Isolation of Casein & Lactose From Milk

Milk is one of nature's foods with almost complete nutrition. It contains essential protein, carbohydrates, vitamins, and minerals, while remaining easily digestible for most people, even young babies.

Casein and Lactose

• Casein is one of the three globular proteins found in milk. This phosphoprotein is found in its salt form, calcium caseinate, in milk. Lactose is a sugar found in milk. This carbohydrate consists of two sugars combined: glucose and galactose.

Purpose

• Many people with an allergy to milk are actually allergic to one of two components of the milk: the casein or the lactose. Removal of these products allows individuals with allergies to tolerate milk. Casein-free dairy products are also used for children with autism, and special lactose-free milk allows people with a lactose intolerance to consume milk.

Process

• There are two ways to remove casein from milk. By adding an acid, the pH of milk is lowered and the casein will clot, allowing for easy removal. Rennin, a natural enzyme found in young calves, can also cause casein to clot for abstraction. After the casein has been removed, the diastereomers alpha lactose and beta lactose can be separately isolated. First, a water-ethanol solution encourages the crystallization of alpha lactose at room temperature, which can be removed with vacuum filtration. Beta lactose can be removed from a concentrated solution. The addition of heat helps crystallize beta lactose, which can then be removed.