Development of a validated model to describe the individual and combined water activity depressing effects of water soluble salt, sugar and fat replacers

The relationship between water activity (aw) and concentration of NaCl, sucrose and various simple and commercial salt, sugar and fat replacers was determined. The model originally developed by Favetto and Chirife (1985) and extended by Roa and Tapia (1998) was successfully used to model the relationship between aw and molality of the binary and multi-component aqueous solutions. These models were then reparameterized to enable the aw to be modeled as function of the water phase concentrations of binary and multi-component solutions. This reparameterization enables the modeling of the aw depressing effects of compounds for which sufficient data required to calculate the molecular weight cannot be obtained. Both models were successfully used to predict the aw of some food products including meat and fish products and mayonnaises with average deviations of 0.0052 from the measured aw, and bias and accuracy factors of 0.995 and 1.0057, respectively.