● UHP (300 MPa) plus mild heat enhances the gel quality of tuna surimi. ● UHP-induced construction of a highly water-retaining gel system. ● UHP induces myofibrillar protein unfolding, leading to a dense, uniform network. This study innovatively employed a synergistic ultra-high pressure (UHP) and mild heat treatment strategy to systematically investigate the key regulatory role of this composite treatment in the structural evolution of fish mince myofibrillar protein (MP) during gelation, revealing its intrinsic connection to the final gel properties. The results indicate that increasing pressure reduces the fluorescence intensity of MP, inducing spatial conformation rearrangement. The secondary structure shifts from α-helix to β-conformation, leading to decreased protein particle size, enhanced solubility, and increased surface hydrophobicity. Compared to conventionally treated samples, protein particle size, solubility, and surface hydrophobicity significantly increased under 300 MPa conditions. These changes facilitated the formation of a denser, more uniform three-dimensional gel network. This not only significantly enhanced gel strength but also established a highly water-retaining system with maximum water holding capacity reaching 90.81% and more uniform water distribution. This study elucidates the mechanism by which mild heat and UHP synergistically enhance fish paste gel properties through protein-protein interactions, providing theoretical support for the precise regulation of texture properties in aquatic products.
Wang et al. (Wed,) studied this question.