Effect of Electric Fields on the activity of polyphenol oxidases

The goal of this study was to evaluate the effect of Electric Fields (EF) on the activity of polyphenol oxidase (PPO) enzymes. EF were first applied to a commercial enzyme and then to an enzymatic extract from avocado. A fungal commercial PPO was treated at 10 kV/cm for 0-6 min and frequencies from 0 to 950 Hz; after the treatments the enzyme had a minimal residual activity (RA) of 12% after 6 min at 260 Hz. The avocado extract was treated at 18 kV/cm at frequencies from 0 to 760 kHz, And it was shown that the PPO was insensitive to frequencies higher than 1000 Hz, below this level, the enzyme was inactivated to a RA of about 15%. These results demonstrated the effectiveness of this Electric Field system on enzyme inactivation. It is important to mention that in this system there was no physical contact between the food sample and the electrodes and therefore the temperature remained constant throughout the processes.