| Purpose: Akkermansia muciniphila has a broad medical prospect as a new probiotic.AKK is the abbreviation of Akkermansia muciniphila and has gradually become a research hotspot in recent years.However,Akkermansia muciniphila is very sensitive to the gastrointestinal environment and oxygen,which has greatly hindered its application.Sodium alginate is by far the most widely used microcapsule wall material.However,untreated sodium alginate has many defects,such as too high molecular weight,easy to cause cell leakage,low mechanical strength,etc.These factors are not Conducive to its probiotic and protective role.Therefore,this study explored the possibility of modifying sodium alginate and combining with other prebiotics to protect the activity of AKK bacteria.Methods: In this experiment,succinic anhydride modified sodium alginate was used to encapsulate AKK bacteria and epigallocatechin gallate(EGCG)was added to protect probiotic activity and increase stress resistance.The microcapsules were made by spray drying technology,and the retained activity of probiotics after spray drying was compared using MTT colorimetry.In addition,we used scanning electron microscopy to determine the surface physical properties of microcapsules and modified materials.At the same time,in order to simulate the possibility of spray-dried microcapsules for storage and transportation in liquid products,we tested the uniformity and stability of microcapsules in the water system using a laser nanoparticle size analyzer.In order to test the stress resistance of microcapsule products,the oxidation resistance of several different microcapsules,the changes in vitality during longterm storage experiments,and the resistance of probiotics encapsulated in different materials to gastrointestinal fluids were tested.In order to verify the biological affinity of the modified material for AKK bacteria,the growth ability of several microcapsule bacteria in mucin liquid culture medium was tested.Conclusion: Experimental data show that the modified sodium alginate can make the surface of the microcapsules smoother and denser during the spray drying process,which can prevent damage.At the same time,EGCG enhances the antioxidant capacity of probiotics by filling the pores inside the microgel.In the 12-day long-term storage experiment,modified EGCG spray-dried modified sodium alginate microcapsules showed better storability and stability.Anti-oxidation experiments showed that the modified sodium alginate microcapsules were effective against hydrogen peroxide.The resistance is stronger,and the cell activity is well preserved when the hydrogen peroxide concentration reaches 2.5 m M,and the test of particle size and Zeta potential shows that it has better uniformity in the liquid,and has a relatively high absolute value of Zeta potential.In the gastrointestinal fluid resistance experiment,modified sodium alginate microcapsules(doped with EGCG)can better protect the probiotic activity in the gastrointestinal tract environment,and it still maintained good after 30 minutes of gastrointestinal fluid immersion Vitality.After analysis of the experimental results,spray-dried EGCG modified sodium alginate microcapsules(containing EGCG)showed excellent performance in a series of experiments.In the material affinity experiment,the materials embedded in several different materials did not affect the normal growth of bacteria,proving that the modified materials were harmless to bacteria.In summary,compared with the unmodified sodium alginate microcapsules,the modified EGCG-doped modified sodium alginate microcapsules greatly improved the storage possibility of Akkermansia muciniphila and the resistance to adverse external factors Sex,thus providing an effective reference method for the production of industrial products targeting this new type of probiotics. |
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