Wheat properties shape microbial succession and flavor profile in high-temperature Daqu fermentation: a multi-omics perspective.

Wheat is the raw material for high-temperature Daqu (HTD). The research on the relationship between the properties of wheat and the quality of HTD is very limited. This study examined the properties of five wheat varieties and the physicochemical properties, flavor substances and microbial communities of HTD during fermentation. These results showed that the stage before the first flipping was a crucial period for volatile flavor substances generation. The formation of flavor substances during this period was closely related to not only lactic acid bacteria but also heat-resistant bacteria, such as Bacillus, Desmospora, Kroppenstedtia and Lentibacillus. Wheat quality characteristics exerted stage-specific regulatory effects on key flavor compound production through modulating specific microbial communities, ultimately influencing Daqu quality. During the early stage, Farinograph quality number(FQN), Sedimentation index, Maximum resistance and Stable time affected 2-methoxy-phenol and butanoic acid via lactic acid bacteria. During the middle stage, the above-mentioned characteristics promoted hexanoic acid and tetramethylpyrazine through Saccharopolyspora and Siminovitchia, respectively. And Wet gluten specifically mediated 2,5-dimethylpyrazine formation. During the late stage, Water absorption and Test weight drove Phenethyl alcohol and tetramethyl pyrazine accumulation via Saccharopolyspora and Saccharomonospora, respectively.