Diffusion coefficients of water and sucrose in osmotic dehydration of papaya

Mass transfer during osmotic dehydration of papaya in sucrose solution has been studied. A mathematical model based on Fick's law for unsteady state mass transfer, considering shrinkage, has been used to calculate the moisture and sugars diffusion coefficients. Also, a diffusional model with simultaneous shrinkage was developed using a finite difference method to solve differential equations, assuming moisture content-dependent diffusivities for moisture and sugars. The validity of both proposed models was verified by the good fit between the experimental and calculated curves. The mean percent relative errors were 2.48 and 9.92 for moisture content, and 4.26 and 22.51 for total sugars content, for Model 1 and Model 2, respectively.