Milk naturally contains not only proteins and lipids; it also contains carbohydrates. Specifically, milk contains the sugar lactose. Lactose is a disaccharide (two-sugar) compound that consists of one...Milk naturally contains not only proteins and lipids; it also contains carbohydrates. Specifically, milk contains the sugar lactose. Lactose is a disaccharide (two-sugar) compound that consists of one molecule each of galactose and glucose, as shown in the structural formula below. Lactose makes up between 2 and 8 percent of milk by weight. The exact amount varies both within and between species.
