The amino acids marked with an asterisk are called essential amino acids, because they cannot be synthesized in the human body, and must be obtained from food directly. All eight essential amino acids are present in casein protein.
Calcium caseinate is produced from skim milk by adding an acid to cause the protein to coagulate, where it can be filtered to separate the curds from the whey.
Sodium caseinate is produced by reacting the acid casein with sodium hydroxide.
Caseinates are used as sources of protein for nutrition.
Besides their nutrient value, casein proteins have many other uses. They are good emulsifiers, helping fats to stay suspended in water based products such as milkshakes, coffee creamers, and ice creams. They are used as binders in processed meats (lunchmeats, sausages, etc.).
Caseins are used in wine-making to clarify the wine, by causing fine particles to coagulate with the protein so they can be easily filtered out or precipitated.
Casein proteins were one of the first plastics, and they are still in use for this purpose. Thin plastic films of casein can be made by adding glycerol or sorbitol as a plasticizer, a substance that lowers the temperature at which a plastic softens, and makes it more pliable.
Caseins are used as food colors, where they make a nice opaque white color, which can then be tinted with other colors as required.