Effect of Phycocyanin–Rosmarinic Acid Conjugate-Stabilized Pickering Emulsions on the Gel Properties of Surimi

This study aimed to investigate the effects of the phycocyanin–rosmarinic acid (PC-Ra) emulsion on the gel quality of surimi. PC-Ra conjugates were synthesized firstly via laccase-catalyzed oxidation at different Ra concentrations, and their physicochemical properties—including grafting degree, sulfhydryl group content, free amino group content, and surface hydrophobicity—were characterized. The results demonstrated that Ra addition effectively reduced free amino groups, achieving optimal grafting at 30 μmol/L along with peak disulfide bond content and surface hydrophobicity in the PC-Ra conjugate. This was thus attributed to covalent bond formation, as confirmed by FTIR spectroscopy. The PC-Ra emulsion was then incorporated into surimi gels and compared with gels containing directly added corn oil. The results indicated that the PC-Ra emulsion significantly improved the textural properties of surimi gels. Furthermore, it enhanced water-holding capacity, reduced cooking loss, and delayed lipid oxidation. Among all formulations, the PC-Ra 30 emulsion exhibited the most pronounced effects and shows potential as a fat replacer in surimi gel preparation, yielding products with superior quality. This study provides a theoretical basis and technical support for developing novel surimi gel products.