Sugar: Addition of sugar to an egg mixture elevates the temperature at which coagulation takes place, the more sugar the greater the heat required to bring about the coagulation. The addition of sugar also increases the heat stability of the proteins.
Salt: The addition of salt to an egg mixture lowers the temperature at which the coagulation takes place. Certain salts such as chlorides, phosphates, sulphate and lactates aid in gel formation in cooked egg mixtures. They may be added before or after heating. If they are added after heating, curdling may occur during the addition.
Acids: Any acid material added to an egg mixture coagulates more rapidly and produces a firmer gel and lower the coagulation temperature of the mixture. Prolonged heating of an acid egg mixture, however, will bring about peptidisation -breaking up of large aggregate of molecules into smaller ones resulting in thinning out of the mass and curdling. The hardness and cohesiveness of egg white gels have been reported to a minimum at pH 6 and increases as the pH is either decreased to 5 or increased to 9.
Starch: It is better to bring the starch mixture to its maximum thickness before adding the uncooked egg, because coagulation and gelatinization temperatures of egg and starch differ.