Structural features of two heteroxylan polysaccharide fractions from wheat bran with anti-complementary and antioxidant activities

► Isolation of arabinoxylans from wheat bran by enzymic treatment and dilute alkali. ► Chemical, FTIR and 1D- and 2D-NMR spectroscopy served for structural analysis. ► The arabinoxylans were contaminated with (1 → 3,1 → 4)-β-glucan and arabinogalactan. ► Both arabinoxylans contained phenolic compounds, the second one also protein. ► The arabinoxylans displayed antioxidant activities and immuno-enhancing effects.