Effect of particle size and microstructure on the physical properties of soybean insoluble dietary fiber in aqueous solution

The objective of this study was to investigate the effect of particle size and microstructure on the physical and functional properties of soybean insoluble dietary fiber (IDF) in aqueous solution. Different IDF suspensions were obtained by ball milling (BM) and high-pressure homogenization (HPH) treatments. The results showed that the BM treatment significantly reduced the particle size distribution of the IDF, and the additional HPH treatment (BM-HPH) caused the IDF to become more porous, resulting in the formation of a honeycomb structure. Samples with a honeycomb network structure had higher hydration capacity and solubility. The water holding capacity, swelling capacity and solubility of I8 reached 18 g/g, 72 mL/g and 35%, respectively. I8 had the highest emulsifying stability and suspension stability. These results of the present study suggested that the reduction in particle size of IDF cannot fully account for its functional properties, of which the honeycomb structure played a more significant role. From the results of this study, it was clear that the functional properties of IDF depend on its small particle size and honeycomb structure. The present study indicated that a combination of BM and HPH treatments provides a new perspective for modifying and utilizing dietary fiber.