The thermodynamic properties of anchovy fillets and enzymatic modified pastes in two hydrolysis degrees (3% HD and 14% HD), at 50, 60 and 70 degrees C were evaluated. The GAB model was used to calculate the values of the monolayer moisture content and the thermodynamic properties of the samples. The enzymatic modification led to the increases of the superficial area and differential enthalpies, and decrease of the differential entropies in relation the samples in natura. The enthalpy-entropy compensation showed that the process was controlled by the enthalpy, it was only spontaneous for the samples in natura. Pore size decreased with enzymatic modification, and all samples were in the limit of region between micropores and mesopores (<2 nm) for moisture content of 15%, and mesopores (from 2 to 50 nm) to moisture content above 15%. (C) 2012 Elsevier Ltd. All rights reserved.