Preparation and properties of multifunctional sinapic acid corn bran arabinoxylan esters

In the present study, corn bran arabinoxylan (CAX) were modified with sinapic acid (SA) by esterification to generate sinapic acid corn bran arabinoxylan esters (SA-CAX) with various substituted degrees. The structure of SA-CAX was characterized by FT-IR, NMR and UV spectroscopy. And the antioxidant activities of SA-CAX were evaluated by scavenging the 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical, emulsion lipid oxidation test and the lipid peroxidant level test. Compared with CAX, SA-CAX exhibited superior antioxidant activities in vitro, which indicated that the attachment of SA to CAX could enhance antioxidant activities of CAX. Moreover, the aqueous solution behavior of CAX and SA-CAX was investigated by light scattering, scanning electron microscopy and rheological measurement. The SA-CAX could form the aggregates even at diluted solutions. The hydrophobic association led to a higher viscosity and stronger gel behavior of the SA-CAX aqueous solution than that of CAX aqueous solution.