PEROXIDASE AND POLYPHENOLOXIDASE ACTIVITIES IN PAPAYA DURING POSTHARVEST RIPENING AND AFTER FREEZING-THAWING

Changes in peroxidase (POD) and polyphenoloxidase (PPO) activities of papaya (Carica papaya), cv Sunrise, during ripening, freezing and shea frozen storage were studied. Fruits were stored at 14 degrees C and 85 90 % RH until maturity for processing was reached (about 21 days). Fruit were frozen cryogenically and frozen slices were stored at -18 degrees C. POD activity increased in pulp tissue up to the ripe stage, showing a maximum value after 7 days cold storage. Similarly, PPO activity showed an important increase (4X initial value) on the same date. The quantity of extractable proteins was at a maximum after 15 days storage at 14 degrees C. Freezing and frozen storage (-18 degrees C) produced an increase of POD activity while PPO activity was only slightly affected.