Characterization of the key aroma-active compounds causing the Douchi aroma in high-temperature Daqu via integrated molecular sensory science, metabolomics, and molecular docking.

"Qu is the backbone of Baijiu", and the production of premium Baijiu depends on high-quality Daqu. The Douchi aroma is a key sensory indicator of Daqu quality. However, the specific aroma-active compounds responsible for this characteristic remain unclear. This study integrated molecular sensory science, metabolomics, and molecular docking to identify the key aroma-contributing compounds and investigate their interaction mechanisms. First, untargeted metabolomics was employed to comprehensively profile metabolites in Daqu samples, leading to the identification of differential compounds. Further combined with quantitative analysis, OAV calculation, aroma recombination, and omission experiments confirmed the key aroma-active compounds responsible for the Douchi aroma. Finally, molecular docking revealed differences in binding energies and amino acid residues, elucidating their synergistic interactions with olfactory receptors. This study systematically characterized the key aroma active compounds of high-temperature Daqu Douchi aroma for the first time, laying the foundation for high-quality production of high-temperature Daqu.