Effects of different molecular weight water-extractable arabinoxylans on the physicochemical properties and structure of wheat gluten.

Abstract

The effects of water-extractable arabinoxylans (WEAXs) with different molecular weights on the physicochemical properties and structure of wheat gluten were studied, a transition between β-turns in β-leaves in the structure of gluten has been demonstrated by Fourier transform infrared spectroscopy when WEAX samples were added. The ratio of weakly hydrogen-bonded β-sheets to strongly hydrogen-bonded β-sheets tended to decrease with increasing WEAX content. FT-Raman analysis demonstrated other changes in the structure of gluten concerning β-structures, the conformation of the disulfide bridges, and aromatic amino acid environments; these changes were dependent on the molecular weight of the WEAX. Native WEAXs of different molecular weights that are present as discrete fragments of the cell wall have had a negative effect on the properties of gluten. However, low molecular weight WEAX has helped gluten maintain the left-left conformation of its disulfide bonds. In addition, the gluten elasticity was reduced by the native WEAX to make it softer, but the WEAX low molecular weight impeded this process and improved the gluten network.