3个蕉类品种果实多酚氧化酶的特性研究

目的]为控制3个蕉类品种多酚氧化酶（PPO）引起的酶促褐变提供理论依据。方法]对3个蕉类品种果实PPO的最适pH与pH稳定性、最适温度与热稳定性以及化合物的影响进行了比较分析。结果]威廉斯蕉、大蕉及粉蕉PPO最适pH分别为8.56、.5、6.5;pH稳定性范围都在pH 6.0～11.0;PPO最适温度分别是60、303、0℃;PPO的耐热性表现为威廉斯蕉PPO〉粉蕉PPO〉大蕉PPO;威廉斯蕉PPO活性的最佳抑制剂是盐酸-L-半胱氨酸,其次是抗坏血酸,再次是NaHSO3;大蕉、粉蕉PPO活性的最佳抑制剂都是抗坏血酸,其次是NaHSO3、盐酸-L-半胱氨酸。结论]3个蕉类品种中威廉斯蕉PPO的耐热性最高,威廉斯蕉、大蕉及粉蕉PPO的化学抑制剂基本一致。

Research on the Characteristics of Polyphenol Oxidase in the Fruit of Three Banana Varieties

Objective] The theoretical basis of the control of fruit-browning caused by polyphenol oxidase(PPO) of three banana varieties was provided.Method] The optimum pH value for PPO,the stability,the optimum temperature and thermal stability of the pH value in the fruit of three banana varieties,and its affecting compound material were compared and analyzed.Result] The optimum pH and optimum temperature for PPO in the fruit of Williams banana,Plantain and Fenjiao banana was 8.5,6.5 and 6.5,and 60,30,30 ℃,respectively.The range of pH value stability was in 6.0-11.0.The heat resistance performance of PPO was Williams banana > Fenjiao banana > Plantain banana.The best inhibitor to PPO activity of Williams banana was hydrochloric acid-L-cysteine;then,hydrochloride and finally,NaHSO3;to PPO activity of Plantains and Fenjiao banana was ascorbic acid > NaHSO3>hydrochloric acid-L-cysteine.Conclusion] Among 3 banana varieties,PPO of Williams banana had the strongest heat resistance and the chemical inhibitor to three banana varieties was basically same.