The effects of green tea and black tea on the total acid, alcohol content, and antioxidant levels in kombucha

This research aimed to determine the effects of green tea and black tea on the total acid content, alcohol concentration, and total phenolic content of kombucha. The fermentation process was carried out over 14 days to monitor changes in key characteristics, including total titrated acid, pH, reducing sugar content, alcohol content, and Total Polyphenol Content (TPC). The results indicated that kombucha made from green tea contained higher alcohol levels and greater phenolic content, whereas kombucha from black tea had a higher acid concentration. By the end of the 14th day of fermentation, the acid content of green tea kombucha reached 0.240 M with a pH of 2.56, while the black tea variant reached 0.246 M with a pH of 2.61. Additionally, the alcohol content peaked on day 14 for both green tea and black tea, at 0.84% and 0.52% (v/v), respectively. The highest Total Polyphenol Content for green tea was recorded on day 12, measuring 344.4 mg/L, while black tea reached its peak of 333.89 mg/L on day 7. Based on the organoleptic tests and the analysis of kombucha contents, the optimal fermentation time for both green tea and black tea kombucha is concluded to be 7 days.