Research On Preparation Of Coconut Oil And Enrichment Of Lauric Acid

Coconut is an important treasure and can be processed into various products.Coconut oil is very healthy and the coconut oil fatty acid is mainly comprised with the carbon chain fatty acid,which is easily to digest and absorb for the patients with diabetes or obesity.Furthermore,coconut oil contains high lauric acid that possesses the functional properties of anti-bacterial and anti-virus.Through investigating the physiological functions of functional oils,the researchers found that a small amount of lauric acid monoglyceride was exists in the breast milk and the lauric acid in the carbon chain of monoglycerides could enhance the absorption of fat and Ca²⁺ions for the babies,and further promoted the bones growth and development of the infants as well as strengthen the baby’s ability to fight a wide range of bacteria and viruses.Three different preparation methods,including squeezing method,organic solvent extraction and aqueous enzymatic extraction,were applied to prepare coconut oil.The extraction rate and basic physical and chemical properties of coconut oils obtained via different methods were measured.And the results showed that aqueous enzymatic method was the best.Properties of coconut oil extracted by aqueous enzymatic method were further investigated.As coconut oil had high content of lauric acid.Urea embedding method,and molecular distillation technology were used to enrich the lauric acid separately at first.And then the two methods were combined for the secondary enrichment of lauric acid.The content of lauric acid in coconut oil was effectively improved.Meanwhile,the orthogonal experiment method was used to optimize the research process,and obtain the optimal process conditions.The main contents and conclusions about the research were as follows:（1）The preparation of coconut oil was performed through pressing method,organic solvent extraction and aqueous enzymatic method and the coconut oil extraction rate was up to 82.8%,90.5%and 83.2%respectively.Based on the scientific analysis of the oil extraction rate and the physical and chemical properties of oils prepared by that three methods,we finally decided to adapt the aqueous enzymatic method for the preparation of coconut oil.The aqueous enzymatic method had no solvent residual and could maximumly retain the various nutrients in coconut oil.The coconut oil obtained then had richer nutrition and lower acid value and peroxide value.Furthermore,through the orthogonal experiment analysis,we found the best preparation technology for aqueous enzymatic method:material:liquid ratio 1:2.enzyme:material ratio 1:15,reaction temperature 55℃,the enzyme addition amount 0.25%,and the reaction time 16h.（2）Adopting urea embedding method to enrich the lauric acid in coconut oil.By single factor test and orthogonal test optimization,obtaining six factors that affect the embedding effect and the important order:A（liquid ratio）>E（stirring temperature）>C（embedding time）>D（mass ratio of urea to fatty acids）>F（stirring time）>B（the embedding temperature）.The optimize the process conditions of enrichment lauric acid of coconut oil via urea embedding method are as follows:the material:liquid ratio 1:2,mixing temperature 50℃,the embedding time 10 h,mass ratio urea to fatty acid 1:1.5,the mixing time 5 h and embedding temperature 20℃.The lauric acid content in coconut oil was 60.05%after enrichment process.Coconut oil yield was 94.53%.（3）Adopting molecular distillation method to enrich the lauric acid in coconut oil.Through single factor test and orthogonal test optimization and the value of poor R,we obtained the important order of influence factors of the molecular distillation about the enrichment rate of lauric acid:A>B>C,namely,the distillation temperature>injecting sample amount>blow film speed.The optimize the process conditions of enrichment lauric acid of coconut oil via molecular distillation method are as follows:distillation temperature 220℃,injecting sample volume 0.2 L/h;and blown film speed 270 r/min.The lauric acid content in coconut oil was 69.55%after enrichment process.Coconut oil yield was 89.32%.（4）Adopting the urea embedding method combined molecular distillation technology to enrich the lauric acid in coconut oil.Through the single factor experiment and the Box-Behnken response surface method,obtaining the optimized prepared conditions for the enrichment of lauric acid in coconut oil are as follows:distillation temperature 234℃,injecting sample volume 0.36L/h and;blown film speed 250 r/min.The lauric acid content in coconut oil was 71.28%after enrichment process.Coconut oil yield was 85.69%.