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

This study aimed to investigate the effects of the <i>phycocyanin-rosmarinic acid</i> (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.