Influence of time and concentration of 1-MCP application on the shelf life of pear 'La France' fruit

'La France' pear (Pyrus communis L.) fruit were exposed to chilling temperature (-1 degreesC) for a week to induce ethylene biosynthesis before they were transferred to 20 degreesC to allow ripening. On 1, 4, or 7 days after the transfer to room temperature, fruit were treated with 20 muL(.)L(-1) 1-MCP for 12 hours. The 1-MCP treatments suppressed ethylene and carbon dioxide production significantly and slowed fruit softening. The shelf life period of fruit with desirable firmness treated with 1-MCP on day 4 was twice that of untreated fruit, with firmness of 1-MCP treated fruit on day I being higher than desirable while that of fruit treated on day 7 was lower than desirable. To determine the optimum 1-MCP concentration for treatment, fruit were exposed to 0.01 to 100 muL(.)L(-1)1-MCP 3 days after the transfer to 20 degreesC. The fruit treated with 1 muL(.)L(-1)1-MCP and less ripened similarly to untreated fruit, having a shelf life of a week. 1-MCP treatments of 10 and 100 muL(.)L(-1) inhibited ethylene and carbon dioxide production, and delayed fruit softening and occurrence of senescent breakdown. The flesh firmness of these fruit maintained suitable eating quality for more than 3 weeks. Our results indicate that 1-MCP treatment of 10 muL(.)L(-1) at 20 degreesC 3 to 4 days after initiation of ripening can extend the shelf life of 'La France' pear fruit. Chemical name used: 1-methylcyclopropene (1-MCP).