Simulation of the multicomponent diffusion during the osmotic dehydration of apple: determination of the diffusion coefficients by the simplex method

Abstract

Water loss and sugar gain were modeling during the osmotic dehydration process of cylinders of apple. The transfer of solute to the fruit and the water to the solution was based on Fick's 2nd law generalized for simultaneous diffusion and solved by the finite element method using the software COMSOL Multiphysics 3.2. The main and cross diffusion coefficients, the relationship between the mass transfer and mass conductivity coefficients, as well, the Biot number were determined on the simulation with the implementation of the simplex optimization method through minimization of the percentage deviations. The value of deviation between the experimental and the simulated data were 5,76% for sucrose and 2,95 for water. The simulation despising the Biot number indicated that the resistance of the film can be disregarded in the phenomenon of mass transfer studied. The system developed to simulate solute and water diffusion will permit control and modulation of the sugar content in cylinder of apple.