3.5. Reducing power
Reducing power is usually evaluated as the antioxidant activity of polyphenols in fruit. As shown in Fig. 6, the treated fruit showed higher reducing power than untreated fruit during storage time, which suggests that the fraction of peels possessed a stronger electron-donating capability in treated fruit. The reducing power of treated fruit increased to a peak on 16th day and then kept at a steady level, which means a stronger antioxidant activity in banana peel tissues during storage.