The objective of this study was to develop a suitable method for determining the effective diffusion coefficient of water in banana (Prata variety) from experimental data of osmotic dehydration (OD) and using this coefficient for predicting dehydration of the same sample under other situations. Different methods were compared in order to determine the best coefficient to be used in the predictive models. The analytical solution of the diffusion equation allowed estimating averaged values of coefficients between the initial moisture and the average sample moisture at a given instant. The numerical method allowed estimating how the effective diffusion coefficient varies with the moisture. The models prediction ability were validated using a dehydration data set not used for estimating the diffusion coefficients. The use of the diffusive model with a coefficient that depends on the moisture content has the best predictive ability, because it takes into account that the coefficient decreases during the OD. (C) 2013 Elsevier Ltd. All rights reserved.