Abstract:The effects of ultrafine grinding on the composition, structural, physicochemical and functional properties of dietary fiber from black rice bran were studied. We analyzed the particle size, microstructure, adsorption properties and antioxidant capacity of dietary fiber of ultra-fine. The results showed that, the particle size and relative crystallinity of insoluble dietary fiber (IDF) and soluble dietary fiber (SDF) of black rice bran could be significantly reduced by ultrafine grinding, so that they showed a looser and more porous state, but their main composition did not change. The swelling capacity, cholic acid adsorption capacity and cholesterol adsorption capacity of IDF of ultrafine black rice bran powder were improved, which were 57.43%, 22.71% and 24.92% higher than that of crude powder, respectively. In addition, the DPPH free radical scavenging capacity and FRAP antioxidant capacity of SDF were increased by 2.8 times and 1.7 times of that of crude SDF. In conclusion, ultrafine grinding can significantly reduce the particle size of black rice bran dietary fiber, promote the formation of loose porous microstructure, and improve the physicochemical and functional properties of IDF. This study provided a theoretical basis for the deep processing and utilization of black rice bran dietary fiber.
