Pentosan

Pentosans are polymers composed of pentoses. In contrast to cellulose, which is derived from the hexose (glucose), pentosans are derived from five-carbon sugars such as xylose. Pentosan-rich biomass is the precursor to furfural.
The pentosan content has been determined for many natural materials:
Pentosans can act as heparinoids, glycosaminoglycans which are derivatives of heparin.
They can have an influence on bread quality.