Desorption isotherms and thermodynamic properties of sweet corn cultivars (Zea mays L.)

P>The desorption isotherms and thermodynamic properties of two cultivars of sweet corn were obtained during the drying process of these products. The isotherms were determined by a dynamic method for various temperature and humidity conditions. Equilibrium moisture content (X-eq) data were correlated by the Guggenheim-Anderson-de Boer model and an artificial neural network (ANN) model. These models were fitted to the experimental data. The X-eq for corn grain increased with an increase in the relative humidity at fixed temperature and decreased with an increase in temperature at a constant relative humidity. The experimental data were analysed by a thermodynamic approach to obtain the isosteric heat of desorption (delta H), differential entropy (delta S), activation energy (E-a) and Gibbs free energy (delta G). The delta H and delta S increased with a decrease in moisture content, while delta G decreased exponentially with an increase in X-eq. The Arrhenius equation was used to obtain E-a values, with Supersweet corn having higher E-a.