Green Synthesis Of Phytosterol Esters And Their Derivatives

Plant sterol ester has many health care functions such as anti-cancer and anti-aging,which is urgently needed by the domestic market.However,the existing industrial production are all chemical methods,and a large number of solvents and chemical catalysts in the production process bring environmental pollution.Therefore,it is of great significance to develop a green preparation method for phytosterol ester products and their derivatives.In order to solve the problems such as long reaction time,high substrate viscosity and poor initial solubility of solveless enzymatic synthesis,the two-stage synthesis process of auto-catalytic reaction coupling enzyme method was developed and verified in tonnage industrial experiment.Firstly,the reaction environment,temperature,substrate ratio and other conditions were optimized.After the autocatalytic reaction,the sterol ester mixture system with lower viscosity and higher solubility was obtained.The sterol ester mixture was coupled with the second step of lipase catalytic reaction,and the sterol conversion rate reached 91.74%after 36 h of reaction.Finally,in the tonnon-scale industrial test,compared with the original process,the reaction time of the new process can be reduced by 57%and the space-time yield of sterol can be increased by 1 times.In addition,a method was designed for rapid synthesis of oleic acid sterol ester at low temperature without catalyst.As a new product,there is still no direct method to determine the content of sterol ester.The traditional method is to obtain the content of sterol ester by measuring the content of free sterol after saponification.In this study,Corona Ultra（CAD）was developed for the direct detection of sterols and sterol esters in samples without hydrolysis and derivatization.The optimum separation degree and retention time were obtained at 25℃ and 0.6 mL/min with optimized column and mobile phase flow rate.The accuracy of sterol oleate was 96.02%.The limits of detection,limits of quantification and relative standard deviation of sterol and sterol ester were measured.In this paper,the synthesis methods of DHA sterol ester and its water-soluble derivatives were studied.DHA and DPA were obtained by hydrolysis and enrichment from algal oil.DHA sterol ester was prepared by auto-catalytic method with the esterification rate of 73.53%.In addition,PEG-sterol diester was synthesized by chemical method and enzyme catalysis in two steps.The single ester product was synthsised after reaction with DMAP for 2 h,after separation and purification.PEG-sterodiester was synthesized with PEG 1000 under the catalysis of Novozyme^? 435 lipase.This study has industrial guiding significance for the synthesis of sterol esters and has been initially confirmed and applied in industrial production.