This episode of the Real Science Exchange podcast was recorded during a webinar from Balchem’s Real Science Lecture Series.

Throughout the last 30 years, the dairy industry has moved to producing highly concentrated versions of milk proteins. In cows’ milk, about 80% of the protein is casein and 20% is in the serum or whey phase. These ratios vary by species. There are three major caseins in cows’ milk: alpha-S-casein, beta-casein, and kappa-casein. The first two are rich in phosphate for calcium binding. Kappa-casein is critical in a micellar structure that allows these structures to stay suspended in the milk. (1:21)

Whey proteins also differ by species. In cows’ milk, about 50% of the whey protein is beta-lactoglobulin. It’s rich in branched-chain amino acids, and it is not present in human milk so it is a focus of allergy research. Alpha-lactalbumin is found in all mammals and is a cofactor for lactose production. (10:34)

Caseins and whey proteins are different from one another and are in completely different classes of proteins. From structure, to size, to amino acid content, to solubility; these two types of proteins are yin and yang. (11:51)

When fluid milk or whey is concentrated by removing water, some sugars and other materials dissolve via evaporation or membrane filtration. It results in dried powders, milk protein concentrate, milk protein isolate, whey protein concentrate and whey protein isolates. Concentrates contain 80-85% protein and isolates contain more than 90% protein. (17:14)

What's driving the current and probably future popularity of these dairy proteins? One, is their versatility in many food applications, and the other is the superior nutritional quality of the proteins. Nearly half of the milk protein concentrate use is for mainstream nutrition and sports beverages. Similar trends have been observed for whey protein isolates. (20:05)

Dairy proteins are very rich in branched-chain amino acids (BCAA) like leucine. BCAAs help initiate protein synthesis, are important for muscle recovery, help with weight loss by maintaining blood glucose levels, are synergistic with exercise, and can promote healthy aging. Dr. Lucey gives several different examples of products utilizing dairy proteins. He predicts that the increased focus on nutrition products, interest in isolating individual proteins and improving export opportunities will continue to drive demand for dairy proteins in the future. (27:21)

All of the main milk proteins have genetic variants, which are minor amino acid differences in the same protein. Variants occur at different frequencies among breeds. Beta-casein has two variants, A1 and A2. There is one amino acid difference out of 209 total amino acids, located at position 67 where a histidine is found in variant A1 and a proline is found in variant A2. When histidine is present, the beta-casein is prone to cleavage at position 67, creating a fragment called beta-casomorphin-7 (BCM-7). When proline is present, it hinders the cleavage of casein at position 67. BCM-7 is an exogenous opioid peptide with the potential to elicit opioid activity on a range of tissues and organs. It’s known as a “bioactive peptide” and some others from milk and cheese have been implicated as anti-hypertensive. (35:26)

In the late 1990s, some researchers claimed that A1 milk was implicated in diabetes, coronary heart disease, autism, and schizophrenia. Subsequent reviews and investigations by significant international bodies found no evidence of these claims. (40:34)

In closing, Dr. Lucey answers questions from the webinar audience. He talks about the potential of breeding cows customized for the production of minor milk components, milk components as renewable bio-plastics, and the superiority of milk proteins compared to plant proteins. Watch the full webinar at balchem.com/realscience. (47:41)

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