Different Conformations Of Beta Lactoglobulin In Vitro Digestion And The Relationship Between The Structure And The Allergicity

Beta lactoglobulin is one of the major allergens in milk machine in milk products,milk does not exist,the vast majority of infants are allergic to it.The phenomenon of beta lactoglobulin is a two dimer form of globular proteins.This spatial structure gives it good stability and potential allergenic properties,while beta lactoglobulin two dimer form resistant,strong enough for acid hydrolysis and enzyme hydrolysis.In the human body through the digestive tract after digestion is still intact and structure by small intestine mucosa absorption,stimulate the body’s immune cells,eventually causing allergic reactions.The linear epitopes of beta lactoglobulin,the conformation of three aspects of peptide and digestion after hydrolysis together determine the allergenicity,Based on our previous studies we found that dynamic high-pressure microfluidization(Dynamic high pressure microfluidization,DHPM)treatment of beta lactoglobulin can make the space conformation of different degrees of unfolding or aggregation changes,The allergic epitope exposed or buried due to its physicochemical properties and allergic changes,but allergic epitope changes of beta lactoglobulin for hydrolysis of the enzyme resistant and enzymolysis products also have what change remains to be investigated.Therefore,this paper intends to simulate the in vivo environment of digestion,relationship after the beta lactoglobulin digestive enzyme reaction solution structure and allergic change.As the modified beta protease solution milk balls provide theoretical reference for the structure and change of allergy.The results of this paper are the following three aspects:(1)Dynamic high pressure microfluidization modified beta lactoglobulin in vitro study of sensitive functional properties caused by the digestive process.Beta lactoglobulin after three different pressure treatment(0.1,80160MPa)after simulated digestion of samples in vitro,according to the previous study of our group we know antigen beta lactoglobulin is treated with the pressure increased firstly and then decreased,but the digestion experiment after the antigen reactivity is gradually reduced,the degree of hydrolysis and SDS-PAGE have a digestive enzyme conditions with different degrees of.160 MPa solution under the effect is good,the degree of hydrolysis 21.3%.We also found in the electrophoresis bands of the small molecule segment is also obvious.(2)Dynamic high-pressure microfluidization simulation of microstructure before and after the digestion process of lactoglobulin in vitro modified beta.The results show that with the in vitro digestion,beta lactoglobulin showed more obvious changes in the environment,scanning electron microscopy and atomic force microscopy we can clearly found protein aggregation structure the trend of volume reduction,combined with static and dynamic light scattering experiments we found that protein molecules were obtained with digestion and aggregation state of different molecular weights.These are possible and in vitro digestion changed the structure of the protein,the effect of the interaction between proteins.(3)Dynamic high-pressure microfluidization simulation study on the molecular structure of the digestive process before and after the lactoglobulin in vitro modified beta.The free sulfhydryl content,surface hydrophobicity,CD,fluorescence and mass spectrometry analysis,the experimental results show that its thiol and surface hydrophobicity are with in vitro digestion showed a growing trend.We found that the fluorescence spectra of the fluorescence intensity increased red shifted,which may be related to enzymatic digestion of internal acid more tryptophan,and CD spectroscopy results show that changes of protein structure,especially beta fold decrease and increase helix content,mass spectrometry experiments That can get different peptides in different conditions of pressure digestion under the pressure of 160 MPa under the condition of m/z 955.488 beta lactoglobulin f(1-8)(LIVTQTMK),m/z 837.444 beta lactoglobulin(142-148)f(ALPMHIR),especially f(142-148)in the presence of beta lactoglobulin alpha helix structure,which may affect the structure of CD beta lactoglobulin and antigenicity.