Short-term frozen storage enhances cross-linking that was induced by transglutaminase in surimi gels from silver carp (Hypophthalmichthys molitrix)

To enhance the application of transglutaminase (TGase) in processing and preserving of frozen surimi, the mechanism that enhances surimi gelation induced by TGase after short-term freezing was investigated. Gel properties and cross-linking extent of surimi gels increased when surimi was frozen at −18 °C for 5-7 days. However when storage time exceeded 10 days, textural properties and water-holding capacity decreased significantly. Moreover, the difference of breaking force and hardness between surimi gels with and without TGase reached the maximum after 3-5 days of frozen storage. Free amino content of myosin increased during the first 7 days, and TGase activity increased significantly during the first 3 days. Short-term frozen storage unfolded myosin structure, decreased α-helix content, and exposed hydrophobic patches, which promoted cross-linking reactions and intermolecular hydrophobic interactions. This study provides some new ideas for the processing, storage and transport of frozen surimi and manufacture of frozen surimi-based products.