Influence of controlled atmosphere storage on polyphenoloxidase activity in relation to colour changes of minimally processed 'Jonagored' apple

The effects of the storage atmosphere composition (2% O-2 + 4% CO2; 2% O-2 + 8% CO2; 2% O-2 + 12% CO2) on polyphenoloxidase activity and phenolic cont ent of the 'Jonagored' apple variety during cold storage was evaluated, and the relationship with enzymatic browning investigated. Controlled atmosphe re storage inhibited the polyphenoloxidase (PPO) activity of apple cubes du ring storage. It seems that the higher the concentration of carbon dioxide in the storage atmosphere the higher inhibition of PPO and the lower browni ng achieved. At the substrate-enzyme levels investigated, the phenolic cont ent, substrate level was the major factor determining darkening.