ABSTRACT This work evaluated the influence of different values of pH (3.0, 4.6, 6.0, 8.0, 9.0 and 10.0) and salt concentrations (0.05, 0.1, 0.2, 0.35 and 0.5) mol/L on the solubility and density of quail (Coturnix coturnix japonica) egg white proteins for three types of salts (NaCl, Na2SO4and [NH4]2SO4). The experiment was carried out in a completely randomized design, using six pH values, five salt concentration levels and two repetitions. The variations in pH and salt concentration values had a significant effect on the protein solubility data. The highest solubility value (99.40 g/100 g) was obtained in the system containing NaCl (0.1 mol/L), at pH 3.0. The lowest solubility value (63.46 g/100 g) was obtained in the system containing Na2SO4 (0.5 mol/L), at pH 8.0. Under the tested conditions, the aqueous solutions of Na2SO4at 0.5 mol/L and pH 8.0 might lead to a higher protein extraction. PRACTICAL APPLICATIONS Determination of protein solubility data are relevant for the food industry and for academic researchers, because they are necessary (1) to define the processing conditions of foods containing different protein sources, (2) to obtain protein concentrates, (3) for the development of the extraction and purification processes of proteins with high aggregate value, such as quail egg white proteins, and (4) to use in the acquirement of other functional properties of foods.