EFFECT OF HIGH-PRESSURE TREATMENTS ON PEROXIDASE AND POLYPHENOLOXIDASE ACTIVITIES

The effects of hydrostatic pressure of 1-9 kbar on peroxidase (POD) an d polyphenoloxidase (PPO) activity were studied. Trials were carried o ut on crude enzymatic extracts obtained from carrots and apples as the sources of POD and PPO, respectively, with different pH values (from 4.5 to 7.0). In both cases pressurization caused a remarkable enzyme a ctivation after 1-min treatments carried out at 3-5 kbar, while a comp lete enzyme inactivation was observed at 9 kbar. The pH values of the crude, enzymatic extracts seemed to affect the degree of activation an d/or inactivation due to different pressure levels. A slight recovery in enzyme activity was measured for POD samples during the first 24 h of storage after the treatments.