Ngày nhận bài: 16-11-2018 / Ngày duyệt đăng: 06-04-2019
Guava (Psidium guajavaL.), a tropical plant, is used as food and medicine to cure certain illnesses. This study aimed to examine changes in physiological indices, phenolic contents, and antioxidant activitiesof two guava cultivars, cv. Dong Du and cv. Dai Loan, during ripening. Guava fruits were harvested at four different stages, namely mature green, color turning, ripe, and overripe. Phenolic content and antioxidant activity were determined using the Folin-Ciocalteu and DPPH methods, respectively. The results showed that during maturation, the diameter and weight ofDong Du cultivar significantly increased, while these variables of the Dai Loan cultivar did not significantly change. Regarding the color index, the L, a, and b values increased, whereas the hue value decreased in both cultivars during fruit ripening. Ascorbic acid content increased during ripening and no difference was found betweentwo cultivars. The phenolic content and antioxidant activity declined during maturation and these values were higher in the Dong Du cultivar compared to the Dai Loan cultivar. The phenolic content and the antioxidant acitivity were strongly correlated (P<0.001), indicating that the phenolic compounds were the major antioxidants in guavafruits. The ripe stage would be a suitable time to harvest fruits for consumption of guava products.
