Innovative Sargassum fusiforme polysaccharide composites for cryoprotection of large yellow croaker (Larimichthys crocea) fillets during frozen storage

Frozen aquatic products quality degrades primarily due to ice crystal formation. This study developed a composite cryoprotectant (CC) consisting of marine Sargassum fusiforme polysaccharide (SFP) for frozen large yellow croaker fillets. The optimal formulation of CC was 1 % SFP, 0.125 % tea polyphenols, and 2.25 % food-grade phosphate. The fillets treated with CC and stored at −18 °C for 80 days showed higher salt-soluble protein content, Ca 2+ -ATPase activity, total sulfhydryl content, apparent viscosity, and a more intact microstructure compared to control group. TCA-soluble peptides and thiobarbituric acid value were lower, indicating improved myofibrillar protein stability and overall fillet quality . The treatment enhanced water retention and distribution characteristics, demonstrating the high cryoprotection efficiency of the SFP-based CC. This novel cryoprotectant shows effects comparable to, or even exceeding, commercial cryoprotectant in mitigating ice crystal-induced damage, making it a promising solution for frozen aquatic products storage.