The Preparation Of Citral Microcapsules And The Study Of Microcapsules' Construction And Stability

In this study, essential oil microcapsules were prepared with citral as the core and carbohydrate as the wall materials by complex coacervation method and spray drying method. The structure, properties and their relationships were investigated.1.Citral microcapsules were prepared with chitosan, alginate sodium and calcium chloride as the wall materials by complex coacervation method.The influence of wall materials amount on the oil content was investigated. The change of oil content and the components of the oil during storage were measured. The experiment showed that the highest oil content of the microcapsule,0.0218g/g, was obtained at the following conditions:alginate sodium3g/100mLH2O, calcium chloride1.5g/50mLH2O, oil lml, chitosan1.2g/100mL1%HAC.Placing the prepared microcapsule in room temperature environment for a while, the oil content of the microcapsule decreased. Because the oil content of the microcapsules was low, we didn't get useful data with gas chromatograph-mass spectrometer to analyze the components of the core.2. Hollow microcapsules were also prepared with chitosan, alginate sodium and calcium chloride as wall materials and cobalt chloride as moisture indicator by complex coacervation method.Water in atmosphere environment affected the morphology, size, pores and specific surface area of the microcapsule. It was found that at room temperature, the sealed microcapsule adsorbed water from the air had increase of the size, pores and specific surface area.3.Citral microcapsules were prepared with chitosan, alginate sodium and methylcellulose as the wall materials by spray drying method. Through the single factor experiments, the influence of the wall materials amount on the oil content of the microcapsule were investigated. The change of the oil content of the microcapsules and the components of the core during the storage were also measured. The highest oil content of the microcapsules,0.1277g/g, was obtained at the conditions ofchitosanlg/30mL H2O, alginate sodium6g/180mL H2O, oill.5mL, methylcellulose1.2g/50mL H2O. The oil content of the microcapsule decreased after stored at room temperature for a certain time. According to the results of gas chromatograph-mass spectrometer, the constituent of oil in microcapsule had changed.The content of p-caresol, methyl acetophenone, ?-terpineol, nerol and geraniol had increased.4.Hollow microcapsule was also prepared with chitosan, alginate sodium and methylcellulose as the wall material and cobalt chloride as the core and moisture indicator by spray drying method.The water in the environment affected the morphology, size, pores and specific surface area of the microcapsules. In as ealed environment at room temperature, microcapsules adsorbed water from air had increased size, pores and specific surface area.5.Compare the microcapsules structure and properties made by complex coacervation method and by spray drying method, the size of the microcapsules made by complex coacervation method was bigger than that by spray drying method.However, oil content of the microcapsules made by complex coacervation method decreased slower than that by spray drying.And the microcapsules from spray during absorbed water slower.