Whey protein is a mixture ofproteins isolated fromwhey, the liquid material created as a by-product ofcheese production. The proteins consist ofα-lactalbumin,β-lactoglobulin, serumalbumin andimmunoglobulins.^[1]Glycomacropeptide also makes up the third largest component but is not a protein. Whey protein is commonly marketed as aprotein supplement.

Whey is left over when milk iscoagulated during the process of cheese production. Coagulation can happen by addingacid orrennet. It is a 5% solution oflactose in water and contains the water-soluble proteins of milk as well as somelipid content.^[2] Processing can be done by simple drying, or the relative protein content can be increased by removing the lactose, lipids and other non-protein materials.^[3]

The main method to extract protein from whey is membrane filteration. A variety of membrane pore sizes can be used to selectively let different components of whey go through or be retained. Whey can be passed through "microfiltration" which blocks bacteria, caseinmicelles, and fat, then passed through "ultrafilteration" (UF) which blocks proteins. The part that does not go through UF is spray-dried into a concentrated whey protein.^[4] There are also other ways to concentrate protein using filtration membranes.^[5]

Ion exchange chromatography is another major method for whey protein extraction. Methods in development include aqueous two-phase extraction and magnetic fishing.^[5]

Microbes have been engineered to produce proteins similar or even "bioidentical" to whey.^[6] Various companies offer microbe-produced whey and cheese; however, none of these companies stipulate the protein composition of their products, but they do contain some of thegenes needed to make whey proteins.^[7][8]

The protein incow's milk is approximately 20% whey and 80%casein.^[9] The protein inhuman milk is approximately 60% whey and 40% casein.^[10] The protein fraction in whey constitutes approximately 10% of the total dry solids in whey. This protein is typically a mixture ofbeta-lactoglobulin (~65%),alpha-lactalbumin (~25%),bovine serum albumin (~8%) (see alsoserum albumin), andimmunoglobulins.^[11] The third largest fragment of whey protein isolate derived from sweet whey isglycomacropeptide or GMP. However, GMP lacks the secondary structure necessary for it to be classified as a protein and is considered a long amino acid chain. These peptides are all soluble in water in their native forms.

There are four major types of whey protein commercially produced:^[12]

• Whey Protein Concentrates (WPC) have typically low - though not absent - levels of fat andcholesterol. They also contain carbohydrates in the form oflactose. Powders are typically between 29%–89% protein by dry weight.
• Whey Protein Isolates (WPI) are processed to remove fat and lactose, and as a result, WPI powders are typically over 90% protein by dry weight. Like WPC, WPI are mild and slightly milky in taste.
• Whey ProteinHydrolysates (WPH) are whey proteins that are predigested and partiallyhydrolyzed for the purpose of easier metabolizing. Their cost is generally higher than WPC or WPI.^[3] Highly hydrolysed whey may be lessallergenic than other forms of whey, due to its much smaller and simpler peptide chains. For this reason it is a common constituent in hypoallergenic baby milk formulas and medical foods.^[13]
• Native whey protein is extracted fromskim milk, rather than being collected as a byproduct ofcheese production. This type of whey does not contain glycomacropeptide, which is formed only after the addition of rennet.^[14][15][16]

There is evidence that whey protein is more bio-available than casein or soy protein.^[17][18]

Whey protein is commonly marketed as adietary supplement, typically sold in powdered form for mixing into beverages.^[19] Whey protein is also commonly used as athickener to improve texture and decreasesyneresis in many types ofyogurt. Yogurt with high amounts of protein have been more commonly found on shelves due to the recently increasing popularity ofGreek Yogurt.^[20]

The primary usage of whey protein supplements is for muscle growth and development. Eating whey protein supplements before exercise will not assist athletic performance, but it will enhance the body's protein recovery and synthesis after exercise because it increases the freeamino acids in the body's free amino acid pool.^[20]

In 2010, a panel of theEuropean Food Safety Authority (EFSA) panel examined the effects of whey protein on weight loss (via both fat loss and increased satiety) and strength and muscle building. The panel concluded that there's no evidence supporting any weight loss claims and that whey protein is roughly as effective for building strength, muscle and lean body mass as other protein sources.^[19]

Although whey proteins are responsible for somemilk allergies, the major allergens in milk are thecaseins.^[21][22]

Whey cheese, such asricotta, is produced from whey and is rich in whey protein (except forbrunost). The whey protein accounts for about 40–45% of the solids content of ricotta.

• Whey Protein HealthnotesArchived 1 December 2009 at theWayback Machine,University of California, San Diego

• Bodybuilding supplements
• Dietary supplements
• Mammalian proteins
• Cheese

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