Effect of postharvest oxalic acid treatment on ethylene production, quality parameters, and antioxidant potential of peach fruit during cold storage

The effects of postharvest oxalic acid (OA) treatment on ethylene production, fruit quality, bioactive compounds and antioxidant activity of peach fruit, were examined. Fruits were treated with oxalic acid immediately after harvest and stored at 1° C and 90% relative humidity for 28 days. The oxalic acid treated peach fruit exhibited significantly lower levels of ethylene production, pH, total soluble solids and weight loss and higher levels of firmness and titratable acidity than control. Also, OA treated fruit exhibited significantly higher total antioxidant capacity, which resulted from higher total phenols and flavonoids accumulation. During storage, activity of peroxidase, catalase, and superoxide dismutase enzymes increased in both control and treated peaches, and peroxidase and superoxide dismutase activities in OA treated fruit were significantly greater than those in control. But, there was no significant difference in catalase activity between OA treated and control fruit. Results suggested that OA treatments could be a promising strategy to delay softening and enhance the phenolic content and antioxidant activity of peaches.