The Studies On Enrichment Of DHA And EPA In Tuna Oil

This paper based on tuna oil as raw material, the process conditions for preparing rich in EPA and DHA glyceride by dry fractionation, lipase TL100 catalyzed hydrolysis, lipase Lipozyme RM IM catalyzed capric acid and tuna oil ester exchange, then orthogonal experiment and response surface optimization were used to optimize the preparation process. The optimum technological conditions for preparation of unsaturated fatty acid esters were obtained, and analyses the composition of the products. The main conclusions were as follows:This paper carries on the analysis to the quality of tuna oil. The results showed that the quality of raw oil is better, reference the provision of the people’s Republic of China aquaculture industry standard- fish oil(SC 3502- 2000), the indicators have reached the refined fish oil level standards, The basic conditions for the preparation of EPA rich and DHA glycerol esters were prepared by the raw material oil. In all fatty acids of tuna oil, the content of Palm Acid、oleic acid、docosahexaenoic acid and Ethernet for Plant Automation was high, and their content was about 60%, and the content of DHA and EPA was 26.86%. The content of fatty acids was maily composed of Dha OP(6.89%)、PDha P(6.69%)、Dha Dha P(5.59%)、Dha ODha(3.79%)、Dha PSt(3.09%)、POP(2.93%)。The raw material composition were analyzed by TLC-FID method, the main components of triglyceride, diacylglycerolganyi and monoacylglycerols were not detected.The article take the crystallization temperature, cooling rate, stirring rate and crystal growing time as factors, riching in EPA and DHA glyceride process were investigated and optimized by dry fractionation preparation. The optimum reaction contions for crystallization temperature, cooling rate, stirring rate and crystal growing time were 0℃, 15 r/min, 15℃/h, 9h. After a triplicate verification, the content of EPA+DHA is 31.36% in liquid oil.The univeriate tests and optimization tests by RSM were applied to determine the influence of factors and optimized the parameters in transesterification of tuna oil and decanoic acid. This paper also established the regression equation of the content of EPA+DHA, respectively. The optimum reaction conditions for temperature, the substrate mole ratio, enzyme load, water load and reaction time were 58℃, 4:1, 4%, 10%, 7.5h. After a triplicate verification, the content of EPA+DHA(40.03%) increased by 26.86%, respectively. The result indicated that triglyceride, monoacylglycerols and diacylglycerolganyi were detected in product and the contents were triglyceride(79.54%), diacylglycerolganyi(15.76%) and monoacylglycerols(4.70%).The univeriate tests and optimization tests by RSM were applied to determine the influence of factors and optimized the parameters in hydrolysis reaction of tuna oil. This paper also established the regression equations of hydrolysis rate and the content of EPA+DHA, The optimum reaction conditions for temperature was 53.30℃, the substrate mass ratio with tuna oil to water was 1:1.49, enzyme load was 3.00% and reaction time was 5.68 h After a triplicate verification, the content of EPA+DHA(46.39%) increased by 26.86%, respectively, and the hydrolysis rate of tuna oil was 50.01%. The result indicated that triglyceride, monoacylglycerols and diacylglycerolganyi were detected in product and the contents were triglyceride(34.58%), diacylglycerolganyi(53.93%) and monoacylglycerols(11.49%).