Lactose
Lactose, the sugar in milk. Lactose is a disaccharide, a type of sugar composed of two simple sugars. Lactose is composed of the simple sugars glucose and galactose. Lactose is about one-sixth as sweet as sucrose (common white sugar).
Lactose is obtained by evaporating whey, the watery part of milk. It is used in some candies, baked goods, and baby foods. It is also used in the production of penicillin and lactic acid.
Chemical formula: C12H22O11.