| Peaonia suffruticosa (peony) is a famous kind of flowers in China, and its seeds containnumerous fat and protein. In this paper, the extraction of oil and protein from peony seed, therefining of peony seed oil and the analysis of peony seed protein were discussed.Firstly, the optimum conditions of the extraction of peony seed oil by ultrasonic assistedand aqueous enzymatic method were studied. The optimum conditions of the ultrasonicassisted extraction were as follows: solvent: petroleum ether (boiling range60-90℃),solid-liquid ratio1:20, ultrasonic power250W, extraction time10min, extraction temperature35℃. The process of the aqueous enzymatic extraction was divided into two parts: theenzymatic procedure which contained three steps and the demulsification procedure. Theoptimum conditions of the exzymatic procedure were as follows: first step, the hydrolysis ofthe cell wall,5%(v/m) cellulose-pectin mixed enzyme was added, the enzymatic time was2.5h; second step, the hydrolysis of the starch,2%(v/m) temperature amylase was added, theenzymatic time was45min; third step, the hydrolysis of the protein,0.4%(m/m) the alkalineprotease was added, the enzymatic time was2h. And the freeze-thaw demulsification methodwas considered as the best demulsification method. Finally, the extraction yield of peony seedoil was28.79%and the extraction rate was up to92.28%by ultrasonic assisted extraction,while, the free oil and total oil yield of the peony oil extracted by aqueous enzymatic methodwas17.65%and25.47%, and the extraction rate of hydrolyzed protein of peony seed was86.25%. The extraction rate of peony seed oil by ultrasonic assisted extraction was larger thanaqueous enzymatic method. However, since both oil and protein can be extracted by aqueousenzymatic, it would be more practical and effective for the utilization of peony seed.Secondly, the refining process of the crude oil extracted by two extraction methodsabove was studied respectively. The optimum conditions were as follows: the amount of wateradded in the degumming procedure was5%(m/m) to the ultrasonic assisted-oil (UAO) and4%(m/m) to the aqueous enzymatic-oil (AEO), the amout of the excess lye and the alkaliconcentration in the alkali deacidification procedure was0.25%and8%to both UAO andAEO, the amount of active carbon in the bleaching procedure was5%(m/m) to UAO and4%(m/m) to AEO. After the refining process, the phospholipid content was reduced from0.25g/100g to0.012g/100g for UAO and0.73g/100g to0.018g/100g for AEO, the acid valuedecreased from3.8to0.32for UAO and3.5to0.29for AEO, the peroxide value droppedfrom0.8to0.29for UAO while raised from0to0.27for AEO. The transparency of bothUAO and AEO were increased and the color of both UAO and AEO were lighter. The fattyacid composition of both UAO and AEO before and after refining was tested by GC-MS tocompare with that of the commercial squeezing oil. The results showed that the peony seed oilwas rich in unsaturated fatty acid, and the main composition of the unsaturated fatty acid of peony oil was linoleic acid and linolenic acid. The unsaturated fatty acid content of UAO was90.24%before refining and89.84%after refining, and92.77%and91.91%for that of AEO,while the unsaturated fatty acid content of the commercial squeezing oil was only86.88%.Because the conditions of the aqueous enzymatic extraction method is mild, so its oil isrelatively high in quality and easy for refining. And all these physical indications afterrefining were close to those of the commercial squeezing peony oil while the unsaturated fattyacid content of the extracted oil was larger.Thirdly, the extraction process of peony seed protein was studied, and the optimumconditions was as follows: the ratio of water1:35, pH11, extraction temperature40℃，extraction time2h. Under these conditions, the extraction rate of peony seed protein is up to87.2%, and the isoelectric point was3.9. After freeze-dried, the purity of the protein extractedfrom the seed meal from ultrasonic assisted and squeezing extracted seed was92.87%and91.28%respectively. The results of the analysis of peony seed protein showed that peony seedprotein had good functions of water absorption, oil absorption, foamalility and emulsifiability.And there was little difference between the protein extracted from different seed meals interms of the protein stucture, the relative molecular mass and the amino acid composition.At last, the hydrolyzed protein in the hydrolyzate from the aqueous enzymatic extractionprocess was extracted by macroporous resin adsorption and its in vitro antioxidant activitieswere tested. After compared the adsorption rate of four kinds of different macroporous resins,D201-C was choosen to be the best for its absorption rate77.08%, the purity of the extractedhydrolyzed protein86.64%and the amount of the active peptide of the extracted hydrolyzedprotein26.35%. And the in vitro test of antioxidant activities of the hydrolyzed proteinextracted by D201-C illustrated strong power of DPPH, OH and O2-scavenging. |
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