Fructose. A fermentable monosaccharide (q.v.) that is a hexose (q.v.) and has a sweetness rating of 170 as compared to 100 for sucrose (q.v.) of which it forms a constituent. Also called levulose because of its optical rotation (q.v.), it is found in invert sugar (q.v.), honey (q.v.), and many fruits, for which reason it is also referred to as fruit sugar. When sucrose undergoes inversion (q.v.), either by a commercial process or in a dough by yeast (q.v.) action, it yields two monosaccharides (q.v.), namely dextrose (q.v.) and fructose. In the production of high-fructose corn syrup (q.v.), part of the dextrose is converted into fructose by either catalytic or enzymatic (q.v.) action to yield a product with a more intense sweetness.