Impact of Polygonum orientale L. flower addition on microbial community of Xiaoqu and volatile compounds of Huangjiu in Fangxian, China

Fangxian Huangjiu is a Chinese rice wine fermented by the unique local starter Xiaoqu with the addition of Polygonum orientale L. (P. orientale L.) flower. This research aimed to elucidate the influence of P. orientale flower on the enzyme activity and microbial community of Fangxian Xiaoqu, and consequently on the physicochemical indicators and volatiles of Fangxian Huangjiu. The results revealed that the P. orientale flower significantly enhanced the acid protease activity and declined the alpha-amylase activity of Xiaoqu. Additionally, it improved microbial community diversity and the species of the dominant bacterial genus in Xiaoqu. For fermentation broth, the types of volatile substances have improved. Furthermore, Spearman correlation analysis revealed that Pediococcus, Kosakonia, Saccharomycopsis, Mucor, Cyberlindnera, and Wickerhamomyces were closely related to the synthesis of volatiles. These findings clarify the role of P. orientale flower and provide the practical basis for the future production of Fangxian Xiaoqu.