Study On Production Of Meduim And Long Chain Triglycerides From Flaxseed Oil

The medium and long chain triglycerides were synthesized by Lipozyme catalyzed transesterification of flaxseed oil and medium-chain fatty acids in solvent- free system. This paper concretely studied two recation systems(systems 1: flaxseed oil with the mixture of caprylic acid and capric acid. systems 2: flaxseed oil with capric acid separately), and the optimum lipase of catalyzing acidolysis flaxseed oils was determined. Besides, process optimization in different systems was investigated using response surface methodology and two different responses-percentage of incorporation of MCFA and content of MLCT were considered as objective functions.The TLC-FID result indicated that monoacylglycerol and diacylglycerol were not detected in raw flaxseed oil; the flaxseed oil was rich in C18:1(22.55%), C18:2(16.18%) and C18:3(50.07%), and the composition of sn-2 fatty acid analysis showed that saturated fatty acids(C16:0 and C18:0) were less while other unsaturated fatty acids were up to 99%; the triglycerides were mainly composed of Ln Ln O(17.06%), Ln Ln Ln(12.61%), Ln LLn(12.24%), LOLn(10.76%), OLn O(7.59%) and the MLCT was not contained.Lipozyme RM IM, Lipozyme TL IM, Novozyme 435, and porcine pancreas lipase were tested in the initial screening for the optimum lipase of catalyzing acidolysis. The result indicated that the catalytic activity of lipase differed from each other. The immobilized lipase RM IM showed the highest incorporation and activity.The univariate tests and response surface methodology were applied to determine the influence factors and optimize the parameters in acidolysis of flaxseed oil with the mixture of caprylic acid and capric acid. Capric acid content in the product was higher than caprylic acid, however, the latter had a faster reaction rate when they reacted with flaxseed oil separately. The optimum reaction conditions for temperature, the substrate mole ratio, enzyme load, water load and reaction time were 75°C, 3.91:1, 3.47%, 10% and 8.38 h, respectively.The contents of MLCT in the mixed acid products were 43.75%, including MLM(6.01%), MML(0.32%), LML(0.48%) and LLM(36.94%). The MLCT were mainly composed of Ln DLn(5.57%), ODLn(5.42%), LDLn(4.48%), Oc Ln Ln(3.52%), Oc Ln O(3.43%).The optimum reaction mixture and conditions for acidolysis of fla xseed oil with capric acid were oil/fatty acid mole ratio of 1:6, 75°C, 5.38 h, 4%(w/w of substrates) Lipozyme RMIM lipase and 10%(w/w of lipase) water. After 3 times of repeated verification, the content of capric acid and MLCT were 24.98% and 60.05%, respectively. The MLCT encompassed four types, namely MLM(12.29%), MML(1.58%), LML(1.42%), LLM(44.32%) and were mainly composed of Ln DLn(11.92%), ODLn(11.08%), LDLn(9.27%), DDLn(6.86%), ODL(4.19%), DDO(3.55%).