The correlations between feruloylated arabinoxylans' structure and their antioxidative properties

To investigate the influence of structural features of feruloylated arabinoxylans (FAXs) on their antioxidant capacities. FAXs from wheat bran were prepared by graded ethanol precipitation. The monosaccharide composition, degree of arabinose substitution (DAS), molecular weight (Mw), total phenolic contents (TPC), phenolic acid profiles, microstructure, and antioxidant capacities of FAXs were determined. These results showed that FAXs were mainly comprised of xylose (40.55-54.11%) and arabinose (35.16-39.78%) with bound phenolic acids (8.32-19.03 mg ferulic acid equivalents/g) and exhibited linear polysaccharides. However due to different separation conditions, the DAS, Mw, TPC, phenolic acid content and microstructure of FAXs varied. In addition, all FAXs exerted certain antioxidant capacities, and FAX-7 and FAX-8 had better antioxidant effects at the same concentration than FAX-6. TPC, total phenolic acid and ferulic acid content showed highly positive correlations with their antioxidant capacities. The antioxidant capacities of FAXs were highly negatively correlated with Mw. These results could improve our understanding of the correlations between FAXs' structural features and their antioxidant activities.