TEMPERATURE AND PH AFFECT TRANSGLUTAMINASE-CATALYZED SETTING OF CRUDEFISH ACTOMYOSIN

Dynamic rheological properties of actomyosin from two species (Alaska pollock, Atlantic croaker) were monitored during preincubation (settin g) at 25 degrees C and 37 degrees C, followed by programmed (1 degrees C/min) cooking to 77 degrees C. Added guinea pig liver transglutamina se enhanced gelation, as indicated by increases in both storage modulu s (G') and percentage of polymerized myosin heavy chain (MHC). In the presence of added transglutaminase maximum G' and MHC polymerization o ccurred at the same conditions of pH and temperature which were optimu m for setting of surimi pastes. This suggested that the transglutamina se-mediated setting reaction in surimi was constrained more by the con formation of the substrate (i.e., myosin) than by that of the enzyme.