This
was determined according to the method of Oyaizu (9).
The PM and PMK sample (2.5 mL) was mixed with an
equal volume of sodium phosphate buffer (200 mM at pH 6.6) and potassium ferricyanide (1%). The mixture was
incubated at 5oC for a period of 20 min, then an equal
volume of thrichloro acetic acid (1%) was added to the
mixture, which was centrifuged at 235×g for 5 min. The
upper layer (5 mL) was mixed with 5 mL of distilled water
and 1 mL of ferric chloride (0.1%). The absorbance was
measured at a wavelength of 700 nm, and the greater value
for the absorbance indicates the greater reducing power.