Cold storage-induced protein denaturation and functional deterioration of freeze-dried surimi powder

Freeze-dried surimi powder (FDSP) was prepared and evaluated the storage-dependent changes in protein properties and their impacts on gel quality. Drying increased the number of disulfide bonds among surimi proteins, indicating dehydration-driven protein association. During subsequent storage, hydrophobic interactions increased further, accompanied by β-structure-associated aggregation and larger protein aggregate formation. These stepwise interaction shifts resulted in a more heterogeneous gel microstructure, increased free water, and an irregular gel appearance, reflecting weakened protein-water interactions within the gel matrix. After 3 months of storage, the gel strength declined to 49.7% of the control, whereas the water-holding capacity decreased by approximately 5%. In contrast, the storage modulus (G'), loss modulus (G″), and complex viscosity (η*) of FDSP gels were maintained or increased, suggesting that drying and storage promoted the formation of a more elastic network despite deterioration in macroscopic mechanical strength.