Preparation of Fangxian traditional Xiaoqu and its evolution of microbial communities and aroma compounds during fermentation.

Fangxian traditional Xiaoqu (FTXQ) is an important factor in the formation of unique aroma of Fangxian Huangjiu. FTXQ with only Polygonum hydropiper L. and FTXQ with Polygonum hydropiper L. and multiple herbs were prepared. Together with their seed Qu, three fermentation broths (FBs) were obtained and used during brewing to investigate differences in microorganisms, aroma compounds, and sensory evaluation. The results indicated that the core communities, including Enterococcus, and Saccharomyces, and 150 volatile aroma compounds, such as phenethyl alcohol were identified, and they showed close relationships. Twenty-three bacterial genera, including Enterococcus, 10 fungal genera like Saccharomyces, and 58 compounds, such as isoamyl octanoate, were the microorganisms and compounds responsible for the differences in the three FBs at different fermentation stages. The herbs added to Xiaoqu could enhance the overall aroma intensities of FBs and probably benefit in inhibiting the production of foodborne pathogens like Cronobacter during brewing.