Matrix-dependent modulation of chemical composition, volatile profile, and biological activity of kombucha beverages from different tea types

Kombucha is a fermented beverage obtained from sweetened tea through the activity of a symbiotic culture of bacteria and yeast (SCOBY). While fermentation-induced transformations are well described, the role of the tea matrix in modulating these changes remains unclear. This study evaluated the influence of five tea types (green, black, Pu-Erh, white, and Oolong) on the chemical composition, volatile profile, microbiological characteristics, and biological activity of kombucha under controlled fermentation. Fermentation followed similar biochemical trajectories across all samples; however, the magnitude and final composition of changes differed significantly between tea types. The initial tea matrix strongly influenced polyphenol transformations, volatile compound profiles, and biological activities. A conserved microbial consortium dominated by Komagataeibacter and Zygosaccharomyces was observed in all variants. These findings demonstrate that kombucha fermentation is a conserved process, while the tea matrix governs the final compositional and functional properties.