Effects of different probiotic fermentations on the quality, soy isoflavone and equol content of soy protein yogurt made from soy whey and soy embryo powder

Abstract

The effects of fermentation with different combinations of probiotic micro-organisms on the consumer quality attributes, soy isoflavone and equol content of yogurt, made from soy whey, soy embryo powder and soy protein powder were investigated. Differences in water holding capacity, texture, apparent viscosity, sensory attributes, soy isoflavone and equol content were studied. Different probiotics had significantly different effects on yogurt quality, soy isoflavone and equol content. Fermentation with Danisco probiotic starter resulted in the shortest fermentation time, the best water holding capacity, textural properties, flavor, sensory scores, the highest total (28) of aroma volatiles detected and the highest content of equol (1022.6 ng/mL). Multivariate statistical analysis of taste and aroma profiles was able to clearly distinguish between yogurts with different sensory scores. These findings indicate that producing yogurt from soy whey, a waste-stream from soybean processing, is a viable way to make a higher-value, health promoting consumer product.