Effects of fermentation temperature on bacterial community, physicochemical properties and volatile flavor in fermented soy whey and its coagulated tofu

In this study, soy whey fermentations under low-temperature (25 °C), high-temperature (37 °C) and simulated natural temperature (dynamic temperatures, 25–37 °C) were performed to analyze the effect of fermentation temperature on the bacterial community, physicochemical properties and flavor compounds in fermented soy whey (FSW), and the further effect on the FSW coagulated tofu. Results indicated that altering the fermentation temperature led to differences in bacterial diversity and quality characteristics of FSW. Lactobacillus (relative abundance 80.21%–99.69%) was the dominant genera in all FSW and exhibited a positive correlation with the contents of lactic acid, alcohols, aldehydes and ketones. Compared with low-temperature fermented soy whey (LFSW) and high-temperature fermented soy whey (HFSW), simulated natural temperature fermented soy whey (SNFSW) showed higher levels in the bacterial community diversity, kinds of volatile compounds and sensory score, and a lower level of beany flavor. In addition, SNFSW gave its coagulated tofu a higher springiness and sensory score, and a lower relative content of beany flavor. Therefore, fermentation temperature can affect the bacterial community, physicochemical properties and flavor compounds of FSW, and further the quality characteristics of FSW-tofu, and SNFSW-tofu had better flavor and taste than other tofus.