Biosynthesis Of Medium-and Long-Chain Triacylglycerols From Camphor Tree Seed Kernel Oil And Soybean Oil Catalyzed By Lipase And Its Separation And Purification

Medium-and long-chain triacylglycerol(MLCT)is a kind of modified product of natural oil.MLCT not only can provide energy quickly and efficiently for the body without causing fat accumulation,but also can provide essential fatty acids,it has become the focus of research in the field of oil.In this study,naturally occurring medium chain-triglyceride,Cinnamomum camphora seed kernel oil(CCSKO),which are rich in resources and have not yet been fully utilized,were used as raw materials to catalyze and biosynthesize MLCT through the immobilized lipase interesterification method in a solvent-free system with soybean oil(SO).The reactions were catalyzed by three immobilized lipases,among which Novozym 435 was found to be the most suitable biocatalyst.Effects of different reaction conditions,including substrate molar ratio(CCSKO/SO),enzyme amount,reaction temperature and reaction time on yield of MLCT were investigated.On the basis of single-factor experiments,the four-factor three-level BBD response surface experiment was designed to obtain the optimal conditions.Optimization results showed that the maximal yield of MLCT was 74.82% under the optimal reaction conditions: substrate molar ratio of 1.2:1(CCSKO/SO),enzyme amount of 10.5%(w/w total reactants),reaction temperature at 65 °C and reaction time of 10.6 h.After a scale-up experiment,the interesterified product was purified by a two-step molecular distillation method and the MLCT was obtained with 94.92% purity.The major triacylglycerol components of MLCT were COC/CPC(37.28%),CLC/CLn La/CLn Ln(18.67%),La LL/La OLa/La PLa(11.62%),CLL(7.83%)and La LL/La LLa/La Ln L(9.26%).The fatty acid profiles and and positional distribution of CCSKO,SO,physical blend,interesterified product and MLCT were further compared.The result showed that the total fatty acid of MLCT contained 61.37% of medium chain fatty acids and 38.63% of long chain fatty acids.The content of saturated fatty acids was 68.99% and the content of unsaturated fatty acids was 31.01%.The sn-2 position of the MLCT enriched with oleic acid(16.59%)and linoleic acid(33.47%)at the sn-2 position and capric acid(43.80%)and lauric acid(31.34%)at sn-1,3 positions.All physiochemical characteristics of MLCT were in accordance with national standards,and the stability analysis of Novozyme 435 in the interesterification reaction showed that it could be used up to 15 times with the remaining activity of over 80%.Due to this configuration of MLCT is beneficial to the human body and may have a great application prospect in functional food,nutraceuticals,and medical foods production as a nutritional ingredient.