Abstract

The effects of ultraviolet-C (UV-C) illumination on postharvest quality and bioactive compounds of yellow bell pepper during refrigerated storage were investigated. The yellow bell pepper fruit were illuminated with three different UV-C dosages, 2.2, 4.4 and 6.6 kJ m^-2 and then stored at 12 ± 1°C for 15 days. UV-C illumination at 6.6 kJ m^-2 showed the best results in maintaining firmness and reducing the increase in weight loss and electrolyte leakage (EL) throughout storage. No significant differences in both weight loss and firmness were detected in the fruit illuminated with UV-C at 2.2, 4.4 kJ m^-2 and the control fruit over storage. UV-C illumination had no effect on the changes in tristimulus colours (lightness, L* value, and yellowness, b* value), ascorbic acid (AsA) and total phenol (TP) contents of the yellow pepper fruit and these remained constant over storage. UV-C illumination at 6.6 kJ m^-2 enhanced total carotenoid (TC), total flavonoid (TF) contents, antioxidant capacity and the activities of antioxidant enzymes including catalase (CAT), superoxide dismutase (SOD), guaiacol peroxidase (G-POD) and ascorbate peroxidase (AsA-POD) when compared to the control fruit. In conclusion, UV-C illumination prevented the loss of firmness, weight and EL increase and enhanced biologically active compounds, especially, antioxidants, in yellow bell pepper fruit.

Key words: Yellow bell pepper fruit, UV-C illumination, postharvest quality, bioactive compounds.