| Probiotics have aroused extensive interest in the researchers because of their superior physiological functions.However,during the utilization of probiotics,external factors such as temperature,oxygen and acid conditions have a serious influence on the survival of probiotics.According to the environmental conditions and the types of probiotics,embedding probiotics with suitable wall materials can not only improve the bioavailability,but also improve the bioavailability of probiotics.The problem of traditional embedding is the use and residue of organic solvents.Excessive organic solvents are harmful to the human body,and microcapsules can greatly reduce the residue of organic solvents.In addition,some foreign scholars have proved that probiotics can promote the absorption effect of some nutrients(such as vitamin D)in the human body.Therefore,the preparation of"double loaded microcapsules containing probiotics and nutrients simultaneously"has important research value.Based on this,the main contents of this paper are as follows:(1)The preparation of polycaprolactone(PCL)embedded with vitamin D particles was carried out by solvent diffusion method,and the embedding situation was verified.The optimum process parameters are as follows:the mass of polyhexyl ester(PCL)of wall material is 0.4 g,the volume ratio of water phase to oil phase is 4:1,the concentration of surfactant is3%,the emulsifying time is 5 min,and the speed of emulsifier is 10000 rpm.On these conditions,the particles prepared had high embedding rate(84.2%)and smaller average particle size(2.5 m).The apparent morphology of emulsion and particles was observed.Particulates have good sphericity,aggregation and adhesion,and poor dispersion.(2)Microcapsules containing probiotics were prepared by solvent diffusion,and the effects of PVA concentration,PCL amount,emulsifying stirring speed,thr second emulsifying stirring speed,and the amount of Span 80 in the internal water surface active agent on the average particle size and embedding rate of microcapsules were studied.The response surface method was used to study the interaction between the influence factors,and the optimum parameters of the preparation of probiotic microcapsules were as follows:PVA concentration was 3.5%,thr second emulsifying stirring speed was 279 rpm,and the PCL amount was 0.39 g.On these conditions,these microcapsules had smaller average particle size(26.03 mu m)and higher embedding rate(89.34%).(3)The double coated microcapsules containing probiotics and vitamin D were prepared by supercritical fluid extraction with uniform distribution of 10~50?m.The effects of different temperature and pressure on the appearance of microcapsules were obtained,and the embedding situation of yeasts and vitamin D was verified.The influence of temperature,pressure and flow rate on solvent removal rate is obtained through single factor experiment.Through the design of orthogonal test,the influence of pressure,temperature and extraction length on the residual rate of organic solvents was obtained through the experimental results.The optimum conditions for the optimum removal rate of organic solvents under the conditions were 12 MPa,40 centigrade and 120 min for the extraction,with a solvent removal rate could reach 99.9994.8%.The survival rate of probiotics was calculated,and the release of microcapsules was studied.The release rules of probiotics and vitamin D in microcapsules were studied.Microcapsules had good storage stability,and microcapsule drug release data had the highest goodness of fit with Higuchi drug release model(R~2=0.9902),and the drug release showed the characteristics of rapid release and slow release. |
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