Predicting phase equilibrium of aqueous sugar solutions and industrial juices using COSMO-SAC

Abstract

COSMO-SAC model was used to predict bubble point pressure, bubble point temperature, water activity, freezing point depression and solubility of sugars in aqueous solutions. COSMO-SAC is based on quantum chemistry computations and has a high predictive character, not requiring a specific parameter calibration for each application. For most systems studied, the results obtained were close to experimental data, with relative mean errors varying from 0.1% to 6.4% for vapor–liquid equilibrium. Solubility results with COSMO-SAC presented the same tendency observed in experimental data, but with higher deviations, probably due to the fact that the loss of crystalline structure in sugars is a kinetic process more than a thermodynamic melting, and does not occur at a single temperature with a constant enthalpy value. COSMO-SAC model was also used to predict industrial juices water activity, bubble point temperature, and freezing point depression. Very low deviations from experimental data were observed for COSMO-SAC calculations, similar to those found for simpler sugar solutions.