| Abstract: | The thermal stability of fish muscle proteins varies between species with considerable implications for storage and processing properties. Myosins were isolated from cod and snapper, cold- and tropical-water fish respectively, and their thermal melting characteristics were compared using differential scanning calorimetry over a range of pH and ionic strength conditions. At pH 6 and ionic strength 0.06 M, cod myosin exhibited a thermal melting transition 10 K lower than snapper myosin, reflecting a comparable differential in transitions attributed to myosin in intact muscle from the two species at 315 and 325 K, respectively. However, with increasing pH and ionic strength, conditions favourable to disaggregation and dissolution of myosin in vitro, the snapper myosin transition decreased to that exhibited by cod myosin, which remained essentially unaffected by the conditions. It is suggested that differences in the aggregation characteristics of fish myosins may explain in part the different thermal melting properties in vitro. |
