TEMPO/NaClO2/NaOCl oxidation of arabinoxylans

Carolina O Pandeirada; Donny W H Merkx; Hans-Gerd Janssen; Yvonne Westphal; Henk A Schols

doi:10.1016/j.carbpol.2021.117781

TEMPO/NaClO₂/NaOCl oxidation of arabinoxylans

Carbohydr Polym. 2021 May 1:259:117781. doi: 10.1016/j.carbpol.2021.117781. Epub 2021 Feb 9.

Authors

Carolina O Pandeirada¹, Donny W H Merkx², Hans-Gerd Janssen³, Yvonne Westphal⁴, Henk A Schols⁵

Affiliations

¹ Wageningen University & Research, Laboratory of Food Chemistry, P.O. Box 17, 6700 AA Wageningen, the Netherlands.
² Wageningen University & Research, Laboratory of Food Chemistry, P.O. Box 17, 6700 AA Wageningen, the Netherlands; Unilever Foods Innovation Centre - Hive, Bronland 14, 6708 WH Wageningen, the Netherlands.
³ Unilever Foods Innovation Centre - Hive, Bronland 14, 6708 WH Wageningen, the Netherlands; Wageningen University & Research, Laboratory of Organic Chemistry, P.O. Box 8026, 6700 EG Wageningen, the Netherlands.
⁴ Unilever Foods Innovation Centre - Hive, Bronland 14, 6708 WH Wageningen, the Netherlands.
⁵ Wageningen University & Research, Laboratory of Food Chemistry, P.O. Box 17, 6700 AA Wageningen, the Netherlands. Electronic address: henk.schols@wur.nl.

PMID: 33674018
DOI: 10.1016/j.carbpol.2021.117781

Abstract

TEMPO-oxidation of neutral polysaccharides has been used to obtain polyuronides displaying improved functional properties. Although arabinoxylans (AX) from different sources may yield polyuronides with diverse properties due to their variable arabinose (Araf) substitution patterns, information of the TEMPO-oxidation of AX on its structure remains scarce. We oxidized AX using various TEMPO:NaClO₂:NaOCl ratios. A TEMPO:NaClO₂:NaOCl ratio of 1.0:2.6:0.4 per mol of Ara gave an oxidized-AX with high molecular weight, minimal effect on xylose appearance, and comprising charged side chains. Although NMR analyses unveiled arabinuronic acid (AraAf) as the only oxidation product in the oxidized-AX, accurate AraA quantification is still challenging. Linkage analysis showed that > 75 % of the β-(1→4)-xylan backbone remained single-substituted at position O-3 of Xyl similarly to native AX. TEMPO-oxidation of AX can be considered a promising approach to obtain arabinuronoxylans with a substitution pattern resembling its parental AX.

Keywords: Arabinoxylan; Arabinuronic acid; Arabinuronoxylan; TEMPO-oxidation.