Multi-layer mucilage of Plantago ovata seeds: Rheological differences arise from variations in arabinoxylan side chains

Long Yu; Gleb E Yakubov; Wei Zeng; Xiaohui Xing; John Stenson; Vincent Bulone; Jason R Stokes

doi:10.1016/j.carbpol.2017.02.038

Multi-layer mucilage of Plantago ovata seeds: Rheological differences arise from variations in arabinoxylan side chains

Carbohydr Polym. 2017 Jun 1:165:132-141. doi: 10.1016/j.carbpol.2017.02.038. Epub 2017 Feb 14.

Authors

Long Yu¹, Gleb E Yakubov², Wei Zeng³, Xiaohui Xing⁴, John Stenson⁵, Vincent Bulone⁴, Jason R Stokes¹

Affiliations

¹ Australian Research Council Centre of Excellence in Plant Cell Walls, School of Chemical Engineering, The University of Queensland, Brisbane, QLD 4076, Australia.
² Australian Research Council Centre of Excellence in Plant Cell Walls, School of Chemical Engineering, The University of Queensland, Brisbane, QLD 4076, Australia. Electronic address: gleb.yakubov@uq.edu.au.
³ Australian Research Council Centre of Excellence in Plant Cell Walls, School of BioScience, The University of Melbourne, Parkville, VIC 3010, Australia.
⁴ Division of Glycoscience, Royal Institute of Technology (KTH), School of Biotechnology, AlbaNova University Centre, Stockholm SE-10691, Sweden; Australian Research Council Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, The University of Adelaide, Waite Campus, Urrbrae, SA 5064, Australia.
⁵ Malvern Instruments, Malvern, Worcestershire WR14 1XZ, UK.

PMID: 28363533
DOI: 10.1016/j.carbpol.2017.02.038

Abstract

Mucilages are hydrocolloid solutions produced by plants for a variety of functions, including the creation of a water-holding barrier around seeds. Here we report our discovery of the formation of three distinct mucilage layers around Plantago ovata seeds upon their hydration. Each layer is dominated by different arabinoxylans (AXs). These AXs are unusual because they are highly branched and contain β-1,3-linked xylose in their side chains. We show that these AXs have similar monosaccharide and linkage composition, but vary in their polymer conformation. They also exhibit distinct rheological properties in aqueous solution, despite analytical techniques including NMR showing little difference between them. Using enzymatic hydrolysis and chaotropic solvents, we reveal that hydrogen bonding and side chain distribution are key factors underpinning the distinct rheological properties of these complex AXs.

Keywords: Arabinoxylan; Plantago ovata; Rheological behaviour; Seed mucilage; Structure.

MeSH terms

Plant Mucilage / chemistry*
Plantago / chemistry*
Seeds / chemistry*
Xylans / chemistry*

Substances

Plant Mucilage
Xylans
arabinoxylan