Abstract: Peony seed oil from the ‘Fengdan’ cultivar was extracted by supercritical CO2 extraction, cold pressing,
and organic solvent extraction, respectively, in order to explore the effect of different extraction methods on oil yield,
physicochemical properties, fatty acid composition and antioxidant capacity in vitro. The results showed that organic
solvent extraction produced the highest oil yield (28.61%), supercritical CO2 extraction was in the middle (28.17%), and
the lowest oil yield (19.14%) was obtained by cold pressing. There were no significant variations in saponification value,
refractive index or relative density among the three extracted oils, while considerable variations in acid value, peroxide
value, iodine value, moisture and volatiles, and color were observed. Moreover, these oil samples had nearly identical
fatty acid composition and content as measured by gas chromatography-mass spectrometry (GC-MS). In addition, their
antioxidant activities in vitro were significantly different and followed the decreasing order of organic solvent extraction >
cold pressing > supercritical CO2 extraction in terms of DPPH (1,1-diphenyl-2-picrylhydrazyl) radical-scavenging rate and
EC50 (concentration for 50% of maximal effect). In conclusion, each method has both advantages and disadvantages for the
extraction of peony seed oil. Cold pressing is advantageous with respect to lower cost, easier operation, simpler process, and
higher safety over the two other methods and therefore it is more suitable for the extraction of peony seed oil.

Key words: physicochemical properties, fatty acid composition, α-linolenic acid, antioxidant capacity