INHIBITION OF APPLE POLYPHENOLOXIDASE (PPO) BY ASCORBIC-ACID, CITRIC-ACID AND SODIUM-CHLORIDE

The inhibiting effect of ascorbic acid, citric acid and sodium chlorid e on Polyphenoloxidase (PPO) of Golden Delicious apple cubes was studi ed. Dipping in ascorbic acid (0. 2-10 g/L range) and in NaCl (0. 2-1 g /L range) solutions for 5 min increases the PPO activity. Citric acid solutions (0.2-10 g/L range) have little or no inhibition of PPO. A 90 -100% PPO inhibition was obtained with a 5 min dip in mixtures of asco rbic acid and citric acid (10 + 2 g/L), and of ascorbic acid and sodiu m chloride (10 + 0. 5 g/L).