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.