Postharvest physiological brown of Hosui pear stored in different O2 and CO2 composition conditions.

Activities of two enzymes(peroxidase,polyphenol oxidase),and contents of malonaldehyde and total phenol of Hosui pear stored in different gas compositions were investigated to seek a effective measure,which could reduce brown of Hosui pear.Results showed no browning symptom appeared in fruit flesh during the whole storage (15 d).Peel of controlled atmosphere(CA)treatment and refrigerated fruits appeared browning symptom from 60 days of storage,no significant differences were observed in CA and refrigerated treatments for peel browning before 120 days of storage,while CA treatments could significantly alleviate the peel browning,inhibit PPO and POD activities and reduce total phenol content of fruit peel during 120～150 days of storage.CA treatment could postpone the time of core browning of fruit,and the CA storage at (8%～10%)O2+3% CO2 could inhibit core browning of fruit completely,in comparison with cold storage.CA treatment could also reduce PPO activity,decrease malonaldehyde and total phenol content of fruit core.The controlled atmosphere treatment of (8%～10%)O2+1% CO2 increased POD activity of fruit core,while the effect of (8%～10%)O2+3% CO2 treatment on POD activity were not significant.Therefore,controlled atmosphere storage alleviated organizational brown mainly through reducing activities of PPO,POD and total phenol content of fruit peel of Hosui pear,and the treatment of (8%～10%)O2+3% CO2 were more effective for controlling browning relative factors.