STUDY ON CHEMICAL AND MICROBIAL PROFILES OF KOMBUCHA AND ITS INTERRELATIONSHIPS

Abstract

Kombucha, a fermented tea beverage, is produced through a dynamic interaction between yeast and bacteria, resulting in the development of organic acids, ethanol, and bioactive compounds that define its unique properties. This study assessed the chemical and microbial profile during kombucha fermentation through six microorganisms — Saccharomyces sp. (Y1), Schizosaccharomyces sp. (Y2), Saccharomyces boulardii (Y3), Gluconobacter (B1), Acetobacter sp. 1 (B2), and Acetobacter sp. 2 (B3) with the aim of establishing an optimal balance in key parameters, including pH, titratable acidity (TA), degree Brix, and alcohol concentration. A Plackett-Burman design was employed to analyze 12 experimental runs, designated as S1 to S12, over a fermentation period of 15 days. Parameters such as pH, TA, Brix, alcohol content, and CFU/ml were monitored at intervals of 0, 5, 8, 12, and 15 days. Statistical analyses, including pareto plots, main effect plots, and interaction plots, were performed using Minitab software, while sensory evaluation was analyzed using GenStat. Y2 emerged as the most influential strain, driving rapid pH reduction, Brix depletion, and Titratable Acidity increase, facilitated by its ethanol production and conversion to acetic acid by Acetic Acid Bacteria (AAB). Y1 ensured that the pH fell within the desired range and moderated ethanol levels, while Y3 contributed to a balanced reduction in sugar and moderated acidity. B1 and B2 played pivotal roles in acetic acid production, regulating pH and preventing over acidification. B3 demonstrated significant acetic acid oxidation and ethanol stabilization. Notably, some runs, like S11, displayed high alcohol content despite low microbial counts, highlighting complex metabolic dynamics. Among the samples, S8 stood out as the most preferred based on appearance, aroma, taste, and overall acceptability in sensory analysis. The study underscores the importance of strategic microbial co-culturing, revealing synergistic combinations to enhance fermentation efficiency and sensory quality. These findings contribute to optimizing kombucha fermentation processes to ensure product quality, compliance with alcohol regulations, and consumer satisfaction.