Thermal inactivation kinetics of vegetable peroxidases

Thermal stability of peroxidases present in raw Vegetable Mixtures was investigated in order to identify adequate mechanisms and corresponding kinetic models of inactivation. Inactivation experiments were carried out for each material at five different temperatures which were from the ranges of 58-74 degrees C for broccoli and potato juices and 62-78 degrees C for carrot juice. Using the multitemperature evaluation of inactivition data, a simple isozyme model was verified for the inactivation of broccoli peroxidase. A combined three-reaction mechanism, which assumed simple irreversible inactivation for one isoform and Lumry-Eyring mechanism for the other one, was identified for carrot and potato peroxidases. (c) 2008 Elsevier Ltd. All rights reserved.