Journal of food science vol:66 issue:5 pages:686-693
Kinetics of lipoxygenase (LOX) inactivation in green peas (Pisum sativum) by temperature and/or pressure was studied at different levels of food complexity, namely in green pea juice and in intact vegetables (insitu study). Pea LOX in both matrices was irreversibly inactivated either by thermal or by combined pressure-temperature treatment, and the inactivation followed a first-order reaction. Pressure levels below 200 MPa retarded thermal inactivation of LOX at temperatures above 60 degreesC. Moreover, above 60 degreesC, enzyme activation under pressure occurred prior to inactivation. At elevated pressure, LOX inactivation rate could be accelerated by a temperature increase above 10 degreesC as well as by a temperature decrease below 10 degreesC. The pressure-temperature dependence of the LOX inactivation rate constants both in green pea juice and in intact green peas was described successfully using the same mathematical model. On the basis of this mathematical model, an iso-rate contour diagram for LOX inactivation in green pea juice and in intact green peas was constructed.