Flax (Linum usitatissimum) Seed Cake: A Potential Source of High Molecular Weight Arabinoxylans?

Water-soluble polysaccharides were extracted from flaxseed cake and analyzed. Two groups were separated by anion-exchange chromatography. The first one (nonretained) was the major fraction (83%) and possessed a high molecular weight (HMW) arabinoxylan (56%) with an Ara/Xyl ratio of 0.32 and an M(w) of 846 000. This polymer was accompanied by a smaller galactoglucan (44%), with an M(w) of 6.5 x 10(4). The latter group (17%), retained by the gel, was further described as a HMW pectin heterogeneous group, with, respectively, 3.1 x 10(5) and 1.3 x 10(5). Despite the presence of HMW arabinoxylans, the investigation of rheological flow sweep at the concentration of 2% (w/v) has shown a slight shear thinning behavior with a small zero-rate viscosity at 9.6 Pa.s.