藕带中多酚氧化酶的酶学性质研究

目的]研究藕带中多酚氧化酶（PPO）的酶学性质。方法]以邻苯二酚为底物,用分光光度法研究pH值、温度和抑制剂对藕带PPO活性的影响,并建立酶促褐变动力学方程。结果]藕带PPO的最适pH值为6.0,最适温度为30℃;Km为0.0344mol/L,Vmax为172.41U/ml,70℃热保温60minPPO的活性基本丧失;抗坏血酸、柠檬酸、L-半胱氨酸和氯化亚锡均能抑制藕带PPO的活性,其中,L-半胱氨酸和氯化亚锡为最佳抑制剂,其次是柠檬酸和抗坏血酸,0.20g/LL-半胱氨酸和氯化亚锡均能有效抑制PPO的活性。结论]该研究可为合理利用藕带资源和科学控制其深加工过程中的酶促褐变提供了参考依据。

Studies on the Enzymatic Characteristics of Polyphenol Oxidase (PPO) in Lotus Sprout

Objective] The research aimed to study the enzymatic characteristics of PPO in lotus sprout.Method] The effects of temperature,pH value and inhibitors on PPO activity of lotus sprout were studied using spectrophotometry method,catechol as substrate,and the reaction kinetic equation was established.Result] The results showed that the optimum temperature and pH were 30 ℃ and 6.0 respectively.The Km,Vmax of kinetic equation were 0.034 4 mol/L,172.41 U/ml,PPO was inactivity when keeping heat in 70 ℃ by 60 min.Ascorbic acid,citric acid,L-cysteine and stannous chloride could all inhibit PPO activity,and the strongest inhibitors of the activity were L-cysteine,stannous chloride,followed by citric acid,ascorbic acid,0.20 g/L L-cysteine,stannous chloride could inhibit PPO activity effectively.Conclusion]The study can provide reference for reasonably utilizing the lotus sprout resources and the scientific control of its enzymatic browning during deep processing.