ABSTRACT
Persimmons are one of the most important export fruits in South Korea, where several tons are exported across the globe each year. In this study, the quality attributes of 'Wonmi' persimmon fruits were evaluated during an export simulation at 0 °C, 10 °C, and 24 °C with a combination of 1-Methylcyclopropene (1-MCP) and modified atmosphere packaging (MAP) treatments. The relative humidity during the export simulation was greater at room temperature (75-92%) and 0 °C (85% to 93%) than at 10 °C (42% to 60%). The results show that the application of 1-MCP and MAP treatments during the export simulation were effective in delaying the ripening of 'Wonmi' persimmons by reducing respiration and ethylene production. The suppressed expression of ethylene synthesis genes and cell wall modification genes reduced the ethylene production and maintain the fruit firmness, respectively. In addition, 1-MCP and MAP treatments were effective in maintaining SSC and color of 'Wonmi' persimmon fruits during the export simulation. Thus, by adopting these treatments, the overall quality of persimmon exports from South Korea can significantly improve.
ABSTRACT
The influence of the preharvest application of chitosan on physicochemical properties and changes in gene expression of 'Garmrok' kiwifruit during postharvest cold storage (0 °C; RH 90-95%; 90 days) was investigated. Preharvest treatment of chitosan increased the fruit weight but had no significant effect on fruit size. The chitosan treatment suppressed the ethylene production and respiration rate of kiwifruit during the cold storage. The reduction of ethylene production of chitosan-treated kiwifruit was accompanied with the suppressed expression of ethylene biosynthesis genes. Moreover, preharvest application of chitosan diminished weight loss and delayed the changes in physicochemical properties that include firmness, soluble solids content, titratable acidity, total sugars, total acids, total phenols, and total lignin. As a result, the preharvest application of chitosan delayed the maturation and ripening of fruit. Expression of genes related to cell wall modification was down-regulated during the early maturation (ripening) period, while those related to gene expression for lignin metabolism were up-regulated at the later stages of ripening. These results demonstrate that the preharvest application of chitosan maintained the fruit quality and extends the postharvest life of 'Garmrok' kiwifruit, possibly through the modulation of genes related to ethylene biosynthesis, cell wall modification, and lignin metabolism.
