Dynamic changes in physicochemical properties, flavor, and microbial communities during kombucha fermentation with...

To address the issues of inefficiency, inconsistency, and uncontrolled microbial composition in traditional kombucha fermentation, this study systematically monitored the dynamic changes in physicochemical properties, microbial communities, and flavor profiles using defined autochthonous strains (Komagataeibacter intermedius C1-KI1, Saccharomyces cerevisiae P1-SC3, and Lactobacillus sakei M-LS) under both mono- and co-culture conditions. Among all treatments, the MS2 group (triple-strain co-culture) exhibited optimal fermentation performance, achieving the lowest pH (2.49) and the highest total acidity (3.28 g/L). High-throughput sequencing revealed distinct microbial communities after fermentation, with Saccharomyces (99.98 % in fungal genus) and Komagataeibacter (89.93 % in bacteria) dominating in MS2. Electronic sensory and gas chromatography-ion mobility spectrometry analysis indicated that esters constituted the predominant volatile flavor compounds, reaching 81.24 % of total volatiles in MS2. This sample exhibited significantly enhanced sourness and richness, reduced bitterness and astringency, and a greater diversity and content of esters, contributing to more pronounced fruity and floral aromas. Spearman correlation analysis confirmed positive associations between dominant microbial genera and key flavor compounds. These findings offer insights for selecting flavor-enhancing functional microorganisms and improving the flavor quality of kombucha, providing a practical strategy for its standardized industrial production.