Encapsulation Mechanisms And Controlled Release Properties Of Bovine Lactoferrin Microcapsules Prepared By High-voltage Electrohydrodynamic Atomization

The incidence of iron deficiency anemia in China is 10-30%.As a member of the ferroportin family,bovine lactoferrin(LF_b)displays great potential in alleviating iron deficiency anaemia.However,the orally delivered LF_b is rapidly degraded during human digestion,and the effect of iron supplementation is greatly reduced.This research utilized microencapsulation to achieve the controlled release of LF_b.Sodium alginate(Na Alg)and citrus pectin(Pectin),which are widely recognized in the food industries,were utilized as the wall materials of the microcapsules.High-voltage electrohydrodynamic atomization(EHDA)was selected as the encapsulation method.The research explored the effect of EHDA treatment on the particle properties,structural characteristics and molecular interaction mechanism of LF_b microcapsules,and revealed its digestive properties,controlled release mechanism and iron supplementation effect.The main contents and results of the research are as follows:(1)To explore the effect of EHDA treatment on the structure of LF_bmicrocapsules.The results demonstrated that the Zeta potential of LF_b nanoparticles prepared by EHDA was significantly increased,which could promote the binding behavior of LF_b nanoparticles with Na Alg or Pectin,resulting in the enhancement of electrostatic interaction,and the improvement of complexation effect and encapsulation ability.The surface structure was more compact and the network structure had a higher degree of cross-linking.(2)To explore the in vitro digestion properties of LF_b microcapsules prepared by EHDA.The results indicated that that EHDA treatment could improve the structural stability of LF_b and the iron content of the microcapsules.In vitro gastrointestinal simulated digestion test in adults showed that LF_b microcapsules prepared by EHDA could not completely protect LF_b from enzymatic hydrolysis.However,the LF_bmicrocapsules prepared by EHDA were found to be relatively resistant to proteolysis in the stomach by in vitro gastrointestinal simulated digestion test of infants and young children,and most of the LF_b still had biological activity.Therefore,the microcapsules prepared by EHDA was beneficial to protect LF_b through the digestive system of infants and young children,thereby exerting its iron supplementation effect.However,EHDA treatment did not significantly improve the controlled release of LF_bin the adult digestive system.In an adult digestive model,oral administration of EHDALF_b-Na Alg or EHDALF_b-EHDAPectin microcapsules still could not achieve the desired iron supplementation effect.In conclusion,EHDA treatment could increase the surface charge of LF_b,resulting in enhanced electrostatic interaction between LF_b and polysaccharide,and enhanced binding affinity.Therefore,the LF_b microcapsules prepared based on EHDA had better encapsulation effect,antioxidant activity and iron content,and the surface structure was tighter and the degree of network crosslinking was more obvious.Compared with the traditional microencapsulation approach,the encapsulation method based on EHDA can improve the protection of the main functional properties of LF_b microcapsules,and is expected to be applied in infant products.However,how to make the oral microcapsule structure completely pass through the adult digestive system still needs to be further studied.