Effects Of Gradual Cooling Combined With 1-MCP Treatment On Storage Quality Of Angeleno Plums

Angeleno plums is one of cold sensitive fruits originating in the United States,high temperature of mature season makes plums postharvest aging rapidly,while long-term storage at low temperature easily lead to chilling injury.1-MCP is a kind of ethylene structure analogue,which is commonly used as preservation in the field of fruit and vegetable storage.Gradually cooling can decline the cold sensitivity of fruits and vegetables.In this experiment,Angeleno plums collected from the Yingkou area as test material,and treated by different concentrations of 1-MCP and gradual cooling process,studied plums' quality change during storage at room temperature(20±1?)and low temperature(0±1?)so as to explore the effect on the long-term storage quality of Angeleno plums when the two methods were commine used.The results showed that:1.Under storage at room temperature,we fumigate Angeleno plums for 24h by 1-MCP with the concentration of 0.5 uL/L,0.75 uL/L,1.0 uL/L.Comparing with the control plums(0 uL/L 1-MCP),1-MCP treatment would be better to alleviate the hardness drop,reduce the loss of reduce sugar,TA,Vc,total phenolic contents,inhibit the increase of cell membrane permeability and MDA accumulation,improve POD and CAT activity and inhibit the activity of PPO,0.75 L/L 1-MCP has the best treatment effect.2.1n the process of cold storage,the hardness of controlled plums(constant low temperature)decreased slowly,the contents of Vc and TA were higher at the early stage of the storage.After 45d storage,controlled plums' cell membrane permeability increased obviously,the content of MDA and proline rised abnormally,chilling injury index increased,the chilling injury occurred;Gradual cooling promote plums' postharvest at the early stage of the storage,the hardness of plums falling fastly,and the content of reducing sugar,Vc,TA and SSC was low.However,in the lately storage,gradually cooling can effectively delayed the increase of cell membrane permeability and reduce the accumulation of MDA and proline content,chilling injury index is low.And maintain the higher nutrient content,improve POD and CAT activity and inhibit the activity of PPO.Therefore,gradually cooling can effectively alleviated chilling injury,to maintain plums' long-term storage quality,comprehensive analysis indicated the 16h-ck cooling procedure works best.3.Compared with the individual treatment,1-MCP combined with gradually cooling not only conducive to keep the fruit hardness,Vc,TA content at a higher level,inhibited the loss of nutrients,but retard the increase of cell membrane permeability and the accumulation of MDA and proline content,lowered the chilling injury index and improve the cold resistance of the fruit,further enhance the nutritional quality and storage quality of plum fruits.4.To sum up,0.75 uL/L 1-MCP gradually cooling process combined with 16h-ck gradually cooling has the best effect on preservation of Angeleno plums,which significantly improved its' long-term storage quality.