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 isotherms with the Clausius-Clapeyron equation, and additionally by both differential scanning calorimetry and thermogravimetric analysis. The two calorimetric techniques showed greater degree of water binding at the product surface at the lower moisture contents. There was a decrease in desorption enthalpy when moisture content was increased. Negative enthalpy values suggested an endothermic reaction probably attributed to biopolymer solution. Results indicated that calorimetric and thermogravimetric analyses are suitable physical methods to estimate isosteric heats of mesquite gum.