Antioxidant Properties of Kombucha Beverage Infused with Ganoderma lucidum and Green Tea from Camellia sinensis (L.) Kuntze with Several Fermentation Times

Kombucha is a functional beverage produced through the fermentation of infused tea or Camelia sinensis (L.) Kuntze (CS) by a symbiotic culture of bacteria and yeast. Apparently, the substrate of kombucha can be substituted to enhance its functional properties. Ganoderma lucidum (GL) is a potential substrate reported to have health benefits. This study aims to evaluate antioxidant properties by comparing different formulations and fermentation times. The formulations prepared in the present study varied in the compositions of GL and CS substrates, namely F1 (100% GL), F2 (75% GL: 25% CS), F3 (50% GL: 50% CS), F4 (25% GL: 75% CS), and F5 (100% CS). The kombucha beverages were fermented for several fermentation times, including 8, 11, 14 and 17 days. The antioxidant activity was evaluated using the free radical scavenging activity of DPPH and the FRP assay. Total phenolics, total flavonoids, and total acids were also determined to support the antioxidant properties, employing the Folin Ciocalteu method, Dowd method, and titration, respectively. Antioxidant activity, total phenolics, and total flavonoids were observed to decrease with the addition of GL substrate, with F5 being identified as the optimum formula based on antioxidant properties. In contrast, total acids were found to increase with an increasing proportion of GL substrate. The use of GL substrate did not prove to enhance the antioxidant properties of kombucha, although a well-produced kombucha beverages continued to be yielded by the fermentation process. Further research should be conducted to evaluate other functional properties of kombucha beverage using GL substrate.