Heated gel forming ability of walleye pollack frozen surimis of various grades, as measured by physical properties of heated gel and its dependence on protein concentration

From ten lots of walleye pollack frozen surimis of various grades, the heated gels of different protein concentrations were prepared by adding 0-150% water. Breaking strength (BS), breaking strain (bs), and gel stiffness (Gs = BS/bs) were measured, and the effect of the protein concentration of the heated gel on their physical values was analyzed. The results were as follows: (1) Of all the surimis tested, the BS and Gs of the heated gel increased exponentially with the increase in the protein concentration of the heated gel. (2) The maximum values of BS and Gs of the heated gels formed without addition of water were higher in the order of SA > FA > A > KA > 2nd grades of frozen surimi. (3) When BS was plotted against Gs, there was a close, positive correlation among those of the heated gels from the ten lots of frozen surimis of various grades. These results indicated that the heated gel forming ability, as measured by BS and Gs levels of the heated gel and its dependence on the protein concentration, is a useful parameter for judging the quality of walleye pollack frozen surimi.