Open AccessPostharvest melatonin treatment inhibited longan ( Dimocarpus longan Lour.) pericarp browning by increasing ROS scavenging ability and protecting cytomembrane integrity
Author(s) -
Luo Tao,
Yin Feilong,
Liao Lingyan,
Liu Yunfen,
Guan Boyang,
Wang Min,
Lai Tingting,
Wu Zhenxian,
Shuai Liang
Publication year - 2021
Publication title -
food science and nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.614
H-Index - 27
ISSN - 2048-7177
DOI - 10.1002/fsn3.2448
Subject(s) - browning , apx , polyphenol oxidase , postharvest , chemistry , superoxide dismutase , catalase , peroxidase , food science , catechol oxidase , flavonoid , horticulture , antioxidant , melatonin , botany , biochemistry , enzyme , biology , neuroscience
Postharvest melatonin treatments have been reported to improve the quality and storability, especially to inhibit browning in many fruits, but the effect had not been systematically investigated on longan fruit. In this study, the effect of 0.4 mM melatonin (MLT) dipping on the quality and pericarp browning of longan fruits stored at low temperature was investigated. The MLT treatment did not influence the TSS content of longan fruits but lead to increased lightness and h° value while decreased a* value of pericarp. More importantly, the treatment significantly delayed the increase in electrolyte leakage and malonaldehyde accumulation, inhibited the activities of polyphenol oxidase and peroxidase, and thus retarded pericarp browning. In addition, the treatment significantly inhibited the production of O 2 •− and H 2 O 2 while promoted the accumulation of glutathione, flavonoids, and phenolics at earlier storage stages in longan pericarp. Interestingly, the activities of ascorbate peroxidase (APX) and superoxide dismutase (SOD) were significantly upregulated but activities of catalase were downregulated in the MLT‐treated longan pericarp. MLT treatment effectively enhanced APX and SOD activities, increased flavonoid, phenolics, and glutathione content, protected cytomembrane integrity, inhibited the production of O 2 •− and H 2 O 2 and browning‐related enzymes, and thus delayed the longan pericarp browning.