Phenylalanine ammonia-lyase is the key enzyme of lignin biosynthesis (Assis et al., 2001). Fresh Bamboo shoots had the highest PAL activity (3.42). However, blanching treatment can decrease its activity dramatically. The PAL activity decreases by 86.26% at 6 min and no PAL activity can be determined at 9 min, indicating that PAL inactivation was also significantly affected (P < 0.05) by blanching time. Besides, PAL was easier to become inactive at higher temperature compared with PPO.