Wei Cheng ¹ Wei Lan ^1* Xuefeng Chen ² Xijia Xue ^3* Huipeng Liang ^4* Zeng H. Wei ⁵ Li Ruilong ¹ Tianquan Pan ^3* Na Li ^3* Hongwen Yang ^3*

• ¹ Fuyang Normal University, Fuyang, Anhui Province, China
• ² Shaanxi University of Science and Technology, Xi'an, Shaanxi, China
• ³ Anhui Jinzhongzi Distillery Co., Ltd., Fuayng, China
• ⁴ Other, Beijin, China
• ⁵ Huaibei Normal University, Huaibei, Anhui, China

Pyrazines are important flavor components and healthy active components in Baijiu, which including tetramethylpyrazine (TTMP). During the brewing process, the traceability of microbial communities and the content distribution characteristics of TTMP are important for improving the quality and style characteristics of compound-flavored Baijiu (CFB). However, the traceability analysis of microorganisms in fermented grains (FG)-used in the production of CFB-lacks quantitative and systematic evaluation. In this study, the microbial communities and TTMP content of Jiuqu (JQ), Liangpei (LP), FG, and pit mud (CP) used in CFB production were characterized; further, coordinate and discriminant analyses were employed to determine differences in microbial communities.Additionally, traceability and correlation analyses were performed to reveal the origin of microbial communities in FG. The source, content, and distribution characteristics of TTMP based on the brewing process have also been discussed. The results showed that most of the bacterial and fungal communities at different levels of FG came from other sources, and the microorganisms of Cladosporium, Acetobacter, Aspergillus, Methanosarcina, and Bacillus were considered have a osculating correlations with TTMP content of FG. Taken together, this study provides insights into the origin of microbial communities in FG and the distribution characteristics of TTMP based on the CFB brewing process. The current findings are conducive for optimizing the fermentation process and improving the quality and style characteristics of CFB. As one of the six major distilled liquors worldwide, Baijiu is preferred by the Chinese people for its unique flavour and cultural significance (Tu et al. 2022). Baijiu is mainly produced via traditional solid-state fermentation, which includes Jiuqu (JQ; starter for fermentation) production, grain steaming, mixed fermentation, distillation, blending, maturation, and other processes (Ye et al. 2021).Baijiu fermentation is an intricate bilateral fermentation process involving multiple strains of microorganisms, including bacteria, yeasts, and moulds, with subtle interactions between microbial communities, physicochemical indices, and environmental factors creating a unique brewing microecology in which microorganisms play a key role (