Steam explosion improves the flavor of Conger myriaster bone powder: Mechanistic insights from changes in physicochemical properties and flavor compounds.

Conger myriaster bone is a nutrient-rich by-product, but its dense structure restricts nutrient accessibility and flavor development. This study evaluated how steam explosion (SE), compared with conventional treatments, modulated its physicochemical structure and flavor formation. SE at 1.0 MPa for 15 min and 1.5 MPa for 3 min induced pronounced structural disruption, evidenced by reduced particle size and a looser, more porous microstructure. This was accompanied by enhanced calcium content, protein digestibility, calcium release, and hydration properties. Structural disintegration promoted the release of Maillard reaction precursors, facilitating formation of heterocyclic compounds (e.g., 2-furanmethanol and 1H-pyrrole-2-carboxaldehyde). Meanwhile, the low-oxygen, high-moisture conditions with instantaneous depressurization suppressed the accumulation of lipid oxidation-derived volatiles, such as nonanal and 1-octen-3-ol. Non-targeted metabolomics revealed remodeling of protein-, lipid-, and carbohydrate-related metabolites, thereby expanding the pool of aroma-related intermediates. These findings reveal the mechanisms by which SE enhances the flavor of fish bone matrices.