Preparation,Characterization And Application Research Of Sodium Alginate-zein Core-shell Microcapsules

Hydrophilic-hydrophobic core-shell microcapsules have attracted much attention in the fields of food,biomedicine and cosmetics due to their unique structural characteristics.However,because it is difficult to assemble hydrophilic and hydrophobic materials together,the preparation of microcapsules with this structure is meaningful.In this paper,hydrophilic sodium alginate(ALG)and hydrophobic zein were used as research objects.Based on the principle of electrostatic interaction,ALG-zein core-shell microcapsules were prepared by two-step extrusion method and one-step extrusion method.Interestingly,it can easily control the shape,particle size and shell thickness of core-shell microcapsules.The core shell microcapsules containing emulsion,thiamine and ethyl maltol were prepared by two step extrusion method,and their controlled release characteristics were explored.In addition,the preparation method was further optimized,and the one-step extrusion method could be used for easy preparation.At the same time,the core-shell microcapsules loaded with buckwheat honey were prepared by the one-step extrusion method,and their water holding capacity,texture characteristics,in vitro release characteristics and antioxidant Activity was studied.The main conclusions are as follows:1.Hydrophilic polysaccharide ALG was selected as the core material and hydrophobic protein zein as the shell.Based on the principle of electrostatic interaction,ALG-zein core-shell microcapsules were successfully prepared by two-step extrusion method.In addition,the particle size,shape and shell thickness of core-shell microcapsules could be controlled by needle diameter,stirring speed and zein concentration.Optical microscopy,fluorescence microscopy,laser scanning confocal microscopy and scanning electron microscope images showed that ALG hydrogel particles and zein formed microcapsules with core-shell structure.The shell was relatively uniform and dense.2.According to the ALG-zein core shell microcapsules prepared in the first chapter,the controlled release characteristics of the encapsulated emulsion,thiamine and ethyl maltol were studied.It was found that core shell microcapsules had a good control effect on the encapsulation of oil MCT,and the food nutrition function factor thiamine had good control release ability,and the inclusion of volatile substances ethyl maltol had good sustained release effect.3.According to the research content of the first two chapters,the preparation method of core-shell microcapsules was further optimized.Based on the principle of electrostatic interaction,ALG-zein core-shell microcapsules were prepared by one-step extrusion method.Based on the principle of electrostatic interaction,ALG-zein core-shell microcapsules were prepared by one-step extrusion method.Its particle size and shell thickness could be adjusted by needle diameter and zein concentration.The microscopic morphology results showed that the ALG gel particles and zein form microcapsules with a core-shell structure,and were easier to prepare than the two-step extrusion method.In addition,a one-step extrusion method was used to successfully construct core-shell microcapsules loaded with buckwheat honey.The microscopic morphology results showed that the ALG microcapsules loaded with buckwheat honey and zein form microcapsules with a core-shell structure,and the shell layer was relatively uniform and dense.The core-shell microcapsules could effectively mask the odor of buckwheat honey and overcome its high viscosity and high fluidity.At the same time,it could significantly improve water holding capacity and texture properties.The core-shell microcapsule had a zein shell layer that could protect and control the release of buckwheat honey,so it could improve the stability and antioxidant activity of buckwheat honey.The combination of buckwheat honey and core-shell microcapsules effectively achieves synergy and provides a theoretical basis for the development of functional buckwheat honey foods.