Changes in respiratory and antioxidative parameters in cucumber fruit (Cucumis sativus L.) stored under high and low oxygen concentrations

摘要

The effects of controlled atmosphere (CA) at 5, 21 (air, control) and 100 % O-2 on chilling injury, respiratory and antioxidative parameters at 5, 10 and 20 degreesC in cucumber fruit were determined. The appearance of chilling injury symptoms in cucumber was delayed in both CA treatments; 100 % O-2 effectively reduced pitting than did the 5 % O-2 treatment. Respiration and ethylene production rates were suppressed in cucumber fruit stored at 5 degreesC to a greater extent in 100 % O-2 than in 5 % O-2 and air. At 20 degreesC, however, 100 % O-2 increased the respiration rate to rates higher than in 5 and 21 % O-2. The respiration rate of cucumber fruit stored in 100 % O-2 at 10 degreesC was lower than control but higher than the fruit stored in 5 % O-2. Analyses of fruit for changes in enzymatic antioxidant; superoxide dismutase (SOD) and catalase, and non-enzymatic antioxidant, ascorbic acid and glutathione revealed that those stored at 5 degreesC, SOD activity temporarily increased on D-1 by 5 and 100 % O-2 treatments; at D-5, its activities in all storage atmospheres increased. Catalase activity in the control fruit was higher than those at both 5 and 100 % O-2, whereas glutathione concentration changed slightly from the initial level at different storage conditions. Ascorbic acid content in all storage atmospheres decreased, exhibiting the same trend throughout the storage period.