Effects of cow's milk to soy milk proportion and the type of commercial culture composition on biochemical, microbiological and sensory characteristics of probiotic soy-Doogh

Recently, the demand for consumption of functional foods is growing rapidly due to the increased awareness of the consumers from the impact of these foods on health. Production of soy based probiotic Doogh will improve the functional potential of products. The aim of this study was to assess qualitative aspects of soy based probiotic Doogh.

In this research, the effects of cow's milk to soy milk proportion (100:0, 75:25, 50:50, 25:75, 0:100) as well as the type of commercial culture composition (ABY-1, MY-720, YO-Mix-210) on biochemical, microbiological and sensory characteristics of probiotic soy-Doogh was investigated. pH, Titrable acidity and redox potential, lactic and acetic percentage as well as viability of probiotics and sensory properties of final product during fermentation and/or refrigerated storage were assessed.

results showed that the shortest fermentation time was observed in treatment with cow's milk to soy milk proportion of 50:50 and culture composition of ABY-1. The highest and lowest viable count of B. bifidum and L. acidophilus during 21 days of refrigerated storage were observed for the treatments with cow's milk to soy milk proportion of 25:75/ ABY-1 and 25:75/ MY-720, respectively. The influence of type of starter culture composition on sensory properties of final products was not significant, while the cow's milk to soy milk proportion 75:25 resulted in the most satisfactory sensory properties.

Considering the results, the cow's milk to soy-milk proportion of 50:50 with any of the types of culture composition was selected as the best treatments from viability and sensory points of view.