Pentosan

Pentosans are polymers composed of pentoses. In contrast to cellulose, which is composed of hexose (glucose) monomers, 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:
 * 29-25%: oat hulls,	cottonseed hulls, barley, sugarcane bagasse, sunflower husks
 * 24-20% wheat straw, flax shives, hazelnut shells, birchwood, eucalyptus wood
 * 8% pinewood
 * 3% peanut shells

Pentosans can act as heparinoids, glycosaminoglycans which are derivatives of heparin.

They can have an influence on bread quality.