Caseins constitute approximately 80% of milk protein. They are present in 4 forms: alpha S 1, alpha S 2, beta and gamma caseins. They are sensitive to the pH acids (ex: lactic acid) and to coagulating enzymes (ex: rennet). These properties are used in cheese-making. These proteins are of excellent nutritional quality and, could be beneficial for some other biological effects (antimicrobic, anti-hypertensive …)