Effects of Melatonin on Postharvest Quality and Active Oxygen Metabolism of'Muscat Hamburg'Grape

TAN Yanxiao; LENG Songning; HAN Shuang; WANG Hongdong; SHI Hongmei; HE Weihua; ZHANG Yu

doi:10.19590/j.cnki.1008-1038.2025.11.006

Abstract：To investigate the effects of exogenous melatonin treatment on the quality and active oxygen metabolism of postharvest'Muscat Hamburg'grape,the fruit was soaked with 50,100,200,400 μmol/L melatonin.The storage quality and flavor quality indexes were determined,such as weight loss rate,abscission rate,decay rate,soluble solids,titrable acid and vitamin C content.Respiratory intensity,ethylene release,hydrogen peroxide content,malondialdehyde content,non-enzymatic antioxidant content,and antioxidant oxidase activity were also monitored.The results showed that different concentrations of melatonin could effectively delay the water loss of fruit ear and inhibit grape seed fall and decay.Among them,200 μmol/L melatonin treatment had the best effect.After 8 days of melatonin treatment,compared with the control group,the content of soluble solids in the fruits of the treatment group was 13.33％higher,the content of titratable acid was 14.17％higher,the content of vitamin C was 23.97％higher,and the hardness was 24.11％higher.Meanwhile,melatonin treatment effectively inhibited the postharvest respiratory intensity and ethylene release of fruits,suppressed the increase in hydrogen peroxide content,delayed the accumulation of malondialdehyde,promoted the accumulation of non-enzymatic antioxidant substances such as total phenols,total flavonoids,and anthocyanins,and enhanced the scavenging ability of free radicals by increasing the activity of antioxidant enzymes.In conclusion,exogenous melatonin treatment had a positive effect on improving the storage quality of'Muscat Hamburg'grape,providing a theoretical basis for the application of melatonin in the postharvest preservation of'Muscat Hamburg'grape.