Polyphenoloxidase and Its Thermal Deactivation in Western Rock Lobster (<i>Panulirus cygnus</i>) Processing

ABSTRACT Polyphenoloxidase (PPO) activity results in blackening or melanosis of tissues in western rock lobster (WRL). The aim of this study is to establish the thermal deactivation constants for WRL PPO and compare them to the thermal lethality of commercial cooking. Decimal reduction values were determined for a range of temperatures, and the theoretical process lethality at 90°C (F90) was calculated. F90 was equal to 36.11 minutes. Process lethality values for standardized commercial cooking of WRL were determined. Comparison of these results to the theoretical F90 value clearly showed that current commercial cooking is inadequate to achieve deactivation of WRL PPO