Microbial composition, bioactive compounds, and sensory evaluation of Kombucha prepared with green tea and black tea

Kombucha, a traditional fermented tea beverage, is produced through the combined action of yeast, lactic acid bacteria, and acetic acid bacteria, offering various health benefits. In this study, green tea Kombucha (K-GT) and black tea Kombucha (K-BT) were prepared using the same batch of tea leaves, and their sensory qualities, microbial composition, and bioactive components were compared. The results indicated that K-GT exhibited a fresh flavor profile, characterized by a subtle sweetness and a mild vinegar taste. Additionally, the K-GT biofilm was found to be the thickest and smoothest among the samples. <italic>Komagataeibacter</italic> can promote the growth of bacterial cellulose membranes and thicken the biofilm, with the highest proportion of K-GT (97%) in the three groups. In contrast, K-BT had a sweet and sour taste with a strong vinegar flavor and a fizzy sensation. The yeast community in K-BT group was the most abundant among the three Kombucha species, and <italic>Zygosaccharomyces</italic> was the dominant bacterial group. Comparative analysis of active components and microbial associations revealed that K-BT produced more amino acids, peptides, purines, pyrimidines, and their derivatives compared to K-GT. Many of these components are microbial metabolites and exhibit stronger bio-protein interaction network regulatory capabilities. This study demonstrates that using different types of tea leaves as the fermentation base for Kombucha significantly alters the structure of the microbial community involved in fermentation. These changes can subtly affect the fermentation quality, bioactive compounds, and biofilm formation of Kombucha, which is highly relevant and valuable for Kombucha beverage manufacturers, biofilm technology experts, and synthetic ecologists.