Chilling injury limits the postharvest handling of many fruit and vegetables. In low-temperature storage trials, control treatments typically consist of fruit stored above the injury threshold. Since chilling exposures for tomato fruit often exceed 2 weeks, controls stored above the threshold continue to ripen, confounding comparisons with fruit maintained at low temperatures. In this study, the ethylene action inhibitor 1-MCP was used to arrest ripening to permit more valid comparisons between fruit stored under the two temperature regimes. Mature-green tomatoes were treated with EthylBloc and then stored at 5 or 15 °C for 2 or 3 weeks after which time the fruit stored at 5 °C were transferred to 15 °C to allow the expression of injury symptoms. 1-MCP inhibited ripening of fruit stored at 15 °C for 2 to 3 weeks. Color, pericarp firmness, and pectin solubilization of MCP-treated fruit stored at 15 °C remained at the values of mature-green fruit, validating their use as controls for these physiological characteristics. After 2 to 3 weeks at 15 °C, MCP-treated fruit resumed normal ripening. Comparing the fruit removed from low-temperature storage with nonripening controls at 15 °C revealed that storage at 5 °C for 2 to 3 weeks decreased the hue (yellowing) but did not affect chroma or lightness, maintained firmness, and did not affect pectin metabolism. Electrolyte leakage increased or remained unaffected by cold storage. MCP-treated fruit had slightly higher electrolyte leakage than non-MCP-treated fruit after storage at either 5 or 15 °C. We conclude that MCP-treated fruit provide adequate controls in experiments designed to study many aspects of low-temperature storage.
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