Effect of magnetic nano−particles combined with multi−frequency ultrasound−assisted thawing on the quality and myofibrillar protein−related properties of salmon (Salmo salar)

Multi−frequency ultrasound−assisted thawing (MUAT) has been proven to be an effective method of maintaining the quality of frozen food. The effects of magnetic nano−particles (MNPs) combined with MUAT and multi−frequency ultrasound−assisted sequential thawing (MUST) on water retention, myofibrillar protein (MP) structural characteristics, function characteristics, and MP aggregation and degradation of salmon (Salmo salar) were studied. The results showed that MNPs combined with multi−frequency ultrasound sequential assisted treatment (MNPs−MUST) significantly improved the thawing rate and the retention of water and had better emulsifying and foaming properties. MNPs−MUST treatment reduced the oxidation and degradation of MP, increased sulfhydryl content, and protected the structure of MP. Confocal laser scanning microscopy (CLSM) indicated that the MP transformed into a filamentous polymer into more evenly distributed units, resulting in higher protein solubility, lower surface hydrophobicity, and lower protein turbidity. Therefore, MNPs combined with MUST has a potential application value in the thawing research of frozen salmon.