A modified UNIFAC model recently proposed in the literature is used to predict thermodynamic properties of aqueous solutions containing different sugars, commonly used in food industries (D-galactose, D-mannose, D-xylose, maltose and lactose), and for which the experimental information available is not sufficient in order to allow the application of UNIQUAC based models. Moreover, the new model is successfully extended to the prediction of the water activity of industrial sugar solutions (e.g., honey and fruit juices), which is used in quality control of foods and processed foods. A comparison with the results obtained from another UNIFAC based model for these solutions is also presented.