Objective The aim of present study was to explore the feasibility of producing high-quality surimi from frozen seawater fish treated with composite antifreeze.

Methods Yellowfin snapper (Acanthopagrus latus), small yellow croaker (Larimichthys polyactis) and golden pomfret (Trachinotus ovatus) were selected to optimize the ratio of phosphate based on freezing point and phase change enthalpy of fish meat, and the effect of antifreeze on the gel forming ability of frozen fish meat was also investigated by the analysis of fish tissue sections, determination of surimi gel strength and analysis of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE).

Results The optimization results showed that the contents of sodium pyrophosphate, sodium tripolyphosphate and sodium hexametaphosphate in the best antifreeze effect for yellowfin snapper and small yellow croaker were 3.0%, 3.0% and 1.0%, respectively, while those in the best antifreeze effect for golden pomfret were 3.0%, 3.0% and 0.1%, respectively. The freezing point and phase change enthalpy of fish meat treated with the antifreeze increased first and then decreased with increasing ice storage time, and the highest value of freezing point and phase change enthalpy appeared at the end of the ice storage with the highest rigidity index. The correlation coefficient between freezing point, phase change enthalpy and phosphate content were more than 0.6. After being treated with antifreeze, the frozen storage damage of fish tissue structure was inhibited. The breaking force and breaking distance of surimi gel in the experimental group were significantly higher than those in the control group at 120 days of frozen storage, while those of the experimental group were close to the control group at 180 days of frozen storage. When the frozen storage time was more than 120 days, the myosin and actin in surimi gels began to degrade, which were not affected by the addition of antifreeze.

Conclusion Therefore, the frozen fish treated with phosphate composite antifreeze can be used to produce surimi within a certain frozen storage time.

Significance  The results of this study provide technical support for the production of high-quality surimi by using frozen fish, thus solving the problem of unbalanced supply of raw fish in different seasons and promoting the sustainable development of aquatic processing industry.