Kinetics of the approach to sorptional equilibrium by a foodstuff

Abstract The kinetics of equilibration of a vegetable foodstuff with moist air are studied on the basis of its cellular structure. The problem is modelled as a coupled heat and mass transfer phenomenon; since there is a significant shrinkage as moisture decreases, the model takes the effect into account by changing the basis for the mass and energy balances. The resulting nonlinear second‐order partial differencial equations are solved numerically; predicted values of moisture decrease and temperature gain with time are compared with experimental data. A sensitivity analysis of the solution to values of the transport properties shows that the value of effective diffusivity and heat and mass transfer coefficient may alter significantly the predicted equilibration kinetics and center temperature. The adopted value for heat of sorption has less influence. Changes in effective thermal conductivity and porosity bear little influence on predictions.