Construction And Performance Evaluation Of Oxidized High Amylose-Sodium Alginate Composite Probiotics Microcapsules

BACKGROUND:Probiotics are a group of microorganisms that can grow and multiply in the human intestinal tract.They have the functions of improving intestinal balance of nature,regulating immunity and maintaining intestinal mucosal barrier.However,the bioavailability of probiotics is low because of their environmental impact during processing,storage and in vivo application.However,because probiotics in the processing and storage process and the application of the process in vivo easily affected by the environment,so low bioavailability.In this paper,Oxidized High-amylose Starch(OHAS)and Sodium alginate(SA)were used as wall materials of microcapsules,to prepare probiotics composite microcapsules,and to evaluate the physical chemistry properties and in vivo activity of the microcapsules.The contents and results of the study are as follows:METHODS:1.Preparation and characterization of oxidized high amylose:conversion of C 6 hydroxyl group of high amylose to carboxyl group by TEMPO oxidation system,using particle size analyzer,Fourier infrared spectrometer,scanning electron microscope,X-ray diffractometer,etc.,the macrostructures and microstructures of OHAS,such as oxidation degree,solubility,particle size and crystal structure,were identified.2.Preparation of microcapsules:using oxidized high amylose and sodium alginate as raw materials,microcapsules were prepared by electrostatic spray method,the internal structure and morphology,loading rate,gastrointestinal tolerance,storage stability and wall material proliferation of the microcapsules were characterized.3.In vivo evaluation:antibiotic diarrhea models were made using a mixture of antibiotic solutions(cefradine and gentamicin),mice were divided into Blank group,Model group,microcapsule(LM)group,empty microcapsule(EM)group and Lactobacillus rhamnosus(LGG)group.The changes in body weight,fecal water content,colon length and histopathological scores,expression of inflammatory factors,contents of short-chain fatty acid and the abundance of intestinal flora were monitored,to evaluate the effect of microcapsule on antibiotic diarrhea in mice,and to evaluate the efficacy of microcapsule in vivo.RESULTS:1.With the increase of oxidant dosage,the solubility of OHAS gradually increased,and the SEM images showed that the surface of the particles gradually changed from smooth to rough and fragmentary structure,the characteristic absorption peak of carboxyl group in IR spectra increased gradually,and X-ray diffraction showed that the crystal morphology of OHAS was destroyed gradually and the crystallinity decreased gradually.2.With the increase of the oxidation degree of high amylose,the entrapment efficiency of microcapsules HAS a tendency to decrease,and microcapsules prepared by high amylose(HAS)and oxidized high amylose(OHAS 10)with 10%oxidation degree have the highest entrapment efficiency,it found that all OHAS could improve the gastric juice tolerance of probiotics better than that of HAS.In addition,in the storage stability experiments,we found that probiotics with the increase of the oxidation of the wall material microcapsule survival time gradually decreased.3.Compared with the model group,the microcapsule group could effectively alleviate the pathological condition of mice,increase the body weight,improve the water content of feces,and decrease the local inflammation of colon tissue(pathological section and the expression levels of inflammatory factors il-1β and TNF-α),the content of total short-chain fatty acid increased(P<0.05),while the microcapsules could regulate the abundance of bacteria,increase the abundance of beneficial bacteria and decrease the abundance of pathogenic bacteria.CONCLUSIONS:1.The C-6 hydroxyl group of amylose was successfully converted to carboxyl group by TEMPO-mediated oxidation system.2.OHAS10-AS group was the best wall material for microcapsules.3.In vivo experiments showed that the microcapsule could alleviate the course of disease in the mice with antibiotic diarrhea,and its therapeutic effect was better than that of the free bacterial solution group.