MODELING OF THE WATER-SUCROSE STATE DIAGRAM BELOW 0-DEGREES-C

The state diagram of sucrose-water solutions was constructed bq the us e of model calculations; the activity coefficient from the UNIQUAC mod el allowed determination of the solution-ice equilibrium curve and the glass transition temperature as a function of the composition was eva luated from the Gordon-Taylor equation. The accuracy of the glass tran sition temperature (T-g') of the maximally freeze-concentrated fractio n, determined from the intersection of both curves, was analyzed and d iscussed, While the UNIQUAC model predicted reliable ice melting tempe ratures in the high sucrose concentration range, a significant variati on of the fitted glass transition curve was obtained due to the select ed temperature values for the glass transition temperature. The calcul ated glass temperatures (T-g') were compared with direct DSC experimen ts. (C) 1997 Elsevier Science Ltd.