Whey protein is a mixture of proteins isolated from whey, which is the liquid by-product left over during cheese production when milk coagulates
. It contains several key proteins such as beta-lactoglobulin (~65%), alpha- lactalbumin (~25%), and serum albumin (~8%), along with immunoglobulins
. Whey protein is water-soluble and is commonly processed into powdered supplements for convenient consumption
. Milk contains two main types of protein: about 20% whey and 80% casein in cow's milk, while human milk has a higher whey proportion (around 60%)
. Whey protein is valued for being a complete protein, meaning it contains all nine essential amino acids necessary for human health
. There are several commercial forms of whey protein:
- Whey Protein Concentrate (WPC): Contains 29%–89% protein by dry weight, with some fat and lactose remaining
- Whey Protein Isolate (WPI): Processed to remove most fat and lactose, typically over 90% protein
- Whey Protein Hydrolysate (WPH): Predigested and partially hydrolyzed for easier absorption, often used in hypoallergenic formulas
- Native Whey Protein: Extracted directly from skim milk, not as a cheese by-product, and lacks some components like glycomacropeptide
Whey protein is popular as a dietary supplement to increase protein intake, support muscle growth, and aid muscle repair due to its high leucine content, an amino acid critical for muscle protein synthesis
. It may also have benefits for cholesterol management and metabolic health
. In summary, whey protein is a high-quality, fast-absorbing protein derived from milk's liquid fraction during cheese making, widely used as a supplement for muscle building and general nutrition
