The dual enhancement of gel properties and storage stability by protamine in low-salt silver carp (Hypophthalmichthys molitrix) surimi.

Reducing salt from 2.0% to 1.0% in silver carp (Hypophthalmichthys molitrix) surimi compromises gel quality and storage stability. This study evaluated the dual effects of protamine on gelation and storage stability in low-salt surimi. Salt reduction decreased gel strength from 2161.66 to 1842.10 g·cm and water-holding capacity from 63.43% to 56.24%, while increasing cooking loss from 9.72% to 19.75%. Addition of protamine at 8 g per 100 g of initial surimi (NP18) reversed these changes, increasing gel strength to 3919.59 g·cm, restoring water-holding capacity to 63.72%, and reducing cooking loss to 11.58%. Mechanistically, protamine enhanced ionic interactions and hydrogen bonding, promoted water redistribution from free to immobilized states, and formed a denser and more continuous gel network. Under 4 °C storage for 16 days, protamine retarded microbial growth and delayed TVB-N and TBARS accumulation. These findings support protamine as a potential ingredient for improving low-salt surimi quality and storage stability.