The Application Of Enzymatic Modification Of Structured Lipids Technology

In order to improve the nutrition and applicability of the lipids, the lipase was used to catalyze the hydrolysis or synthesis of the glyceride, changing the structure and composition of the lipids.In this study, enzymatic modification of structured lipids was employed to synthesis of monoglyceride, diglyceride and human milk fat.Esterification of glycerol and oleic acid catalyzed by lipase Candida sp.99-125 was selected to synthesize monoglyceride (MAG) and diglyceride (DAG) in solvent-free system through comparing with hydrolysis of soybean oil. Six reaction variables were optimized by single variable experiment and the response surface methodology (RSM). The optimal conditions to the synthesis of MAG and DAG were different:The optimal glycerol/oleic acid molar ratio, beta-cyclodextrin/lipase mass ratio, catalyst load and reaction temperature were 6:1,0,5%,50℃for MAG, and 5:1,1.5,10%,40℃for DAG, respectively. The optimal water content and agitator speed for both MAG and DAG synthesis were 10% and 190r/min, respectively. Under the optimal conditions,49.6% MAG and 54.3% DAG were obtained after 8h and 4h, respectively, and the maximum of 81.4% MAG plus DAG (28.1% MAG and 53.3% DAG) was obtained after 2h. Above 90% purity and 85% recovery of MAG and DAG can be obtained by silica column separation. Effect of water on the esterification of glycerol and oleic acid catalyzed by lipase Candida sp. 99-125 was investigated and the results showed that water plays multiple roles, it not only has strong influence on the catalytic activity and stability of the lipase but plays a crucial role in the interfacial catalysis of lipase.In the synthesis of human milk fat, different analysis methods were established according to the product standards. Acidolysis was selected as the production method through comparing alcoholysis and was optimized through the orthogonal experiments. The optimal conditions was lipase Candida sp.99-125 10% wt-% Substrate, lard/oleic acid molar ratio 1:5.5, temperature 43℃, reaction time 4h, hexane as the solvent, V (ml)=(oleic acid mass+lard mass)×10.39.83% OPO was obtained after optimization, the proportion of palmitic acid at sn-2 position accounted for 52.82%, which has met the demand of two main indicators, palmitic acid at sn-2 position accounted for the total palmitic acid (%)≥52%, OPO(%)≥40%.