Conformational Behavior, Topographical Features, and Antioxidant Activity of Partly De-Esterified Arabinoxylans.

Yubia De Anda-Flores,Alexel J Burgara-Estrella,Ana Luisa Martínez-López,Judith Tanori-Cordova,Elizabeth Carvajal-Millan,Agustin Rascon-Chu,Jaime Lizardi-Mendoza,Martin R Pedroza-Montero

doi:10.3390/polym13162794

Yubia De Anda-Flores, Alexel J Burgara-Estrella + Show 6 more

Open Access

https://doi.org/10.3390/polym13162794

Copy DOI

Abstract

This study aimed to investigate the effect of arabinoxylans (AX) partial de-esterification with feruloyl esterase on the polysaccharide conformational behavior, topographical features, and antioxidant activity. After enzyme treatment, the ferulic acid (FA) content in AX was reduced from 7.30 to 5.48 µg FA/mg polysaccharide, and the molecule registered a small reduction in radius of gyration (RG), hydrodynamic radius (Rh), characteristic ratio (C∞), and persistence length (q). A slight decrease in α and a small increase in K constants in the Mark–Houwink–Sakurada equation for partially de-esterified AX (FAX) suggested a reduction in molecule structural rigidity and a more expanded coil conformation, respectively, in relation to AX. Fourier transform infrared spectroscopy spectra of AX and FAX presented a pattern characteristic for this polysaccharide. Atomic force microscopy topographic analysis of FAX showed a more regular surface without larger hollows in relation to AX. The antioxidant activity of FAX, compared to AX, was reduced by 30 and 41% using both 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS+) and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) methods, respectively. These results suggest that feruloyl esterase treatment of AX could offer a strategy to tailor AX chains conformation, morphological features, and antioxidant activity, impacting the development of advanced biomaterials for biomedical and pharmaceutical applications.

Highlights

Arabinoxylans (AX) are non-starch polysaccharides that mainly form the cell wall of cereal grains
The tri-ferulic acid (FA) structure was not detected in these samples
The di-FA content was not affected after de-esterification treatment, proving that the enzyme only acts on the FA residues

Summary

Introduction

Arabinoxylans (AX) are non-starch polysaccharides that mainly form the cell wall of cereal grains. AX can be recovered through chemical or enzymatic treatments from cereal by-products such as Distiller’s dried grains with solubles (DDGS), the principal maize by-product from the ethanol industry [1]. In the cell wall of grains, AX are cross-linked with other components like cellulose microfibrils by hydrogen bonds, which confers specific stability characteristics [2,3]. AX polymeric chain consists of xylose in β-1,4 with ramifications of α-L-arabinofuranose in α-1,3 and α-1,2. Arabinose can be esterified with ferulic acid (FA). Small amounts of dimers (di-FA) and trimers (tri-FA) of FA can be present in AX [4,5,6]

Objectives

Results

Conclusion