Enhancing antioxidant activity and flavor profile of buni fruit (Antidesma bunius) kombucha through optimized fermentation conditions

Abstract

Kombucha, a fermented beverage, is a rich source of antioxidants and offers various health benefits. This study explored the potential of Buni fruit (Antidesma bunius) in kombucha production, evaluating its chemical, biological, and antioxidant properties and sensory perceptions of Buni Fruit Kombucha under different fermentation conditions, including sugar concentration (5% and 10%), incubation temperature (4°C and 30°C), and fermentation duration (7 and 14 days). The chemical analysis of Buni fruit kombucha revealed a consistent decrease in pH, a gradual decline in sugar concentration, and an increase in total titratable acidity, highlighting significant changes during fermentation. During the 14-day incubation period, the microbial population dynamics of kombucha showed a significant decrease in total plate count and yeast count, but an increase in beneficial lactic acid bacteria. A significant difference in antioxidant activity was observed, with the highest activity recorded at an IC₅₀ value of 61.32 ± 1.24 µL/mL. Sensory evaluation revealed no significant difference in the colour of kombucha among treatments, but there are significant differences in taste and aroma. The optimal conditions for enhancing antioxidant activity and sensory properties were found to be a 5% sugar concentration and fermentation at 30°C for 7 days. GC-MS analysis revealed the presence of three major compound groups (carboxylic acids, alcohols, and esters). These findings suggest that Buni has a high potential for use in creating functional foods through fermentation, which can contribute to developing functional kombucha beverages using fruit substrates to enhance their benefits and flavour profile.