Study On Synthesis Of Phoshpholipids Enriched With Conjugated Linolenic Acid By Lipase

Phospholipids are a class of functional lipids that are ubiquitous in nature.They are major constituents of cell membranes and play important roles in maintaining the normal form of cell membranes and regulating the vital movement.They have been widely used in pharmaceutical,food,textiles and cosmetic products.Because of the molecular structure of phospholipids,most natural phospholipids cannot meet the demand of pharmaceutical industry.Thus the study of modification to obtain various functional phospholipids has been paid more and more attention to by people.Compared with physical and chemical modification,enzymatic of phospholipids that could keep their natural configurations is one of the hot research areas.As a newly found functional polyunsaturated fatty acid,conjugated linoleic acid has good effect on human physiological health and disease cure.In recent years,people found that polyunsaturated fatty acid in phosphatide was absorbed by body easier than that in triglyceride,and paid more and more attention to the dual role of polyunsaturated fatty acid and phospholipids.In this paper,We use Thermomyces lanuginosus immbolization lipase(Lipozyme TL IM)and immobilized bio-imprinted Aspergillus niger lipase as catalyst to catalytic synthesis of phospholipids enriched with CLA.We optimized the synthesis conditions to increase the unsaturated degree and the incorporation of conjugated linoleic acid.The main contents of the dissertation were as follows:(1)In this study,the conjugated linoleic acid ethyl ester was screened as acyl donor and Lipozyme TL IM as catalyst,n-hexane was determined as the appropriate reaction system and optimized synthesis conditions of phospholipids enriched with CLA.Under the optimal process conditions,the iodine value of CLA-PL was 90.92g/100 g,and the incorporation of CLA was 27.64%.So as to prepare the high purity of lecithin enriched with CLA,the soybean lecithin(PC?94)instead of powder soybean phospholipid,the iodine value of phosphatidylcholine enriched with CLA(CLA-PC)was 103.54 g/100 g and the incorporation of CLA was 29.22% under the optimized one-step process.Based on preparation research,this paper also discussed the preparation of phosphatidycholine enriched with CLA by two-step feeding method.Under the optimal condition of two-step feeding method,the iodine value of CLA-PC was 107.14 g/100 g,and the incorporation of CLA was 31.35%.Compared with previous method,the incorporation of CLA of phosphatidycholine enriched with CLA by two-step feeding method was higher.(2)The process of the immobilized bio-imprinted Aspergillus niger lipase was researched,and the different conditions of prouducing immobilized bio-imprinted lipase was optimized.The best producing condition is 300 mg conjugated linoleic acid ethyl ester,3 ml ethanol as cosolvent,300 mg Tween-80 as surfactant,20 min for bio-imprinting,5 g D4020 resin as supporter.Under these conditions,the effect of esterification of immobilized bio-imprinted lipase was highest.We use this immobilized bio-imprinted lipase as catalyst to catalytic synthesis of phospholipid enriched with CLA,the iodine value of CLA-PL was 85.77 g/100 g by test,and the value can be increased by 33% compared with that of original phospholipid.The incorporation of CLA was 25.23%.In the same catalytic conditions,Lipozyme TL IM was used to catalytic synthesis phospholipids enriched with CLA,the iodine value of CLA-PL was 88.82g/100 g,it can been seen that there was a little difference between the two enzymes.