Changes in PPO and POD activities of oxalic acid-treated and control fruits during storage are shown in Figs. 2C and 2D, respectively. PPO and POD activities of acid treated fruits were low and changed slightly during storage, while those of the control fruits were higher and changed significantly. PPO and POD activities of control fruits increased and reached a maximum on the first day and then decreased. During 5 days of storage, there were significant differences in PPO and POD activities between the acid-treated fruits and control fruits. Hot water dipping followed by 10% oxalic acid treatment gave the best inhibition of PPO and POD activities.