Abstract: In order to study the effect of short-wave ultraviolet (UV-C) treatment on the color and physiological quality of green pepper, different doses of UV-C were used to treat green pepper to get the best treatment dose. Green bell peppers were treated with short-wave ultraviolet (UV-C) at a dose of 0.25 kJ/m2 to explore the changes in sensory quality, total chlorophyll, carotenoid, flavonoid and total phenol contents, and peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), polyphenol oxidase (PPO), phytoene synthase (PSY) and lycopene-β-cyclase (LCYB) activities during subsequent storage at room or cold temperatures. The results showed that UV-C treatment significantly improved the appearance of green bell peppers, slowed down the degradation of chlorophyll, and reduced the activities of PSY and LCYB at room temperature, affecting the synthesis of carotenoid, inhibiting the increase in carotenoid and flavonoid contents and consequently delaying green bell peppers from turning red. In addition, compared with the control group, UV-C treatment reduced PPO activity, effectively delayed browning, induced the synthesis of phenolics, and enhanced the activities of POD, CAT and APX leading to improved antioxidant capacity. To sum up, UV-C treatment could delay green bell peppers from turning red, maintain the physiological quality during storage, and extend effectively the shelf life of green bell peppers, which will provide a theoretical basis for the postharvest preservation of green bell peppers.

Key words: green bell peppers; short-wave ultraviolet; color; quality