A moving boundary model for fruit isothermal drying and shrinkage: An optimization method for water diffusivity and peel resistance estimation

A moving-boundary FEM model describing fruits isothermal drying was employed as an inverse problem to estimate water diffusivity and peel resistance including shrinkage. The water diffusivity and peel resistance were estimated by the Levenberg-Marquardt optimization algorithm based on the experimental drying curves. The surface resistance is the sum of the peel and the boundary layer resistances, the latter being negligible compared to the former. The estimated resistance of the peel is found to be reduced by 62% as the drying temperature increases from 45 degrees C to 65 degrees C and by 55% as the drying temperature increases from 55 degrees C to 65 degrees C. The proposed model predicts efficiently water content, shrinkage and water diffusivity.