Effect of Application Timing of Deastringency and 1-Methylcyclopropene Treatments on Fruit Quality Attributes and Physiological Disorders of Two Astringent Persimmon Cultivars during Cold Storage

Abstract

Astringent persimmon (Diospyros kaki Thunb.) fruit are treated with high levels of CO2 or alcoholtreatments to remove bitterness, but additional treatments are needed to maintain fruit firmness forlong-term cold storage. Currently, 1-methylcyclopropene (1-MCP) is widely employed to maintainfruit firmness during cold storage. The objective of this study was to evaluate the effects ofapplication timing of a combination of deastringency and 1-MCP treatments on fruit qualityattributes and the incidence of physiological disorders in the cold-stored astringent persimmon fruitof two cultivars, ‘Tonewase’ and ‘Sangjudungsi’. Fresh weight loss gradually increased in‘Tonewase’, regardless of the timing of the deastringency and 1-MCP treatment. However, the1-MCP treatment alone resulted in the smallest loss of fresh weight compared with the othertreatments in ‘Sangjudungsi’. Fruit firmness was highly maintained by the 1-MCP treatment,regardless of cultivar and application timing. Furthermore, the soluble solids content (SSC) was notaffected by the 1-MCP treatment, but was significantly reduced by the deastringency treatment. TheSSC was highly retained in ‘Sangjudungsi’. The variation in various color variables was greater in‘Sangjudungsi’ fruit than in ‘Tonewase’ fruit. Compared with the other treatments, the combinationof 1-MCP and deastringency treatments significantly reduced all color variables at both of the peelregions of ‘Tonewase’ fruit. Fruit softening, decay, and wilting rates were highest in the combined1-MCP and deastringency treatments in ‘Tonewase’ fruit. On the other hand, ‘Sangjudungsi’ wasrelatively less susceptible to physiological disorders during cold storage. Overall, our results showthat astringent persimmon cultivars require individually-tailored management techniques immediatelybefore cold storage to retain fruit quality.