Variation of the Content and Antioxidant Activity of Active Substances in the Kombucha Fermentation of Mulberry Leaves

With the increasing emphasis on healthy living, Kombucha beverages are becoming more and more popular. Recently, fermented Kombucha with different materials and investigated the efficacy have become hot topics. In this paper, mulberry leaves were used as substrates for Kombucha fermentation. The active substances contents and antioxidant activities of the fermented mulberry leaf infusion were significantly enhanced. After being fermented for 10 days, the total phenolic substances and total flavonoids in the Kombucha fermented mulberry leaf infusion were 7.38 and 12.24 times higher than those in the unfermented mulberry leaf infusion, respectively. While the mulberry leaf infusion that fermented for 6 days had the highest antioxidant capacity. The Ferric (Fe3+) reducing power, ABTS+ radical scavenging capacity, and hydroxyl radical (·OH) scavenging capacity were enhanced by 90.3%, 21.82%, and 46.2%, respectively. In conclusion, after being fermented by Kombucha, the antioxidant properties of mulberry leaf infusion were significantly improved, which will contribute to expanding the subsequent development and application of mulberry leaf.