Abstract:

Kombucha, a fermented beverage, is popular for its prophylactic and therapeutic properties. Kombucha is a traditionally black tea infusion fermented with a symbiotic bacteria and yeast consortium (SCOBY) under aerobic conditions for 7-21 days. However, the beneficial properties of kombucha vary according to the substrate kind, fermentation conditions, and SCOBY consortium. The present study has screened the physicochemical, bioactive, antimicrobial, and sensory properties of beverages produced by fermenting black, green, rosehip, and licorice tea infusions with kombucha starter culture for 21 days. Tea infusions before and after fermentation; pH value, titratable acidity (TA), pellicle weight, color values (L*, a*, b*, ΔE), total phenolic content (TPC), antioxidant capacity against DPPH (2,2-diphenyl-1- picrylhydrazil) radicals, and antimicrobial activity was measured. Antimicrobial activity is applied to various foodborne pathogens such as Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and C. albicans with based disc diffusion method and spectrophotometric technique. In this study, tea type statistically affected all parameters except pH in kombucha beverages (p<0.05). The highest TPC and antioxidant activity were determined in the green tea kombucha sample. All kombucha beverages, especially those prepared by fermentation of licorice and green tea infusions, showed the highest antimicrobial potential against E. coli and S. aureus, respectively. Consequently, it is vital to prefer kombucha fermented with SCOBY instead of consuming beverages prepared with various plants' infusions to increase many beneficial properties and provide additional benefits.

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