高静压和热处理对蘑菇多酚氧化酶的钝化动力学分析

Effect of High Hydrostatic Pressure and Heat Treatment on PPO Inactivation and Kinetic Analysis

研究了高静压处理HHP(100～1 600 MPa,0.2～25 min)和热处理(55～80℃,0.2～20 min)对双孢蘑菇多酚氧化酶(polyphenoloxidase,简称PPO)的钝化效果,并分析了钝化动力学。随着处理压力、温度的升高和处理时间的延长,钝化效果增强。在600 MPa以下压力处理后,PPO活性残存率均大于88%,表明600 MPa以下处理压力对PPO的钝化效果较差。而800、1000、1200、1400和1600 MPa压力下处理25 min,PPO活性残存率分别下降到66.42%、52.83%、27.20%、2.20%和0.01%,表明800 MPa以上压力能有效钝化蘑菇PPO。应用一级动力学模型拟合热处理对PPO的钝化动力学,各温度条件下拟合的决定系数R2都在0.960以上,表明PPO的热钝化符合一级动力学模型;应用两段式模型对HHP钝化蘑菇PPO的动力学进行拟合,决定系数R2均大于0.982,HHP钝化蘑菇PPO符合两段式钝化动力学。

The effect of high hydrostatic pressure （I-IHP） treatment and heat treatment on the stability of Agaricus bisporus mushroom polyphenoloxidase （PPO） was studied. Residual activities of the PPO were investigated after HHP treatment at 100 - 1 600 MPa for 0.2 - 25 min and heat treatment at 55 - 80℃ for 0.2 - 20 min. The HHP and heat inactivation kinetic of mushroom PPO were analyzed by first-order and biphasic model. The results showed that the effect of inactivation was improved with the pressure and temperature increasing, as well as the treatment time increasing. The residual activities were all higher than 88% when treated at pressure lower than 600 MPa, indicated that treatment at pressure lower than 600 MPa had limited influence on the activity of PPO. After HHP treatment at 800, 1 000, 1 200, 1 400 and 1 600 MPa for 25 min, the residual activity reduced to 66.42% , 52.83, 27.20% , 2.20% and 0.01% , respectively. The first-order model was used to analyze the survival curves of heat treatment. All of the coefficients of determination （R2） were higher than 0. 960, which proved that the first-order model fit the microbial inactivation kinetics curve well. However, as R2 were all higher than 0.982, the biphasic model was proved to be more suitable than the first-order model to describe the kinetics of PPO inactivation treated by HHP.