The frozen surimis were prepared on addition of 8% sorbitol (S) or 0.25% sodium polyphosphate (P), or their combination (SP), and stored at −25°C for 8 months. The quality of the frozen surimis was evaluated by determining breaking strength (BS), breaking strain (bs), and gel stiffness (GS) of the two-step heated gels. The results obtained were as follows:
(1) The quality of the gel formed from the surimi with SP was much superior than those of the others. Even if the P was mixed at a grinding step with NaCl, the quality of the gel formed was compatible to that from the surimi with SP.
(2) In particular, the bs of the gel from the surimi with SP was of much higher value, although the effect of P reduced when the gel was formed from frozen surimi with S after long-term storage.
(3) The linear relations between the BS and the GS (=BS/bs) were very close between the two types of gels formed from the surimis with SP, while that of the gel formed from the surimi with S alone was clearly different.
These results indicated that a role of the P in the frozen surimi was to improve the quality of the two-step heated gel by a reinforcement of bs.