Determination of Potential Antimicrobial Activities of some Local Berries Fruits in Kombucha Tea Production

Abstract In this study, physicochemical, microbiological, and sensory properties, antibacterial and antifungal effects of kombucha teas produced with some small berry fruits (blackberry, raspberry, and red goji berry) were investigated. During fermentation, titratable acidity and pellicle biomass weights increased whereas water activity, brix, viscosity, L* and b* values decreased. At the end of fermentation, the highest minerals determined in the samples were potassium and magnesium. Also, catechin and gallic acid were detected in all samples. Samples produced with blackberry were the most appreciated ones in all criteria. The highest antibacterial and antifungal effects were determined in samples containing blackberries on Staphylococcus aureus and Rhizopus nigricans (24.36 and 20.53 mm zone diameters). The antibacterial effect, MIC, and MBC values (0.023 and 0.016 mg/L) on Staphylococcus aureus. Regarding the antifungal effect, the MIC and MFC values were determined in tea produced with blackberry on Rhizopus nigricans with 0.035 mg/L, and 0.023 mg/L.

Protective effect of kombucha tea against tertiary butyl hydroperoxide induced cytotoxicity and cell death in murine hepatocytes.

Kombucha (KT), a fermented black tea (BT), is known to have many beneficial properties. In the present study, antioxidant property of KT has been investigated against tertiary butyl hydroperoxide (TBHP) induced cytotoxicity using murine hepatocytes. TBHP, a reactive oxygen species inducer, causes oxidative stress resulting in organ pathophysiology. Exposure to TBHP caused a reduction in cell viability, increased membrane leakage and disturbed the intra-cellular antioxidant machineries in hepatocytes. TBHP exposure disrupted mitochondrial membrane potential and induced apoptosis as evidenced by flow cytometric analyses. KT treatment, however, counteracted the changes in mitochondrial membrane potential and prevented apoptotic cell death of the hepatocytes. BT treatment also reverted TBHP induced hepatotoxicity, however KT was found to be more efficient. This may be due to the formation of antioxidant molecules like D-saccharic acid-1,4-lactone (DSL) during fermentation process and are absent in BT. Moreover, the radical scavenging activities of KT were found to be higher than BT. Results of the study showed that KT has the potential to ameliorate TBHP induced oxidative insult and cell death in murine hepatocytes more effectively than BT.