The spatial heterogeneity of aroma compounds and microbial communities during the stacking process of Qingke Jiangxiang Baijiu

To research the aroma profiles and bacterial community structure during different periods of the stacking process of Qingke Jiangxiang Baijiu (QJB), we conducted a stacking experiment,samples from both the inner and outer layers of the pile were collected at 0, 12, 24, 36, 48 and 60 hours and analyzed using 16S rRNA sequencing for bacterial communities and GC × GC-TOF MS for aroma profiling.The results showed that the key aroma compounds involved in the inner layer included Prenol, 2-Heptanol, Butanoic acid 2-methylpropyl ester, etc.The LEfSe identified that the dominant bacterial genera associated with 2-methyl-1-propanol are Klebsiella,etc. The outer layer with additional herbal, floral, and apple-like aromas included 3-methyl-1-Butanol acetate, 2-Furanmethanol,etc.The genera mainly responsible for the production of ethyl acetate, ethyl octanoate, ethyl decanoate during the stacking process are Limosilactobacillus and Lactiplantibacillus. The microbial genera closely related to 3-methyl-butyric acid are Weissella. The genera that are closely associated with 2-pentyl-furan include Bacillus and Saccharopolyspora.In the outer layer, the dominant bacteria associated with ethyl hexadecanoate are Limosilactobacillus and Companilactobacillus. The genera positively correlated with 3-methyl-1-butanol and acetoin are Kroppenstedtia, Pediococcus,etc. The dominant bacterial genera associated with ethyl acetate are Saccharopolyspora, Pseudonocardiaceae, and Oceanobacillus.In the last 2 days of inner,the primary metabolic pathways:FUCCAT-PWY,PWY-5384,etc.In the stages of stacking, the main fungal genera were Byssochlamys, Thermomyces, Thermoascus, and Microascus, Aspergillus. The main metabolic pathways of outer included Porphyrin,chlorophyll metabolism,etc.Through the investigation of microbial communities and flavor compounds during the piling process of QJB, revealed the correlation between key microorganisms and major flavor compounds, providing a reference for further advancing the production of Qingke baijiu under the conditions of high-altitude hypoxia and low oxygen.