Study On The Enrichment Of Glyceride Of ω-3PUFA

It is by now well established that the polyunsaturated fatty acids (ω-3 PUFA), especially eicosapentaenoic (EPA), docosahexaenoic(DHA) acids , are beneficial to health. EPA and DHA have been recognized have different physiological function. EPA was recently shown to have such highly beneficial effects as preventing coronary heart diseases, hypertriglyceridem, blood platelet aggregation and lowering blood cholesterol, thus reducing the risk of arteriosclerosis, inflammation and various carcinomas. DHA is important in the development of the central nervous system of infants. In this work, glyceride of EPA DHA was synthesized by glycerol and EPA/DHA which was separated from hydrolytic fish oil.First, a high performance liquid chromatography (HPLC) method was developed for determination of EPA and DHA in hydrolytic fish oil.Chromatogram with high resolution was obtained using the column of Sunfire-C18 (5μm,250×4.6mm)with PDA detector at 205nm and the mobile phase of methanol and water with 0.2% formic acid at a flow rate of 1mL/min at 35°C.Then, this analysis method was compared with GC which was prescribed in GB.Chemical hydrolysis is better than enzymatic hydrolysis in degree of hydrolysis and the yield of EPA/DHA, thus optimizing the conditions of chemical hydrolysis. The optimum conditions: saponification time 60min, 50℃, ethanol/water 6:1(v/v), 150r/min, the degree of hydrolysis was 95.46% and the recovery of EPA and DHA were 91.24% and 88.87%. C18 was used to isolated EPA/DHA in hydrolysis fish oil, it was identified by MS. The purity of EPA was identified by HPLC.The conditions for lipase-catalyzed synthesis of EPA/DHA and glycerol in a batch reactor were optimized. Hexane was confirmed as the lipase-catalyzed reaction solvent, and 4A molecular sieve as desiccant. The molar ratio of EPA/DHA to glycerol was 3:1, the concentration of EPA/DHA was 0.2mol/L, the amount of lipase was 17g/L, the molecular sieve was added after 24h. The condensation of EPA/DHA and glycerol was conducted with vigorously shaking in a water bath at 40℃for 48 hours. The degree of esterification on EPA was 95% and the content of tri-EPA was 93.3%,and for DHA,the degree of esterification was 94.5% and the content of tri-DHA was 93.2%. And then, the structures of tri-EPA and tri-DHA were validated by MS and 1H-NMR, 13C-NMR.For large-scale production in industry, a continuous reaction would be preferred. In this study, a packed-bed reaction system was designed to continuously synthesize EPA/DHA and glycerol. The influences of the addition of molecular sieves, the molar ratio of substrates, and the superficial residence time of substrate solution were emphatically studied in detail. The degree of esterification on EPA and DHA were 31.4% and 29.7% when the molar ratio of EPA/DHA to glycerol was 3:1,the superficial residence time was 2hours at 45℃in 1,4-dioxane.9.3% and 8.8% tri-EPA and tri-DHA were detected. Although the results can provide practicality for industry with its increased reaction efficiency, more work have to do to improve the yield of synthesization.