Determination of moisture desorption enthalpy of mesquite gum with differential scanning calorimetry and thermogravimetric analysis

Moisture sorption isotherms were determined for mesquite gum at 25, 35 and 45 degrees C. The water desorption enthalpy was calculated from the isother ms with the Clausius-Clapeyron equation, and additionally by both different ial scanning calorimetry and thermogravimetric analysis. The two calorimetr ic techniques showed greater degree of water binding at the product surface at the lower moisture contents. There was a decrease in desorption enthalp y when moisture content was increased. Negative enthalpy values suggested a n endothermic reaction probably attributed to biopolymer solution. Results indicated that calorimetric and thermogravimetric analyses are suitable phy sical methods to estimate isosteric heats of mesquite gum.