[(Science: biochemistry) a 6 carbon sugar (hexose) abundant in plants. fructose has its reducing group (carbonyl) at C2 and thus is a ketose, in contrast to glucose that has its carbonyl at C1 and thus an aldose. sucrose, common table sugar, is the nonreducing disaccharide formed by an alpha linkage from C1 of glucose to C2 of fructose (latter in furanose form). fructose is a component of polysaccharides such as inulin, levan. a simple Sugar found in honey and in many ripe fruits.