Synthesis Of Phosphatidylserine By Transphosphatidylation In Natural Oil Medium

Phosphatidylserine（Phosphatidylsering,PS）,also known as diacylglyceryl phosphate serine,is a kind of natural rare phospholipid,which has been widely used in the functional food and cosmetics industries.Clinical studies have proven that PS as one of the main components of the human brain cell membrane.PS can improve nerve cell function,improve memory,enhance attention,stabilize mood,and assist in the treatment of Alzheimer’s disease through oral administration.However,phosphatidylserine is rare in nature and difficult to preserve,so its synthesis and storage have become a major challenge for people.In response to these problems,this project uses a bioenzymatic conversion method,using natural oils instead of traditional toxic and harmful organic solvents to synthesize phosphatidylserine,and microencapsulating the coconut oil containing phosphatidylserine obtained after the reaction.First,the effect of different edible oils as solvents on the transphosphatidylation was explored.It is preferred that the production rate of phosphatidylserine is higher when coconut oil and olive oil are obtained as solvents.Therefore,the coconut oil-water system and olive oil-water system were constructed,and the main factors affecting the synthesis of phosphatidylserine were optimized.Subsequently,acacia and gelatin were selected as wall materials,and phosphatidylserine microcapsules were prepared by a complex coacervation method.The main factors affecting the microcapsule embedding rate were optimized,and the main factors affecting the microcapsule formation effect were explored.The findings are as follows:（1）Phospholipase D（PLD）was used to catalyze phosphatidylcholine（PC）and L-serine（L-Serine）in phosphatidyl transfer reaction to synthesize phosphatidylserine（PS）in coconut oil-water system.The influence of the main factors such as the molar ratio of substrate,temperature and p H on the synthesis of phosphatidylserine in the system,the optimal conditions for the synthesis of PS in the reaction system composed of virgin coconut oil-water and refined coconut oil-water are:the molar ratio of substrate is 100:1,temperature33°C,two-phase volume ratio 2:1,p H 5.5,the reaction reached the maximum conversion rate at 60min,of which the maximum rate of phosphatidylserine in virgin coconut oil-water system was 94%,The maximum production rate of phosphatidylserine in the refined coconut oil-water system was 90%.It is about 25%higher than the traditional two liquid system（ethyleneglycol-water syster）.（2）The main factors influencing the synthesis of phosphatidylserine by phospholipase D catalyzed in olive oil-water system were investigated,including the influence of substrate molar ratio,temperature,p H,and two-phase volume ratio on the synthesis of PS.The optimal conditions are:the molar ratio of the substrate is 100:1,the temperature is 33°C,the volume ratio of the two phases is 2:1,the p H is 6,the reaction reaches the maximum conversion rate at 80 min,and the maximum production rate is 90%.（3）Because the purified PS is difficult to store and easily oxidized,this project will use PS-coated coconut oil solution as the capsule core,and more common gum arabic and gelatin as the wall material to prepare PS-coconut oil microcapsules.Explore the important factors that affect the embedding rate during the preparation of microcapsules.The conclusions are as follows:the optimal core-wall ratio was 2:1,the optimal p H was 3.5,and the optimal wall material ratio(M_arabin:M_gelatin)was 1.The best complex agglomeration time is 15 min,the optimal emulsification speed is 8000rpm/min,and the optimal stirring speed is 750 rpm/min.Subsequent investigations into two important factors affecting the microcapsule formation effect,the results found that:at p H 3.5-4.0,the microcapsule particle size distribution was uniform and the shape was regular;when the stirring speed was 700rpm/min,the microcapsule particle size was uniform and the shape was round.