Peroxidase is an enzyme conventionally used to monitor and evaluate the heat treatment extent, because it is one of the most heat-stable enzymes, occurring in a considerable number of vegetables (Goncalves et al., 2007). The POD activity in FBS was 0.75, which decreased to 0.22 at 3 min and no POD activity can be detected at 6 min. The result suggested that POD was sensitive to high temperature and could become inactive in short time at higher temperature. This experimental result was similar to the blanching result of Goncalves et al. (2007) concluded from pumpkin. They observed that the POD activity in pumpkin decreased by 90% after heating for 3.9 min at 95 °C.