Preparation Of Probiotics And Inulin Nanoparticles Microcapsule And Their In Vitro Bacteriostatic Effect On Salmonella Gallinallium

The abuse of antibiotics has led to food safety and public health problems.The European Union and other countries have banned the use of antibiotics,and China will soon face this problem.Microecological additives are safe and effective alternatives to antibiotics.The microcapsules prepared in this project are synbiotics microecological agents,that is,probiotics and prebiotics,which are coated together in pectin/chitosan microcapsules as core materials,to study the effect of the microcapsules on in vitro bacteriostasis of Salmonella Gallinarilum.First,microcapsules were prepared under laboratory conditions.The experiment was divided into three groups,the first group was pectin/chitosan microcapsules containing Pediococcus acidilactici(PC(PA)MCs),the second group was pectin/chitosan microcapsules containing Pediococcus acidilactici and inulin(PC(PA-Ⅰ)MCs),and the third group was pectin/chitosan microcapsules containing Pediococcus acidilactici and inulin nanoparticles(PC(PA-PIN)MCs).Firstly,the optimal concentration of pectin as wall material was determined.Secondly,PA,PA-Ⅰ and PA-PIN were prepared by optimizing the reaction parameters with the embedding rate,particle size,appearance,viable bacteria number of microcapsules before and after freeze-drying,and inulin nanoparticles labeled by FITC.At the same time,different coating materials were compared.Then,PA in simulated gastrointestinal tract was determined by plate viable bacteria counting technique.PA PA-Ⅰ and PA-PIN microcapsules of Pediococcus acidilactici showed viable bacteria count,survival rate and release performance,bacteriostasis of Salmonella Gallinarilum,growth of Pediococcus acidilactici in co-culture experiments,and concentration of short chain fatty acids(SCFAs).The results show that:(1)When pectin concentration is 5%,the prepared microcapsules are round and not easy to break.It is suitable for preparing microcapsules.The particle sizes of PC(PA)MCs,PC(PA-Ⅰ)MCs and PC(PA-PIN)MCs were 1.9 mm,1.92 mm and 2.01 mm,respectively,and the morphology was uniform.From the SEM images that we can see that PC MCs have a careful internal structure,no wrinkles,no cracks,holes and damage.It shows that the efficiency of microencapsulation is high,and it has a good protection effect on the core material.The encapsulation rate and bacterial load of PC(PA)MCs,PC(PA-1)MCs and PC(PA-PIN)MCs before and after freeze-drying were not significant(P>0.05),but the encapsulation rate of PC MCs after Internalization of PINs into PA and bacterial load after freeze-drying were higher than those of other two groups,indicating that the PC MCs of Internalization of PINs into PA had better effect.Inulin nanoparticles were labeled by FITC.PC(PA-PIN)MCs were slowly released into PA at pH 7.2 for 3 hours.Inulin nanoparticles were successfully internalized into PA.(2)The survival rate of unpacked PA of PC MCs was almost zero after 60 minutes of simulated gastric fluid at pH 2.0.The survival rates of PC(PA)MCs and PC(PA-Ⅰ)MCs were significantly higher than those of PA group(P<0.05),while PC(PA-PIN)MCs were significantly higher than those of PC(PA)MCs and PC(PA-Ⅰ)MCs groups(P<0.05).The results show that PC MCs can provide better protection under specific conditions.After 30 minutes of simulated intestinal fluid treatment,the release rate of PC MCs was more than 60%.However,the survival rate of PC(PA)MCs,PC(PA-Ⅰ)MCs and PC(PA-PIN)MCs in stomach was significantly higher than that of uncoated PA in intestinal fluid(P<0.05),indicating that double-coated microcapsules had good release ability in intestinal fluid.(3)PA,PC(PA)MCs,PC(PA-Ⅰ)MCs and PC(PA-PIN)MCs all have bacteriostasis against Salmonella.The bacteriostasis ability of PC(PA-PIN)MCs was the lowest,the bacteriostasis ability of PC(PA)MCs and PC(PA-Ⅰ)MCs was significantly higher than that of PC(PA)MCs and PC(PA-Ⅰ)MCs(P<0.05),and the antimicrobial activity of PC(PA-PIN)MCs was the highest.(4)In the co-culture experiment,it was found that there was no significant difference in the viable counts of the four groups of microcapsules of Pediococcus acidilactici over time,indicating that the internalization of inulin nanoparticles into Pediococcus acidilactici did not affect the growth of Pediococcus acidilactici.The yield of PC(PA-Ⅰ)MCs and PC(PA-PIN)in acetate,butyrate and SCFAs was significantly higher than that of PA and PC(PA)MCs(P<0.05)in the concentration of acetate,propionate,butyrate and total SCFAs in SG(Salmonella Gallinarilum)treatment for 9 hours.There was no significant difference between the two groups,but the yield of PC(PA-PIN)MCs and total SCFAs was the highest,and the bacteriostatic effect was good.In summary,Inulin nanoparticles as probiotics of Pediococcus acidilactici microcapsules have significant bacteriostatic effect on Salmonella Gallinarium in animal intestine,which is expected to become a green feed additive and be applied to the production of young animals.