Whey protein is a mixture of proteins isolated from whey, the liquid material created as a by-product of cheese production. The proteins consist of α-lactalbumin, β-lactoglobulin, serum albumin and immunoglobulins. Whey protein is commonly marketed as a dietary supplement, and various health claims have been attributed to it. A review published in 2010 in the European Food Safety Authority Journal concluded that the provided literature did not adequately support the proposed claims. For muscle growth, whey protein has been shown to be slightly better compared to other types of protein, such as casein or soy.
Production of whey
Whey is left over when milk is coagulated during the process of cheese production, and contains everything that is soluble from milk after the pH is dropped to 4.6 during the coagulation process. It is a 5% solution of lactose in water with lactalbumin and some lipid content. 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. For example, spray drying after membrane filtration separates the proteins from whey.
Whey can be denatured by heat. High heat (such as the sustained high temperatures above 72 °C associated with the pasteurization process) denatures whey proteins. While native whey protein does not aggregate upon renneting or acidification of milk, denaturing the whey protein triggers hydrophobic interactions with other proteins, and the formation of a protein gel.
The protein in cow's milk is 20% whey and 80% casein. The protein in human milk is 60% whey and 40% casein. The protein fraction in whey constitutes approximately 10% of the total dry solids in whey. This protein is typically a mixture of beta-lactoglobulin (~65%), alpha-lactalbumin (~25%), bovine serum albumin (~8%) (see also serum albumin), and immunoglobulins. These are soluble in their native forms, independent of pH.
Major forms and uses
Commercially produced whey protein from cow's milk typically comes in four major forms:
- Concentrates (WPC) have typically a low (but still significant) level of fat and cholesterol but, in general, compared to the other forms of whey protein, they are higher in carbohydrates in the form of lactose — they are 29%–89% protein by weight.
- Isolates (WPI) are processed to remove the fat and lactose — they are 90%+ protein by weight. Like whey protein concentrates, whey protein isolates are mild to slightly milky in taste.
- Hydrolysates (WPH) are whey proteins that are predigested and partially hydrolyzed for the purpose of easier metabolizing, but their cost is generally higher. Highly hydrolysed whey may be less allergenic than other forms of whey.
- Native whey protein is extracted from skim milk, not a byproduct of cheese production, and produced as a concentrate and isolate.
Whey protein is commonly marketed as a dietary supplement, typically sold in powdered form for mixing into beverages. Whey protein is now also quite commonly used as a thickener to improve the texture and decrease syneresis in many types of yogurt. Yogurt with high amounts of protein have been more commonly found on shelves due to the recently increasing popularity of Greek yogurt. The products have varying proportions of the major forms above, and are promoted with various health claims. The primary usage of whey protein supplements is for muscle growth and development. During exercise, muscle proteins get broken down into free amino acids and then undergo the process of oxidizing in mitochondria to produce energy. 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 free amino acids in the body's free amino acid pool. In 2010 a panel of the European Food Safety Authority (EFSA) examined proposed health claims made for whey protein: satiety, weight loss, reduced body fat, increased muscle, increased strength, increased endurance and faster recovery after exercising. The EFSA eventually concluded that the provided literature did not adequately support the proposed claims.
- Farrell, HM; Jimenez-Flores, R; Bleck, GT; et al. (2004). "Nomenclature of the Proteins of Cows' Milk—Sixth Revision". Journal of Dairy Science. 87 (6): 1641–1674. doi:10.3168/jds.s0022-0302(04)73319-6. ISSN 0022-0302. PMID 15453478.
- EFSA Panel on Dietetic Products, Nutrition and Allergies (2010). "Scientific Opinion on the substantiation of health claims related to whey protein". EFSA Journal. 8 (10): 1818. doi:10.2903/j.efsa.2010.1818.
- Tang, Jason E.; Moore, Daniel R.; Kujbida, Gregory W.; Tarnopolsky, Mark A.; Phillips, Stuart M. (1 September 2009). "Ingestion of whey hydrolysate, casein, or soy protein isolate: effects on mixed muscle protein synthesis at rest and following resistance exercise in young men". Journal of Applied Physiology. 107 (3): 987–992. doi:10.1152/japplphysiol.00076.2009. PMID 19589961.
- "Whey." The Encyclopædia Britannica. 15th ed. 1994
- Foegeding, EA; Davis, JP; Doucet, D; McGuffey, MK (2002). "Advances in modifying and understanding whey protein functionality". Trends in Food Science & Technology. 13 (5): 151–159. doi:10.1016/S0924-2244(02)00111-5.
- Tunick MH (2008). "Whey Protein Production and Utilization." (abstract). In Onwulata CI, Huth PJ (eds.). Whey processing, functionality and health benefits. Ames, Iowa: Blackwell Publishing; IFT Press. pp. 1–13.
- Jay R. Hoffman & Michael J. Falvo (2004). "Protein - Which is best?". Journal of Sports Science and Medicine (3): 118–130.
- Luhovyy BL, Akhavan T, Anderson GH (2007). "Whey proteins in the regulation of food intake and satiety". Journal of the American College of Nutrition. 26 (6): 704S–712S. doi:10.1080/07315724.2007.10719651. PMID 18187437. S2CID 25573353.
- Haug, A; Høstmark, AT; Harstad, OM (2007). "Bovine milk in human nutrition – a review". Lipids Health Dis. 6: 25. doi:10.1186/1476-511X-6-25. PMC 2039733. PMID 17894873.
- Lee YH (November 1992). "Food-processing approaches to altering allergenic potential of milk-based formula". J. Pediatr. 121 (5 Pt 2): S47–50. doi:10.1016/S0022-3476(05)81406-4. PMID 1447634.
- Alan L. Kelly; Seamus A. O'Mahony. "Technologies for whey processing: "Is there a better whey?"" (PDF). Dairyaustralia.com.au. Retrieved 19 May 2016.
- Burrington, Kimberlee. "Technical Report: Milk Fractionation Technology and Emerging Milk Protein Opportunities" (PDF). USDairy. U.S. Dairy Export Council. Retrieved 23 May 2016.
- "Leprino Foods enters direct-to-consumer whey protein market with Ascent Protein". 23 May 2016. Retrieved 1 June 2016.
- Morifuji, Masashi (2010). “Comparison of Different Sources and Degrees of Hydrolysis of Dietary Protein: Effect on Plasma Amino Acids, Dipeptides, and Insulin Responses in Human Subjects”. J. Agric. Food Chem. 58 (15): 8788–8797.
- "Protein Quality - Macros Inc - Does Protein Quality Matter".
- Calbet, JA (2002). “Plasma glucagon and insulin responses depend on the rate of appearance of amino acids after ingestion of different protein solutions in humans.”. J Nutr. 132 (8): 2174–82.
- Guo, Mingruo (2019). Whey Protein Production, Chemistry, Functionality, and Applications. Temple University: John Wiley & Sons Ltd. pp. 119–122. ISBN 9781119256052.
- Wal JM (2004). "Bovine milk allergenicity". Ann. Allergy Asthma Immunol. 93 (5 Suppl 3): S2–11. doi:10.1016/S1081-1206(10)61726-7. PMID 15562868.
- Burks W, Helm R, Stanley S, Bannon GA (2001). "Food allergens". Curr Opin Allergy Clin Immunol. 1 (3): 243–248. doi:10.1097/01.all.0000011021.73682.01. PMID 11964696. S2CID 26812470.
- "Ricotta Cheese". Canadian Dairy Commission. Retrieved 15 September 2019..
- Whey protein resources, National Dairy Council
- Whey Protein Healthnotes, University of California, San Diego