Galactose is a six-carbon aldose monosaccharide and a C-4 epimer of glucose, with the molecular formula C6H12O6. It exists primarily in the D-form in nature and is a key component of lactose in milk. Galactose plays essential roles in cellular metabolism, glycoprotein and glycolipid synthesis, and is metabolized via the Leloir pathway. It is less sweet than glucose and occurs in various plant gums and pectins. Industrially, it is used in food formulations and biochemical research. The compound is stable under normal conditions but can undergo Maillard reactions when heated with proteins.