 The major whey protein in the nonfat milk solids is known as beta-lactoglobulin, and a crucial feature of its structure is that there exists a single sulfhydryl group that is protected by the alpha helix, and when heating of the milk solids occurs, these groups participate in disulfide exchanges with other molecules.This interchange prevents the renaturation of the whey proteins.If the crosslinking of the sulfide groups does not occur, the whey proteins can rebond and weaken the gluten network.