Abstract
Most of the probiotic foods are dairy products. Presently, yogurt is the most widely used probiotic products in the world. The purpose of this study was to evaluate the effect of whey protein concentrate and oligofructose on viability of Bifidobacterium lactis and physicochemical and sensory characteristics of low-fat stirred yogurt. Probiotic yogurt containing oligofructose (0.5%, 1%, and 1.5%) and whey protein concentrate (0.5%, 1%, and 1.5%) were prepared and stored at 4°C for 21 days. Microbial, physicochemical and sensory properties of yoghurt samples were examined on days 1, 7, 14 and 21 and compared with control sample (sample without oligofructose and whey protein concentrate). The results showed that stirred yogurt with 1.5 % whey protein concentrate and 1.5 % oligofructose had the best sensory properties. The samples containing 1.5 % of whey protein concentrate and three levels of oligofructose (0.5%, 1%, and 1.5%) had the highest levels of probiotic bacteria. According to the results of this study, stirred yogurt with 1.5 % whey protein concentrate and 1.5 % oligofructose was chosen as the best sample in terms of physicochemical, microbiological and sensory features.
