Abstract: No chilling injury symptom appeared on green pepper fruits and membrane permeability little changed during storage at 9℃ for 8 weeks. But the fruits stored at 2℃ had slight chilling injury symptom only after 1 week and suffered severe chilling injury when the storage duration surpassed 4 weeks with rapid increase in membrane permeability. Compared to pepper fruits at 9 ℃, SOD (Superoxide dimutase)activity of fruits at 2℃ was lowered and CAT (catalase)activity of them decreased much more than SOD. POD (peroxidase)activity of fruits at chilling temperature was lower than that of fruits at 9℃, but increased abruptly to a climax in 7th week. 50℃ hot water dip 10 minutes or 53℃ 5 minute (prestorage heat treatment) significantly alleviated chilling injury and manifestly hindered increase in membrane permeability of pepper fruits stored at 2℃. Compared to control, 50℃ heat treatment had no obvious effect on SOD activity and 53℃ significantly improved SOD activity in week 3, week 4 and week 5. Both heat treatments significantly elevated CAT activity and the effect of them in increasing CAT activity was more obvious than SOD. POD activity of fruits heated declined slowly without significant drop and abrupt increase happened in control fruits during storage at 2℃. It suggested that the chilling injury of green pepper fruits during storage at chilling temperature had relationship with decrease in activated oxygen scavenging enzyme activity, especially the decrease in CAT, resulting in misbalanced metabolisms of activated oxygen. Prestorage heat treatment alleviated chilling injury of green pepper fruits by elevating the activity of activated oxygen scavenging enzyme, especially CAT, maintaining metabolism balance of activated oxygen and therefore preventing mem- brane lipid peroxidation.

Key words: green pepper fruits, chilling injury, anti-chilling injury, activated oxygen, storage