A fundamental 2-D model was developed to predict the heat and mass transfer that occur during the frying and cooling process of tortilla chips. Semi-empirical correlations were included to account for structural changes. such as shrinkage and expansion due to puffing. All water present in the tortilla chip was considered bound and led to shrinkage when removed. The parameters that were studied included water saturation. S-w. oil saturation, S-o. temperature, T, and pressure, A Liquid flow results from convective flow due to the gradient in total gas pressure and capillary flow due to the gradient of capillary force. Gas movement results from convective flow due to the total gas pressure gradient and Knudsen diffusion due to the concentration gradient. The only transport phenomenon during cooling is oil absorption, which is assumed to be a function of the capillary pressure. (C) 2002 Elsevier Science Ltd. All rights reserved.