Postharvest hot air and hot water treatments affect the antioxidant system in peach fruit during refrigerated storage

Peach fruit are susceptible to chilling injury (CI) during low temperature storage. In this study, the effect of hot air (HA, 38 °C for 3 h) and hot water (HW, 48 °C for 10 min) treatments on CI, fruit quality, reactive oxygen species (ROS) and antioxidants in peach fruit during storage at 4 °C was investigated. The results indicated that HA or HW treatments maintained fruit quality, decreased Reactive oxygen species (ROS) and enhanced antioxidants activity of fruit. However, HW was more effective than HA in alleviating internal browning (IB) symptoms in fruit. HW treatment may be easier to affect the antioxidant system in peach fruit due to the higher heat transmission in water. HA treatment had no effect on either AsA metabolism or GSH metabolism. However, HW enhanced the AsA metabolism in the early stage of storage and the GSH metabolism in the late stage of storage. Enhanced AsA-GSH metabolism and up-regulated expressions of PpaSOD5, PpaCAT1 and PpaAPX2 in the HW treated fruit might play an important role in maintaining the lower ROS level and IB index during refrigerated storage.