Analysis of Sensory Qualities and Microbial Community Structure in the Fermented Grains by Low-Temperature Daqu from Different Regions of China.

Low-temperature Daqu (LTD) serves as the starter for the fermented grains (FG) of Light-amora Baijiu, yet its impact on FG remains unclear. This study assessed the differences in sensory attributes and microbial community structures of the FG fermented by LTD from two regions through electronic sensing and MiSeq high-throughput sequencing. The results showed significant differences in odor and taste between the two FG groups (P < 0.05). The dominant bacteria in both FG groups were mainly Lactobacillus (74.05%), and dominant fungi were Saccharomycopsis (44.30%) and Saccharomyces (37.84%). The microbial differences in the both groups may be manifested in the low abundance of microbial communities. The fermentation environment of LTD and FG is very different, resulting in their microbial community structure and bacterial gene function being significantly different. LTD had more anaerobes with higher expression of transport and metabolic genes for amino acid and lipid functions, whereas FG contained more facultative anaerobes with higher expression of carbohydrate transport and metabolic genes. Notably, 71.77% of endemic bacteria were found in FG but absent in LTD. Overall, our results indicated that different LTD had a greater impact on the sensory and low-abundance microflora of FG, enhancing our understanding of its role in fermentation processes.