Rheological and emulsifying properties of arabinoxylans from various cereal brans

Abstract

The aim of this research is to investigate the molecular characteristics, rheological performance and emulsifying properties of arabinoxylans (AXs) obtained from corn bran, wheat bran and red/white sorghum bran using 0.625M sodium hydroxide solution for 2.5 h at two different extraction temperatures (25 °C & 85 °C). The AXs extracted from sorghum bran had higher ferulic acid content, protein content and degree of branching than other AXs. The relatively high extraction temperature (85 °C) resulted in a decrease in molecular weight and an increase in the ratio of arabinose to xylose. Wheat bran AXs with the highest molecular weight exhibited the highest viscosity. Most of AX solutions displayed Newtonian behavior at a low concentration but shear-thinning behavior at a high concentration except corn bran AXs. Laccase oxidation promoted the crosslinking of cereal bran AXs, and the gel point only appeared in red sorghum bran AX extracted at 25 °C. The O/W emulsions stabilized by AXs from sorghum bran possessed the smallest particle size less than 0.81 μm, suggesting that sorghum bran AXs had a better emulsifying capability followed by corn bran AXs and wheat bran AXs. The difference among various sources of AXs has a greater effect on emulsification performance as compared to extraction temperature.