Ultrasound modification of a dual-protein hybrid: structural-functional synergy for developing low-fat, high-protein shrimp products

The intensive farming of Litopenaeus vannamei has gradually led to market saturation and declining returns due to overproduction. Shrimp surimi products are a growing segment of the seafood market, but their gelling properties are compromised by the inevitable frozen storage and distribution. To bypass the need for chemical modification agents, ultrasound was applied to composite systems of denatured soy protein isolate and shrimp myofibrillar protein to mitigate this deterioration. Ultrasonic treatment markedly increased composite solubility from 39.65 % to 175.58 % and reduced the mean particle diameter from 282.96 nm to 203.33 nm, enhancing both emulsifying activity and stability. Scanning electron microscopy revealed a denser and more homogeneous gel microstructure after sonication. Secondary structural analysis showed a partial α-helix to β-sheet transition and a significant decrease (10.33 %) in total sulfhydryl content, indicating disulfide bond formation that strengthened the gel network. These structural modifications yielded firmer gels with higher water-holding capacity and lower cooking loss. The resulting shrimp sausage exhibited improved texture and flavour, balanced nutrition, and a favourable sensory score. Free amino acid analysis indicated ultrasound-driven release of umami and sweet related amino acids, further intensifying the palatability of the sausages. These findings provide a theoretical and practical foundation for producing low-fat, high-protein shrimp sausages with high-quality and high-value-added.