超声处理钝化鲜切苹果多酚氧化酶动力学研究

Inactivation Kinetics of Polyphenol Oxidase of Fresh-cut Apple by Ultrasonic Treatment

研究了超声处理对鲜切苹果多酚氧化酶的钝化效果,并采用一级动力学分析了超声功率（240-600 W）、温度（30-50℃）对鲜切苹果多酚氧化酶的钝化动力学影响。结果表明,鲜切苹果多酚氧化酶的最适温度是30℃,随着热处理时间的延长酶活逐渐下降。超声功率、时间、温度都能显著影响钝化多酚氧化酶的效果,随着超声功率的增加、时间的延长以及温度的升高,超声处理对鲜切苹果多酚氧化酶的钝化效应越大。苹果多酚氧化酶的钝化符合一级反应动力学模型,随着功率和温度的升高,k值上升,D值下降。超声处理降低了多酚氧化酶的热敏感性。

The effects of ultrasonic treatment on inactivation of polyphenol oxidase（ PPO） activity of fresh-cut apple were investigated,and inactivation kinetics of PPO was analyzed by using a first-order reaction kinetic under the following experimental conditions： ultrasonic power（ 240- 600 W） and ultrasonic temperature（ 30- 50 ℃）. The results indicated that the optimal temperature of PPO of fresh-cut apple was 30 ℃,and enzyme activity gradually decreased with the increasing heat treatment time. The inactivation of PPO could be significantly affected by the ultrasound of power,processing temperature,and processing time. With the increasing ultrasonic power,temperature and prolonged ultrasonic processing time,the inactivation of PPO became more significant. The inactivation of PPO was fitted well to the first-order reaction kinetic model under the experimental conditions. The k value raised and the D value decreased with the increasing ultrasonic power and processing temperature. Ultrasonic treatment reduced the thermal sensitivity of PPO.