Aqueous and alcoholic adducts of steviol and steviol glycosides in food products containing stevia

High content of steviol glycosides in stevia leaves is a cause of their high popularity as. a natural sweetener of various sugar-free food products. Stevioside (13 [(2-O-beta-D-glucopyranosyl-beta-D-glucopyranosyl)oxy]-ent-kaur-16-en-19-oic acid beta-D-glucopyranosyl ester) is one of the main steviol glycosides in stevia leaves known for its hydrolytic instability responsible for the formation of simple steviol glucosides (steviolbioside, rubusoside, steviol monoside) and steviol. However, the formation of hydroxy and alkoxy adducts of stevioside and of its hydrolysis products has not yet been reported. The performed experiments prove that water and alkoxy adducts are formed not only during temperature processing of stevioside but also of stevia and stevia-containing food products. Their quantities depend on environment pH, water concentration and food composition. Although they are formed in small amounts their biological activity is unknown and should be recognized.