Effects of steam explosion on the structural, physicochemical, and functional characteristics of dietary fiber in sorghum grains

The steam explosion (SE) approach is a green and environment-friendly method used for modifying sorghum grains. This study aimed to investigate the effects of SE strength variation on the chemical composition, structural, physicochemical, and functional properties of total dietary fiber (TDF) in sorghum. According to the findings of our study, SE treatment significantly improved the soluble dietary fiber (SDF) content from 2.74% to 6.57% and reduced the insoluble dietary fiber (IDF) content from 13.43% to 5.99%. The results of SEM, FTIR, and XRD indicated that SE treatment caused TDF to collapse and to form a honeycomb structure with many cavities, resulting in a larger particle size, stronger typical sugar esters absorption peaks, and higher crystallinity in TDF. The STA results demonstrated SE treatment improved the thermal stability of TDF. Similarly, SE treatment improved TDF's water/oil holding capacity, swelling, glucose-binding, and α-amylase inhibitory activity. As confirmed by the results of structural and correlation analysis, the appropriate SE treatment caused positive effects in TDF's physicochemical and functional characteristics. From a functional perspective, TDFs with excellent functional properties have a great potential for applications in the food industry, such as anti-digestion additives. • Steam explosion increased the extraction yield of soluble dietary fiber in sorghum grains. • SEM observed an increased honeycomb structure in total dietary fiber. • Steam explosion improved the thermal stability of total dietary fiber. • Treatment increased glucose-binding and α-amylase activity inhibitory of total dietary fiber.