Effect of combined pressure and temperature on soybean lipoxygenase. 2. Modeling inactivation kinetics under static and dynamic conditions

In previous research, kinetics for irreversible inactivation of soybean lipoxygenase (LOX) by combined pressure and temperature have been thoroughly studied in the pressure range 0.1-650 MPa at temperatures varying from 10 to 64 degrees C (Ludikhuyze et al. J. Agric. Food Chem. 1998, 46, 4074-4080.). In the present paper a mathematical model describing the variation of the inactivation rate constant of soybean LOX as a function of pressure and temperature was finalized, starting from the Eyring equation. In the latter equation, the temperature-dependent parameters (k(refP,)V(a)) were replaced by mathematical expressions. Subsequently, the proposed model structure was verified to predict likewise the extent of inactivation under variable pressure and temperature conditions, provided the kinetic parameters were re-estimated. Finally, it was observed that multiple application of high-pressure enhanced the inactivation of soybean LOX, the effect becoming more pronounced at low temperature and when the amount of cycles increased.