Pickering Emulsion Templating Methodology-Based Ginger Essential Oil Microcapsules And Their Performance And Effect On Regulation Of Intestinal Microbiota

Ginger essential oil(GEO)has many physiological activities because of the main active ingredient.The development and application of colonic localization delivery system is of great significance to the realization of colonic nutrition.However,the physical and chemical properties of GEO are unstable and its compliance is poor when taken directly.Palygorskite is a kind of natural nanomaterial and is beneficial to intestinal function and health.Therefore,preparation of GEO microcapsules by palygorskite-stabilized pickering emulsion templating methodology was investigated in this study.Microencapsulation can improve the stability and biological activity of GEO,as well as expand its application range in the food industry.Besides,it can provide a theoretical basis for the further development and application of GEO.There are no reports on preparation of GEO microcapsules by Pickering emulsion template method.Therefore,in this study,O/W Pickering emulsion stabilized by acid modifiedna no-palygorskite particles was used as a template.GEO extracted by supercritical CO₂ was used as core material,pectin and chitosan hydrochloride were used as wall material.GEO microcapsules were prepared and their characterization and properties of colonic localization and sustained-release were studied.The colonic localization and sustained-release performance of GEO microcapsules were studied by simulated digestion experiment in vitro.The in vitro fecal anaerobic fermentation system and high-throughput sequencing technology were used to study the regulatory effect of GEO microcapsules on intestinal flora.The following are the results of this study:1?O/W Pickering emulsion was stabilized by acid modified palygorskite particles,and GEO extracted with supercritical CO₂ was used as oil phase.The wettability of solid particles wascharacterized by three-phase contact angle(?)at the oil/water interface.The effects of particle mass fraction,oil phase volume fraction and water phase pH value on the stability of Pickering emulsion were investigated.At the condition of palygorskite particle concentrations 1.0%,oil phase volume fraction 10%,and water phase pH 7.5,Pickering emulsion has good stability,relatively uniform droplet size and uniform particle size distribution.Based on the above stable Pickering emulsion,preparation of colonic localization GEO microcapsules would be investigated.The preparation process of GEO microcapsules was optimized by response surface methodology.The optimal preparation process was as follows:ratio of core to wall 1:2,stirring speed 600 rpm,water-bath temperature 55?,water-bath time 3 h,and inlet air temperature180?.The encapsulation efficiency of GEO microcapsules prepared under these conditions was 94.064±0.133%.2?The physical and chemical properties and characterization of GEO microcapsules were studied by laser particle size analyzer,fluorescence microscope,SEM,TEM,FTIR,GC-MS,TGA and DSC.The results showed that the average particle size of GEO microcapsules was 5.04?m,the density was low(0.264±0.006g/cm³),the water content was low(1.922±0.047%),the water solubility was high(97.630±0.221%),and the fluidity was good(34.940±0.320°).Fluorescence microscopy,SEM and TEM observation showed that GEO microcapsules were spherical and round in shape.The formation mechanism of GEO microcapsules was analyzed by FTIR,which indicated that GEO was embedded by electrostatic reaction between the wall materials.GC-MS analysis showed that microencapsulation could effectively maintained the main volatile component of GEO.TGA and DSC analysis showed that GEO microcapsules had good thermal stability.The release properties of GEO microcapsules under different environmental temperatures and humidity showed that the release kinetics of GEO microcapsules followed the release kinetics of Rigter-Peppas,and the release accorded with the non-Fickian diffusion.Microencapsulation can improve the storage stability of GEO.The experiment of simulated digestion for48 h in vitro showed that the ginger essential oil microcapsule released less in stomach and small intestine,the cumulative release rate of GEO microcapsules in colon was 82.915±5.181%,which showed good colonic localization and sustained release effect.3?The in vitro fecal anaerobic fermentation system and high-throughput sequencing technology experiment showed that both GEO and GEO microcapsules could reduce pH value,increase the contents of short-chain fatty acids(acetic acid,propionic acid,butyric acid,valeric acid,isobutyric acid and isovaleric acid).The number of Bifidobacterium and Lactobacillus increased,and the proliferation of Enterococcus was inhibited.GEO and GEO microcapsules can both regulate the structure of intestinal flora of animals with normal diet,as well as promote the proliferation of probiotics and inhibit the growth of harmful bacteria.The effects of GEO microcapsules and GEO on regulating intestinal flora were similar,indicating the microencapsulation maintained the biological activity of GEO.