Sorption isosteric heat determination by thermal analysis and sorption isotherms

A procedure based on thermal analysis thermogravimetry (TG) and differentia l-scanning calorimetry (DSC) was examined to compute isosteric heat of sorp tion for water. DSC measurements on samples with different moisture content allowed determining enthalpy variations due to water vaporization. Thermog ravimetries performed on the same samples enabled a link to be made between enthalpic measurements and weight losses and thus compute isosteric heats. The procedure was applied to cauliflower and potato starch. From equilibri um isotherms by applying the Clausius-Clapeyron equation, the isosteric hea ts of sorption were calculated. The comparison of the values obtained throu gh both procedures showed a good agreement.