Viscosity of Multicomponent Solutions of Simple and Complex Sugars in Water

Sugar is a key ingredient widely used in food industries mainly in the form of solution in water. Due to different physical and chemical properties, different simple and complex sugars are mixed together to obtain the optimal mixture mainly in terms of freezing point and sweetness capability. Aiming to measure some of these relevant properties, in this paper viscosity data and starting freezing temperature have been measured for a wide range of binary, ternary, and quaternary sugar solutions in water. The onset freezing temperature for solutions was calculated from DSC data, applying a new iterative numerical technique. From viscosity data, a method was developed to calculate the viscosity of multicomponent aqueous solutions of simple and complex sugars, also including temperature effects. The proposed model estimates the viscosity of a multicomponent solution by assuming the summability of the contribution from binary solution viscosity and introducing pairwise interaction parameters. The values of these parameters, as a function of temperature and composition, have been estimated from experimental data of binary and ternary solutions. Quaternary solution data have been used to check the model in a predictive way. The resultant predictions were good (error below 15 %) for diluted solutions, but agreement fails for concentrated solutions. Therefore, another parameter, taking into account ternary interactions, was added, and the model results fit the experimental data within a 10 % maximum error over the entire concentration and temperature range.