褪黑素对枇杷果实贮藏品质的影响OA

[Objective]This research aimed to explore the effects of exogenous melatonin on the quality of'Dawuxing'loquat fruits during low temperature storage and shelf life,in order to screen out the appro-priate melatonin concentration,to provide reference for the storage of loquat fruits.[Method]Loquat fruits were soaked in 0(distilled water,CK),50,100,150,and 200 μmol/L melatonin for 1 h,and stored at 4℃for 30 days and then at 20℃for 3 days.The fruit decay rate,weight loss rate,hardness,cohesion,soluble solid(TSS)content,soluble sugar content,titrable acid(TA)content,carotenoid content,total phenol content,malondialdehyde(MDA)content,lignin content,cold damage index,relative conductivity,and ac-tivities of superoxide dismutase(SOD),catalase(CAT),ascorbate peroxidase(APX),phenylalanine am-monlyase(PAL),cinnamate dehydrogenase(CAD),and peroxidase(POD)were determined to analyze the physiological changes and changes of related quality indexes.[Result]Melatonin treatment can reduce the weight loss rate,decay rate and hardness of loquat fruits during storage,and maintain their cohesion.The contents of soluble solid matter,soluble sugar,titrable acid,total phenol and carotenoid in fruits treated with 100 μmol/L melatonin were increased by 6.9％,19.1％,41.9％,69.9％and 38.5％,respectively,compared with the control when stored at low temperature for 30 days,and were increased by 10.4％,39.0％,95.3％,73.8％and 41.3％,respectively,compared with the control when the fruits were trans-ferred to shelf(stored for 33 days).Melatonin treatment decreased the chilling damage index,relative con-ductivity and malondialdehyde(MDA)content of fruit during storage,and maintained the activities of su-peroxide dismutase(SOD),catalase(CAT)and ascorbate peroxidase(APX).Compared with the control,the relative conductivity and MDA content of fruits treated with 100 μmol/L melatonin showed the largest decrease after low temperature storage for 30 days,with reductions of 15.1％and 17.3％,respectively.SOD and CAT activities first increased and then decreased during storage.SOD,CAT and APX activities of fruit treated with melatonin were significantly higher than those of control at 30 d and 33 d of storage,with the largest increase observed in treatment of 100 μmol/L melatonin.Melatonin inhibited the activities of phenylalanine ammoniase(PAL),cinnamate dehydrogenase(CAD)and peroxidase(POD)in loquat fruits in the middle and later stages of storage,and the lignin content in fruits treated with 100 μmol/L melatonin was significantly lower than that in the control at the end of low temperature storage and shelf life.[Con-clusion]Melatonin soaking can effectively maintain the appearance quality,physiological characteristics and nutritional quality of loquat fruit during storage,and 100 μmol/L melatonin has the best effect.