Effect of Malolactic Fermentation Conditions on Bioactive Compounds and Antioxidant Capacity of Red Dragon Fruit (Hylocereus polyrhizus) Wine

Abstract

This study was conducted to evaluate the impact of malolactic fermentation (MLF) by Lactobacillus plantarum on the physicochemical and bioactive characteristics of red-fleshed dragon fruit (Hylocereus polyrhizus) wine. A 2-factor completely randomized design was applied, including 3 fermentation temperatures (20, 25 and 30 °C) and 3 bacterial inoculum levels (105106and 107CFU/mL). Parameters monitoring over 7 weeks included pH, malic acid, lactic acid, total polyphenol content, betacyanin, and antioxidant activity (IC50-DPPH). The results indicated that 20 °C combined with an inoculum of 106CFU/mL represented the favorable condition, ensuring efficient malic acid degradation (0.16 g/L after 7 weeks), increased pH (4.06), while maintaining high levels of betacyanin (174 mg/L) and polyphenols (98.5 mg GAE/L), thereby preserving antioxidant capacity (IC50= 13.1% v/v). These findings provide a scientific basis for optimizing the production process of red-fleshed dragon fruit wine, aiming to develop products with high sensory and bioactive value.