Effect of chlorophyll degradation and pheophytinase activity of Chinese kale under low temperature storage and ultraviolet C irradiation

The degreening due to the breakdown of chlorophyll affects the quality and shelf life of the postharvest vegetables.In order to investigate the relationship between chlorophyll degradation and pheophytinase ( PPH) activity of postharvest Chinese kale, the changes of chlorophyll content and PPH activity were investigated under different temperature storage and ultraviolet C ( UV - C ) irradiation. The results showed that the PPH activity increased rapidly under 22℃ storage.The activity on the 3d was 200% of that on the 0d whereas that percentage was 135% under 4℃ storage.The chlorophyll a content under 4℃ storage was 2.8 fold of that under 22℃ storage. The UV - C irradiation decreased the PPH activity. The activity increase 14% on the first day, whereas that percentage was 50% without UV-C treatment.The chlorophyll a content was 1.3 fold compared with that of control on the 5d. Therefore the low temperature and UV- C irradiation inhibited the rapid increase of PPH activity and decrease the chlorophyll breakdown.