Improving the extractability of arabinoxylans and the molecular weight of wheat endosperm using extrusion processing

Cereal derived arabinoxylans (AXs) are non-starch polysaccharides that have immunomodulatory activities. These activities are thought to be related to the low molecular weight fractions of AXs. Wheat and wheat by-products are rich in AXs, however, the water extractable fraction of AXs in wheat products is low. Water extraction of AXs can be improved by extrusion processing, which increases the extractability of the water soluble fraction. The aim of this study was to determine the extractability and molecular weight of the water soluble fraction of AXs from wheat endosperm after extrusion at screw speeds of 80 and 160 rpm. Extrusion processing significantly (P < 0.05) increased the water extractability of AXs in a screw-speed dependent manner (13.07 ± 0.12% at 80 rpm and 15.45 ± 0.16% at 160 rpm compared to8.95 ± 0.10% in the non-extruded control) due to a significant increase (P < 0.05) in low molecular weight fractions of AXs in extruded samples.