Casein from Latin caseus, “cheese” is the name for a family of related phosphoproteins. These proteins are commonly found in mammalian milk,
making up 80% of the proteins in cow milk and between 20% and 45% of the proteins in human milk. Casein has a wide variety of uses, from being a major component of cheese, to use as a food additive, to a binder for safety matches. As a food source, casein supplies amino acids; carbohydrates; and two inorganic elements, calcium and phosphorus.
- Casein paint is a fast-drying, water-soluble medium used by artists. Casein paint has been used since ancient Egyptian times as a form of tempera paint, and was widely used by commercial illustrators as the material of choice until the late 1960s when, with the advent of acrylic paint, casein became less popular. It is still widely used by scene painters.
- Casein-based glues were popular for woodworking, including for aircraft, as late as the de Havilland Mosquito.Casein glue is also used in transformer manufacturing (specifically transformer board) due to its oil permeability. While largely replaced by synthetic resins, casein-based glues still have a use in certain niche applications, such as laminating fireproof doors and the labeling of bottles.
- Some of the earliest plastics were based on casein. In particular, galalith was well known for use in buttons. Fiber can be made from extruded casein. Lanital, a fabric made from casein fiber (known as Aralac in the United States), was particularly popular in Italy during the 1930s. Recent innovations such as QMilch are offering a more refined use of the fiber for modern fabrics.