Effect of wheat hardness on flavor compounds and microorganisms in medium-high temperature <i>Daqu</i>

Wheat is the main raw material of medium-high temperature Daqu (MHTD), Daqu is a crude enzyme preparation for Baijiu fermentation. In this experiment, soft and hard wheat were selected and mixed in different ratios to produce MHTD. The results showed that soft wheat was more likely to carry the dominant microorganisms in Daqu, such as Bacillus and Aspergillus, and was rich in flavor precursors. The best use ratio of soft wheat was 15%, which had better hygroscopicity, more thorough fermentation, balanced microbial community structure, and significantly increased the content of volatile flavor substances, especially the content of pyrazine and ester increased by two times. The study clarifies the optimal application ratios of soft and hard wheat in the production of MHTD, revealing the impact of raw materials on the microbial community and flavor structure of Daqu. This provides a theoretical basis for further improving the quality of Daqu.