Postharvest combined chitosan and melatonin treatment maintain antioxidant capacity and cell membrane integrity of fresh-cut broccoli by inducing reactive oxygen species scavenging system

Broccoli is susceptible to senescence and quality deterioration during storage. Previous study showed that chitosan (CTS) and melatonin (MT) treatment alone could maintain the redox balance of fruit and vegetables tissues and prolong shelf life, but effects of combination treatment of CTS and MT on reactive oxygen species (ROS) metabolism and antioxidant characteristics of fresh-cut broccoli during storage are still unclear. The data of the present study showed that the combination treatment of 5 g L −1 CTS and 100 μmol L −1 MT increased the activities of catalase (CAT) and superoxide dismutase (SOD), and the activities of antioxidant enzymes, such as ascorbate peroxidase (APX), glutathione reductase (GR), dehydroascorbate reductase (DHAR), and monodehydroascorbate reductase (MDHAR), and increased the antioxidant contents, suh as ascorbate (AsA) and glutathione (GSH), in the tissues of fresh-cut broccoli during storage, and then reduced the accumulation of superoxide anion (O 2 .- ) and hydrogen peroxide (H 2 O 2 ). In addition, the combination treatment of CTS and MT decreased relative conductivity of cell memebrane and malondialdehyde (MDA) content, and increased DPPH radical scavenging and FRAP antioxidant capacity. In conclusion, the combination treatment of CTS and MT can alleviate the cell membranes damage and maintain antioxidant capacity by increasing the antioxidant activity of fresh-cut broccoli. • CTS/MT compound treatment increased SOD and CAT activities of fresh-cut broccoli. • CTS/MT compound treatment activated the AsA-GSH cycle in fresh-cut broccoli. • CTS/MT compound treatment decreased H 2 O 2 and O 2 .- contents of fresh-cut broccoli. • CTS/MT compound treatment maintained cell membrane integrity of fresh-cut broccoli. • CTS/MT compound treatment enhanced antioxidant ability of fresh-cut broccoli.