Effect Of Harvest Date, Storage Temperature And Hot Water Treatment On Preservation Of Jing’an Ponkan

Jing’an Ponkan(Citrus reticulata Blanco cv. Jing’an Ponkan)is one of the excellent varieties citrus, which has many cultivation area in Jiangxi Province. In the actual production, extensive harvest, poor infrastructure and backward technology caused certain economic losses of Jing’an Ponkan. In this study, the experimental material was Jing’an Ponkan. The effect of different harvest date and storage temperature on postharvest physiology and fruit quality were investigated in order to determine the optimal harvest date and the best storage temperature. In addition, the optimal hot water treatment condition of Jing’an Ponkan was also studied. The study has important practical implications for the actual production application to the postharvest storage of Jing’an Ponkan, and provide important theoretical basis for citrus harvest, postharvest storage, preservation and other related technology. The main study contents and results were as follows:1. The Jing’an Ponkan fruits of harvest Ⅰ(235 days after blooming, DAB), harvest Ⅱ(247 DAB), harvest Ⅲ(257 DAB) and harvest IV(267 DAB) were stored at(10±1) ℃ and RH 85%-90% for 120 d. At the end of storage, the decay rate of harvest I fruits was the lowest in four treatments, meanwhile, it owned the highest weight loss rate, but poor fruit appearance and quality; the decay rate of harvest III and IV fruits were 17% and 34% higher than that of harvest Ⅱ fruits, and both the differences were significant. What?s more, harvest Ⅱfruits owned lower respiratory intensity and MDA content, higher SOD and POD activity, and better fruit quality by comparing with the others. Integrated all the indicators, the storage quality of harvest II fruits is better than the others. Therefore, the optimum harvest date of Jing’an Ponkan was harvest Ⅱ(247 DAB).2. The Jing’an Ponkan fruits were stored at 4 ℃, 7 ℃, 10 ℃, 13 ℃ and room temperature(CK) for 120 d. At the end of storage, compared with other treatments, the fruits stored at 10 ℃ could reduce respiratory intensity effectively, maintained higher TSS, TA, VC and total sugar content, decreased MDA accumulation, and owned higher SOD and POD activity, which achieved better preservation effect. Therefore, the best storage temperature of Jing’an Ponkan was 10 ℃.3. The Jing’an Ponkan fruits were stored at(10±1) ℃ and RH 85%-90% after soaked in different water of 35 ℃, 40 ℃, 45 ℃, 50 ℃, 55 ℃ and clean water(CK) for 3 min, then stored for 120 d. At the end of storage, compared with CK, the hot water treatments could inhibit decay rate and weight loss rate effectively, maintained better total sugar content, TA and TSS content. At the same time, the accumulation of MDA could be inhibited effectively, and owned higher SOD and POD activity in the later period of storage, delayed the senescence effectively. Among them, 50 ℃ hot water soaked for 3 min was the best hot water treatment.