D-fructose is a ketohexose monosaccharide and one of the three most common dietary monosaccharides along with glucose and galactose. It occurs naturally in fruits, honey, and many vegetables as a component of sucrose. In its open-chain form it is a polyhydroxy ketone with the carbonyl group at C2. In aqueous solution it predominantly exists as cyclic hemiketals (beta-D-fructofuranose and beta-D-fructopyranose). It is sweeter than glucose and is widely used as a sweetener in food industry. Fructose is metabolized primarily in the liver via fructokinase and is a key intermediate in glycolysis. It has high solubility in water (approximately 4000 g/L at 25 °C) and is used in various biochemical pathways including the Maillard reaction in cooking.