Effects of Heat‐Stable Alakaline Protease Activity of Atlantic Menhaden ( Brevootii tyrannus ) on Surimi Gels

Heat stable protease isolated from the sarcoplasmic fraction of menhaden ( Brevoorti tyrannus ) muscle tissue was characterized as to optimum temperature and pH against casein substrate and its degradative action on actomyosin and surimi during heating. The optimum conditions for activity were 60°C at a pH of 7.5 to 8.0. Activity dropped off remarkably at temperatures below 45°C or above 70°C and when pH was below 7.0 or above 8.0. The enzyme(s) was capable of degrading actomyosin as observed by sodium dodecyl sulfate electrophoresis. This implicated a causative role for this protease system in the texture degradation observed during thermal processing of menhaden surimi at temperatures of 50‐70°C.