The sugar present in milk is primarily lactose. Here’s a breakdown of its composition, linkage, and function:
Composition:
- Lactose is a disaccharide sugar composed of two monosaccharides: glucose and galactose.
- The chemical formula for lactose is C₁₂H₂₂O₁₁.
Linkage:
- The two monosaccharides in lactose are linked together by a glycosidic bond, specifically a β(1→4) linkage.
- This means that the glucose molecule is linked to the galactose molecule through a bond between the first carbon of the glucose and the fourth carbon of the galactose, with the hydroxyl group on the first carbon of glucose oriented upwards in the β configuration.
Function:
- Energy Source: Lactose serves as a significant energy source in milk for young mammals, as it is readily digestible.
- Absorption of Calcium: Lactose may also facilitate the absorption of calcium and other minerals in the intestines.
- Gut Health: In some cases, lactose can act as a prebiotic, promoting the growth of beneficial gut bacteria.
Summary:
Lactose is the primary sugar in milk, composed of glucose and galactose linked by a β(1→4) glycosidic bond. Its primary functions relate to energy provision, mineral absorption, and gut health.