Exploring the dynamic characteristic of typical kombucha induced by symbiotic microbiota succession from four Chinese...

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.