Modeling of the water-sucrose state diagram below 0 degrees C

The state diagram of sucrose-water solutions was constructed bq the use of model calculations; the activity coefficient from the UNIQUAC model allowed determination of the solution-ice equilibrium curve and the glass transition temperature as a function of the composition was evaluated from the Gordon-Taylor equation. The accuracy of the glass transition temperature (T-g') of the maximally freeze-concentrated fraction, determined from the intersection of both curves, was analyzed and discussed, While the UNIQUAC model predicted reliable ice melting temperatures in the high sucrose concentration range, a significant variation of the fitted glass transition curve was obtained due to the selected temperature values for the glass transition temperature. The calculated glass temperatures (T-g') were compared with direct DSC experiments. (C) 1997 Elsevier Science Ltd.