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 x 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. (C) 2015 Elsevier Ltd. All rights reserved.