Solution properties and taste behavior of lactose monohydrate in aqueous ascorbic acid solutions at different temperatures: Volumetric and rheological approach

The densities and viscosities of lactose monohydrate in aqueous ascorbic acid solutions with several molal concentrations m = (0.00-0.08) mol kg(-1) of ascorbic acid were determined at T = (298.15-318.15) K and pressure p = 101 kPa. Using experimental data apparent molar volume (phi(V)), standard partial molar volume (phi(0)(V)), the slope (S-V*), apparent specific volumes (phi(Vsp)), standard isobaric partial molar expansibility (phi(0)(E)) and its temperature dependence (partial derivative phi(0)(E)=partial derivative T)(p);the viscosity B-coefficient and solvation number (S-n) were determined. Viscosity B-coefficients were further employed to obtain the free energies of activation of viscous flow per mole of the solvents (Delta mu(0 not equal)(1)) and of the solute (Delta mu(0 not equal)(1)). Effects of molality, solute structure and temperature and taste behavior were analyzed in terms of solute-solute and solute-solvent interactions; results revealed that the solutions are characterized predominantly by solute-solvent interactions and lactose monohydrate behaves as a long-range structure maker. (C) 2016 Elsevier Ltd. All rights reserved.