Effect of UV-C treatment on chlorophyll degradation, antioxidant enzyme activities and senescence in Chinese kale (Brassica oleracea var. alboglabra)

The changes in chlorophyll content, antioxidant enzyme activities and senescence in Chinese kale (Brassica oleracea var. alboglaba) irradiated with different UV-C dosages (1.8, 3.6, 5.4 and 7.2 kJ m^-2) were determined during storage at 20°C. The irradiation dose of 3.6 and 5.4 kJ m^-2 delayed leaf yellowing depicted as higher hue values and chlorophyll contents and lower activity of chlorophyllase, Mg-dechelatase and chlorophyll-degrading peroxidase as compared to the other treatments. Similarly, UV-C treatment delayed the decrease in activities of antioxidant enzymes, particularly peroxidase (POD) and superoxide dismutase (SOD). It also reduced ethylene production and respiration rates. The results indicate that UV-C irradiation could be a useful non-chemical treatment to delay senscence and improve shelf life of Chinese kale.