ABSTRACT
The rapid deterioration of fresh fish quality is caused by microbial and endogenous enzyme activities in the postmortem animal. Current methods for preserving fresh fish quality mostly aim at controlling microbial growth and metabolism, while the adverse effects of endogenous enzymes are grossly overlooked. High hydrostatic pressure technology has great promise as a food processing tool for preserving fresh seafood quality as it inactivates both microorganisms and enzymes. The application of high hydrostatic pressure on homologous proteases from fish and mammalian sources indicated that the fish enzymes were more susceptible to pressure inactivation than their mammalian counterparts. The degree of sensitivity of the enzymes to pressure depended both on the level and duration of pressurization. However, the pressure- inactivated enzymes showed re-activation during storage, and required combination treatments with a protease inhibitor to assure a more complete or permanent inactivation of the enzymes. Furthermore, pressure treatments of the fish muscle tissue resulted in significant (p<0.05) changes in color, with the color with increasing pressure presenting an increasingly cooked appearance to the flesh. Fish gels formulated by pressure treatment also showed improved strength and elasticity up to 2000 atm for 10 min holding time, beyond which both the texture and elasticities of the pressure-induced gels deteriorated.
