Acidulate; Acidulated water

To acidulate a food item means to make it slightly acid, most often by adding lemon juice or vinegar. Acidulated water (water that has been mixed with an acid, typically lemon juice) is commonly used to prevent cut pieces of fresh fruit from becoming brown from exposure to air. The fruit may be placed in enough acidulated water to cover it completely, or it may simply be tossed with enough to coat the cut surfaces. Approximately 1 tablespoon (15 ml) lemon juice per 1 quart (960 ml) of water is sufficient.