366 Effects of Postharvest Heat, Methyl Jasmonate Dip, and 1-Methylcyclopropene Vapor Treatments on Quality Maintenance and Decay Development in `Golden Delicious' Apples

Abstract

Air heat, methyl jasmonate dip, and vapor treatments with the ethylene action inhibitor 1-methylcyclopropene (MCP) were used to evaluate their effects on ripening-related characteristics and susceptibility to fungal decay in `Golden Delicious' apples (Malus ×domestica Borkh.) through 5 months of storage at 0 °C and ripening at 20 °C for 7 days. Preclimacteric fruit were treated with MCP vapor at a concentration of 1 μL•L-1 for 18 h at 20 °C, 38 °C air for 4 days, methyl jasmonate dip at concentrations of 10-5 and 10-4 for 3 min at 20 °C, combinations thereof, or left untreated before storage in air at 0 °C. One set of untreated fruit was stored in a controlled atmosphere of 1.5 O2 and 2.5% CO2 at 0 °C. The MCP treatment and CA storage delayed ripening, as indicated by better retention of green peel color and flesh firmness, and the reduced respiration, ethylene production rates, and volatile (both flavor- and superficial scald-associated) levels that were observed upon transferring the fruit to 20 °C. The MCP treatment followed by air storage delayed ripening more than CA storage. The heat treatment also delayed ripening but hastened skin yellowing. While methyl jasmonate dips had no significant effect on ripening, they were the only treatments used that reduced the incidence of postharvest decay and discolored the surface of some fruit. The results indicate that MCP may provide an effective alternative to CA for maintaining quality during cold storage and ripening. The results also indicate that methyl jasmonate dip treatment may reduce postharvest decay of fruit while maintaining fruit quality.