Kombucha Fermentation Enhanced the Flavor and Functional Properties of Blackberry Juice Beverage

Kombucha has been shown to improve the flavor profile and nutritional value of fermented beverages. In this study, blackberry juice beverage fermented with kombucha consortium (BJBF) was prepared at 28°C and 37°C, and the impact of fermentation temperature on the physicochemical properties and volatile flavor compounds of BJBF was analyzed. Results showed that the counts of acetic acid bacteria and yeast in blackberry juice beverage (BJB) significantly increased after fermentation, and these microorganisms exhibited better growth at 28°C. Compared with unfermented blackberry juice beverage (UBJB), fermentation by the kombucha consortium decreased the pH value and contents of sugar, anthocyanins, citric acid, and malic acid in BJB, while increasing color parameters and contents of lactic acid and acetic acid. In addition, BJBF showed an increased glucuronic acid content, which is a key health-promoting component in the kombucha consortium. Fermentation by the kombucha consortium at 28°C remarkably enhanced the flavor of BJBF, where alcohols, esters, and aldehydes served as key contributors to its characteristic flavor profile. The obtained results indicated kombucha consortium fermentation could effectively enhance the health-promoting potential and flavor profile of BJB, with fermentation temperature and time being identified as crucial factors.