EVALUATING POLYPHENOL, FLAVONOID CONTENT AND ANTOXIDANT CAPACITY OF PURPLE STAR APPLE FERMENTATION (Chrysophyllum cainito)

Abstract

Purple star apple (Chrysophyllum cainito) has biological activities with antioxidant properties and is widely grown in the provinces of the Mekong Delta. The study aimed to evaluate the polyphenol (the Folin-Ciocalteu method), flavonoid content (the AlCl₃ colorimetric method) and antioxidant capacity (the DPPH method) of star apple juice before and after fermentation. The highest polyphenol and flavonoid content in the purple star apple fruit juice sample after 10 days of fermentation were at 5.57 mg GAE/mL and 44.661 mg QE/mL, respectively, higher than the pre-fermentation juice sample at 2.416 mg GAE. /mL and 16.088 mg QE/mL. After 10 days of fermentation, the strongest antioxidant capacity for the three free radical removal experiments DPPH, ABTS and Fe³⁺ ion reduction was 0.319%, 0.147% and 0.539%, respectively. The fruit juice after fermentation has higher antioxidant capacity than the fruit juice before fermentation.