Effect of Carbon Monoxide Fumigation on the Respiration and Oxidase Activities of Postharvest Jujube

Postharvest jujubes were fumigated with 5, 10, 20 or 40 μmol/L carbon monoxide (CO) for 1 h and then preserved for 30 d at ambient temperature. The effects of CO fumigation on the respiration and oxidase activities of postharvest jujube were determined. Results showed that low CO concentrations (5–10 μmol/L) could restrain the increases of respiration rate, malonaldehyde content, and relative membrane permeability of postharvest jujube. However, high CO concentrations (20–40 μmol/L) showed adverse effects on jujube preservation. Jujube fumigated with 10 μmol/L CO demonstrated optimum effects, and this CO concentration effectively reduced the oxidase activities including lipoxygenase, cytochrome oxidase, polyphenol oxidase and ascorbic oxidase during jujube storage time. As for the reduction of respiration rate and oxidase activities, the delay of membrane lipid peroxidation, fumigating jujube with appropriate concentration of CO might be applied to preserve postharvest jujube and other fruits.