Antioxidant Activity and Antibacterial Activity of Fermented Coconut Water by L. Plantarum and L. Fermentum

Coconut water (CW) is a nutritious natural beverage, rich in vitamins, minerals, carbohydrates, proteins, and enzymes, and is low in fat and ‎calories. It has been associated with health benefits such as antidiabetic and antihyperlipidemic effects. Fermentation of CW may enhance its ‎bioactivity, particularly its antioxidant properties and inhibition of starch-hydrolyzing enzymes. This study investigated the antioxidant and ‎antibacterial activities of fermented coconut water (FCW) using Lactobacillus plantarum ATCC 8014 and Lactobacillus fermentum ATCC ‎‎14932. After 48 hours of fermentation, the total phenolic content (TPC) increased significantly to 18.91 mg/mL GAE in FCW with 10% ‎allulose and to 25.23 mg/mL GAE in FCW with 10% xylitol. Both fermented samples showed improved ABTS and DPPH radical scavenging activity, although their hydroxyl radical scavenging capacity was lower than that of unfermented CW. Antibacterial assays revealed that ‎FCW with 10% xylitol inhibited the growth of Staphylococcus aureus ATCC 25523, Escherichia coli ATCC 10536, and multiple Salmonel‎la strains. In contrast, FCW with 10% allulose showed no antibacterial activity. These findings suggest that xylitol-enriched FCW may serve ‎not only as a sustainable beverage but also as a natural antioxidant and antibacterial agent for potential applications in functional food, gut ‎health, and food preservation systems‎.