WATER ACTIVITY IN SOLUTIONS CONTAINING ORGANIC ACIDS

Abstract
A thermodynamic model for the activity coefficient was used to predict au in some food-related solutions. Water activity values for organic acids solutions (malic, tartaric and citric) were measured experimentally and used to adjust interaction parameters for the UNIFAC model. The partial dissociation phenomenon for weak electrolytes in aqueous systems was considered and concentrations of species were calculated. Predictions of au with mean deviations of 0.26% were obtained.