Mechanism of quality maintenance during storage in heat-treated horticultural crops

热处理是指在40 ~ 50℃的温度下，用热空气或热水对园艺作物进行短时间的处理，其对贮藏品质的生理效应，以及对病原菌和害虫的控制作用，已有报道。本文论述了热处理的品质保持机理。结果表明，热处理抑制了贮藏过程中冷害的发生（在35℃下热空气处理1至3天）。2）在贮藏的西兰花小花的熟化上，我们确定了叶绿素降解中镁脱螯合物的特征以及热处理的抑制效果结果表明，热处理能有效地抑制黄瓜果实冷害的发生（45℃热空气处理2小时），推测这种抑制可能是由于过氧化氢清除酶、抗坏血酸过氧化物酶和过氧化氢酶活性的控制。因此，采后热处理对长门结珠吉和黄瓜果实冷害和青花菜小花败育有抑制作用。这也说明，低温处理对冷害的抑制作用可能是通过控制膜脂的变化和过氧化氢清除酶的活性来实现的，而低温处理对果实品质的影响可能是通过控制叶绿素降解酶的活性来实现的，从而使果实在采后品质得以保持。

Heat treatment is a method that horticultural crops are treated with hot air or hot water at 40 to 50℃ for a short time, and the physiological effects on keeping quality have been reported in addition to the control of pathogens and pests by heat treatment We deal with the mechanism of quality maintenance by heat treatment.1) In green sour citrus fruit, Nagato-yuzukichi, we found that the occurrence of chilling injury during storage was suppressed by the heat treatment(hot air treatment at 35℃ for 1 to 3 days) after harvest.2) On the degreening of stored broccoli florets, we determined the characterization of Mg-dechelating substance in chlorophyll degradation and the inhibitory effect of heat treatment (hot air treatment at 50℃ for 2 hours)on degreening.3) We determined that the active oxygens might be involved in the occurrence of chilling injury in cucumber fruit Moreover, the occurrence of the injury was effectively suppressed by the heat treatment (hot air treatment at 45℃ for 2 hours), inferring that the inhibition could be due to the control of the activities of hydrogen peroxide-scavenging enzymes, ascorbate peroxidase and catalase.From these results, we suggest that the heat treatment after harvest has an inhibitory effect on the chilling injury of Nagato-yuzukichi and cucumber fruits and the degreening of broccoli florets. We also imply that the inhibitory effect on chilling injury might be in order to control the changes in membrane lipid and the activities of hydrogen peroxide-scavenging enzymes and that the effect on degreening might be due to the control of the activities of chlorophyll-degrading enzymes, resulting in the quality maintenance of these horticultural produce after harvest.