Maize Gelling Arabinoxylans Isolated by a Semi-Pilot Scale Procedure: Viscoelastic Properties and Microstructural Characteristics

Abstract

Maize processing generates several co-products as if distillers dried grains with solubles (DDGS) where maize bran denotes an important fraction and represents a source of arabinoxylans (AX). The objective of this research was to extract gelling AX from DDGS and to investigate the rheological and microstructural characteristics of the gels formed. AX presented a yield of 4.2% (w/w dry basis), an arabinose to xylose ratio of 0.61, a ferulic acid (FA), diferulic acid, and triferulic acid content of 0.54, 0.10 and 0.01 µg/mg AX, respectively, and a Fourier transform infrared (FT-IR) spectrum typical of AX. The intrinsic viscosity [Tl] and viscosimetric mass values for AX were 280 mL/g and 206 kDa, respectively. AX solution at 2% (w/v) formed gels induced by laccase as cross-linking agent. Cured AX gels registered storage (G’) and loss (G”) modulus values of 77 and 0.3 Pa, 152respectively, and a diferulic acid content of 0.20 µg/mg AX, only traces of triferulic acid were detected. Scanning electron microscopy (SEM) analysis of the lyophilized AX gels showed that this material resembles that of an imperfect honeycomb.