关键词: 莱阳梨, 微真空贮藏, 果肉褐变, 生理机制

Abstract: The changes of CAT, SOD, POD, LOX and PPO activities, H2O2, MDA and polyphenol contents, O2- production rate, membrane permeability and pulp browning index in Laiyang pears during micro-vacuum storage at pressure levels between 500 torr and 600 torr and temperature of (3 ± 1) ℃ were analyzed. The results showed the micro-vacuum storage could significantly improve the activities of SOD, CAT and POD, reduce the activities of LOX and PPO, attenuate the release rate of O2-, decline the contents of H2O2 and MDA, slow down the increase of relative electric conductivity and delay pulp browning, when compared with the atmospheric pressure storage at same temperature (P＜0.05). Similarly, microvacuum storage could reduce reactive oxygen species and lipid peroxidation, maintain membrane structure and function, and delay pulp browning of Laiyang pears by improving endogenous antioxidant enzyme activity and reducing LOX activity. On the other hand, it also could inhibit the metabolism of phenolic substances, and reduce PPO activity and oxygen content in the storage environment, thus delaying pulp browning of Laiyang pears.

Key words: Laiyang pear, micro-vacuum storage, pulp browning, physiological mechanism