purée The effect of HPTP of pumpkin purée on the residual activity of PPO is shown in Fig. 2. The percentage of residual activity of PPO compared to control pumpkin purée varied as a result of HPTP between 112% (300 MPa at 70◦C) and 40% (900 MPaat 70◦C). All treatments significantly reduced the PPO activity with the exception of the treatment at 300 MPa/70◦C, which increased the PPO activity. At 600 and 900 MPa, the inactivation of the PPO was similar for all combinations of pressure and temperature tested, whereas the effect of processing at 300 MPa was related to the initial temperature of processing.At 300 MPa, treatments performed at 60 and 80◦C achieved an intense enzyme inactivation (especially at 80◦C), while the treatment at 70◦C enhanced the activity of the PPO.