Mass transfer during osmotic dehydration of green bean in salt solution: A polynomial approximation approach

Abstract

In this study, moisture and solute variations inside cylindrical green bean samples during osmotic dehydration in salt solution were predicted using a modified lumped mathematical model. The polynomial approximation approach was used to obtain the average moisture and solute concentrations in the radial direction. Results of the proposed model were compared with the experimental data, obtained from osmotic dehydration of long cylindrical samples of green bean in different temperatures and concentrations of salt solution, as well as the exact solution of the original partial differential equation. Results show that the P. A. method's predictions followed the general trend of the experimental dehydration curves. Also dehydration curves show a good agreement between the P. A. and exact analytical method's predictions. The values of mean relative errors between the P. A. method's predictions and experimental data are between 14 and 24%. Also the related mean relative errors for exact analytical method are between 10 and 27.5%. Although the exact analytical solution provides better results, as expected, but considering the approximate nature of the P. A. method and in view of the fact that the deviations of P. A. and the exact analytical methods from the experimental data are comparable, the P. A. method could be used because of its simplicity.