Submitted to: Postharvest International Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 10/29/2004
Publication Date: N/A
Interpretive Summary: Preservation of apple fruit quality during storage and marketing requires active management of a number of factors. Holding fruit at low temperatures slows ripening and loss of quality, but proper temperature management is often lacking when fruit are displayed in retail markets. Apple ripening is promoted by ethylene, an odorless gas produced by the fruit that stimulates softening and other processes that lead to reduced eating quality. Interfering with the capacity of the fruit to respond to ethylene leads to slower ripening even at relatively warm temperatures and therefore an extended period over which fruit quality remains high. A comppound recently commercialized, 1-methycyclopropene, blocks ethylene perception by apple fruit and results in delayed ripening. Evaluation of the use of this material indicates apple cultivars differ in their response to 1-MCP, but in general the material provides an additional tool to manage apple fruit quality during storage and marketing.
Technical Abstract: Many potential benefits of 1-methylcyclopropene (1-MCP) to manage fruit quality during and/or after storage have been identified. The degree to which ripening processes are inhibited and quality maintenance enhanced by 1-MCP is dependent of several factors. Responses induced by 1-MCP increase with concentration from 0.0l uL L**-1 to 1 uL L**-1 and saturation responses occur in 12 h exposure when 1 uL L**-1 of 1-MCP is applied. In general, fruit temperature during treatment was not critical at the tested concentrations and duration. Experiments conducted with 'Delicious' and 'Gala' apples indicated that fruit harvested after optimum maturity for long-term CA is benefited from use of 1-MCP. However, the potential for long-term storage of late harvested fruit remains low compared to fruit harvested earlier. The duration of responses induced by MCP can also be influenced by an interaction between fruit maturity and treatment concentration. Riper fruit may require higher MCP concentration (1 uL L**-1) for maximum duration of MCP-induced responses. The length of the delay between harvest/cooling and treatment is another critical factor determinant of 1-MCP efficacy. Experiments conducted with 'Granny Smith' and 'Gala' apples indicated that maximum control of fruit softening, superficial scald and senescent breakdown is achieved by treatment as soon after harvest as possible.