Effects of compound of crisped tilapia and common tilapia on surimi gel quality

Tilapia (Oreochromis sp.) is one of the most productive and widely consumed aquaculture species worldwide, with China’s breeding output exceeding 1.89 million tons in 2024. Surimi from common tilapia suffers from weak gel strength and rapid quality deterioration during storage, failing to meet market demands of medium-to-high-end surimi products. Crisp tilapia, a special variant cultivated with broad bean feeding, possesses much denser muscle fibers and serves as an ideal raw material for elastic surimi. Nevertheless, surimi solely made from crisp tilapia exhibits excessive hardness, unbalanced flavor and high manufacturing costs. Blending two types of tilapia surimi enables complementary performance in texture and flavor, yet the quality regulation rules and the conformational evolution of myofibrillar protein in this mixed system remain unclear. Common tilapia surimi is limited by poor gel strength and unstable storage quality, while pure crisp tilapia surimi is associated with high costs and overly rigid texture. This work aims to explore the synergistic effect and underlying mechanism of blended tilapia surimi for overall quality improvement. Surimi gels were manufactured at mass ratios of common tilapia to crisp tilapia (10:0, 8:2, 7:3, 6:4, 5:5, 0:10). A series of indicators were comprehensively characterized, including gel strength, water holding capacity (WHC), water distribution, dynamic rheological behaviors, sensory attributes, electronic tongue and nose signals, volatile flavor profiles, and myofibrillar protein conformation. The results showed that an increased proportion of crisp tilapia remarkably elevated gel strength, WHC, and the ratio of immobilized water, along with enhanced storage and loss moduli. The abundance of flavor compounds gradually increased, with growing contents of aldehydes, unsaturated alcohols, and characteristic esters. The 5:5 blending group achieved the optimal balanced performance in terms of texture, water retention, and flavor harmony.Notably, the protein in this group exhibited a higher β-sheet content, a reduced proportion of random coil, and moderate intrinsic fluorescence intensity, indicating the ordered rearrangement of the secondary and tertiary structures of myofibrillar protein. The 5:5 compounding strategy compensates for the defects of single raw materials by reconstructing myofibrillar protein conformation, optimizing water distribution, and regulating key volatile compounds, which serves as an effective processing technique for producing high-quality tilapia surimi. This study provides theoretical support and technical references for the efficient utilization of raw materials, product quality upgrading, and differentiated market development in the tilapia processing industry.