OSMOTIC DEHYDRATION OF YACON SLICES: EFFECT OF DIFFERENT POLYOLS ON MASS TRANSFER PARAMETERS

ABSTRACT – The aim of this study was to evaluate the parameters of mass transfer in the dehydration of yacon slices with different polyols as osmotic agents. The samples were immersed on hypertonic solutions (40 °Brix) of xylitol, maltitol, erythritol, isomalt and sorbitol at 25 °C. The kinetics of solid gain (SG), water loss (WL) and water activity (aw) of the yacon slices were evaluated over 120 minutes of osmotic dehydration. The effective diffusion coefficients of water and solids were calculated by the diffusive model of Fick. The results showed that the SG was greater in samples treated with solutions of erythritol and lower in isomalt and maltitol solutions. Samples immersed in solutions of sorbitol and xylitol showed intermediate SG. The samples treated in solutions of sorbitol, xylitol and erythritol presented higher water diffusion coefficients and were more effective at reducing parameters of WL and aw than the other polyols. The model of Fick represented well the differences between the kinetics of WL and SG for the tested polyols. 1