Citric acid is an anti-browning agent, which prevents polyphenoloxidase (PPO) by suppressing the food pH and binding the Cu2+ in an active site of PPO to form an inactive complex (Martinez and Whitaker, 1995)Since pH has a profound effect on anthocyanin stability and color expression. The control of the pH in the washing treatments has been considered an important factor (Sistrunk and Moore, 1979).