Mass transfer kinetics of the osmotic dehydration of yacon slices with polyols

Abstract

Osmotic dehydration using different polyols was studied. Yacon slices were immersed in solutions of xylitol, maltitol, erythritol, isomalt and sorbitol. The kinetics of solid gain (SG), water loss (WL) and water activity (aw) were evaluated (0, 10, 30, 45, 60, 90 and 120 min). The effective diffusion coefficients of water (Deffw) and solids (Deffs) were calculated with the models of Fick and Barbosa Júnior et al. At the end of the process, the highest SG was obtained with erythritol solutions; the lowest with sorbitol and maltitol and intermediate values of SG were acquired in osmotic processes with solutions of isomalt and xylitol. The samples treated in sorbitol, xylitol and erythritol solutions presented the highest Deffw and were more effective at increasing WL and reducing aw. The model of Barbosa Júnior et al. presented the best fitness. The Deffw/Deffs ratio showed better results for osmotic processes involving sorbitol and xylitol.