• hydrostatic pressure, fish proteases;
  • viscosity;
  • α;2-macroglobulin;
  • response surface


Effects of combination treatments involving hydrostatic pressure, pH, and crude α;2-macroglobulin on muscle protease activity and viscosity were investigated using response surface methodology. Statistical analysis showed the model was very significant, predicting responses with high accuracy. Proteolytic activities were reduced with increasing pressure and inhibitor concentrations while pH elicited a quadratic response. Reducing pH and increasing pressure also reduced viscosity of tissue homogenate, but inhibitor concentration did not affect (p > 0.05) this response. The proteases did not show any tendency to regain activity during 3 weeks storage possibly due to a crude inhibitor in the homogenate and did not seem to have any direct influence on viscosity as shown by a low correlation (r =–0.30). Viscosity progressively increased during this period.