Solubility of Proteins from Quail (Coturnix coturnix japonica) Egg White as Affected by Agitation Time, pH, and Salt Concentration

The solubility of proteins from quail egg white subjected to different agitation times, pH, and NaCl at 25°C was evaluated in this study. The greatest solubility achieved was obtained in the 0.05 mol/L of NaCl, pH 10.0, and under agitation for 1 h. The lowest solubility was found in the NaCl 1.0 mol/L, pH 3.0, and agitated for 2 h. Under the test conditions, aqueous solutions of NaCl 1.0 mol/L, pH 3.0, and agitated for 2 h may provide the greatest extraction index of proteins from quail egg white because these conditions promoted the protein precipitation in a large extension.