KINETICS OF OSMOTIC DEHYDRATION OF MANGO

Abstract

The effects of sucrose syrup concentration (40–70 g/100-g solution) and temperature (40–90C) on water loss and sucrose uptake by mango mesocarp slices during osmotic dehydration were investigated. The effective diffusivities for mass transfer were determined using the slope method based on the Fickian diffusion model. Water loss and sucrose uptake were proportional to the square root of osmotic contact time, implying that the process is Fickian. The specific mass transfer rate constants and effective diffusivities (De), derived from Fick's unsteady-state diffusion equation, increased with temperature and sucrose syrup concentration. De values for water loss and sucrose uptake, which ranged between 2.59 × 10−6 to 5.12 × 10−6 m2/h and 1.70 × 10−6 to 4.14 × 10−6 m2/h, respectively, were related to absolute temperature using an Arrhenius-type relationship. The activation energies, which fell in the range previously reported for diffusion-controlled processes, increased with sucrose syrup concentration and varied from 9.74 to15.16 KJ/mol.