Fresh sliced apples discolor and turn an ugly brown when exposed to the air. According to the University of Illinois, enzymes in light colored fruits cause the oxidation responsible for the change in color and loss of vitamin C. When preparing sliced apples for cooking or canning, care must be taken to prevent oxidation. Although the juice of a lemon may do the trick for small quantities, there are more efficient ways to prevent discoloration.
Pour 2 qts. of cold water in a large bowl.
Dissolve 1 tsp. of powered ascorbic acid in the water. Look for ascorbic acid powder in the canning aisle. Although there are several other products available, such as citric acid powder, the Michigan State University Food Preservation Series suggests that powdered ascorbic acid is the most effective in preventing discoloration.
Soak sliced apples in the mixture to keep slices fresh and white while you pare the remainder of the apples. Apple slices or wedges remain crisp and white until serving time. Remove, pat dry and use for cooking or serve as snacks.