Properties of Proteolytic Enzymes from Muscle of Octopus ( Octopus vulgaris ) and Effects of High Hydrostatic Pressure

The proteolytic activity of octopus arm muscle exhibited optimum activity at 40°C and 60°C, at optimum pH 2.5 and 4.0, respectively. The proteinases were inhibited strongly by cysteine‐ and aspartic‐proteinase inhibitors and, to a lesser degree, by serine‐proteinase inhibitors at 40°C, and by cysteine‐proteinase inhibitors at 60°C. High pressure did not modify the temperature and pH autolytic activity profiles. The autolytic activity at 40°C was reduced by high pressure; however, it was increased at an incubation temperature of 60°C, mainly in muscle pressurized at 7°C. Aspartic‐proteinase was the most sensitive to high pressure. The autolysis of myofibrillar proteins was reduced by high pressure, which was evident in MHC band.