Abstract: Abstract：The effects of direct cooling and gradual cooling on chilling injury，fruit quality and active
oxygen metabolism in kiwifruit（Actinidia deliciosa‘Xuxiang’）during cold storage were investigated. The
results showed that the gradual cooling treatment significantly reduced chilling injury index and chilling
injury incidence，maintained higher accepted fruit percentage and shelf-life quality，and inhibited the
accumulation of malonaldehyde and the increase in membrane permeability. Moreover，the gradual cooling
treatment maintained higher activities of superoxide dismutase，catalase and ascorbate peroxidase，and
lower activity in lipoxygenase than direct cooling fruit during the storage，and kept lower levels of
superoxide anion production rate and H2O2 content. These results indicate that gradual cooling treatment
retard chilling injury in ‘Xuxiang’ fruit which may be related to enhancing the activities of active oxygen
scavenging enzymes and reducing the accumulation of active oxygen. The gradual cooling（10 ℃→5 ℃
for 2 days→2 ℃ for 2 days→0 ℃ ± 0.5 ℃）had a better effect.

Key words: kiwifruit, postharvest, chilling injury, cooling, active oxygen metabolismpostharvest, chilling injury, cooling, active oxygen metabolismpostharvest, chilling injury, cooling, active oxygen metabolism