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Inactivation of Peroxidase by Ultraviolet–Visible Irradiation: Effect of pH and Melanoidin Content

Falguera, Víctor, Moulin, Anthony, Thevenet, Laurent, Ibarz, Albert
Food and bioprocess technology 2013 v.6 no.12 pp. 3627-3633
fruit juices, irradiation, melanoidins, models, pH, peroxidase, temperature
Ultraviolet-visible irradiation has been proved to be effective in inactivating microorganisms and some enzymes in some foodstuff such as fruit juices and other derivatives. This piece of work provides some details that may help to understand the interaction between ultraviolet-visible radiation and horseradish peroxidase. When this enzyme is subjected to this process, the first stage of activation is observed, followed by the second stage of inactivation. Both activation and inactivation phases largely depend on the pH and less so on the temperature at which irradiation is performed. Peroxidase inactivation can be properly described by a kinetic model in which two consecutive steps are assumed and also by means of the Weibull equation. The study of the behavior of peroxidase in irradiated solutions that contain different concentrations of melanoidin leads to the conclusion that the enzyme is most affected by the radiation between 225 and 275 nm. ©Springer Science+Business Media New York 2012.