Structural Changes and Functional Properties of Soluble Dietary Fiber From Buckwheat Bran by Different Processing Treatments

This study investigated the effects of seven processing methods on the structure and functional properties of soluble dietary fiber (SDF) from Tartary buckwheat bran, including microwave radiation, high-pressure steam, Aspergillus niger fermentation, Trichoderma viride fermentation, and combinations of these methods with microwave radiation. The results showed that microwave-assisted Aspergillus niger fermentation microwave-assisted fermentation (MA-S) was the most effective method for improving the structure and functional properties of SDF, significantly increased the SDF content. Scanning electron microscopy (SEM) revealed that MA-S-treated SDF had a typical honeycomb-like porous structure. X-ray diffraction (XRD) analysis showed that MA-S treatment significantly increased the crystallinity of SDF and improved its thermal stability. Functional property analysis revealed that MA-S-treated SDF had excellent water-holding capacity (WHC), oil-holding capacity (OHC), swelling capacity (SC), and glucose adsorption capacity (GAC). Additionally, MA-S-treated SDF had enhanced adsorption capacity for cholesterol, nitrite, and bile salts under simulated gastrointestinal pH conditions. Antioxidant activity measurement showed that MA-S treatment significantly improved the DPPH free radical scavenging activity of SDF. Moreover, different extraction methods resulted in differences in the monosaccharide composition of SDF, with glucose, galactose, xylose, arabinose, and uronic acid being the most significantly affected. This study provides new insights and scientific evidence for the development of functional Tartary buckwheat bran SDF, which has significant implications for its application in functional foods.