Carboxymethyl cellulose-based water barrier coating regulated postharvest quality and ROS metabolism of pakchoi (Brassica chinensis L.)

•Novel CMC-based cross-linking coating embedded with liquid paraffin was prepared.•Ionic cross-linking and liquid paraffin reinforced water barrier of CMC coating.•Spraying coating reduced water loss and improved postharvest quality of pakchoi.•Coating treatment enhanced ROS scavenging capacity and reduced lipid peroxidation.•Antioxidant enzymes, AsA-GSH cycle and phenylpropanoid metabolism were regulated.