Study On Three Kinds Of Pomegranate Seed Oil, Protein And Polyphenol

Pomegranate (Punica grantum L.) belongs to Punica L. of Punicaceae, widelydistributed in the whole world. China is rich in Pomegranate resources and it has beencultivated for more than2000years in China. Pomegranate is not only nutritious, but rich in avariety of physiological active substances, with the effect of a variety of pharmacology.Pomegranate seeds were by-product in pomegranate processing. Pomegranate seed oil was akind of functional oil, amino acid composition of pomegranate seed protein were relativelycomplete, was a high-quality protein, and pomegranate seeds also contain a small amount ofactivity of polyphenols. These materials would bring huge benefits to human beings.In this study, pomegranate seeds of Shannxi Lintong ‘SBT’,‘JPT’,‘SSL’ as the material,the pomegranate seed oil, seed protein and seed polyphenols were studied respectively. Theresults were as follows:Part1. Seeds were isolated from three pomegranate varities. Then their crude fatcontents were determinated and the seeds oils were extracted. And then the oils’ fat acids andother components were analysed by GC-MS, and their physicochemical properties weretested. Hereafter, the oils’ antioxidant capacities were assayed, and the components andantioxidant capacities of the unsaponificable substances of the oils were studied. The resultsshowed that:Crude fat contents of the3seed samples were very significant difference, and in order of‘SSL’>‘JPT’>‘SBT’. Their oils’ Peroxide Value and Acid Value were all accord with therequirement of international and national standads; The3oils all consist of10kinds of fattyacid mainly, and their unsaturated fatty acid contents were more than90%. Punica acidcontent was the highest amoung them. Its relative content in the3oils follows the order of‘SBT’>‘JPT’>‘SSL’; The3oils all had certain DPPH·, ABTS+· and·OH scaveging abilities,and inhibition ability to beta carotene/linoleic acid bleaching. And these antioxidant effectsincreased with the increase of dosage. At same dosage, the antioxidant capacities order of the3oils was ‘SBT’>‘JPT’>‘SSL’; The unsaponificable substances samples of3oils allcontains8kinds of ingredients, they were mainly phytol, squalene, cholesterol, stigmasterol,fucus sterol and alkanes, and the tocopherol’s content was the highest among them. They had the certain radical scaveging effect on DPPH· and ABTS+·.Part2. Crude protein and Storage protein contents of the three kinds of seed weredetermined, and proteins of the3kinds of seed were extracted respectively. Then, the aminoacid composition of the protein extracts were analysesed and compared. And then,‘JPT’pomegranate seed was selected as raw material to optimize the protein extraction technology.The results showed that:Total protein contents of3pomegranate seeds followed the order of ‘JPT’>‘SSL’>‘SBT’.Contents of different storage proteins of them followed the order of gluten> globulin>albumin globulin> prolamin; Sixteen amino acids were detected in each of the3kinds ofseed protein extracts. Tryptophan was not detected probably due to its hydrolysis lost by HCl.Most essential amino acids were detected except methionine and tryptophan. The amino acidconstitutes of the3protein extracts were same, and the essential amino acids were relativelycomplete; Isoelectric point (pI) of pomegranate seed protein was3.8. The optimizedtechnological conditions for extraction of pomegranate seed protein were as follows: Controlthe liquid ratio was1:25, add the defated seed power into NaOH solution with concentrationwas0.15mol/L, extract at50℃for40min, and then tested the rate of the protein extraction.Under this condition, the protein extraction yield was72.5%.Part3. Polyphenols components and contents of3kinds of pomegranate seed werestudied, and their antioxidant capability was assayed and compared. The results showed that:Pomegranate seed polyphenols content were very lower compared with that of oil andprotein. For different varieties, the total phenol, total flavonoids, total tannin andproanthocyanidin contents all had significant difference. Catechins, punicalagin and caffeicacid contents were higher then other phenolics; The pomegranate seed polyphenols hadstronger in vitro antioxidant ability. The antioxidant capacities of the3kinds of pomegranateseed were in the decending order of ‘SSL’>‘SBT’>‘JPT’.