Study on characteristic aroma compounds of Qingke baijiu and their biosynthesis mechanism

In this study, the electronic tongue, electronic nose, GC–MS, and GC-IMS technologies were used to analyze the raw materials, Daqu, and raw liquor of Qingke Baijiu throughout the entire brewing process. Similar to other alcoholic beverages, esters and alcohols were the main volatile flavor components. It was worth noting that in these samples, benzaldehyde and ethyl palmitate were the common aroma components. Among them, benzaldehyde had a toasted flavor, and ethyl palmitate had a waxy aroma. Important flavor compounds were identified based on their odor activity values (OAVs), while variable importance in projection (VIP) scores helped identify the different compounds. The biosynthesis pathways of important flavor compounds in Qingke Baijiu primarily involve butyrate metabolism, glycolysis, gluconeogenesis, phenylalanine metabolism, and fatty acid elongation. The results can not only deepen the understanding of the characteristics of aroma compounds and the flavor formation mechanism of Qingke Baijiu, but also provide scientific basis for optimizing the production process and improving the aroma of Qingke Baijiu.