| Liposomes are closed vesicles formed by self-assembly of phospholipids.Preparation of liposomes usually requires the addition of a certain amount of cholesterol.However,excessive cholesterol intake increases the risk of cardiovascular and cerebrovascular diseases and atherosclerosis.With the improvement of people's demand for food quality and health,cholesterol limits the further development of liposomes in food industry.Phytosterols are structurally similar to cholesterol and have a healthier effect.Studies have shown that it is feasible to use phytosterols to prepare liposomes,but the effect of phytosterols on the stability of liposomes is not clear.Therefore,this thesis mainly discussed the effects of plant sterols with different molecular structures on the stability of liposomes,in order to prepare a new liposome with good stability,and to study its slow-release effect on eugenol,in order to further apply it to the health delivery system of functional food.The main results are as follows:(1)The results of liposome particle size and Zeta potential showed that sterol had a significant effect on liposome particle size(p<0.05).The particle sizes of cholesterol liposomes,?-sitosterol and stigmasterol liposomes were 98.24±1.21 nm,106.27±0.90 nm and 107.27±0.59 nm,respectively.Stigmasterol increased the particle size of the liposomes to a greater extent than ?-sitosterol,but in the mixed sterol liposomes,stigmasterol could better control the particle size of the mixed sterol liposomes than ?-sitosterol.At the same time,sterol had no significant effect on the Zeta potential of the liposomes,and the Zeta potential of the single sterol liposomes and the mixed sterol liposomes was about-30 m V.(2)was studied by fluorescence probe sterol liposome membrane characteristics,the research results show that the addition of sterol can make phospholipid membrane structure become more close together,with a small amount of stigmasterol or replace cholesterol beta sitosterol,influence of liposome membrane structure is lesser,Dante of phenol to join has negative effect to the liposome membrane structure.FTIR spectra showed that there was hydrogen bond interaction between sterol and phospholipid head group,and the membrane structure of the mixed sterol liposome was consistent with that of the single sterol liposome.No new chemical bond was formed between eugenol which was encapsulated in liposomes and phospholipid.The results of thermal analysis showed that eugenol and sterol could decrease the transformation temperature of liposomes.(3)Using particle size and Zeta potential as indexes,the environmental stability of sterol liposomes was investigated.The results showed that the addition of sterol improved the salt stability and p H stability of liposomes,but did not significantly improve the temperature stability.Mixed sterol did not change the salt stability and p H stability of the liposomes,but the temperature stability of the mixed sterol liposomes became worse.When the amount of ?-sitosterol replacing cholesterol was more than 25 mol%,the temperature stability of the mixed ?-sitosterol liposomes decreased.In addition,eugenol had no significant effect on the salt stability of the mixed sterol liposomes,but significantly worsened the temperature stability and p H stability of the mixed sterol liposomes.(4)?-sitosterol significantly affected the encapsulation rate of eugenol(p < 0.05),and the encapsulation rate of eugenol was significantly increased when the amount of?-sitosterol replacing cholesterol was more than 50%.The highest encapsulation rate of eugenol mixed sterol liposomes was 84.35±0.92%,and the highest drug loading was12.88±0.31%.The results of in vitro release and release kinetics showed that the release of eugenol liposomes followed Weibull equation,and sterol had no significant effect on the release of eugenol. |
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