Effect of steam explosion on structural, physicochemical and functional properties of dietary fiber of Tartary buckwheat

Steam explosion (SE) has emerged as an effective physical pretreatment technology for modifying food materials and their byproducts. This study investigated the impact of SE on the structural, physicochemical, and functional properties of soluble (SDF) and insoluble dietary fiber (IDF) derived from Tartary buckwheat. The results showed that SE promoted the conversion of IDF to SDF, released phenolic compounds from SDF and IDF, altered monosaccharide profiled, and reduced the particle size of SDF and IDF. SE decreased the crystallinity of SDF but increased that of IDF. These structural changes are directly linked to marked improvements in physicochemical and functional properties of the fibers. SE significantly increased the water-holding capacity, oil-holding capacity, swelling capacity of both fibers. Cholesterol adsorption capacity increased significantly, especially at pH 7.0 for 120 min. Both SDF and IDF of steam-exploded buckwheat exhibited strong glucose adsorption capacity and α-amylase inhibitory activity, reduced the glucose dialysis retardation index, increased the absolute value of zeta potential, improved the DPPH•, ABTS• + , and •OH scavenging capacities. The functional properties of SDF were significantly superior to those of IDF. It was confirmed that SE is a viable technique for upgrading Tartary buckwheat dietary fiber into a high-quality functional ingredient. • Effects of steam explosion (SE) on SDF and IDF obtained from Tartary buckwheat were compared. • SE is beneficial for the conversion of IDF to SDF. • The FTIR and XRD results showed the changed structure of SDF and IDF. • Appropriate SE improved the functional properties of SDF and IDF. • DF and polyphenols bound to DF exhibit synergistic effects on their functionality.