Combined effect of temperature and controlled atmosphere on storage and shelf-life of 'Rocha' pear treated with 1-methylcyclopropene.

The combination of temperature and atmosphere composition for storage of Pyrus communis L. 'Rocha' treated with 1-methylcyclopropene was investigated. Fruits treated with 312 nl l(-1) 1-methylcyclopropene were stored at 0 ℃ and 2.5 ℃ in air and controlled atmosphere (CA) (3.04 kPa O2+ 0.91 kPa CO2). Fruits were removed from storage after 14, 26 and 35 weeks, transferred to shelf-life at approximately 22 ℃ and assessed for ripening and quality, symptoms of superficial scald and internal browning and the accumulation of biochemical compounds related to scald after 0, 1 and 2 weeks. Superficial scald occurred only in fruits stored for 35 weeks in air at 2.5 ℃. Levels of conjugated trienols and α-farnesene increased during the first 26 weeks in storage, remaining constant thereafter. During shelf-life, conjugated trienols were higher in fruits stored in air at 2.5 ℃. Internal browning developed in shelf-life after 26 weeks at 2.5 ℃. Pears in air at 2.5 ℃ were not able to stand a 2-week shelf-life after 35 weeks of storage, while fruits stored at 0 ℃ under CA ripened slowly after the same storage period. The retention of firmness during shelf-life of 1-methylcyclopropene-treated 'Rocha' pear can be overcome by elevating the storage temperature from 0 ℃ to 2.5 ℃, but CA is a required complement to avoid excessive softening after long-term storage. The ratio carotenoid/chlorophyll increased during storage and shelf-life, as plastids senesced. CA reduced the rate of chlorophyll loss during the first 14 weeks in storage, but its effect was reduced afterwards. 'Rocha' pear treated with 1-methylcyclopropene had a similar post-harvest behaviour during long-term storage at 0 ℃ in air or at 2.5 ℃ under CA.