Development and physicochemical characterization of tomato kombucha formulated with banana lactic acid fermentate

In this study, tomato kombucha was produced by combining a tomato fermented extract containing green tea with a lactic acid fermented extract derived from banana, followed by fermentation and maturation. The aim was to investigate its physicochemical properties and biological activities to assess its potential as a functional food material. Physicochemical analysis revealed that tomato kombucha contained 4.5 °Brix of soluble solids, a pH of 3.12, and a total acidity of 3.02%. The organic acid composition and total polyphenol content were higher than those of the individual tomato fermented extract and banana lactic acid fermented extract, indicating that mixed fermentation enhanced the levels of bioactive compounds. Antioxidant activity was confirmed through multiple assays. Tomato kombucha exhibited stronger DPPH radical scavenging activity than other groups, over 85% ABTS․+ scavenging activity, reducing power comparable to positive controls, and more than 90% hydrogen peroxide scavenging activity. In addition, it demonstrated high tyrosinase inhibitory activity. Cellular experiments using 3T3-L1 preadipocytes revealed that tomato kombucha suppressed lipid accumulation during differentiation without cytotoxic effects. These findings indicate that tomato kombucha possesses antioxidant, tyrosinase inhibitory, and anti-adipogenic properties, supporting its potential as a promising functional beverage and food ingredient.