Study On The Extraction And Antioxidant Activity Of Penoy Seed Oil

The paper mainly studied the extraction of peony seed oil with water-organic solvent and ultrahigh pressure technology. Also, it studied the influence of ultrahigh pressure assisted extraction on the composition and acid value of peony seed oil. What’s more, antioxidant activity of peony seed oil was researched.① Water-organic solvent extraction of peony seed oil.When the ratio of peony seed powder to water was 6 g/mL, the degumming effect of water-organic solvent extraction was as well as the traditional high temperature hydration, showed that water-organic solvent extraction realized the oil extraction and degumming at the same time.Optimization of the extraction conditions on account of considering the aspects of solvent dosage, extraction yield of peony seed oil and antioxidant activity using the response surface methodology, were turned out as follows:ratio of solid to liquid (16 mL/g), temperature (58℃), time (70 min). Under those conditions, the predictive value of extraction yield was 31.36%, the actual value was 30.78%, and DPPH clearance rate was 85.12%.② Ultrahigh pressure assisted extraction of peony seed oilThrough the optimization by response surface methodology (BBD), the optimization scheme that had the highest extraction rate was given by the software: 280.69 MPa,9.97 min and 40.83℃, and the extraction yield reached 28.57%. In order to validate the scheme, considered the function of instrument, we determined to take parallel experiment (280 MPa,10 min,41℃) 3 times, as a result, the average extraction yield was 28.7%, and the error to software prediction value was 0.46%.③ The peony seed oil refiningAfter deacidification, acid value of peony seed oil was 0.2 mg/g, which match the national standard for first level soybean oil. After decolorization with activated clay, using spectrophotometer determined the absorbance value, the decolorization rate was 93.2%, and oil color looked clear, pale yellow. After deodorization, the sensory tests confirmed to have no peculiar smell, and clear. In terms of peroxide value, POV value rose significantly. For phospholipids, saponification value, refraction coefficient, did not produce significant changes in the refining process.④ Influence of ultrahigh pressure assisted extraction on the composition and acid value of peony seed oilThe change rule on the number of component in the peony seed oil was as follows: first rose (from atmospheric pressure to 350 MPa), fell (350 to 500 MPa), then rose (500 to 550 MPa), and decreased (550 to 600 MPa), reaching the peak value 11 at 350 MPa, achieving the minimum 4 at 500 Mpa, the minimum was as same as the atmospheric pressure treatment.Linolenic acid did not detected only in the atmospheric experimental group, other ultrahigh pressure treatment group all did. The change rule on the content of linolenic acid was as follows:first rising (from 350 to 500 MPa), then falling (from 500 to 600 MPa), reaching the maximum at 450 MPa and 500 MPa,63.26%,63.20%, respectively.As for the unsaturated fatty acids content (linoleic acid and linolenic acid), atmospheric pressure experimental’s was 57.04%. The change rule on content of unsaturated fatty acids in the peony seed oil was as follows:first dropped (atmospheric pressure to 350 MPa), then rose (350 to 500 MPa), and fell (500 to 550 MPa), then rose again (550 to 600 MPa), reaching the minimum 41.00% at 350 MPa, or the maximum 88.00% at 500 MPa.The change rule of the acid value was completely contrary to the change rule of unsaturated fatty acid, reaching the maximum 15.4 at 350 MPa, or the minimum 3.5 at 500 MPa.It could preliminary infer the changing rule of the Lipoxidase activity:first rising (atmospheric pressure to 350 MPa), fell (350 to 500 MPa), then rose (500 to 550 MPa), and last dropped (550 to 600 MPa).⑤ The antioxidant activity of peony seed oilThrough DPPH clearance test, EC50 of peony seed oil was 0.13 g/mL, and walnut oil’s was 0.25 g/mL. As to OH-·removal experiments, the result was as similar to DPPH, OH-·scavenging ability of the peony seed oil was overwhelming stronger than walnut oil’s, when the concentration was 0.5 g/mL, the hydroxyl radical scavenging ability still was inferior to the peony seed oil. The peony seed oil and walnut oil were basically identical, only at 30 seconds; after 30 seconds, the super oxygen anion radical removal ability of peony seed oil was stronger than walnut oil’s.