Effect Of 1-MCP,MAP On Quality And Core Browning Of ’Yali’ Pear

This thesis utilized the technology of modified atmosphere packaging storage and 1-MCP,and used ’Yali’ pears as experimental material to study impacts of modified atmosphere packaging（MAP）and 1-MCP on quality and cores’ brown stain when pears are stored.The experiment designed four experimental groups,i.e.,control,1-MCP,MAP,1-MCP+MAP.Modified atmosphere packaging（MAP）inhibited the increasing of CO₂ and ethylene concentration in the process of the long term storage,which can be thought to inhibit fruit respiration rate and ethylene releasing rate.Of all the treatments,1-MCP+MAP inhibited the respiration and ethylene rate significantly,but modified atmosphere packaging was not to reduce oxygen concentration obvious.With the extension of storage time the firmness decreased gradually,and the modified atmosphere packaging maintenance firmness better than that of the control group.Soluble solid content increased first and then decreased,and there was a slight upward in shelf life,but changing of the concentration was not obvious.The maintenance of soluble solid content of modified atmosphere packaging was not better than 1-MCP.During storage,titratable acid and vitamin C of pears decreased with the extention of storage time.The titratable acid decreased rapidly in the early storage compared with control,but maintenance better in the late period of storage,and the MAP treatment has the better effect than that 1-MCP+MAP.Compared with other treatments,1-MCP+MAP treatment could effectively maintain the content of vitamin C during the storage and reduced the decay significantly.There was a delay of cores’ brown index with modified atmosphere packaging treatment compared with control.Modified atmosphere packaging inhibited the appearance time of PPO and POD activity.The PPO activity of browning tissue was much higher than that of not browning in the early storage.The POD activity in the browning core tissue was lower than that of not browning.1-MCP+MAP treatment keep a higher SOD activity in the not browning core tissue than all the other treatments.But the POD activity was not significant inhibitory in the late storage.1-MCP+MAP treatment inhibited the rising of MDA content during storage than that of MAP.These results suggested 1-MCP+MAP was an effective strategy to reduce core browning.It inhibited membrane peroxidation,followed by suppression in PPO activity,which decreased the opportunity of PPO enzyme contacting with phenolic compounds.