Quantitative Profiling of Feruloylated Arabinoxylan Side-Chains from Graminaceous Cell Walls

Abstract

Graminaceous arabinoxylans are distinguished by decoration with feruloylated monosaccharidic and oligosaccharidic side-chains. Although it is hypothesized that structural complexity and abundance of these feruloylated arabinoxylan side-chains may contribute, among other factors, to resistance of plant cell walls to enzymatic degradation, quantitative profiling approaches for these structural units in plant cell wall materials have not been described yet. Here we report the development and application of a rapid and robust method enabling the quantitative comparison of feruloylated side-chain profiles in cell wall materials following mildly acidic hydrolysis, C18-solid phase extraction (SPE), reduction under aprotic conditions, and liquid chromatography with diode-array detection/mass spectrometry (LC-DAD/MS) separation and detection. The method was applied to the insoluble fiber/cell wall materials isolated from 12 whole grains: wild rice (Zizania aquatica L.), long-grain brown rice (Oryza sativa L.), rye (Secale cereale L.), kamut (Triticum turanicum Jakubz.), wheat (Triticum aestivum L.), spelt (Triticum spelta L.), intermediate wheatgrass (Thinopyrum intermedium), maize (Zea mays L.), popcorn (Zea mays L. var. everta), oat (Avena sativa L.) (dehulled), barley (Hordeum vulgare L.) (dehulled), and proso millet (Panicum miliaceum L.). Between 51 and 96% of the total esterified monomeric ferulates were represented in the quantified compounds captured in the feruloylated side-chain profiles, which confirms the significance of these structures to the global arabinoxylan structure in terms of quantity. The method provided new structural insights into cereal grain arabinoxylans, in particular, that the structural moiety α-l-galactopyranosyl-(1→2)-β-d-xylopyranosyl-(1→2)-5-O-trans-feruloyl-l-arabinofuranose (FAXG), which had previously only been described in maize, is ubiquitous to cereal grains.

Phenolic Substances in Beer: Structural Diversity, Reactive Potential and Relevance for Brewing Process and Beer Quality

“…Ferulic acid is mainly found in the arabinoxylan‐rich aleurone layer while p ‐coumaric acid is present in higher concentrations in the husk (Holtekjølen et al., ; Nordkvist et al., ). Ferulic acid is esterified to the O‐5 position of the arabinose substituents of arabinoxylan (Schendel, Meyer, & Bunzel, ). With their carboxyl and phenolic hydroxyl groups, phenolic acids are able to form ester or ether links with cell wall polysaccharides.…”

Development of a thermophilic coculture for corn fiber conversion to ethanol

“…1, Supplementary Table 1). This side chain belongs to the series of side chains containing the unusual L-Galp residue that are abundant in corn fiber but have also been found in other cereal GAXs 18,22,23 . The side chain 3 represented 13% of the total carbohydrate and contained α-D-Xylp, another unusual sugar in plant cell wall xylans ( Fig.…”

Caracterização De Genótipos De Sorgo Biomassa Para Bioenergia

“…Tabela 1 -Comparação de médias dos resultados de FDN (fibra detergente neutro), FDA (fibra detergente ácido), celulose, hemicelulose, lignina e cinzas, obtidos para a caracterização dos genótipos de sorgo biomassa. A hemicelulose de gramíneas, como o sorgo, contém polissacarídeos do tipo arabinoxilanas (Schendel et al, 2016). De acordo com a Tabela 2, podemos observar que o perfil dos açúcares xilose e arabinose variaram entre os genótipos avaliados.…”