Improving functional properties of wheat bran by steam explosion: Insights from structural characteristics,...

The effects of roasting, autoclaving, microwaving, and steam explosion (SE) on the structural properties, chemical composition, and bioactivity of wheat bran powders were investigated. Compared to the others, SE significantly enhanced the contents of total phenolics and total flavonoids by 44.08%-75.58% and 21.04%-74.77%, respectively. This led to increase DPPH and ABTS radical scavenging activities by 21.62%-113.53% and 35.27%-38.61%, along with enhanced tyrosinase inhibitory activity by 59.78%-225.64%. Furthermore, SE treatment improved the total crystallinity index, hydrogen bond intensity, and thermal stability of wheat bran. Untargeted LC-MS metabolomics analysis revealed extensive metabolic reprogramming, with 1938 differentially abundant metabolites (1120 upregulated and 818 downregulated). Enrichment analysis highlighted significant alterations in cofactor biosynthesis and tryptophan and tyrosine metabolism. These findings demonstrated that SE induced beneficial structural and metabolic changes that collectively enhanced the functional properties of wheat bran, providing a solid scientific basis for its application in developing value-added functional food ingredients.