2D-DIGE images of the egg-white proteins from the fresh (left) and cooked (right) hen eggs. Nine large spots (ovalbumin, ovalbumin X, ovalbumin Y, ovotransferrin, ovoglycoprotein, ovoinhibitor, TENP, clusterin, Hep21 protein) are clearly visual in both gel images. The contents of most of these proteins were comparable in the two images, except two heat-sensitive proteins (ovotransferrin, ovoglycoprotein), whose concentrations reduced in the cooked case.