Production Of Structured Lipid Rich In Arachidonic Acid

Polyunsaturated fatty acid glyceride is the esterification product by glycerol and twoPoly-unsaturated fatty acids, and is mainly composed of monoglycerides, diglycerides andtriglycerides.Diacylglycerol is esterified by glycerol with two fatty acids. According to thedifferent chemical structure, diacylglycerol can be divided into1,3-diacylglycerol(DAG),3and1,2-(2,3) diacylglycerol (DAG),2(2,3) two isomers. Diacylglycerol isthe microscale elements in natural plant oils, the intermediate of lipid metabolic in thehuman body, and the main ingredients recognized by safe (GRAs) food ingredients. It isalso a kind of multifunctional additives, and it is because of these features so thatDiacylglycerol is widely used in medical, food industry and other industries. Triglycerideis the main components of the natural oils, which consists of diacylglycerol with one fattyacid. In the human’s body, most organizations are permitted to use triglyceride to provideenergy, and also, according to the location of the fatty acids in glycerin skeletondifferences, triglyceride can be divided into symmetrical structured triacylglycerols andunsymmetrical structured triglycerides.In recent years, with the deep development of the lipid chemistry and nutrition study,we have more understanding about lipid composition, structure and physicochemicalproperties and nutritional properties.Some research results have also showed that thepancreatic lipase secreted by duodenal in human body and lipoprotein lipase used fordecomposing chyle particles and low density lipoprotein can priority catalytic hydrolysisSN-1,3fatty acids structured lipid, so the use of fatty acids is up in the esterificationposition of fatty acids in structured lipid. Even if the composition of fatty acids in edibleoil is almost similar, the triglyceride molecular acylation position is different. It will alsoaffect the absorption and utilization of these fatty acids in human and determine the greaseof nutrition and application value. So the structure, chemical and physical properties of theTAGs and DAGs and its effects on human health begin to become the focus research toscientists. Besides, the acylation position effect of fatty acid in TAGs and DAGs has verysignificance to guide the research of functional oils. Firstly, the production of1,3-dioleoylglycerol through esterification of glycerol witharachidonic acid using immobilized1,3-specific lipase (Lipozyme RM IM) as a catalystin solvent-free system was analyzed. We also investigated the influences of substratemolar ratio, reaction time, amount of enzyme and reaction temperature on the conversionrate of the content of1,3-dioleoylglycerol. According to response surface optimization,the optimum technical conditions were established as follows:(arachidonic acid:glycerol)2.5:1for substrate molar ratio,7.9%for amount of enzyme and57℃at2.7hfor reaction temperature and time, under these conditions of the content of1,3-dioleoylglycerol were about72.1%in TAGs and DAGs.Then,1,3-dioleoylglycerol is purified by silica gel column chromatography, and itspurification concentration can be reached to90%, and but the recovery is about56.75%.Finally，we use the1,3-dioleoylglycerol purified by silica gel column chromatography,palmitic acid as raw materials, and the1-Ethyl-3-(3-dimethyllaminopropyl) carbodiimidehydrochloride (EDCI) and4-dimethylaminopyridine (DAMP) as the catalyst to synthesis1,3-arachidonic acid-2-palmitic acid triglycerides. Chemoenzymatic synthesis ofstructured triacylglycerols is confirmed by the final result analyzed with TLC and highperformance liquid-mass spectrometry (HPLC-MS) and the final samples of1,3-arachidonic acid-2-palmitic acid glyceride contains only a small amount of1,2-arachidonic acid-3-palmitic acid glyceride.