Study On Preparation Of Linalool Microcapsules By Complex Coagulation Of Chitosan And Gum Arabic

The application of microencapsulation technology in encapsulating spice flavors can not only delay the release of flavors,but also increase the fragrance retention time and achieve controlled release effects.Meanwhile,the core material can be isolated from the external environment,and the stability and activity can be improved with the the microencapsulation technology.This technology is widely used in food,cosmetics,textile,printing,medical supplies,industrial materials and other fields.Complex coacervation is a method by using two or more water-soluble and oppositely-charged polymers to induce phase separation by electrostatic interactions or intermolecular hydrogen bonds,hydrophobic bonds,and polarity induction,thus the condensed phase can be formed and the core material can be encapsulated in microcapsules.In this study,chitosan?CS?and gum arabic?GA?were used as the wall materials and Linalool as the core material.The microcapsules were prepared by complex coacervation.The experimental content is mainly divided into three parts.The first part discussed the influence of different factors on the re-agglomeration of chitosan-gum arabic.Based on the turbidity of the equilibrium phase and the yield of the condensed phase,the effect of the ratio of chitosan/gum arabic,the concentration of the reactants,the pH value,the reaction temperature and the reaction time were investigated on the complex agglomeration reaction.Experiments showed that all the factors mentioned above can affect the complex condensation reaction,and therefore affected the turbidity of the equilibrium phase and the yield of condensed phase.The highest condensed phase yield can be obtained when the GA/CS ratio is 3,the total wall material concentration is 0.5%-1.5%,the pH value is 4.5,the reaction temperature is40°C-60°C,and the reaction time is 60 minutes.In the second part,the core/wall ratio,wall material concentration,emulsifier concentration,stirring speed and homogenization speed were investigated to study the effects on the formation of chitosan-Arabic gum microcapsules.Through the observation of the microstructure of the microcapsules,the following conclusions have been drawn:the optimal homogeneous emulsification effect can be obtained with the 16000 rpm/min homogenization power and the addition of Tween 80 which accounts for 2.5%of the mass of the essence;the best of core materials and wall materials The ratio is 1:1;the optimal wall material concentration is 1.0%;the stirring speed is 600 rpm.The microcapsules prepared under this condition have a better spherical structure with smaller particle size and uniform dispersion.Microcapsules with the morphology of spherical structure,small particle size and well homogeneity had been prepared.The third part had characterized the structure and properties of the microcapsules.The morphology of the microcapsules is analyzed by FTIR,SEM,particle size analyzer,and TGA.The particle size,embedding rate?EE?and loading capacity?LC?were characterized.The following conclusions were obtained:the prepared microcapsules were spherical,uniformly dispersed in solution and had an average particle size of 3.27?m;the-NH₂ of chitosan and-COOH in acacia disappeared in the infrared spectrum of the microcapsules which demonstrated that chitosan and gum arabic agglomerates were formed by the mutual attraction of positive and negative charges.Under the optimal condition,the loading capacity of the microcapsules prepared was 20.74%,the embedding rate was 35.26%,and the yield was 77.30%.