Acid electrolytic water treatment improves the quality of fresh-cut red pitaya fruit by regulating ROS metabolism and phenylpropanoid pathway

Abstract

The current study delved into the effect of acid electrolytic water (AEW) treatment on the quality of fresh-cut red pitaya fruit during storage at 4 ℃. The findings reveal that AEW treatment effectively suppressed the respiratory rate and malondialdehyde content, while also slowing down the decline in titratable acidity and total soluble solids contents of fresh-cut red pitaya fruit. Furthermore, AEW treatment markedly reduced the production of superoxide anion and hydrogen peroxide, and inhibited the activity of polyphenol oxidase and peroxidase. Moreover, AEW treatment significantly enhanced the activity and expression of beneficial antioxidant-related enzymes such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR), glutathione peroxidase (GPX), monodehydroascorbate reductase (MDHAR), and dehydroascorbate reductase (DHAR). Additionally, AEW treatment elevated the contents of total phenols and flavonoids in the fresh-cut red pitaya fruit. This increase was accompanied by elevated activity and expression of enzymes involved in the phenylpropanoid pathway such as phenylalanine ammonia-lyase (PAL), cinnamate 4-hydroxylase (C4H), and 4-coumarate: CoA ligase (4CL). The AEW treatment also modulated the expression of HcMYBs that are likely involved in regulating reactive oxygen species (ROS) metabolism and phenylpropanoid pathway. Overall, AEW treatment preserves fresh-cut red pitaya fruit quality by activating ROS metabolism and the phenylpropanoid pathway, offering potential for postharvest produce storage.