What is casein?

There are two kinds of protein in cow’s milk - casein and whey. Eighty percent of the protein in cow’s milk is casein and 20% of the protein is whey. Traditionally, the casein in cow’s milk was used to make cheese and whey protein was a side-product of that manufacturing process. In recent years with the increased demand for protein in sports food supplements, some dairy manufacturers have begun to extract the casein directly from skim milk using a complex filtering process. The end result is a spray dried casein protein powder with a protein concentration of 80-85%.

The individual protein molecules in casein are built together in very large structures of protein molecules. These large supra-molecules in casein are called "micelles". Some casein products are called "micellar casein", named after this particular style of molecular organization. The micelles are in fact so big that you can feel them in the mouth. That is why a casein mixed with water can have a "gritty" feel to it; the micelles do not completely dissolve in water.

The micelles are very solid and it takes a long time for digestion to pick them apart and make the amino acids available for the cells and muscle in the body. You can think of casein as a slow release protein; it takes 5-8 hours for the digestion to complete the processing of casein. The advantage of slow digestion is that you will be supplied with a steady stream of amino acids for muscle synthesis over a period of 2-8 hours.

Read more about the benefits of taking casein supplement.

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