Regular milk contains a substance known as lactose, which is a sugar made up of two simple sugars; galactose and glucose. Certain people are unable to digest this sugar and suffer from a condition known as lactose intolerance. Those suffering from this condition do not produce enough of the enzyme lactase, which breaks down the lactose in the digestive system. If these people consume products containing lactose, such as milk, they may experience a number of symptoms such as bloating, cramping, rumbling stomach, flatulence (gas), diarrhea, nausea and even vomiting. The most common treatment for this condition is modifying the diet to avoid lactose. For most people this means drinking an alternative milk, such as soy, or switching to a lactose free milk.
How is lactose free milk made?
Basically to make lactose free milk you need to convert the lactose from the milk into the simple sugars galactose and glucose. However, this is not as simple as adding the enzyme lactase to the milk because the enzyme would then remain in the milk. Instead the enzyme is attached to a larger molecule, to make it easier to remove, and it is then added to the milk. The lactose molecules are drawn to the enzyme and they are broken down into galactose and glucose. Once this process is complete the lactase enzyme, which remains attached to the larger molecule, is removed from the milk. The milk has an identical nutritional value as regular milk, but it will be sweeter because glucose and galactose are sweeter sugars than lactose. This is due to the fact that lactose has a different molecular shape and does not bind well with the sweetness receptors on the tongue.
Did you know?
In 2001 the Finnish company Valio produced the first lactose free milk without the sweet taste. They did this by developing a way to remove the lactose from the milk instead of converting it.