Gels of Ferulated Arabinoxylans: Rheology, Structural Parameters and Microstructure

One of the major by-products of bioethanol production is distillers dried grains with solubles (DDGS). Maize is one of the main sources for the production of this biofuel. In this way, dietary fiber represents the principal fraction of DDGS, which could be a potential source of added-value biomolecules such as ferulated arabinoxylans (AX). In this chapter, ferulated arabinoxylans extracted from DDGS (DDGAX) were gelled and the gels were studied in terms of rheology, structural parameters and microstructural characteristics. The DDGAX formed gels at 2% (w/v) induced by laccase. The mechanical spectrum and strain sweep of DDGAX gel presented the typical behavior of a solid-like material. The gels swelling ratio (43 g water/g DDGAX) suggested the formation of a compact polymeric network which decreased the water uptake of the gel. DDGAX gels presented an average mesh size value of 96 nm. The surface of the gels was analyzed by scanning electron microscopy revealing a heterogeneous microstructure resembling an imperfect honeycomb. These results indicate that ferulated arabinoxylans from DDGS form elastic and macroporous gels, presenting a microstructure with irregular pore sizes.

Keywords: Arabinoxylan gels, Ferulic acid, Gelling capability, Microstructure, Structural properties, Swelling.