The DPPH radical scavenging activity of methylated PLFP and purified PLFP were determined to evaluate their antioxidant activities. As shown in Fig. 1, the DPPH radical scavenging activity of the purified PLFP was 22.1%, significantly (P < 0.05) higher than all the methylated PLFP samples. From the results obtained in this study, a high volume of methyl iodide represented a high degree of methylation for PLFP. By increasing the degree of methylation, the DPPH
radical scavenging activity decreased. However, no further decrease was observed when the volume of methyl iodide increased in the range of 0.2–0.8 ml. The correlation coefficient between degree of methylation and DPPH radical scavenging activity was
determined to be 0.72.