Impact of lactic acid fermentation using Lactiplantibacillus plantarum on the physicochemical, phytochemical, and biological properties of Antidesma bunius (L.) Spreng. fruit juice

Lactic acid fermentation is a transformative method, converting polyphenols in plant-based juices into bioactive derivatives. Antidesma bunius (L.) Spreng. fruit, with its high polyphenolic content, presents an opportunity for innovative functional food products. In this study, changes in physicochemical properties, polyphenolic contents, and in vitro biological activities of lactic acid-fermented A. bunius fruit juice were investigated. Fermentation by Lactiplantibacillus plantarum resulted in significant changes in the physicochemical, phytochemical, and biological properties of A. bunius juice. The initial decline and subsequent increase in LAB count aligned with changes in total soluble solids, pH, and total titratable acidity, indicating lactic acid production. Total polyphenols were retained after 48 h, while the total flavonoids increased after 72 h fermentation. The antioxidant activities in terms of H2O2 scavenging and Fe3+ reducing power increased at 24 h and 48 h, respectively. Alpha-amylase inhibition peaked at 48 h fermentation, while α-glucosidase inhibition declined but remained significant. HPLC analysis showed that gallic acid and catechin were the specific bioactive compounds that significantly increased after fermentation. Chemometric analysis showed that gallic acid and catechins had the most positive effect in the improvement of biological activities specifically α-amylase and α-glucosidase inhibition, and H2O2 scavenging activities. The study revealed that lactic acid fermentation of A. bunius fruit juice enhanced its physicochemical properties, polyphenolic content, and specific biological activities.