Exploring the dynamic characteristic of typical kombucha induced by symbiotic microbiota succession from four Chinese regions: A comprehensive analytical framework.

To investigate the microbial diversities and dynamic quality properties of kombucha, the successional changes with different periods from four regions were comprehensively characterized and compared. A total of 197 indigenous yeast and bacterial strains were isolated, involving Gluconobacter, Komagataeibacter, Starmerella and Zygosaccharomyces spp. The successional dynamics of the kombucha communities in different regions were evaluated. The b* values of all kombucha decreased continuously as fermentation progressed. Results indicated that proper fermentation timing significantly influenced nutritional composition and aroma characteristics. A gradual increase in the content of individual monomeric phenols during the middle and late stages of fermentation (days 6-15). Overall, the Shaanxi (SX) region exhibited the highest content of the 10 phenolics detected on day 9, with 273.45 mg/L, followed by the Hunan (HN) region on day 9 (206.49 mg/L). Higher concentrations of bioactive compounds were produced during later stages, which determined the antioxidant properties. A total of 94 volatile compounds were identified and 32 volatiles with relative odor activity value (rOAV) ≥ 0.1. Four regions showed a decreasing trend in the number of aromas in the later stages of fermentation. The predominant compounds were acids, esters and alcohols during the later fermentation stages, which decanal, trans-β-ionone and damascenone serving as characteristic aromas. The partial least-squares regression analysis revealed that apple juice, fruity and sour apple odors showed an intensely positive impact on the overall acceptability of the kombucha.