Evaluation of the Impact of Papain‐Treated Textured Soybean Protein on the Gel Properties of Surimi Gels

The gelation properties of surimi gels are a critical quality attribute for processed seafood products. This study systematically assessed the impact of textured soybean protein (TSP) on gel strength, rheological properties, microstructural characteristics, and protein-protein interactions of surimi gels using texture profile analysis, dynamic oscillatory rheometry, scanning electron microscopy (SEM), and surface hydrophobicity measurements. The results indicate that supplementation of 10% wet-based papain-treated TSP (TSPp) significantly enhances the gel strength (p < 0.05) and water-holding capacity of surimi gels. This improvement is primarily attributed to the role of TSPp particles as active fillers that reinforce the myofibrillar protein network, as well as hydrophobic interactions between the polar groups of TSPp and fish myosin, which facilitate protein cross-linking. The optimal functionality is achieved with the addition of 10% TSPp, as evidenced by an increase in breaking force compared to the control group. However, the inclusion of excessive TSPp (>20%) has a detrimental effect on network continuity, due to the dilution of myofibrillar proteins. Moreover, the correlation analysis demonstrated significantly positive relationships between gel strength, disulfide bond content, and surface hydrophobicity. The findings of this study demonstrate that TSPp can serve as a viable plant-based modifier for surimi gels, providing a sustainable alternative to animal-derived additives without compromising textural properties.