Analysis of chemical characteristics and antioxidant activity test of kombucha black tea and butterfly pea flower (Clitoria ternatea L.) based on fermentation time

Free radicals are one of the triggering factors for degenerative diseases. Free radical activity can be minimized or prevented in the presence of antioxidant compounds. The butterfly pea flower (Clitoria ternatea L.) has long been used as a traditional medicine to cure various diseases. Previous research has shown that the Butterfly pea flower has bioactive compounds, one of which is flavonoids, which act as antioxidants. Butterfly pea flower can be used as another substitute in making black tea-based kombucha drinks. Kombucha fermentation can increase the benefits of Butterfly pea flower with the presence of organic acids, minerals, and vitamins produced during the fermentation process. This study aims to determine the effect of fermentation time on chemical characteristics including pH, reducing sugar content, and antioxidant activity. Based on analysis of variance ANOVA showed that the length of time fermentation had a very significant effect (P>0.01) on pH, reducing sugar content and antioxidant activity of black tea and Butterfly pea flower kombucha. The longer the fermentation time, the lower the pH and sugar content in the medium. Optimum antioxidant activity occurred on the 8th day of fermentation in the variation of treatment P3 (3:3) which was 89.74%. These results indicate that black tea kombucha and Butterfly pea flower are categorized as having high antioxidant activity at the interval of 68.45% to 89.74%.