ScholarWorks@중앙대학교

초록

The early-season cultivar of ‘Changjo’ Asian pear is popular in commercial cultivation for its premium fruit quality at harvest and after cold storage. However, the effects of fruit maturity at harvest time and postharvest 1-methylcyclopropene (1-MCP) treatment have not yet been determined. The fruit quality attributes, targeted metabolites, and non-enzymatic and enzymatic antioxidant scavenging metabolism by the combination effects of fruit maturity and postharvest 1-MCP treatment, were evaluated in the fruit of ‘Changjo’ Asian pears stored at 0.5°C and 90% relative humidity for 6 months. The fruits were harvested at two maturity stages: immature and mature and treated with 1 μL∙L-11-MCP at 22°C for 16 h. Fruit fresh weight loss, soluble solids content, and ethylene production rate were highest in 1-MCP-treated mature fruit during cold storage, compared with the other treatment groups. Peel lightness and yellowness increased, and hue angle decreased during storage, despite 1-MCP treatment and fruit maturity. However, the cortex colour variables were mostly higher in 1-MCP-treated fruit than in untreated fruit during cold storage. Fructose and glucose increased during cold storage, irrespective of 1-MCP treatment or maturity; however, sorbitol was higher in immature than in mature fruits, even with 1-MCP treatment. Levels of malic and shikimic acids were higher in immature than in mature fruit, regardless of 1-MCP treatment during cold storage. In immature fruit, arbutin, ferulic acid, quercetin, epicatechin, gallic acid, caffeic acid, and total phenolic compounds increased in untreated fruit but catechin, rutin, and p-coumaric acid increased in 1-MCP-treated fruit. In mature fruit, the level of quercitrin was highest in 1-MCP-treated fruit during cold storage. Superoxide anion radicals and dehydroascorbic acid increased in untreated immature fruit, whereas hydrogen peroxide was higher in untreated mature fruit. Malondialdehyde, reduced glutathione, and glutathione oxidized contents increased in 1-MCP-treated mature fruit during cold storage. The enzymatic activities such as phenylalanine ammonia-lyase, polyphenol oxidase, superoxide dismutase, catalase, glutathione peroxide, and glutathione S-transferase showed higher activity in 1-MCP-treated immature fruit, whereas ascorbate peroxidase, monodehydroascorbate reductase, and glutathione reductase activities increased in 1-MCP-treated mature fruit. Overall, the quality of ‘Chanjo’ Asian pear in long-term cold storage is more strongly affected by fruit maturity at harvest rather than by postharvest 1-MCP treatment.

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