Investigation On Purification Technologies Of ω-3PUFA And The Oxidative Stability Of Relative Products

ω -3PUFA Polyunsaturated Fatty Acids( ω -3PUFA), including a -Linolenic acid(ALA), Eicosapentaenoic acid(EPA) and Docosahexaenoic acid(DHA), possess well physiological activities. Traditional purification methods have many disadvantages, such as recovering solvent, complicate operation, high cost, making ω-3PUFA decomposed, etc. Technologies, including urea inclusion, combination of supercritical CO2 extraction-fractionation and urea inclusion, were investigated. Furthermore, a ginger essential oil obtained by supercritical CO2 extraction was used as an antioxidant of concentrated fish oil fatty acid ethyl esters (FAEE) and its anti-oxidative activity was measured. The research results are valuable for producing ω -3PUFA goods and their natural antioxidant.Urea inclusion method was adopted with a stepped temperature dropping to purify ω-3PUFA. The optimum ratio of ester-urea is 1 : 15. After first separation cycle, the content of ALA in perilla oil and the total content of both EPA and DHA in fish oil were increased to 85.68% and 67.32% respectively. With the increase of the urea amount, the contents of ALA and EPA+DHA can be further concentrated to 87.1% and about 70% respectively.Accompanying with a temperature, pressure program, the supercritical carbon dioxide extraction-fractionation technology was used to purify the fish oil FAEE obtained from urea inclusion and the fish oil FAEE can be separated by chain length. Consequently, the total content of EPA and DHA in the fish oil can be concentratedto 90% further. The experiment results shows that under the conditions of a pressure from UMpa to 15MPa with an increment of 0.5MPa, an extraction temperature of 35℃, a fractionation temperature distribution from bottom 40℃ to top 85℃ with an increment of 15℃, and a CO2 flow rate of 5NL/min, the purifying result of the fish oil FAEE achieved a highest yield. By combining urea inclusion method and supercritical carbon dioxide extraction-fractionation technology, the contents of EPA and DHA were enriched to 67.10% and 90.31% from 12.11% and 17.93% respectively.The tests of oxidative character and stability of the concentrated fish oil FAEE show that the automatic oxidative rate of the concentrated fish oil FAEE is accelerated by increasing temperature. Both ginger essential oil and vitamin E can retard the oxidation of fish oil FAEE. The anti-oxidative activity of ginger oil was higher than vitamin E. The combination of ginger oil and vitamin E can reinforce the anti-oxidation activity and exhibits a strong coordinative effect.Gas chromatographic method was employed to determine fatty acids in the fungus which were cultivated by using the perilla oil containing ALA as ferment precursor. As a result, four funguses that can produce EPA were screened out. The content of EPA in fungus M96 is 1.72%. The results provided important clues for searching new EPA and DHA sources from biomass.