Blasting extrusion processing: the increase of soluble dietary fiber content and extraction of soluble-fiber polysaccharides from wheat bran

In this study, soluble dietary fiber (SDF) content of wheat bran was significantly increased from 9.82 ± 0.16 (w/w, %) to 16.72 ± 0.28 (w/w, %) by a novel blasting extrusion processing with enhanced water retention capacity and the swelling capacity. In addition, a water-soluble polysaccharide (WBP) was isolated and extracted from extruded SDF. WBP was successfully purified from SDF by column chromatography systems with the average molecular weight (Mw) of 4.7 × 10(4)Da, containing arabinose, xylose, glucose, and galactose. With the molar ratio of 0.76:0.99:1.00:0.12. Our results suggest that WBP owned 1 → 2, 1 → 3, 1 → 2, 6 and 1 → 4, 1 → 4, 6 glycosidic bonds in the absence of 1 →, 1 → 6 glycosidic bonds. In vitro antioxidant assays (DPPH, ABTS+ radical scavenging capacities, and ferric ion reducing capacity) demonstrated that WBP possesses good antioxidant capacity, and it could be potentially used as a natural antioxidant for use in functional food, cosmetic and pharmaceutical industries.