Recent Advances in Research on the Biosynthetic Pathways of Arabinoxylan and Its Health Functionality

Arabinoxylan (AX) is the major hemicellulose in grass cell walls as a component of lignocellulosic biomass with the highest abundance and yield on terrestrial land area. AX is an obstacle for biomass saccharification as the structural polysaccharides linked to lignin from the supporting tissues like culm and sheath of the grass energy crops, while it has immunomodulatory and prebiotic functions as the dietary fibers from cereal grains. AX is thus interesting from two points of view: the use of a carbon-neutral and renewable energy resource and the use of a healthy functional polysaccharide like barley β-glucan. Elucidation of its fine structures and biosynthetic mechanisms contributes the field evaluation of energy crops and cereal cultivars, as well as for functional food developments. This review outlines the current research status of the chemical structure and biosynthetic mechanism of AX, together with the development of its use as a health-functional polysaccharide.