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

Abstract

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 β-(1→4)-linked xylan backbone possessed un-substituted (1,4-linked β-Xylp, 36.2%), mono-substituted (β-1,3,4-linked Xylp, 5.9%), and di-substituted (1,2,3,4-linked β-Xylp, 12.1%) xylose units as the main chains, though other residues (α-Araf-(1→, β-Xylp-(1→, α-Araf-(1→3)-α-Araf-(1→ or β-Xylp-(1→3)-α-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.

Arabinoxylan as well as β-glucan in barley promotes GLP-1 secretion by increasing short-chain fatty acids production

“…Arabinose and xylose, which are the arabinoxylan fractions, accounted for 4.9% and 8.3% of BF; bgl were 20.4% and 40.4%, respectively. A previous study reported arabinose and xylose ratios of 26.3% and 38.3%, respectively, for whole-grain barley extracted with alkali [ 18 ], results which are mostly consistent with this study. Therefore, SDF of BF had a high purity of β-glucan, and bgl had high arabinoxylan.…”

Structural and rheological characterization of water‐soluble and alkaline‐soluble fibers from hulless barley

“…25 There are limited studies addressing the ASF structure extracted from highland hulless barley. However, two recent studies have reported molecular weights for alkaline extracted hulless barley fiber in the range of 2.98 × 10 5 Da 8 and 2.22 × 10 5 Da, 26 in agreement with the finding of the present study.…”

“…Such highly multiply-branched arabinoxylan structure have not been previously reported in the literature for hulless barley or other common cereal AXs. 8,[25][26][27] Among the arabinosyl residues, higher abundances were found in the multiple branched residues, including '→2,3,5)-Araf-(1→', '→3,5)-Araf-(1→' and '→3)-Araf-(1→', compared to the terminal units 'Araf-(1→', which suggests a complex molecular structure of AX in the ASF fiber. The presence of 5-linked arabinose branches is known to be associated with the existence of etherified ferulic acids on the fiber molecule, 27 suggesting that this ASF fiber may exhibit a high level of covalent attachment of ferulic acids, potentially leading to superior antioxidant properties.…”

Recycling of wheat gluten wastewater: separation, characterisation, and solution rheology of arabinoxylans

“…1b, revealing a wide single peak at 3410 cm −1 which indicates the hydroxyl O‐H stretching vibration of polysaccharide. Additionally, a small band at 2922 cm −1 corresponds to the C‐H stretching and bending vibration of methyl and methylene, respectively (Yao et al ., 2021). The characteristic absorption peaks of sugar, at 1416 cm −1 and 1385 cm −1 , suggest the presence of polysaccharide components, thereby inferring the polysaccharide nature of the component (Jinxin et al ., 2023).…”

“…This observation contrasts with the spongy network structures of AX extracted from spring wheat flour (Campa‐Mada et al ., 2013). However, it aligns with the solid morphology of AX extracted from bran‐removed barley (Yao et al ., 2021). The differences in the SEM results could potentially be attributed to variations in the pretreatment and extraction methods employed for the AX source materials.…”