Effect of chlorine dioxide on the control of postharvest diseases and quality of litchi fruit

摘要

Litchi (Litchi chinensis Sonn.) is an important subtropical fruit crop with high market value. However, rapid pericarp browning and decay of litchi fruits caused by infection of microorganisms during storage can result in up to 50% of postharvest loss prior to consumption. New methods are urgently needed for effectively overcoming these problems. In this?study, we tested the efficacy of chlorine dioxide for the control of postharvest diseases of litchi fruit. Inactivation kinetics of litchi anthracnose by ClO2?solution concentrations ranging?from?5, 10, 20, 40, 60, 80 and 120 mg/l?was also studied. The fruits of the cultivar ‘Huaizhi’ were first treated with 80 and 120 mg/l?ClO2?and then stored at 20°C for 7 days. The effect of the ClO2treatments on the postharvest physiology was investigated. The results showed that 5 mg/l?ClO2?solution could significantly inhibit litchi anthracnose spore germination. In addition, treatments with 80 and 120 mg/l?of ClO2?significantly reduced postharvest decay and peel browning of the fruit, inhibited polyphenol oxidase (PPO) and peroxidase (POD) activity, retained total?soluble solids?(TSS)and titratable acidity?(TA) content, and increased?phenylalnine ammonialyase (PAL) activity and?malondialdehyde?(MDA) content. However,?ClO2?solution did notsignificantly influence?CO2?and C2H4?production of the fruits, compared with those in the untreated control. Overall, 120 mg/l?ClO2?solution treatment was effective in inhibiting postharvest diseases and improving the quality of litchi fruits.