黄冠梨储藏期间果皮PPO和POD酶活性变化与鸡爪病发生关系研究

摘要

Objective: Experiment was conducted with the Huangguan pear fruit infected with Ji Zhua Disease in order to study the reasons of the occurrence of this disease and its relationship with PPO and POD during storage. Methods: ① Pretreatment of Huangguan pear: the test pears were soaken in 2 % CaCl2 solution for 15 min and 1 % pullulan solution for 5 min, and then they were kept cool during storage. Indexes were determinate every 30 days. ②Measured enzyme activity: The PPO and POD were extracted from the Huangguan pear peel treated by two methods. PPO activity was measured at 420 run, and POD activity was measured at 470 nm. ③ Ji Zhua disease statistics: It was illustrated by the incidence of diseased fruits in the proportion of the total fruit. Results: The results indicated that pears peel dipped calcium and coated with pullulan reduced PPO and POD activity. PPO and POD were delayed appearance of peak activity and reduced its peak. PPO activity of pears dipped calcium had been being with a minimum at a low level. PPO activity and POD activity of pears dipped calcium and coated with pullulan were significantly lower than control fruit (P<0.01), but with no significant difference between them (P> 0.05). At the end of storage, incidence rate of control fruit was 33.33 %; incidence rate of pears treated with calcium was 0; incidence rate of pears coated with pullulan was 3.33 %. Pears treated with calcium were the best. Conclusion: In Huangguan pear peel, that PPO activity increased and POD activity decreased accelerated the occurrence of Ji Zhua disease during storage.%目的:探明黄冠梨储藏期间鸡爪病发病与PPO和POD酶活性变化关系.方法:①原料预处理:以黄冠梨为试材,分别用2％CaCl2溶液浸泡15 min和1％普鲁兰多糖溶液浸泡5min处理实验材料,低温冷藏,每隔30天取样一次进行指标测定；②酶活性测定:取两种处理的黄冠梨果皮分别提取PPO和POD并在420 nm下测定PPO活性和470 nm下测定POD活性；③鸡爪病发病情况统计:以病果在总果实中所占比例来说明发病情况.结果:浸钙和普鲁兰多糖涂膜处理黄冠梨,两种处理都不同程度地降低了果皮中PPO活性和POD活性,都延迟了PPO和POD活性高峰的出现,且降低了其峰值,浸钙处理PPO活性最低且一直处于较低水平,PPO活性和POD活性都极显著地低于对照果(P＜0.01),但浸钙和普鲁兰多糖处理之间差异不显著(P＞0.05).贮藏末期,对照果发病率为33.33％;浸钙处理果未见发病；普鲁兰多糖涂膜处理果发病率仅为3.33％.浸钙处理效果较好.结论:黄冠梨储藏期间,PPO活性的上升和POD活性的下降,加速了黄冠梨鸡爪病的发生.