低温贮藏和短波紫外线辐照对芥蓝采后叶绿素降解及脱镁叶绿素酶活性的影响
Effect of chlorophyll degradation and pheophytinase activity of Chinese kale under low temperature storage and ultraviolet C irradiation
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摘要: 采后叶绿素降解造成绿叶蔬菜失绿,直接影响产品的感官品质和货架寿命。以研究芥蓝采后叶绿素降解和脱镁叶绿素酶（PPH）之间的关系为目的,考察了温度以及短波紫外线（UV-C）辐照对贮藏过程中芥蓝叶绿素含量及脱镁叶绿素酶活性变化的影响。结果表明常温22℃贮藏时,PPH活性在前期快速上升,第3d时约为第0d的200%,而在低温4℃时酶活仅为第0d的135%,第3d时叶绿素a的含量是常温时的2.8倍;UV-C辐照降低了PPH活性,第1dPPH酶活仅上升14%,而对照则上升50%,第5d时叶绿素a的含量是对照的1.3倍。因此低温和UV-C辐照抑制了贮藏过程中PPH酶活性的快速上升,从而降低了叶绿素降解的速度。Abstract: 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.
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