Alterations in Biochemical Characteristics, Flavor, and Microbial Community During the Storage of Suancai

This study examined how storage influences the flavor profile and microbial composition of Suancai. To achieve this, we combined physicochemical measurements with analyses of both volatile and non-volatile metabolites, assessments of microbial diversity, and multivariate statistical modeling. Specifically, we investigated changes in physicochemical parameters, organic acids, amino acids, biogenic amines, volatile compounds, and microbial communities before and after storage. The results revealed that, after one year of storage, the pH and nitrite levels in Suancai decreased significantly, whereas the titratable acidity increased substantially. Among the organic acids, lactic acid and oxalic acid remained dominant both before and after storage. In terms of amino acid composition, glutamic acid, aspartic acid, and alanine were present in relatively high concentrations. A total of 69 volatile compounds were detected in Suancai, with esters and alcohols representing the major groups. Odor activity value analysis identified nonanal and phenethylaldehyde as key contributors to the overall aroma profile. Correlation analysis further indicated that Lactobacillus, Halomonas, and Chromohalobacter were the dominant bacterial genera linked to flavor development. Specifically, Lactobacillus exhibited strong positive correlations with phenylethanal, nonanal, ethyl octanoate, and ethyl decanoate, whereas Debaryomyces was positively associated with allyl isothiocyanate, 3-butenyl isothiocyanate, and ethyl ionone.