Effects of Different Extraction Methods on the Quality and Antioxidant Properties of Paeonia suffruticosa Seed Oil

The effects of the instant press extraction,hydraulic press and n-hexane extraction methods on "Danfeng" Paeonia suffruticosa seed oil extraction as well as the oil yield,physicochemical properties,main components and antioxidant properties of the extracted oil were studied. The results showed that there were significant difference (p<0.05) of the oil yields among the three methods of hexane extraction (31.26%),instant press method (14.27%) and hydraulic method (7.81%),respectively. There was no significance variance (p>0.05) between instant press extraction and hydraulic press method on the oil iodine value,and very significance variance (p<0.01) on the saponification value (p>0.05). The water content and volatile components and peroxide value of hexane extraction and hydraulic oil were significantly higher than that of instant oil (p<0.05),and the acid value of the oil extracted from n-hexane was significantly higher than that of the other two methods (p<0.01).There were no significance varianceon the palmitic acid,linoleic acid and squalene contents of the three methods (p>0.05),butthe contents of stearic acid and oleic acid in peony seed oil extracted by n-hexane were significantly higher than those in the other two methods (p<0.01). Linolenic acid accounted for 30.98% of the total fatty acid in instant press method,which was significantly higher than that of hydraulic (23.22%) and n-hexane extraction method (15.98%) (p<0.01),and beta glutamol was the highest in the instant pressing method,and there was significant difference among the three methods (p<0.01).The results of antioxidant evaluation showed that the removal of 1,1-two phenyl-2-three nitrophenyl hydrazine (DPPH) free radical was slightly higher than that of the hydraulic method,and the scavenging ability to the hydroxyl radical was more than that of the instant pressed peony seed oil. The absorbance value of the hydraulic peony seed oil in the range of 270~450 nm was higher than that of the other two methods,which showed a good sunscreen effect. Practically,the peony seed oil could be extracted by the instant press or hydraulic method firstly,then the oil cake could be extracted with hexane,combination of the two steps would improve the oil nutrition as well as contribute to the high oil extraction rate.