Effect of fermentation time on physicochemical and sensory quality of kombucha tea

Abstract:

While industrial soft-drink consumption continues to rise, a contrasting trend has emerged: fermented beverages like kombucha are gaining popularity among health-conscious consumers who value probiotic content and low sugar. This research investigated how fermentation duration (0, 5, 10, 15, and 20 days) influenced the physicochemical properties, organic acid profile, microbial dynamics, and sensory acceptability of kombucha prepared from black tea using a Symbiotic Culture of Bacteria and Yeast (SCOBY) at the Bogor Institute of Agricultural Technology, Bogor, West Java during February-March 2023. A single-factor completely randomised design with four replications was adopted. As fermentation progressed, pH declined from 6.8 to 2.7, total acidity rose from 0.08 to 1.28%, total sugars dropped from 10.1 to 3.2%, and total phenolic content increased from 84 to 213 mg GAE L⁻¹. Acetic acid was the dominant organic acid (42.1% of total), followed by glucuronic acid (28.3%). Sensory evaluation showed that 10-day kombucha scored highest for overall acceptability (8.1 on a 9-point scale), offering a balanced sweet-sour profile. Fermentation beyond 15 days produced an excessively vinegary taste that panellists rejected. Ten days appears to be the optimum fermentation window for a palatable, antioxidant-rich kombucha from black tea under Bogor's ambient conditions.