Preparation And Stability Of DHA Algae Oil Liposomes By High Pressure Microfluidizer

Docosahexaenoic Acid(DHA)has physiological functions such as preventing cardiovascular diseases,promoting brain development,and relieving Alzheimer's disease.DHA in algae oil is mainly in the form of triglycerides and has the advantages of high metabolic absorption rate,high bioavailability,strong stability and good safety.However,DHA algae oil has problems such as easy oxidation,poor solubility,and limited application,which seriously affects its function and restricts its use in food processing.Liposome is a good biological carrier,which has the advantages of amphiphilicity,targeting and long-term effect.In this study,DHA algae oil was prepared into liposomes by thin film dispersion-high pressure microfluidizer homogenization technology,in order to extend the storage stability of DHA algae oil,improve its solubility,and increase processing utilization.Firstly,the preparation process of DHA algae oil liposomes was studied.The mean particle size and encapsulation efficiency were used to evaluate the effects of concentration of soybean lecithin,the mass ratio of lecithin to DHA algae oil,the mass ratio of lecithin to cholesterol,the dosage of Tween-80,the homogenization pressure of high pressure microfluidizer,and the homogenization times.A total of six factors affect DHA algae oil liposomes.On the basis of the single factor experiment,the regression model was established through the three-factor and three-level response surface optimization experiment,and the quadratic polynomial regression equation was fitted as:Y=91.39+14.40A-5.92B-7.40C-0.7875AB+5.90AC+3.39BC-1.45A~2-11.64B~2-9.18C~2,R~2=0.9780.The best preparation process parameters were obtained:soybean lecithin concentration 20 mg/m L,lecithin to DHA algae oil mass ratio 4:1,lecithin to cholesterol mass ratio 11.9:1,Tween-80 15%,138MPa,and 5 times.Under these conditions,the results of the verification experiment are:the mean particle size is(59.35±3.05)nm,the PDI is 0.189±0.025,the encapsulation efficiency is(94.2±2.9)%,and the zeta potential is(-37.7±2.5)m V.Subsequently,the morphology and stability of DHA algae oil liposomes were analyzed and evaluated.The microstructure of DHA algae oil liposomes observed by transmission electron microscope(TEM)was spherical and uniformly distributed.Compared with the DHA algae oil liposomes without high pressure microfluidizer homogenization(C-L),through differential scanning calorimetry(DSC)analysis,it was found that the high pressure microfluidizer homogenization treatment effectively improve the phase transition temperature.Stability analysis experiments showed that DHA algae oil liposomes treated with this technology(MF-L)have good physical stability,storage stability,oxidation stability,ionic strength stability,p H strength stability.And the low temperature conditions are more beneficial to the function of liposomes.Finally,the gastrointestinal digestion stability of liposomes in vitro was tested.The changes in mean particle size and zeta potential were measured.From the initial stage to the gastric digestion stage and then to the intestinal digestion stage,the mean particle size of MF-L showed an overall increasing trend,and the absolute value of zeta potential showed a law of first decreasing and then increasing.Confocal laser scanning microscope(CLSM)was used to observe the changes in the microstructure of the MF-L and C-L.The results showed that MF-L have strong stability.Through simulated in vitro digestion experiments,the release behavior of MF-L was studied.The results showed that it remained intact in gastric digestion and released during intestinal digestion.MF-L showed good release properties.DHA algae oil liposomes were fitted with zero-order equation,first-order equation,Higuchi equation,and Ritger-peppas equation,and the diffusion mechanism was confirmed,which conformed to Fickian diffusion.