Kinetic models for thermal inactivation of multiple pectinesterases in citrus juices

First-order kinetic model of a two-component system was applied to investigate heat inactivation of multiple pectinesterases in citrus juices, The conventional log-linear model was applied to determine D- and z-values of thermolabile and thermostable pectinesterases in citrus juices, respectively, for use in the two-component model. A parameter for concentration of enzyme populations in the juice was included in the model, The two-component model predicted results were in better agreement with the observed heat pasteurization curves than those predicted by the log-linear kinetic model. The two-component model is especially useful for optimizing temperature-time conditions for pasteurizing citrus juices.