Densities, rho, for glycine, L-alanine, L-valine, and L-leucine [(0.05 to 0.30) m] in aqueous lactose solutions ranging from pure water to 6 mass% lactose were determined at T = (293.15, 298.15, 303.15, and 308.15) K. The density was used to compute apparent molar volume, V-phi, partial molar volume at infinite dilution, V-phi(0), and experimental slope, S-V were obtained and interpreted in terms of solute-solvent and solute-solute interactions. These data were used to calculate the (partial derivative V-phi(0)/partial derivative T)(P) values. The partial molar volume of transfer, Delta V-phi(0) from water to aqueous lactose solutions at infinite dilution has also been calculated. In addition to this, the linear correlation of V-phi(0) with number of carbon atoms in the alkyl chain of amino acids was utilized to determine the respective contributions of NH3+COO-, and CH2 groups to V-phi(0). (C) 2010 Elsevier Ltd. All rights reserved.