Citric acid is the most abundant organic acid in strawberry, followed by malic acid (Holcroft and Kader, 1999). Citric acids is added as an acidifier in industry to most fruit and berry products and widely used in the food industries for controlling the browning. Citric acid is an anti-browning agent, which prevents polyphenoloxidase by suppressing the food pH and binding the Cu2+ in an active site of PPO to form an inactive complex