Study Of Enrichment And Esterification Of Polyunsaturated Fatty Acids In Seal Oil

Seal oil is one kind of animal fats and oils which is extracted from the seal. Main active components of it are polyunsaturated fatty acids, such as eicosapentaenoic acid(EPA),docosapentaenoic acid(DPA) and docosahexaenoic acid(DHA). This dissertation systematically studied the physic-chemical properties of seal oil, the concentration of polyunsaturated fatty acids, the lipase-catalyzed esterification of polyunsaturated fatty acids and glycerol.This paper dealed with the determining of the physic-chemical properties of seal oil including iodine value, acid value, peroxidation value, refractive index, specific gravity, water component and saponification value. By means of Spectral analysis of UV, IR and MS, we preliminarily analyzed the components, structures and content of the fatty acids in seal oil. The factors of time, temperature which influence saponification were simply studied. The optimum conditions for saponification: 1h, 60(C. Under these conditions, a fatty acid yield of 93.2% was obtained, and the product contained 5.71% EPA, 10.53% DHA and 4.82% DPA.Urea inclusion reaction parameters such as crystallization temperature, crystallization time, weight ratio of urea to free fatty acid were examined. By response surface methodology, the optimum conditions were obtained as: the crystallization time of 20h, the crystallization temperature of 4(C, the weight ratio of urea to free fatty acid of 4:1. Under these conditions, the content of EPA,DHA and DPA could be raised from 21.06% to 72.19%, and the yield of uninclusion fatty acids was 17.91%.This paper reports on the synthesis of glycerides by enzymatic esterification of polyunsaturated fatty acids with glycerol. The lipase Novozym 435 from Candida Antarctica was used to catalyze this reaction. The main fators influencing the degree of esterification were water content, temperature, the amount of enzyme and glycerol/fatty acid ratio. The optimum reaction conditions were establishied as: glycerol/free fatty acid weight ratio of 0.12:1, 48h, 50(C, 10%(w/w of free polyunsaturated fatty acids) lipase and 0% water. Under these conditions, the degree of synthesis of 96.58% was obtained.The results we got would be useful for the further study, application and development of the seal oil.