Effects of NaOH/NaCl pickling on heat-induced gelation behaviour of egg white

Effects of the brine solution with different NaOH concentrations on the physicochemical properties, intermolecular forces, and gel properties of duck egg whites were studied. The free alkalinity, salt content and surface hydrophobicity of egg whites increased as the pickling time and NaOH concentration increased. The primary intermolecular forces (disulfide bonds and hydrophobic interactions) in the alkali egg white gels were increased firstly and then decreased, resulting from the fact that the proteins were degraded under strong alkali conditions during the late stage of the pickling process. Changes of hardness and springiness of egg white gels were closely related with the interactions of the protein molecules. Thereinto, the change tendency of springiness was in accordance with the changes of hydrogen bond of egg white gels. The colour of the egg white gels obtained from alkali treatment changed from white to amber during pickling.