Saltiness enhancement of microwave-heated gel matrix focused on Na⁺ "burst" release behavior and matrix fragmentation...

Nowadays, modulating the microstructure of meat products matrix through physical processing to achieve salt reduction has attracted widespread attention. This study compared saltiness perception in pork pieces of steam heating versus direct microwave processing/ microwave reheating, with a focus on Na⁺ in protein matrix release mechanism during oral processing. The results showed that microwave direct heating and reheating significantly enhanced saltiness perception compared to steam control. Furthermore, the myofibrillar protein gels simulation system showed that microwave-induced gels resulted in a maximum 14.17% increase in the Na⁺ release content compared to steam heating, despite the same Na⁺ retention. In the initial oral breakdown in MP gels, the "burst" release of Na⁺ caused by direct microwave processing might be related to enhanced gel rigid structure breakdown. With subsequent oral chewing, the gel matrix induced by microwaves was more prone to deformation, which was conducive to the release of Na⁺ from the network structure. It was noteworthy that the microwave reheating promoted disulfide bond-mediated aggregation in light meromyosin, increasing food bolus viscoelasticity and friction in the last stage of oral processing. Meanwhile, the rigid structure breakdown induced by oral friction further triggered a "burst" release of Na⁺. This study provided theoretical guidance for the protein structure design of reduced-salt meat products.