Optimal storage temperature and 1-MCP treatment combinations for different marketing times of Korla Xiang pears

Maintenance of green color is the primary indicator of quality in the market evaluation of Korla Xiang pears at present and can generally be achieved through early harvesting and decreasing the storage temperature, but the fruit quality was reduced by early harvesting, and the decreasing storage temperature increased the risk of chilling injury. The objectives of this study were to determine the optimal storage parameters for different storage times and to find ways to preserve the green skin color of pears. Specifically, we analyzed the effects of the ethylene inhibitor, 1-methylcyclopropene(1-MCP), combined with low temperature on quality and maintenance of the green color of Korla Xiang pears during storage. We found that 1-MCP and/or low temperature reduced the loss of green color at 20°C after being removed from cold storage. In addition, 1-MCP significantly inhibited the decline of titratable acid and ascorbic acid but had no significant effect on fruit firmness and total soluble solids. Low temperature with or without 1-MCP inhibited the release of ethylene, inhibited the decline in the stalk preservation index, inhibited the increase in decay rate and weight loss rate during storage, and inhibited the increase in the core browning index after 225 days of storage. Different storage temperatures had different effects on the quality of Korla Xiang pears. Despite inhibiting ethylene release, a storage temperature of –1.5°C increased the respiration rate. Storage at –1.5°C caused core browning early during storage due to chilling injury, whereas at 2°C core browning occurred late during storage due to senescence. In late storage, 1-MCP had no significant effect on the maintenance of Korla Xiang pear quality at 2°C. Based on these results, we determined the optimal combinations of low temperature and 1-MCP treatment to maintain pear quality while avoiding chilling injury. For different marketing times, the optimal conditions for storage until New Year's Day(a storage duration of 90 days) are 2°C or 1-MCP combined with 2°C. For storage until the Spring Festival(a storage duration of 150 days), the optimal conditions are 0°C or 1-MCP combined with 0°C, and for storage until May(a storage duration of 225 days), the best conditions are 1-MCP combined with –1.5°C.