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Stevia (Stevia rebaudiana Bertoni) is “very easy to grow,” said Michael Britten-Kelly, Treatt USA’s natural products manager, during the fall meeting of the Society of Flavor Chemists and Chemical Sources Association. However, the plant, sought-after for the natural sweetening properties of its extracts, grows best in temperate climates. Today, stevia is primarily grown in China, though U.S. domestic largescale growing is taking place in California, Georgia and North Carolina.
The extract contains at least 11 stevia glycosides; the four major components focused upon in commerce are rebaudioside A, C, D and the stevioside. Britten-Kelly explained, “Because of the complex constitution of the extracts in the marketplace, people will often find that from one manufacturer to another, one person’s 95% stevia is different from another person’s 95% stevia and it has to do with the balance of all these components.”
A large number of stevia extracts have been self-declared as GRAS without objection by the U.S. Food and Drug Administration. Stevia leaves are not acceptable in foods. Extracts have to be purified to at least 95% stevia glycosides. The European Union has set up a stevia standard that is equivalent to about 200 ppm of stevioside and 240 ppm of rebaudioside A.