Covalent bonding in pressure-induced fish protein gels

Surimi pastes were gelled by pressure, incubation at 25 degrees C, cooking, or their combination. Differential scanning calorimetry and solubility measurements indicated that myosin denaturation and disulfide bond formation occurred during pressure-induced gelation. Time of pressure treatment had little effect on gel fracture properties. Nondisulfide covalent polymerization of myosin did not appreciably occur during pressure-induced gelation, but was prevalent in gels incubated at 25 degrees C, even when such incubation followed pressure treatment. That combination treatment increased the stress value of cooked gels more than six times, indicating synergy of pressure with the endogenous enzyme transglutaminase, thought to be responsible for gelation of surimi pastes at 25 degrees C.