Effects of exogenous oxalic acid on radical oxygen metabolism in postharvest wolfberry (Lycium bararum L.) fruits.

The experiment was carried out to study the effects of oxalic acid treatments on the correlated indexes of radical oxygen metabolism.The fruits of Ningqi NO.3 were dipped in 5 mmol/L oxalic acid solution for 10 min as treatment,and dipped in water as control,then stored at ambient temperature(20 ℃).The results showed that oxalic acid treatment resulted in decrease in superoxide (O-2·) production,hydrogen peroxide(H2O2) content and malondialdehyde(MDA) content,increase in superoxide dismutase(SOD) and catalase(CAT) activities,while decline in lipoxygenase(LOX).The peroxydase(POD) activity in treatment was higher than control after postharvest 3 d.The disease index and decay rate were lower than control at the end of storage(Postharvest 5 d).It was suggested that oxalic acid treatment could decrease radical oxygen metabolic speed,and increase antioxidant capacity,which led to delaying of fruit maturation.The results indicated that oxalic acid treatment might be a new approach to fresh-keeping of postharvest wolfberry fruits.