A Study On Postharvest Physiology Of Chilling Injury And Preventing Techniques In 'OKuBa' Peach Fruit

In this study, OkuBa peaches showed chilling injury (CI) symptoms after 3 weeks of cold storage at 0 1C, as indicated by inhibition of expiration rate and ethylene production for chilling stress and abnormal ripening with low firmness, but reduced extractable juice and mealy texture of fruit, which is referred as woolliness. After chilling injury occurred, control peaches could not maintain normal edible quality and commercial value with increasing of decay incidence and cold storage time was limited.HWD treatment at 42 C for 5 min promoted normal ripening and softening, maintaining higher level of extractable juice and better edible quality. Increasing content of soluble protein and heat-stable protein involved in the enhancement of CI tolerance in peach fruit. During the later period of cold storage, this treatment increased the activities of -1,3 glucanase and chitinase, resulting in retarding increasing of decay incidence significantly.During the later period of cold storage treatments incubated with 1 and 10 mol/L MeJA maintained higher expiration rate and ethylene production, promoted normal ripening and softening with higher level of extractable juice, TSS, reducing sugar, total sugar and Vc, and alleviation of CI and decay incidence. The application of low concentration MeJA at 1 and 10 mol/L enhanced SOD, CAT and AsA-POD activities, reducing the accumulation of active oxygen species, maintained higher activities of PAL and PPO, increasing resistance to chilling stress and pathogenic organism, resulting in retarding occurrence of senescence and decay.Incubation of 1-MCP at 0.75, 1.50 1/L increased expiration rate and ethylene production gradually in peach during the later period of cold storage. Thereby at ripening period, these fruit softened normally and maintain high extractable juice and good quality with high and balanced PE and PG activities. During shelf life at 25 C, 0.75, 1.50 1/L 1-MCP maintained better edible quality and retarded occurrence of decay, in relation to the significant increasing of PAL and PPO activities at the end of cold storage induced by 1-MCP treatment.