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 refl ected 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 infl uenced 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 purifi cation of stevia leaf extracts to obtain pure glycosides is not necessary for it to become a commercially acceptable sweetener.

With the mainstream emergence of natural sweeteners such as stevia, which is available in different commercial formulations, suitability for yogurt needs to be validated. The present study aimed to determine the appropriate concentration level of 3 processed stevia sweeteners/supplements in commercial plain low-fat yogurt flavored with natural vanilla. Three different levels of sucrose, aspartame, an erythritol and 95% rebaudiana A stevia sweetener, a 95% pure mix of maltodextrin and steviol glycosides, and a cold water stevia extract were used in the study. The just-about-right level for each sweetener and consumer acceptability of each naturally flavored low-fat vanilla yogurt were evaluated. Results from penalty analysis demonstrated that only 0.7% of stevia containing maltodextrin and 95% steviol glycoside was necessary, whereas higher levels (between 4.0 to 5.5%) were more appropriate for stevia containing erythritol and 95% rebaudiana A or cold water extract of stevia, respectively. The concentrations of stevia sweeteners used influenced the perceived sweetness and sourness. In general, consumers disliked the yogurt sweetened with stevia or aspartame, and neither disliked nor liked the yogurt sweetened with sucrose, which was largely driven by perceived sourness of the base yogurt. The findings underline the importance of careful selection of stevia type and concentration as well as optimizing yogurt cultures and fermentation conditions before product launch.