Nutrient composition of cultivated stevia leaves and the influence of polyphenols and plant pigments on sensory and antioxidant properties of leaf extracts

摘要

Stevia rebaudiana is an introduced crop in India. The leaf and its extract although sweet have a bitter after taste that precludes commercial acceptability. The composition of the leaf reflected a high nutritive value and polyphenol concentration averaging 4.15% by weight of dried leaf. Variably processed extracts enriched with polyphenols, pigments and a mixture of both were evaluated for sensory attributes by a semi trained panel when added to cofee and lime juice. Presence of polyphenols influenced the acceptability of the sweeteners marginally, while chlorophyll was found unacceptable in any of the extracts. The antioxidant activity of the extracts was synergistic when it was mixed with coffee and lime juice. Complete purification of stevia leaf extracts to obtain pure glycosides is not necessary for it to become a commercially acceptable sweetener.