Flax ( Linum usitatissimum ) Seed Cake: A Potential Source of High Molecular Weight Arabinoxylans?
Résumé
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 Mw of 846 000. This polymer was accompanied by a smaller galactoglucan (44%), with an Mw of 6.5 × 104. The latter group (17%), retained by the gel, was further described as a HMW pectin heterogeneous group, with, respectively, 3.1 × 105 and 1.3 × 105. 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.