronic toxicity of rebaudioside A.   Food Chem. Toxicol.  (in press, 2008).  PubMed link
11.  Brusick, D.J.  A critical review of the genetic toxicity of steviol and steviol glycosides.  Food Chem. Toxicol.  (in press, 2008).  PubMed link

Other links:
Stevia on Wikipedia

SweetenerBook.com

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