PAL activity was analyzed by using a modified method of Assis, Maldonado, Muñoz, Escribano, and Merodio (2001). 2 g mortar of fresh-cut lotus root was homogenized in a cold 10 mL solution of 0.05 mol/L sodium borate buffer (pH 8.0) containing 0.5 g polyvinylpyrrolidone, 5 mmol/L 2-mercaptoethanol and 2 mmol/L EDTA at 4 °C.