Relatively lower PAL activity ( Fig. 4C) and higher PPO activity ( Fig. 4E) were detected in the samples from 5 to 10 days after curing compared to the control. Interestingly, higher PAL and the decreased PPO activity were associated with the decreased total phenolic content in the control potato tissue, while relative lower PAL activity and higher PPO activity were associated with increased total phenolic content in the curing potato.