Preparation,Characterization And Release Characteristics Of Microcapsules Of Volatile Oil From Atractylodes Macrocephala Koidz

Atractylodes macrocephala volatile oil has high medicinal value and has many functions such as anti-cancer,antibacterial and anti-oxidation.However,the volatile oil of Atractylodes macrocephala has an odor,which is easily oxidized and volatilized in the air,and the loss is serious.The microcapsule technology is used to embed the volatile oil of Atractylodes macrocephala to prevent or reduce the volatilization and oxidative deterioration of volatile oil and improve the taste.In this experiment,three different types of microcapsules were prepared by inclusion complexation method,spray drying method and complex coacervation method,respectively.The best production process of Atractylodes macrocephala volatile oil microcapsules was studied by single factor test and response surface optimization experiment with embedding rate as the main index.Microcapsules were characterized by particle size distribution,Fourier transform infrared spectroscopy,scanning electron microscopy and thermogravimetric analysis.The release law of the prepared microcapsules in the simulated intestinal juice environment was studied and a suitable release kinetics fitting model was established.The specific results are as follows:The optimal process for the preparation of Atractylodes macrocephala volatile oil-?-cyclodextrin microcapsules by water-bath method was as follows:the inclusion temperature was 60.77?,and the ratio of wall material to core material was 8.14:1,the ratio of water to wall material is 15.29:1,and the inclusion time is 45 min.At this time,the embedding rate was 51.35%;the optimum preparation conditions of spray drying method are:inlet air temperature is 175?,feed rate is 640 L/h,and emulsifier dosage is 5%.The core wall ratio was 0.32,the gelatin content was 21.13%,the solid content was 29.51%,and the HLB was 13.53,and the embedding rate was 88.35%.The optimal embedding process for preparation of Atractylodes macrocephala volatile oil microcapsules by complex coacervation method was as follows:chitosan mass fraction was 0.898%,sodium alginate mass fraction was 2.5%,core-wall ratio was 0.382,and reaction temperature was 45?,the embedding rate is 94.05%under this condition.The experiment proves that compared with the inclusion complex method,the spray drying method and the complex coacervation method greatly improve the embedding rate of the volatile oil microcapsules of Atractylodes macrocephala,the complex coacervation method is mild,and the embedding,separation,purification and drying processes of the spray drying method are completed simultaneously,which is very simple.Fourier infrared spectroscopy proved that all three methods successfully embedded the volatile oil of Atractylodes macrocephala in the wall material.The results of scanning electron microscopy showed that the microcapsules prepared by spray drying method were regular in shape,small in particle size,smooth in surface and free from cracks.The surface of microcapsules of Atractylodes macrocephala prepared by complex coacervation method had pleats on the surface,which was rough and crack-free.The results of particle size analysis showed that the microcapsules prepared by spray drying method were uniform and the particle size was the smallest,the average particle size was 4.75 ?m,the inclusion complexing method was the second,the average particle size was 357.93 ?m.The microcapsules prepared by the complex coacervation method have the largest average particle size of 416.28 ?m.The results of thermogravimetric analysis indicated that the volatile oil microcapsules prepared by the complex coacervation method had better thermal stability than that prepared by spray drying.Both spray drying method and complex coacervation method have their own advantages and disadvantages.In different application fields of Atractylodes macrocephala volatile oil microcapsules,suitable preparation methods can be selected according to different needs.The release of the two microcapsules in the simulated gastric juice in vitro is in line with the kinetic law represented by the Logistic model.The cumulative release rate of the microcapsules prepared by the spray drying method is higher than that of the microcapsules prepared by the complex coacervation method.The cumulative release rate of microcapsules in intestinal fluid is much higher than that in gastric juice,indicating that microcapsules have certain protective effects and sustained release effects on volatile oil.