Application of lactic acid bacteria in kombucha fermentation

Kombucha, traditional fermented beverage, is typically prepared by fermenting sweetened black tea using tea fungus (symbiosis of acetic acid bacteria and yeasts). Because of useful effects of lactic acid bacteria (LAB) as well as L- and D-lactic acid, LAB suspension of natural isolates was added in fermentation broth 48 hrs. after beginning of the process. Fermentation process and basic parameters were measured and compared with control (traditional) Kombucha. Changes in pH values and titratable acidity, as well as number of yeasts, acetic acid bacteria and LAB in beverages with added LAB strains did not have significant differences compared with control Kombucha. In other words, usual course of Kombucha fermentation was maintained. Content of L- and D-lactic acid in beverages with added LAB strains was noticeably higher than in control Kombucha. LAB strain 2 produced much more lactic acid although its number decreased during fermentation compared with strain 1 which kept almost the same number even during storage (10 days in refrigerator). LAB viability during Kombucha fermentation and their lactic acid production are not directly connected and can be considered as strain-resistant characteristics.