Mathematical Simulation of Batch Convective Drying of Food with Sorption Isotherms Calculated by Ross Equation

Abstract

Mathematical simulations of the batch convective drying of cassava and carrot were developed employing predicted sorption isotherm. Sorption isotherms of carrot and cassava were predicted by Ross equation in conjunction with Raoult's Law and Norrish equations. The predictions considered the average chemical composition of the main solutes and nonsolutes on dry basis through a FORTRAN computational program that calculated the water activity at different moisture contents. The predicted and experimental water activity values were fitted by multiple linear regression to obtain empirical parameters from the Henderson modified equation. No difference was found between drying curves of these foods developed by simulation with sorption isotherms obtained experimentally and predicted through chemical composition. Therefore, it is possible generalize the simulation of food drying without necessity to have experimental data of water activity with saving time of operation.