Study On Optimization Of Peel Browning Inhibition Of Post-harvest Huangguan Pear And Its Mechanisms

Huangguan pear is one of the major pear varieties in our country, with early maturity,good quality, high yield and other good qualities, however the incidence of peel browning,commonly known as Ji Zhua disease, become a technical problem in its production and distribution. Based on former researches, the test aimed to optimize the method of inhibition browning. The paper was focused on the change rules of phenolic metabolism, antioxidant system, lipid peroxidation and their collection with jizhua disease. The test aimed to reveal the regulatory mechanism of ethylene on controlling peel browning. The results showed that:(1) According to the peel browning of post-harvest huangguan pear treated by different means, we found that cold condition, NaCl soak and ethylene plus 1-MCP treatment had a better result, while delay cooling treatment was less effective against peel browning, showing the peel browning rate was even higher than the control group, what’s more, whether 50 mg/L or 5 mg/L ethylene treatment could suppress the peel browning completely and had the best control effect. Linking the different experimental treatment and the results, ultimately, we thought 5 mg/L ethylene treating huangguan pear 8 h in 20 oC environment was the best approach.(2) The test results of edible quality showed that: compared to rapid cooling treatment,ethylene treatment can effectively inhibit peel browning and maintain postharvest quality of huangguan pear. Ethylene treatment didn’t reduce fruit hardness, TA and TSS, besides,maintained the flesh a better antioxidant activities and kept a better storage and shelf-life quality.(3) Ethylene treatment inhibited the peel browning mainly related to phenolic metabolites, respiration rate, lipid peroxidation and antioxidant enzymes. The phenolic metabolites results show that ethylene treatment effectively delayed the decomposition rate of total phenolic, inhibited PPO activity and reduced the incidence of Jizhua disease. Ethylene treatment can significantly reduce the pear electrical conductivity, respiration rate and the activity of POD, as a result, effectively prevent the destruction of the cell membrane structure.SOD, CAT, APX activity of 5 mg/L ethylene treatment was obviously higher than the control group. 5 mg/L ethylene treatment reduced the membrane lipid peroxidation and improved the pear antioxidant capacity and chilling tolerance.