An approximate method for nonlinear diffusion applied to enzyme inactivation during drying

An approximate model was developed for nonlinear diffusion with a power-function variation of the diffusion coefficient with concentration. This model may serve for the computation of desorption times and concentration profiles in non-shrinking or shrinking slabs, cylinders or spheres, under isothermal as well as non-isothermal conditions.<p/>For the kinetics for thermal enzyme inactivation, a relation was postulated, which includes a possible moisture dependence of the inactivation rate, which was tested by experiments with soy bean lipoxygenase, entrapped in a glucosecalciumalginate gel.<p/>The model was applied to the simulation of enzyme inactivation during drying and tested by drying experiments with soy bean lipoxygenase in the above-mentioned model material.<p/>Good agreement was observed between the results, obtained with the approximate model, the numerical solution of the complete model and the experimental results.