Lipase-Catalyzed Modification Of Cinnamomum Camphora Seed Oil To Produce Structured Lipids

Structured lipids (SL) are special lipids which are obtained by modifying naturalfats and oils. SL have lots of physiological functions and nutritional properties, thusthey are drawing more and more attentions in terms of both application andproduction. In this study, the technology of lipase-catalyzed modification wasemployed to produce SL such as diacylglycerol (DAG), medium-and long-chaintriacylglycerols (MLCT) and human milk fat substitutes (HMFS). The main results ofthe present study were as follows:1. The lipase-catalyzed reaction of Cinnamomum camphora seed oil (CCSO)and glycerol was studied to produce DAG, rich in medium-chain fatty acid (MCFA)in a solvent free system using immobilized lipase-Lipozyme RM IM as a catalyst.Response surface methodology was used to optimize the reaction conditions ofglycerolysis. The optimal parameters were as follows: substrate molar ratio of CCSOto glycerol,2.3:1; enzyme load,11.7wt%; reaction temperature,72℃; and reactiontime,15h. Under the optimal conditions, DAG content could reach51.60%in thereaction product. The contents of capric acid (C10:0) and lauric acid (C12:0) in theDAG oil were54.68%and39.79%, which remained the similar fatty acidcomposition as CCSO. The product has nutritional properties of both MCFA andDAG, which will enrich the knowledge of functional oil.2. MLCT enriched SL was synthesized through enzymatic interesterificationfrom CCSO and Camellia oil (CO) using Lipozyme RM IM as a biocatalyst. Resultsshowed that55.81%of total MLCT species was obtained in the interesterifiedproduct under the optimal conditions of substrate molar ratio of1:1.5(CCSO:CO) at60℃for3h. Fatty acid profiles and physiochemical characteristics of theinteresterified product were investigated. Results showed that the product containedpredominantly oleic acid (88.69%) at Sn-2position of TAG, while MCFA weremainly distributed at Sn-1,3positions, which could be beneficial for human health.Furthermore, natural antioxidants such as tocopherols and squalene were detected inthe product. It should be mentioned that the smoke point of the interesterified product was much higher than that of the physical blend, which meant that suchMLCT-enriched SL could be used for cooking purpose.3. The enzymatic reaction of CCSO and oleic acid was studied to produceHMFS in a solvent free system using Lipozyme RM IM as a catalyst. Responsesurface methodology was used to optimize the reaction conditions of acidolysis. Theoptimal parameters were as follows: substrate molar ratio of oleic acid to CCSO,5:1;enzyme load,12.5wt%; reaction temperature,60℃; and reaction time,28h. Underthe optimal conditions, the incorporation of oleic acid could reach59.68%in thereaction product. The content of MCFA at Sn-2position of TAG was over70%, whileoleic acid was mainly distributed at Sn-1,3positions, which was similar to thecomposition of human milk fat. Thus, it could be used in the production of infantmilk formula. In order to determine the stability of immobilized lipase-LipozymeRM IM in the acidolysis reaction, the experiments of lipase recycle utilization wascarried out under the optimal conditions. Results showed that Lipozmye RM IMcould only be used for9cycles. Urea adduction fractionation was used to refine theHMFS. The lowest acid value of the product was achieved when the weight ratio ofoil to urea was1:2. Under this condition, the TAG content of HMFS was77.28%, andits physicochemical indexes were all under the limit of national standards.