A naturally occurring sweetener, stevia is derived from the leaves of the Stevia rebaudiana plant, a low-growing shrub native to South America. Although its entry into the lucrative sugar substitute market did not come until the late 20th century, indigenous peoples in South America have long used the herb for its sweetening and medicinal properties. Methods of extraction vary and have played a role in the market appeal of stevia as a sweetener.
Properties of Stevia
Marketed in the United States primarily as a sugar substitute, stevia derives its sweetening properties from stevioside, a glycoside found in the leaves of the stevia plant. Stevioside is said to be 200 to 300 times sweeter than sugar, according to osteopath Joseph Mercola and naturopath Kendra Degen Pearsall, authors of "Sweet Deception." Although stevia has been touted in U.S. as a no-calorie sugar substitute, the herb is loaded with multiple nutrients and has been used as an antimicrobial agent and to treat diabetes and hypertension.
History
Cultivated for centuries by the indigenous peoples of Paraguay and southern Brazil, stevia has had problems gaining a foothold in the U.S. sugar substitute market. The U.S. Food and Drug Administration has never given formal approval for stevia's use as a food additive, but the agency in 2008 did concede that there were no grounds for objecting to its use in food. Another factor in stevia's slow start in the sugar substitute market has been the bitter aftertaste that characterized some of the stevia brands first put on the market. Improved extraction techniques have helped to address this problem.
Extraction Techniques
Early extraction techniques produced an end product with a bitter aftertaste that many sugar substitute consumers found unappealing. As of late 2010, state-of-the-art extraction techniques are producing a purer product with significantly less aftertaste. The basic technique begins with the pressurized extraction of fluid from stevia leaves, followed by clarification and crystallization of the plant residue, according to Stevia.com. To purify the end product, stevia manufacturers may employ ion-exchange resins, precipitating agents or electrolytic techniques.
"Greening" the Extraction Process
In an analysis of the comparative merits of using water or methanol for the pressurized extraction process, Czech researchers found that both appeared to work equally well. In findings published in the August 2007 of "Analytical and Bioanalytical Chemistry," they report that the optimal temperature for both water and methanol is 110 degrees Celsius, or 230 degrees Fahrenheit. Although concluding that water and methanol work equally well, the researchers observe that "extraction with pressurized hot water . . . presents a possibility for upscaling the extraction process and establishing a 'green' method for isolation of stevioside. . . . "
Comparison of Sugar Substitutes
One of stevia's strongest selling points in the battle of the sugar substitutes is its ability to increase glucose tolerance, according to Linda Page, author of "Diets for Healthy Living." While aspartame, saccharin and sucralose, the other major contenders in this market, all tend to increase one's cravings for sweets, stevia does not. It stands alone in its ability to sweeten foods without adding calories and avoids any adverse impact on the adrenal glands or pancreas, according to Rita Elkins, author of "Stevia: Nature's Sweetener."
References
- "Sweet Deception: Why Splenda, NutraSweet and the FDA May Be Hazardous to Your Health"; Joseph Mercola and Kendra Degen Pearsall; 2006
- Stevia.com: Questions & Answers About Stevia
- "Analytical and Bioanalytical Chemistry"; Comparison of Two Different Solvents Employed for Pressurised Fluid Extraction of Stevioside from Stevia Rebaudiana: Methanol Versus Water; Jaroslav Pol et al.; August 2007
- "Diets for Healthy Living: Dr. Linda Page's Natural Solutions to America's 10 Biggest Health Problems"; Linda Page; 2005
- "Stevia: Nature's Sweetener"; Rita Elkins; 1997
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