What is Whey?

Whey or milk serum is a liquid derived from milk rich in proteins and peptides. Whey proteins and peptides play a crucial role in the innate immunity of the off-springs of milk producing mammals including humans. Whey remains as a byproduct after milk has been coagulated or curdled and strained. This milk byproduct is produced during the manufacture of cheese or casein and has several commercial uses. Rennet, a complex of enzymes produced in any mammalian stomach, is often used in the production of cheese. “Sweet whey” is a byproduct of the manufacture of rennet type hard cheeses like cheddar or Swiss cheese. “Acid whey”, or sour whey, is a byproduct produced during the manufacture of acid types of dairy products, for example during the manufacture of cottage cheese or strained yoghurt.

Protein components of whey include serum albumin (SA), α-lactalbumin (α-LA), β-lactoglobulin (β-LG) and immunoglobulins (IgGs) as well as several minor proteins including lactoferrin, lactoperoxidase and lysozyme. These proteins have important antimicrobial and carrier functions. Most protein sequences are now known for the whey proteins and their genetic properties and factors responsible for quantitative variability in their expression, are well documented in the literature. To determine the physico-chemical characteristics or properties of whole whey, including free amino acids, peptides and proteins, whey can be analyzed using a combination of amino acid analysis, electrophoresis, chromatography and several spectroscopic methods.