Eqs. (1) and (2) show a two-exponential kinetic model, proposed
earlier for OD combined with PEF (Amami et al.,
2005) and used here to describe the mass transfer. This model
involves two simultaneous processes with different kinetic
coefficients: (a) convection, with fast solute transfer from the
humidified solid surface and from outer broken cells to the solvent;
(b) diffusion, with a slower solute transfer from the inside
of the solid.