Anthon Gordon E, Sekine Yukio, Watanabe Nobuo, Barrett Diane M
Department of Food Science and Technology, University of California, Davis, California 95616, USA.
J Agric Food Chem. 2002 Oct 9;50(21):6153-9. doi: 10.1021/jf020462r.
Thermal inactivation kinetics have been determined for pectin methylesterase (PME), polygalacturonase (PG), and peroxidase (POD) in tomato juice. Two parameters, the inactivation rate constant (k) at a reference temperature and the activation energy for inactivation (E(a)), were determined for each enzyme. For PME and PG, the k and E(a) values reported here do not agree with those in several previously published reports. These differences can be explained either by the differences in pH values used for inactivation determinations or by inadequacies in the heating methods used in some previous studies. POD showed simple first-order inactivation kinetics and was less thermally stable than either PME or PG. When different cultivars of tomatoes were evaluated, there was no difference in the thermal inactivation kinetics of these enzymes.
已测定了番茄汁中果胶甲酯酶（PME）、多聚半乳糖醛酸酶（PG）和过氧化物酶（POD）的热失活动力学。针对每种酶，测定了两个参数，即参考温度下的失活速率常数（k）和失活活化能（E(a)）。对于PME和PG，此处报道的k和E(a)值与之前几篇已发表报告中的值不一致。这些差异要么可以用失活测定中使用的pH值差异来解释，要么可以用一些先前研究中加热方法的不足来解释。POD表现出简单的一级失活动力学，并且热稳定性比PME或PG都低。当评估不同品种的番茄时，这些酶的热失活动力学没有差异。
