What is whey (simple answer)?
Whey is a protein found in milk and dairy. It is an complete protein. This means it contains all the amino acids your body needs to function and build important body parts like liver cells and muscles. Due to the fact that they are so easily digested, acid whey and sweet whey are considered some of the best protein foods for human consumption. Check out the summary of whey health benefits!
What is whey (complicated answer)?
There are two main types of proteins in milk, whey and casein. Whey is the liquid protein remaining after milk has been curdled and strained to make yogurts and cheeses. In curdling, milk casein proteins are denatured through acid or heat. Denatured proteins lose their ability to form a 3-D structure and tend to bind together forming large clumps. These protein clumps are strained out to form yogurt or cheese leaving the excess liquid and whey protein. About 20% of milk protein is whey (Krissansen 2007).
Whey is a high quality food. It contains nutrients such as whey proteins (beta-lactoglobulin, alpha-lactalbumin, bovine serum albumin, immunoglobulin), lactoferrin, fatty acids, lactose (milk sugar), lactic acid, vitamins, minerals and other substances. In addition to being a complete protein source, whey is high in branched chain amino acids and sulfur containing amino acids. Branched chain amino acids promote muscle growth and can also be used by muscles as fuel. Sulfur containing amino acids, cysteine and methionine are used by the body to make glutathione, an important antioxidant.
Whey can be acidic or sweet. The type of whey formed depends on the type of cheese or yogurt. Acid whey is the by-product of soft cheese, fresh cheese, yogurts and cottage cheese. It is normally curdled with lactic, citric or acetic acid. Sweet whey is the by product of hard or pressed cheeses normally made with rennet. Acid whey has a lower pH than sweet whey since more of the lactose, or milk sugar, in the whey is converted into lactic acid. Acid whey also contains more minerals such as calcium, zinc and potassium.
Liquid whey and whey protein have many health benefits.
- Krissansen GW. Emerging health properties of whey proteins and their clinical implications. J Am Coll Nutr. 2007;26:713S-23S. Pubmed.