Fig. 2. Antioxidant activities of different fractions at the same concentration (5 mg/mL). The value of each fraction is the mean value (± SD) for three independent experiments, each of which was performed in triplicate; the values represent the DPPH·, ·OH, and ${\text{O}}_2^{-}$ of these fractions (P1, P2, P3, P4), respectively; NAC represents N-acetyl cysteine which was a standard antioxidant protein sample to compare the degree of antioxidant capacity with the purified samples.