Enhancement of surimi gel-strength from blue round scad (Decapterus maruadsi) and its application in the development of high-toughness Yanpi

The utilization of blue round scad ( Decapterus maruadsi ), a low-value fish species, is currently limited by the poor gelling functionality of its native proteins. This study developed an integrated processing strategy to enhance the surimi quality and create a high-toughness Yanpi wrapper. An optimized enzymatic pretreatment (0.04% composite protease, 45 °C, pH 9.0, 80 min) was first established, which effectively reduced the muscle shear force to 5.58 kgf, improving processability. Subsequently, a thermo-mechanical extrusion process (screw speed 350 r/min, 135 °C, water-to-material ratio 1:2) was applied, which significantly facilitated protein network reformation, yielding a superior gel strength of 532.8 g·cm. Using this enhanced surimi, a Yanpi formulation was optimized (4:1 surimi-to-potato starch ratio, 3% mixed hydrocolloids, and 0.3% TGase). The resulting product exhibited an excellent textural profile with high toughness (244.15 g·cm) and desirable brittleness (4.71 kg). This work provides a scalable technical framework for valorizing underutilized marine resources into high-value functional foods.