Albumin, a simple protein found in most animals and in some plants. Albumins dissolve in water and dilute salt solutions and coagulate (curdle or clot) in the presence of heat. Egg albumin, which is usually spelled albumen, accounts for more than half of the protein content in egg white.
Albumins are usually named according to where they are found in nature. For example, the albumin found in blood serum is called serum albumin. The blood serum of all vertebrates (animals with backbones) contains albumin. The protein value of meat and milk is partially determined by the albumin content. Albumins are contained in the seeds of certain plants, such as beans, peas, and peanuts. Albumins are also present in grains, in poppy-seed oil, and in the fleshy part of coconuts.
The white of an egg is sometimes a successful remedy for certain types of poisoning because, in coagulating, the albumin coats the poison and prevents it from taking effect. In some industries, such as dye-making, albumins are used as clarifying agents. As the albumins coagulate, they clarify (remove impurities from) liquids. Concentrated albumin from human blood serum is administered intravenously as a treatment for extreme shock and hemorrhage.
Blood, egg, and milk albumins are widely used in industry. Ox blood albumin, for example, is used in textile printing to hold the colors to the fabric. Egg albumin that has been beaten to a froth is often used in prepared foods to give them body. Milk albumin is used in making adhesives and varnishes.
Egg albumin is also called ovalbumin. Alternate names for milk albumin are lactalbumin and whey albumin. Albumins are compounds of carbon, hydrogen, oxygen, and (usually) sulfur. Ovalbumin contains phosphorus in addition to these elements.