Impact of compound fungal bran Qu fortification on Sichuan bran vinegar fermentation and product quality.

In this study, we used compound fungal bran koji to enhance the fermentation of Sichuan bran cupi. Analysis of the microbial composition of cupei showed that Aspergillus, Saccharomyces, Wickerhamomyces, Rhizopus, Lactobacillus, and Acetobacter are the primary genera involved in fermentation. The addition of enriched Qu (BQF) for intensive fermentation increased the relative abundance of Wickerhamomyces and Rhizopus during the initial and mid-stages of fermentation while influencing the dynamics of Aspergillus, Lactobacillus, Acetobacter, and other genera. Compared to the BQ group (control group), the BQF group demonstrated a 5.32 % increase in total acid content, 9.23 % improvement in starch usage, and 14.74 % increase in total ester content. Furthermore, the flavor compounds, including esters, alcohols, and acids, in the cooked vinegar of the BQF group increased by 49.89 %, 1.02 % and 16.13 %, respectively. These results were consistent with the sensory evaluation. These findings demonstrate that Qu significantly improved the flavor of bran vinegar.