Effects of 1-methylcyclopropene and modified atmosphere packaging on fruit quality and superficial scald in Yali pears during storage

The Yali pear（Pyrus bretschneideri Rehd.） is susceptible to superficial scald during prolonged cold storage and at shelf life. This study investigated the effects of 1-methylcyclopropene（1-MCP） and modified atmosphere packaging（MAP） on changes of fruit quality and superficial scald during cold storage and at shelf life in Yali pear. Compared with MAP, the combination of MAP and 1-MCP（MAP＋1-MCP） treatment reduced the carbon dioxide and ethylene content inside the packaging bag. The 1-MCP, MAP, and MAP＋1-MCP treatments reduced the superficial scald index, malondialdehyde content, O2^-· production rate and relative conductivity and inhibited the accumulation of α-farnesene and conjugated trienes in the peel. 1-MCP and MAP＋1-MCP treatments maintained a higher phenolic content and enhanced the catalase and superoxide dismutase activities in the fruit, while reduced activities of lipoxygenase and polyphenol oxidase in the peel preceding the onset of superficial scald. Comprehensive analysis indicated that the MAP＋1-MCP treatment is the most effective method tested for improving the quality of Yali pears during cold storage and at shelf life.

Inhibitory Effects of 1-MCP and DPA on Superficial Scald of Dangshansuli Pear

Dangshansuli pear is one of crisp pears and has a non-climacteric respiratory pattern. Dangshansuli pear fruits were treated with 1 000 or 2 000 μL L-1 diphenylamine （DPA） for 1 min, or with 0.5 μL L-1 1-methylcyclopropene （l-MCP） for 12 h before cold storage at （2±0.5）℃ for up to 210 d. Incidences of superficial scald and related physiological indexes were investigated during storage. The results showed that superficial scald occurred in control fruit with a rate of over 90% after 210 d at cold storage plus 10 d at room temperature. Treatments with 1 000 and 2 000 μL L-1 DPA and 0.5 μL L-1 l-MCP inhibited the accumulation of a-farnesene, conjugated trienes, total phenolic contents, and malondialdehyde （MDA） during storage. The treatments also decreased leakage of cell membrane and the activity of polyphenol oxidase （PPO） in the peel. These results indicate that 1-MCP and DPA treatments inhibit and postpone the occurrence of superficial scald of Dangshansuli pears remarkably in cold storage and post-storage shelf life, respectively, while the mechanisms were different. The results above may provide a theoretical evidence for the agriculture production.