Isolation, Physicochemical Properties, and Structural Characteristics of Arabinoxylan from Hull-Less Barley

Arabinoxylan (HBAX-60) was fractioned from alkaline-extracted arabinoxylan (HBAX) in the whole grain of hull-less barley (Hordeum vulgare L. var. nudum Hook. f. Poaceae) by 60% ethanol precipitation, which was studied for physicochemical properties and structure elucidation. Highly purified HBAX-60 mainly composed of arabinose (40.7%) and xylose (59.3%) was created. The methylation and NMR analysis of HBAX-60 indicated that a low-branched beta-(1 -> 4)-linked xylan backbone possessed un-substituted (1,4-linked beta-Xylp, 36.2%), mono-substituted (beta-1,3,4-linked Xylp, 5.9%), and di-substituted (1,2,3,4-linked beta-Xylp, 12.1%) xylose units as the main chains, though other residues (alpha-Araf-(1 ->, beta-Xylp-(1 ->, alpha-Araf-(1 -> 3)-alpha-Araf-(1 -> or beta-Xylp-(1 -> 3)-alpha-Araf-(1 ->) were also determined. Additionally, HBAX-60 exhibited random coil conformation in a 0.1 M NaNO3 solution. This work provides the properties and structural basis of the hull-less barley-derived arabinoxylan, which facilitates further research for exploring the structure-function relationship and application of arabinoxylan from hull-less barley.

Automated summary

Arabinoxylan (HBAX-60) was fractionated from alkaline-extracted arabinoxylan (HBAX) in hull-less barley, composed mainly of arabinose and xylose with a low-branched xylan backbone and other residues. Analysis showed a random coil conformation in solution, providing insights for further research and applications of this arabinoxylan.