Lactose. There is a reason why some infant formulas are labeled lactose-free. Some babies are not able to digest lactose thus lactose-free milk is necessary. He may or may not able to synthesize enough substance to digest lactose. At some point in human life, he may stop digesting lactose due to some unknown reasons, making him lactose intolerant.
According to wiki, lactose intolerant may have the following symptoms: diarrhea, bloating, flatulence and other gastrointestinal disorder.
What is Lactose?
It is a carbohydrate. A disaccharide composing of two monosaccharide units, glucose and galactose. A milk sugar which cannot make the milk sweet.
Why Lactose Intolerant?
The disaccharide lactose is not usable by the human body. The bond between glucose and galactose should be broken by enzyme lactase. Then the free glucose molecule will be transported throughout the body as primary source of energy. The free galactose on the other hand, according to our biochemistry teacher will be converted to glucose and will also be transported throughout the body.
The body naturally produce lactase. If the enzyme production is not enough, the symptoms then manifest.
Making the milk lactose-free
A milk is lactose-free if it is made of milk alternative such as soy milk and rice milk. The whole milk is treated with lactase and subjected to favorable conditions. The lactose is not present but its two components still exist. Or, according to our biochem professor, more and more milk formulas as of date have added artificial lactase. It will help break down the lactose when the milk is ingested. Such milk should be prepared with not so hot water. Enzymes are proteins which are degraded under high temperature.