Effect of several cryoprotectants on the physicochemical and rheological properties of suwari gels from frozen squid surimi made by two methods

Functionality of squid surimi (Dosidicus gigas) made by two methods (isoelectric precipitation A, and acid washing, B) and stored for 6 months at −15 °C, was analysed as a function of several cryoprotectants. The cryoprotectant effect was studied in terms of the ability to form suwari gels (SA and SB) from the two kinds of surimi. Chemical analyses to detect protein aggregation, dynamic oscillatory tests at constant temperature (10 °C) and temperature sweep tests from 10 to 90 °C were performed.Frozen storage of surimi samples produced two different effects on the thermo-rheological properties of SA and SB suwari gels: in SB samples there were no significant differences over frozen storage. Of the SA samples, the ones with trehalose retained their initial viscoelastic properties best at 10 °C; moreover, trehalose significantly altered the pattern of the thermal gelation profile in SA samples, making it similar to SB samples. All these thermo-rheological results are consistent with protein solubility and electrophoresis (SDS–PAGE) data evidencing protein aggregation.