ABSTRACT
Hemicelluloses are a diverse group of carbohydrate polymers that vary among different plant groups and between primary and secondary walls.
Structurally, hemicelluloses are plant cell wall polysaccharides that have a backbone of β-1,4-linked-D-pyranosyl residues, such as glucose, mannose and xylose, in which O4 is in the equatorial configuration. To the backbone are attached short side-chains. The structural similarity between hemicellulosic backbones and cellulose most likely gives rise to a conformational homology that can lead to a strong noncovalent association of hemicelluloses and cellulose microfibrils.
In the cell walls, hemicelluloses are matrix polymers of relatively low molecular weight which are associated with cellulose and other polymers. They are known to bind tightly to cellulose microfibrils via mostly hydrogen bonding.
In contrast with cellulose containing only D-glucose, hemicelluloses are composed of several different sugars. The hemicellulosic sugars include: the five-carbon sugars that include xylose and L-arabinose and the six-carbon sugars and the six-carbon sugars that include D-glucose, D-mannose, D-galactose, L-rhamnose, L-fucose, D-galacturonic acid, and D-glucuronic acid.
Hemicelluloses can be divided into four major structural groups: xyloglucans, xylans, mannans, and β-1,3;1,4-glucans
