The interspecific pear cultivar ‘Greensis’ has become a highly demanded pear cultivar due to its unique flavor of sweetness, crispness and juiciness. This study evaluated the postharvest storage quality of ‘Greensis’ pear at two maturity levels, treated with the 1 µL L-1 1-methylcyclopropene (1-MCP), pre-storage conditioning (PSC), and the combination treatment of 1-MCP and PSC before long term cold storage at 0.5 °C for 6 months. Both the incidence and severity of physiological disorders, such as cortex and core browning, were significantly reduced in PSC treatments, meanwhile, the severity levels of cavity were notably lower in treated fruit compared to untreated (control) fruit. Among the targeted metabolites, soluble carbohydrates and organic acids particularly, sucrose and shikimic acid were lower in mature fruit than immature fruit. Moreover, the contents of glucose, fructose, malic acid and shikimic acids were higher in PSC treated fruit than the other treatments especially in mature fruit. The branched-chain amino acids, including isoleucine and leucine, glutamic acid and phenylalanine, in all treatments were lower in immature fruit, meanwhile, methionine was higher in mature fruit. Additionally, in immature fruit, the contents of asparagine, serine, threonine and proline in the combination treatment of 1-MCP and PSC were higher than the other treatments. In addition, the phenolic contents of all treated fruit were higher in immature than mature fruit especially in chlorogenic acid, arbutin, caffeic, p-coumaric acid, and gallic acid after long term cold storage. Overall, these results suggested that the higher accumulation of phenolic compounds and specific amino acid contents in immature fruit play as a defense mechanism and enhances cold stress tolerance during long-term cold storage. Furthermore, PSC treatments effectively maintain the postharvest fruit quality by reducing the physiological disorders in cold stored ‘Greensis’ pear.
