Study On The Mechanism And Control Technology Of Chilling Injury And Physiological Sisease Of Pomegranate

Chilling injury, peel browning, decay and weight loss are important factors that affect pomegranate quality in post-harvest preservation. Pomegranate is low temperature-sensitivity fruits and abnormal low temperatures can easily lead to fruit chilling injury. It will be damage the fruit appearance, accelerate peel browning and decay. Factors that affect chilling injury and disease include fruit species, origin, harvest time, storage conditions and so on.Mengzi sweet pomegranate as experiment materials, research the fruit chilling injury temperature and physiological changes, research the regulation effect for pomegranate Chilling injury of MeJA. Determined the fruit pathogens by the method of microbes isolation, purification and identification. Using Chitosan coating to inhibition of bacteria and research its fresh-keeping effect, in addition, the experiment research the fruit best maturity, MAP fresh-keeping film and CA concentration.Observation fruit chilling injury index, determines the fruit chilling injury temperature is 1℃, fruit will while storage temperature<1℃, the fruit which storage in 0℃ will appeared slight chilling symptoms while 20d and the chilling index up to 0.54 while130d, the Peel appeared a lot of brown spots. The high temperature (3℃,4℃) will accelerated Peel Brown and fruit decay, then we can determines 2℃ is suitable storage temperature.Cold injury destroys the structure of fruit peel and the peel surface cracks, rough skin, reduce the waxy layer, the weight loss rate increase, destruction pericarp membrane structure, membrane permeability, MDA content is increased,0℃ storage fruits appeared abnormally elevated respiratory rate when storage 40d, when storage time reached 130d, cell membrane permeability reached 57.46%, MDA content 23.47umol/g. FW, cold injury and high temperatures accelerate peel browning, and the peel browning is closely related to PPO activity and polyphenol content, the correlation coefficients (R2) were 0.821,0.729.MeJA increase the soluble protein content and enhance fruit resistance, 0.1mmol/L MeJA treatment fruit, the browning index, decay rates were reduced 39.48%,29.61% compared with CK, it effectively keeping the fruit outside light and nutritional quality.The result of Microbial separation, purification and identification show that the Aspergillus niger, Penicillium purpurescens and BotryosPhaeria is pomegranate main pathogens. Aspergillus niger is field pathogens and have high separation rate in the fruit, it will lead to the fruit soft rot, Penicillium purpurescens occurred mainly in fruit injury sites, the disease field will appear moldy or soft rot, BotryosPhaeria occurred in the late storage stage, the disease fruits surface appeared large area of mildew, spot Brown and flooding, it occurred mainly high temperature storage fruit.Chitosan have good inhibitory effect on three pathogens, the 1.0% chitosan processing fruit decay rate is 4.4% and lower 45.68% than the CK when its storage 130d, and the weight loss rate is2.24%, the fruit appearance is best.Pomegranate is non-high respiration fruit, fruit should be timely late harvest, the 8-9 ripe fruit can effectively browning index, the fruit use of 0.02mm PE cling film packaging or 02:4%, CO2:5% atmosphere treatment can effectively maintain fruit quality.