Lower ultrasound power assisted dissolution of rabbit myofibrillar protein in low-salt systems mediated by sodium pyrophosphate

This study explores the mechanism by which sodium pyrophosphate (TSPP) combined with lower intensity ultrasound (LIU) improved the dispersibility of myofibrillar proteins (MPs) in low salt medium. TSPP combined with LIU (0.16%+500W, 0.2% TSPP+300W) can achieve the effect of high ultrasound treatment alone (HIU, 600W) in improving the dispersibility of MPs. MPs in TSPP medium exhibited dissociation of scaffold proteins (MyBP-C, α-actinin) and release of myosin/actin monomers – effects mirroring HIU modification. This triggered the whole conformational shift from stable β-sheet to flexible α-helix structures, destabilized the MPs architecture and inducing the MPs unfolding and exposure of active functional groups. The destabilized structure facilitated LIU-driven further depolymerization and unfolding of MPs, enabling reorganization into soluble oligomers through various covalent interaction modes. Due to the increased surface charge and hydrophilicity, the MPs remained highly dispersed. Modulating the media environment is a crucial strategy for optimizing the energy efficiency of ultrasound-based protein modification. • The intervention of TSPP achieved the improvement in MPs dispersibility under LIU. • The synergistic mechanism between TSPP and LIU was revealed from scaffold proteins. • Flexible MPs conformation facilitated LIU induced dissociation and reconstruction. • LIU combined with TSPP induced soluble oligomers by various covalent crosslinking.