Abstract
Hassaku (Citrus hassaku Hort. ex Tanaka) fruits were stored at 2°, 5°, 10°, 15° and 20°C under low (75-80%) and high (90-95%) relative humidity conditions. The changes in biochemical characteristics and physiological behavior of fruit peel, and their relationship to the degree of rind-oil spot were investigated. Total soluble solids (TSS), titratable acidity (TA) and TSS/TA ratio were not clearly different among temperature treatments until 30 days in storage. Thereafter they apparently varied more in particular under low RH conditions than under high RH. But these characteristics were not associated with the severity of rind-oil spot. Organic acid content of whole fruits and their 3 separated portions was decreased in similar patterns with a longer storage period. TNC and reducing sugar of whole fruit peel decreased without a particular pattern, but, the separated portions showed greater fluctuation. It is noted that low RH conditions had more effect on the changes in biochemical metabolites than high conditions. The change in CO2 and C2H4 production of fruits were relatively constant and were higher level at high temperature as compared to low temperature in storage. After fruit stored at low temperature (2°, 5°C) was transferred to 20°C, abnormal respiration was found. An increment in the rate of CO2 and C2H4 production was associated with the severity of rind-oil spot of fruit stored after 90 days at 10°C under low RH conditions. TNC was also closely related to the severity of rind-oil spot.
