Effects of fermentation with lactic bacteria on the structural characteristics and physicochemical and functional properties of soluble dietary fiber from prosomillet bran

Prosomillet bran was fermented with lactic bacteria and the changes of the structure and physicochemical and functional properties of its soluble dietary fiber (SDF) were investigated. Results showed the yield of SDF was increased from 4.2% to 7.6% after fermentation, and the odor intensity and flavor characteristics were also significantly changed. SEM and FTIR assay indicated that the microstructure after fermentation became looser and more porous, and both of UF-SDF and F-SDF had characteristic absorption peaks of polysaccharides. Fermentation also reduced the crystalline area and thus affected the thermal stability of SDF by X-ray diffraction and thermal analysis. In addition, the physicochemical and functional properties such as solubility, water and oil holding capacity, swelling capacity, nitrite, sodium cholate and cholesterol adsorption capacity were improved as well. The phenolic content and free radical scavenging capacity also increased significantly. The above results showed that F-SDF could be applied as a functional ingredient in food industry. •Fermentation changed the flavor of prosomillet bran and increased the yield of SDF.•The structure and monosaccharide composition of SDF were changed after fermentation.•F-SDF exhibited higher solubility, WHC, and WSC than UF-SDF.•The antioxidant and adsorption capacities of SDF were improved after fermentation.