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Inactivation kinetics of food enzymes during ohmic heating

Author:
Jakób, Alina, Bryjak, Jolanta, Wójtowicz, Halina, Illeová, Viera, Annus, Július, Polakovič, Milan
Source:
Food chemistry 2010 v.123 no.2 pp. 369-376
ISSN:
0308-8146
Subject:
enzyme inactivation, kinetics, enzymes, enzyme activity, ohmic heating, food processing quality, model food systems, pasteurization, alkaline phosphatase, pectinesterase, peroxidase
Abstract:
Ohmic heating of milk and fruit and vegetable juices was carried out at several incubation temperatures to investigate inactivation of alkaline phosphatase, pectin methylesterase and peroxidase. Mechanisms of inactivation of these enzymes and corresponding kinetic models were verified for each food material, using the multitemperature evaluation of inactivation data. Compared to inactivation by conventional indirect heating, kinetic parameters were changed but inactivation mechanisms remained the same. The kinetic parameter changes were relatively minor for pectin methylesterase and alkaline phosphatase. A significant destabilization of the labile isozyme fraction of peroxidase occurred by the effect of ohmic heating when the greatest decrease of stability was obtained for carrot juice.
Agid:
787236