Acidic electrolyzed water improves the postharvest quality of jujube fruit by regulating antioxidant activity and cell wall metabolism

Abstract

Disease development of ‘Lingwu Long’ jujube fruit treated with acidic electrolyzed water (AEW) at 4 ± 1℃ for storing 30 d was evaluated by the reactive oxygen species (ROS) metabolism, phenylpropanoid metabolism, and cell wall metabolism. Compared to the control, jujube fruit treated with AEW had a lower disease index. At the end of storage, AEW treatment maintained lower malondialdehyde (2.1 μmol kg−1) and superoxide anion generation rate (41.5 nmol g−1 min−1) compared to the control, while enhancing catalase (127.2 U g−1) and superoxide dismutase activities (244.2 U g−1). AEW treatment increased 1,1-diphenyl-2-picrylhydrazyl scavenging ability and hydrogen peroxide. The higher contents of ascorbic acid and glutathione were related to higher activities of ascorbate peroxidase, glutathione reductase, monodehydroascorbate reductase, and dehydroascorbate reductase in AEW-treated jujube fruit. Moreover, the highest activities of phenylalanine ammonia lyase (21.1 U g−1), cinnamate-4-hydroxylase (304.2 U g−1), and 4-coumarate-CoA ligase (6.4 U g−1) and contents of total phenolics (5.3 g GAE kg−1) and total flavonoids (0.3 mg RE g−1) were observed in AEW-treated fruit compared to the control. Higher firmness, Na2CO3-soluble pectin, cellulose, and hemicellulose and lower water-soluble pectin in AEW-treated fruit were due to lower activities of polygalacturonase, pectinate lyases, β-galactosidase, and cellulase. As a result, AEW could be used for decreasing decay occurrence and maintaining storage quality of jujube fruit.