Modeling of Mass Transfer during Osmotic Dehydration of Apple Using an Enhanced Lumped Model

In this study, an improved lumped model has been developed for transient one-dimensional mass transfer inside a solid material during osmotic dehydration using a polynomial approximation method. The proposed model was validated by experimental water loss and solid gain data obtained from osmotic dehydration of infinite slab and infinite cylindrical-shaped samples of apple in sucrose solution. Experiments were conducted at nine combinations of three solution concentrations (30%, 40%, and 50% w/w) and three temperatures (30 degrees C, 40 degrees C, and 50 degrees C). The two-parameter model, developed by Azuara et al., was used to predict water loss and solid gain at equilibrium condition and moisture and sucrose diffusivities were estimated by fitting the experimental moisture loss and solid gain data to the Fick's second law of diffusion. The predicted values of average water loss and solid gain by polynomial approximation method fit approximately well to the experimental data and also to the predicted values by the exact analytical method. The values of mean relative errors for the polynomial approximation method with respect to the experimental data were estimated between 15.0 and 19.1%. Also, the related mean relative errors for exact analytical method were between 4.5 and 8.1%.