Osmotic Dehydration of Cassava Cubes: Kinetic Analysis and Optimization

Abstract

The present work had the objective of studying the osmotic dehydration process of cassava cubes (ManihotesculentaCrantz.) in ternary solutions containing water, sucrose, and sodium chloride. The osmotic dehydration process was studied by using a 24 factorial planning with central points at different conditions of temperature (19-63°C), solute concentration (23-67% w/w), operating time (70-190 min.) and NaCl concentration (0-20% w/w). The process optimization was verified through the performance ratio of minimum solids gain, in conjunction with the maximum moisture loss and reduction of water activity of the material. From the analysis, the optimum condition for osmotic dehydration of cassava cubes was temperature52°C, concentration of the osmotic solution 56%solute,10% NaCl concentration,160 minutes of immersion time and 180 rpm . The study of osmotic dehydration kinetics in the optimized condition showed that the moisture loss reached equilibrium in 180 minutes and the solids gain in 30 minutes. The model of Azuara and contributors was fitted to experimental data of moisture lost and total solids gain, in the optimal condition and good agreement were obtained. From this comparison, the average effective diffusivity coefficients of moisture (1.99x10-8m2/s) and total solids (2.77x10-8m2/s) were estimated.