Identification of key differential compounds in different quality grades of base liquor during the production of Jiang-flavored baijiu

The production process of Jiang-flavored Baijiu is highly elaborate, and the flavor characteristics and quality of the base liquor (BL) exert a substantial impact on the quality of the final product. A total of 130 typical samples from three quality grades within seven fermentation rounds were examined. Based on sensory evaluation, gas chromatography-flame ionization detection (GC-FID) technology was employed to detect 59 principal volatile compounds within the samples. Subsequently, K-means clustering, partial least squares discriminant analysis, and odor activity values were combined to analyze the compound variation trends and key differentiating compounds. The results demonstrated that in the seven fermentation rounds, 10 key differentiating compounds significantly affect the BL quality; in each round, 6 compounds markedly influence the quality level. Among them, the contents of acetic acid, ethyl acetate, lactic acid, and acetaldehyde were correlated with the BL quality grade and have the potential to act as quality indicators.