Kombucha is a fermented beverage generally made with tea, sucrose, and a symbiotic colony of bacteria and yeast (SCOBY). There has been a recent surge in both kombucha consumption as well as research, stemming from a long list of purported health/therapeutic benefits. Many of the therapeutic effects of kombucha are from strong free radical scavenging and antioxidant abilities of phenolic compounds produced from the fermentation process of the beverage. Despite reports of the phenolic content of kombucha fermented with various teas, little is known of kombucha fermented with a substitute for sugar and tea. This study analyzed the phenolic content of kombucha fermented with blueberry juice (BBJ) in lieu of tea broth over a 14-day fermentation period. Pre-fermented black tea kombucha generally has a sugar content of 0.08 g/ml and a pH around 5; however, after a 14-day fermentation period, the sugar content and pH levels decrease due to the metabolism of sugars to acetic and lactic acid. BBJ contains higher sugar content and lower acidity than black tea; however, it was able to support the growth of the kombucha culture. After the 14-day fermentation period, sugar concentration was found to decrease to 1.83 g/ml and the pH level decreased to 2.76. Comparison of total phenolic and free anthocyanin content pre- and post-fermentation demonstrated an increase of 67% and 26%, respectively. The increase in phenolic and free anthocyanin content may suggest that the SCOBY is able to increase the bioavailability of the antioxidant compounds within BBJ. This study supports the successful development of an alternative kombucha beverage.

Analysis of kombucha tea fermented with blueberry juice

253rd National Meeting (2017)

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