Kombucha and its nutrients: a qualitative analysis of vitamin C comparing green tea and a plant-based drink fermentation

Introduction: Kombucha, a plant-based beverage originating from China over 2000 years ago, is primarily known for its health benefits attributed to catechins (polyphenols) present in Camellia sinensis leaves. The fermentation of green tea by a colony of bacteria and yeast cultured on a cellulose film called SCOBY (Symbiotic Culture of Bacteria and Yeasts) produces kombucha, including numerous biochemical changes and generating bioactive compounds that are crucial for health. This study aimed to compare the antioxidant capacity and physicochemical parameters of green tea with kombucha to determine changes in vitamin C levels before and after fermentation. Material and Methods: Experimental data were collected manually, reflecting common practices among kombucha producers worldwide. The following variables were evaluated: pH, density, room temperature during fermentation, alcohol content (%), ⁰BRIX (soluble solids), and vitamin C presence. Results: A statistical analysis using PAST software indicated significant differences (p < 0.01) in density and ⁰BRIX decrease by the 6^th day of fermentation (indicating active fermentation). The fermented drink exhibited a notable 31% decrease in pH and a substantial 65% increase in vitamin C levels (which increased by 17% (p < 0.01) after the second fermentation cycle) compared to green tea. Conclusion: Thus, the study results indicate that fermentation leads to the formation of important organic acids and significantly increases vitamin C levels in unflavored kombucha obtained from the first and second fermentation cycles.