Whey protein is a mixture of proteins isolated from whey. Whey is the liquid part of milk that separates during cheese production.
Milk actually contains two main types of protein… casein (80%) and whey (20%).
Whey is found in the watery portion of milk. When cheese is produced, the fatty parts of the milk coagulate and the whey is separated from it as a by-product (4).
If you’ve ever opened a yogurt container to see liquid floating on top, this is whey. Cheese makers used to discard it before they discovered its commercial value (5).
After being separated during cheese production, whey goes through a series of processing steps to become what people generally recognize as whey protein… a powder that is added to shakes, meal replacements and protein bars (6).