Chemical Profile and Antioxidant Capacity of Kombucha Tea by the Pure Cultured Kombucha

Kombucha tea is a traditional drink with a unique flavor, which was obtained by fermenting sugared green tea or black tea with "tea fungus" (Kombucha). This study aimed to produce pure cultured Kombucha and investigate the change of functional components and flavor substances. In the study, an acetic acid bacteria, Komagataeibacter oboediens SW-1, was obtained and used to ferment Kombucha tea with one lactic acid bacteria and two Yeasts. The results showed that the Kombucha tea was prepared with the pure cultured Kombucha. The contents of polyphenols and flavonoids were increased by 55.96% (0.097–0.471 mg/mL), and 88.89% (0.113–0.612 mg/mL) in black tea Kombucha (BTK). In green tea Kombucha (GTK), their contents were increased by 134.65% (0.137–0.535 mg/mL), and by 103.56% (0.219–0.743 mg/mL). The highest titratable acidity was 12.68 g/L in BTK and 15.02 g/L in GTK, and the contents of nine organic acids were 9.82 g/L in BTK and 9.26 g/L in BTK. Flavor analysis showed that 42 and 52 flavor compounds in GTK and BTK were detected, respectively. The correlation analysis of volatile flavor compounds showed that 14 substances had a significant contribution to the composition of typical Kombucha tea flavor.