Also known as egg white. Depending on the size of the egg, albumen accounts for most of an egg’s liquid weight, about 66%. The white contains more than half the egg’s total protein, a majority of the egg’s niacin, riboflavin, magnesium, potassium and sodium, and none of the fat. The white of a large egg contains about 17 calories.
Albumen color is opalescent and doesn’t appear white until an egg is beaten or cooked. The cloudy appearance comes from carbon dioxide. As eggs age, carbon dioxide escapes, so the albumen of older eggs is more transparent than that of fresher eggs.
The albumen consists of four alternating layers of thick and thin consistencies. From the yolk outward, they are designated as the inner thick or chalaziferous white, the inner thin white, the outer thick white and the outer thin white. As an egg ages, the egg white tends to thin out because its protein changes in character. That’s why fresh eggs sit up tall and firm in the pan while older ones tend to spread out.
When you beat egg white vigorously, it foams and increases in volume six to eight times. Egg foams are essential for making meringues, puffy omelets, soufflés, angel food and sponge cakes.