Effects of Exogenous Melatonin on Postharvest Physiological Characteristics and Storage Quality of Pepper Fruit
[Objective]It is to explore the effects of exogenous melatonin on postharvest physiological characteristics and storage quality of pepper fruits.[Method]The pepper fruit was soaked with different concentrations(0,50,100,150,200 and 250 μmol/L)of melatonin for 2 h to determine the optimal melatonin concentration for postharvest preservation of pepper fruit.Furthermore,the changes of color,senescence,nutritional quality,and antioxidant enzyme activity of pepper fruit during storage were analyzed after the optimal melatonin concentration treatment.[Result]The appropriate concentration(100～200 μmol/L)of melatonin treatment could significantly reduce the weight loss rate and malondialdehyde content of the fruit(the 12th day of storage),improve the fruit hardness,and maintain the fruit brightness and flavor quality.When the melatonin concentration was 150 μmol/L,pepper fruit indicators such as color,hardness,soluble solids and soluble protein had the best value,compared with the control group,increased by 8.70%(represented by L*),27.73%,23.22%and 24.64%,respectively.However,the content of malondialdehyde of pepper fruit decreased by 32.48%compared with the control group.Further dynamic analysis showed that 150 μmol/L(optimum concentration)exogenous melatonin had little effect on the physiological quality of pepper fruits at the early stage of storage.However,after 8 days of storage,exogenous melatonin could significantly increase the activities of catalase and peroxidase in pepper fruits,reduce the weight loss rate,malondialdehyde content and soluble pectin content of fruits,and maintain the brightness and hardness of fruits.Furthermore,exogenous melatonin treatment could also improve the flavor quality of pepper fruits during storage.After 8 days of storage,the contents of vitamin C,soluble protein,soluble solids and total phenols in pepper fruits of the exogenous melatonin group were higher than those of the control group,and the growth rates were 11.71%～21.0%,5.55%～12.93%,15.21～25.32%and 11.05%～24.03%,respectively.[Conclusion]Exogenous melatonin can induce the enhancement of antioxidant enzyme activity in pepper fruit,reduce the accumulation of malondialdehyde and soluble pectin,thereby inhibiting fruit senescence and maintaining or improving the quality of pepper fruit during storage.
万方数据
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