What food contains ascorbic acid?
Red Bell Pepper
Orange juice, from frozen concentrate
Green bell pepper
Strawberries 1/2 cup
Potato, baked with skin
Cabbage greens, frozen, boiled
Covering the food with citric acid prevents browning because the acid reduced the pH below the optimum level for the enzyme (polyphenoloxidase) to catalyze the oxidative enzymatic browning reaction. Covering the food in ascorbic acid also prevents browning because ascorbic acid is an antioxidant which interferes with the browning reaction by preventing the intermediate products from being converted into melanins (the brown pigment).