In addition to the Group of caseins represent the whey proteins from which the English coming and whey protein , called the second, important protein fraction of the milk of mammals . The protein content of cow's milk of about 3.3% is made up of ca. 2.7% casein and about 0.6% whey protein together. Compared to the animal world, the protein content in human breast milk is only around 0.9% and the whey protein content is greater than the casein content. Whey protein is considered a complete protein because it contains all nine essential amino acids . The human body cannot produce these amino acids itself and has to take them in with food because they are essential for life. These are called: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine. The name whey protein is derived from the fact that the proteins in this fraction are the main component of the proteins in whey .
- α- lactalbumin approx. 20% (0.1% of cow's milk)
- β-lactoglobulin approx. 45% (0.25% of cow's milk)
- Immunoglobulins approx. 10%
- Proteose peptone approx. 20%
- Serum albumin approx. 5%
Whey proteins are sensitive to heat and denature when heated. When milk is boiled, β-lactoglobulin in particular is responsible for the skin on the surface. Whey proteins are also high in branched chain amino acids , such as about 20-25% of most dietary proteins. Whey proteins are classified as nutritionally valuable (high biological value ). They are therefore the main component of whey-based protein powders for building muscle .
Whey protein types
Whey protein concentrate
The simplest form of whey protein is a whey concentrate . It is mainly produced by ultrafiltration . It has a lower protein content of around 70 to 80%. Because the raw material is easy to manufacture in the dairies , it is much cheaper than whey protein isolate and hydrolyzate . Hence, it is considered the first choice by the nutritional supplement suppliers in the manufacture of their products. With a carbohydrate content of around 6 to 8% and a fat content of around 4 to 7%, the nutrient ratio is slightly lower than that of the isolate.
Whey protein isolate
Two different processes are used in the production of whey protein isolate. In the ion exchange process, the whey proteins are adsorbed on the ion exchanger and eluted , which means that the protein preparation contains more salts . No salts are used in the production of whey protein isolate using the microfiltration process. This enables a particularly high level of purity to be achieved, with a protein content of around 90 to 96% and a low fat, carbohydrate and lactose content of less than one percent. Furthermore, whey protein isolate is particularly suitable for people with lactose intolerance due to its practical lack of lactose .
Whey protein hydrolyzate
The hydrolysis process is used in the production of whey protein hydrolyzate . By hydrolysing (splitting) the protein chains into the smallest fragments ( peptides ), whey protein hydrolyzate can be absorbed more quickly by the body . The higher the degree of hydrolysis, the higher quality and more expensive the protein. The bitter taste is a disadvantage. Whey protein hydrolyzate is therefore mainly used in amino acid tablets and capsules, where the bitter taste only plays a subordinate role. Whey protein hydrolysates are added to mixtures of various high-quality proteins (multi-component proteins) in small proportions. By mixing different types of whey protein, an individual combination of taste, tolerance and protein content can be created.
- Hans-Dieter Belitz, Werner Grosch, Peter Schieberle (ed.): Textbook of food chemistry. Edition: 5, Springer, 2001, p. 494, ISBN 3-540-41096-1 .
- John T. Brosnan, Margaret E. Brosnan: Branched-Chain Amino Acids: Enzyme and Substrate Regulation In: The Journal of Nutrition . Volume 136, No. 1, 2006, pp. 207S-211S.
- LM Huffman, WJ Harper: Maximizing the value of milk through separation technologies. In: Journal of dairy science. Volume 82, Number 10, October 1999, pp. 2238-2244, PMID 10531613 . .
- A. MacDonald: Which formula in cow's milk protein intolerance? The dietitian's dilemma. In: European Journal of Clinical Nutrition. Volume 49 Suppl 1, September 1995, pp. S56-S63, PMID 8647064 . .