Evaluation of Mass Transfer Kinetics for Osmotic Dehydration of Oyster Mushrooms (Pleurotus sajor-caju) in Salt-sugar Solution

Abstract

Oyster mushrooms (Pleurotus sajor-caju) were osmotically dehydrated in a salt-sugar solution to remove moisture prior to hybrid microwave drying. Sodium chloride-sugar concentration (15 %:45°B–15 %:65°B), solution temperature (30–60 °C) immersion time (15–240 min) and solution to fruit ratio (4:1 to 8:1) were taken as independent process variables. The effect of various process parameters on mass transfer kinetics was studied. An analytical solution for unsteady-state mass transfer based on Fick’s second law of diffusion was carried out to mathematically describe water loss and solute gain. Effective water diffusivity was in the range of 3.0–1.59 × 10−9 m2/s whereas solute diffusivity values were between 9.44 × 10−10 m2/s and 1.02 × 10−9 m2/s, under these experimental conditions. Based on statistical results, page model gave best goodness of fit on the experimental data.