The kiwi fruit (Actinidia deliciosa cv. 'Hayward') should be ripened at any step during postharvest handling before consumer consumption. This is essential for freshly harvested kiwi fruit. But, this requires correct temperatures and ethylene concentrations. More testing of a newly developed ethylene generator using charcoal for commercial purposes is needed. This study was conducted to investigate the optimum storage temperatures and the effect of ethylene on the postharvest quality of kiwi fruit. Three different ethylene concentrations of 10, 50, and 100 µL·L -1 were used on fresh kiwi fruit stored at different temperatures of 10, 15, and 20℃. The quality changes of the fruits were assessed by sensory evaluation and by measuring firmness, soluble solids content, titratable acidity, and ethylene production. Higher storage temperatures and ethylene concentrations softened the kiwi fruit quickly and led to the rapid loss of acidity while soluble solid contents of fruit increased to a significant extent during the same storage period. Similarly, the firmness of ethylene-treated fruits stored at 20 and 15℃ dramatically decreased in the experiment while treated fruits stored at 10℃ decreased only slightly. Quality characteristics of kiwi fruits stored at 15 and 20℃ were better than those of fruits at 10℃. With regards to the effect of temperature, fruits stored at lower temperatures took a longer time to ripen and retained their quality longer. The newly developed ethylene generator maintained the ethylene concentration in the 5 kg box at 40 -400 µL·L -1 . The ethylene generator could also be used to soften persimmons.

The effects of temperature and length of cold storage on the quality maintenance of fresh "Gold" kiwifruit were investigated. Physio-chemical properties were analyzed in kiwifruit held at 2°C and 6°C temperatures compared to fruit at room temperature (20~28°C) during 8 weeks of storage. Low temperatures (2°C and 6°C) significantly delayed softening and soluble solids content (SSC) accumulation compared to higher temperature (20~28°C). Physico-chemical properties of fruits, including weight losses, firmness, SSC, titratable acidity (TA), SSC/TA ratio, and flesh color properties were monitored during storage. Fast firmness loss was detected in fruit stored at higher temperatures compared to low temperature (2°C). Similar results were observed for acidity according to storage temperature and length of cold storage, whereas SSC increased to the limited values (%Brix) during storage. The soluble solids content (SSC) increased markedly during the first 60 days of storage and remained almost constant thereafter for all treatments. SSC accumulation rates decreased from 5 weeks after storage probably due to differences between initial and ripe kiwifruits, and SSC decreased with each passing week due to natural starch conversion over time. The SSC/acid ratio increased from 18 to 27 until 5 weeks after storage and then slowly declined in all kiwifruit stored at different low temperatures. Sensory evaluation results showed no differences in kiwifruit flesh color stored at two storage temperatures of 2°C and 6°C. Temperature and length of cold storage affect the Quality Maintenance of fresh kiwifruit (Actinidia chinensis Planch) 257

This study was conducted to investigate the optimum storage temperature and the effect of ethylene on the postharvest quality of astringent persimmon (Diospyros kaki L) 'Cheongdobansi' fruits. We treated fruits with 10 µL･L -1 ethylene at 20, 15 and 10°C. Our results indicated that higher storage temperature rapidly reduced firmness and astringency. The soft persimmon fruits stored at 15°C showed the best quality relative to the fruits stored at 20°C and 10°C. Our findings also showed that ethylene generators, which are sold on the market, can effectively induce persimmons to soften in plastic film.

Chuhwang' pear fruit was harvested at 187 days after full bloom and stored at 0℃ for 70 d after gradual cooling (GC) treatment for 20 d. Direct cooling (DC) treatment was used as a control, and this involved direct storage at 0℃ after harvest. Following GC treatment, a weight loss of 4.62% was recorded. In addition. after 30 d of storage at 0℃, the incidence of skin blackening was almost completed and incidence rate in GC treatment significantly decreased to 13.9% compared to 72.2% in DC treatment. Furthermore, in term of GC treatment, the total color differences (ΔE), hardness, and sucrose contents were somewhat lower, but the electrolyte leakage rate and respiration rate were slightly higher than those of DC treatment. Moreover, the contents of hexose, ascorbic acid, and total polyphenol and DPPH radical scavenger activity were slightly higher for the GC treated samples. The activities of polyphenol oxidase and lipoxygenase and thiobarbituric acid reactive substances were low following GC treatment, and no significant differences in the antioxidant enzyme activities were observed between treatment groups. Therefore, these results indicate that the GC treatment prior to cold storage appears to inhibit skin blackening in 'Chuhwang' pear fruit by decreasing the chilling sensitivity.

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