Inactivation of polyphenol oxidase by high-intensity pulsed magnetic field and kinetic model

In order to find an effective method to control the activity of polyphenol oxidase (PPO) in vegetable and fruit, the effects of pulsed magnetic field (PMF) on the activity of PPO were investigated. The data were adjusted to different models to study the kinetics of PPO inactivation by PMF. The results showed that when PPO was exposed to PMF at field strengths of 2.5, 3.5 and 4.5 tesla (T) for 5 to 40 pulses, residual activity of PPO decreased with the increase of field strength and number of pulse. The maximum inactivation of PPO was achieved at 4.5 T for 40 pulses, in which 93.10 % of the enzyme activity was lost. The inactivation data were fitted by three kinetic models, which were Bigelow Model, Hülsheger Model and Weibull distribution function. Results showed that Weibull distribution function gave better fittings for the inactivation of PPO by PMF than Bigelow or Hülsheger models. It can be concluded that PMF is an effective non-thermal food preservation technology to inactivate PPO in vegetable and fruit. Weibull Model fits the inactivation data well, which provides reference for practical application.