Microencapsulation And Cocrystallization Of Several Tobacco Flavorings Preparation,Characterization And Slow And Controlled Release

Cigarette aroma is an important indicator of the quality of cigarettes,as well as a key feature and marker of cigarette brand image.However,many flavors and fragrances have shortcomings such as volatility and oxidation by air,resulting in short retention time and deterioration,which limits their development in the cigarette field.In order to ensure that the designed cigarette aroma is rich,thick,coordinated and has a certain style,the cigarette must be flavored.At present,slow and controlled release technology consisting of new raw materials and processes has gradually become the development trend of new tobacco products.In this thesis,the cocrystal and microencapsulation technologies of synthetic latent aroma substances are used to improve the stability of volatile tobacco flavors and fragrances,which help to improve the quality of cigarettes and provide new ideas for the development of low-tar cigarettes.The main research content as follows:1.O-Vanillin-pyrazinamide cocrystal,o-vanillin-thiourea cocrystal and methyl vanillin-5-chlorosalicylic acid cocrystal are produced by using solvent room temperature volatilization method.Characterization and analysis by infrared spectroscopy（IR）and powder X-ray diffraction（PXRD）are used to confirm the formation of new phase cocrystal.The crystal structures are determined by single crystal X-ray diffraction:o-vanillin-pyrazinamide cocrystal and o-vanillin-thiourea cocrystal belonged to the monoclinic system with space group P2₁/c.Methyl vanillin-5-chlorosalicylic acid cocrystal belonged to the triclinic system with space group P1.Hirshfeld surface analysis show that the H···H interaction contributed the most to the intermolecular forces in the three cocrystals,which made the crystal stacking structure more stable.Thermogravimetric analysis（TGA）further confirm that the cocrystal of the synthetic latent fragrance substances could improve the thermal stability of vanillin-like fragrances and achieve the effect of controlled release.2.The new salt form of pyrazine-Acesulfame is produced by using the solvent room temperature volatilization method.Characterization and analysis using IR and PXRD confirm that a new salt type with high purity was obtained.The new salt type of pyrazine-Acesulfame is determined by single crystal X-ray diffraction to belong to a monoclinic crystal system with space group P2₁/c,each asymmetric unit containing half a protonated pyrazine cation and one deprotonated acesulfame anion.The results of Hirshfeld surface analysis show that the most important intramolecular interaction in this salt type is O···H,accounting for 37.1%,which is favorable to the stability of the crystal structure.In addition TGA confirms that the cocrystal of the synthetic latent fragrance substances can be able to improve the thermal stability of pyrazine spice.3.Based on the microemulsion system,the maltodextrin（MD）-octenyl succinic anhydride（OSA）stabilized structure is formed by calcium ion cross-linking for the encapsulation of peppermint oil.The morphology and particle size of the microcapsules are characterized by scanning electron microscopy（SEM）,transmission electron microscopy（TEM）and dynamic light scattering（DLS）,and the optimized process conditions for the preparation of microcapsules are determined by single factor analysis using the average particle size and encapsulation rate as indicators:core to wall ratio of 2:1,pH 9,homogenization time of 40 min,120%calcium chloride,and optimal encapsulation rate of38.33%.It is further confirmed by various means that the MD-OS-mint oil microcapsules prepared under the optimized process conditions are able to slow down the volatilization rate of peppermint oil and achieve the effect of slow and controlled release.