Glucose is a simple monosaccharide and the most abundant carbohydrate in nature, serving as a primary energy source for living organisms. It exists in open-chain and cyclic forms, predominantly as α-D-glucopyranose or β-D-glucopyranose in solution. In food science, it functions as a sweetener, humectant, and precursor in Maillard reactions contributing to flavor and browning. Chemically, it is an aldohexose with five hydroxyl groups enabling extensive hydrogen bonding. It is produced industrially via starch hydrolysis and plays central roles in glycolysis, glycogen storage, and cellular respiration. Its optical activity and mutarotation are key physical properties studied in carbohydrate chemistry.