Thermodynamic analysis of the sorption process of mesquite gum

Determination of the thermodynamic parameters, allows for a more thorough interpretation of sorption isotherms and provides a better insight into sorption mechanisms. In this work, the adsorption and desorption isotherms of mesquite gum were determined at 25, 35 and 45degreesC. All isotherms were fitted using the GAB model and the thermodynamic properties were estimated by Othmer's method. The hysteresis decreased when temperature increased. However the effect of temperature was higher on the desorption isotherms, indicating the existence of metastable states. The adsorption process showed smaller enthalpy values during the hysteresis as compared to desorption process. The minimum integral entropy for the adsorption and desorption was located around 14 g H2O/100 g dry solids. This suggests that it is possible to deter-mine the most suitable conditions for storage, using adsorption or desorption isotherms.