Thermal inactivation of polyphenoloxidase in pineapple puree

Prevention of browning in pineapple puree by thermal inactivation of enzyme, Polyphenoloxisase (PPO), was examined between 40 and 90 °C and in relation to exposure time. The amount of inactivation was measured as a function of time and temperature under isothermal conditions. Reaction rate constant and activation energy (Ea) as well as Decimal reduction time (D) and z-value of thermal inactivation, were determined. The rate of inactivation varied with temperatures and follows a logarithmic law. Kinetic studies showed that the thermal inactivation (40–90 °C) of the PPO followed first-order kinetics.