a sirupy, or white crystalline, variety of sugar, c6h12o6 (so called from turning the plane of polarization to the right), occurring in many ripe fruits. dextrose and levulose are obtained by the inversion of cane sugar or sucrose, and hence called invert sugar. dextrose is chiefly obtained by the action of heat and acids on starch, and hence called also starch sugar. it is also formed from starchy food by the action of the amylolytic ferments of saliva and pancreatic juice.