Effect of Fermentation Time on Antioxidant Activity and Alcohol Content of Black Tea (Camellia sinensis) Kombucha Yoga Angkawijaya Kristiawan (a), Catarina Aprilia Ariestanti (a*)
(a) Departement of Biology, Faculty of Biotechnology, Duta Wacana Christian University, Dr. Wahidin Sudirohusodo No. 5-21, Kotabaru, Gondokusuman, Yogyakarta, Daerah Istimewa Yogyakarta, Indonesia
Abstract
Kombucha as one of the fermented beverages has been widely recognised for its various health benefits, one of which is high antioxidant activity. This study aimed to evaluate the effect of fermentation duration on antioxidant activity and alcohol content in black tea (Camellia sinensis) kombucha. Fermentation was conducted for 21 days using Symbiotic Culture of Bacteria and Yeast (SCOBY) starter culture. (SCOBY) STARTER CULTURE. The results showed that the antioxidant activity of kombucha reached its peak on day 14, with the highest free radical inhibition value of 64%. The decline in antioxidant activity began to be seen after day 14, along with the reduced activity of microorganisms in the culture. In addition, the alcohol content in kombucha tea increased during the initial phase of fermentation, reaching a peak on days 7 to 14 with the highest level of 0.45%, before decreasing due to the conversion of alcohol to acid by acetic acid bacteria. In contrast, unfermented regular tea showed significantly lower antioxidant activity and alcohol content and stabilised throughout the observation period. Fermentation for 7 to 14 days was the optimal duration. This study supports the use of fermentation as an effective method to improve the quality and health benefits of kombucha tea. Further studies can be conducted calculating sugar content and total microbial values.
