Effect Of Ultrasonic Combined With Glycation Modification On The Functional Properties And Structure Of Bovine Serum Albumin

Bovine serum albumin was glycosylated with lactose after ultrasonic pre-treatment to investigate changes in functional properties,conformation characteristics.And the main components of BSA-lactose glycation reaction products were carried on the systematic study,to supplement and complete the basic theory of ultrasound effect on protein glycation reaction,and provide the correspondent theoretical guidance to improving the application of protein glycation reaction in food industry.Using the ultrasonic pre-treatment combined with glycation were used to processing proteins,and the physicochemical property,such as emulsifiability,thermal stability and reducing power were studied.SDS-PAGE and the degree of graviting indicated that BSA grafted with lactose through covalent bonds to form glycoprotein under dry heat treatment.With the increase of ultrasonic power,the glycation reaction degree first increased and then decreased,glycation reaction degree also first increased and then decreased,In general,in the BSA-lactose system,the glycation degree of BSA with ultrasonic pretreatment than non-pretreatment.The results showed that ultrasonic pre-treatment combined with glycation can significantly increased the reducing power and enhance the BSA emulsification and emulsion stability of BSA.Compared to the non-pretreatment BSA,the thermal stability of samples were increased.Ultrasonic pre-treatment combined with glycation significantly increased the emulsifiability,thermal stability and reducing power,with the highest values observed at 90 W.This result showed that ultrasonic pre-treatment combined with glycation can improve the functional properties of protein.Using the ultrasonic pre-treatment combined with glycation were used to processing proteins,the effect on the structure of the BSA was studied through spectroscopy methods.These results showed that during the process of ultrasonic pre-treatment combined with glycation reaction,the tertiary and secondary structure of BSA has changed,this was reflected in the increase in free sulfhydryl groups content,surface hydrophobicity and ?-helix.lead to some aromatic amino acid residues were sheltered,hydrophobic groups which located in internal molecular were exposed.With DPPH radical-scavenging activity and ABTS radical-scavenging activity asevaluation indexes in vitro evaluation before and after in vitro digestion of BSA oxidation resistance,the results showed that ultrasonic pretreatment combining glycation modification can significantly increase the oxidation resistance of BSA.Besides,Glycation modification BSA after gastric and intestinal digestion of its oxidation resistance decrease.Ultrasonic pretreatment combining glycation modification BSA decrease in a greater degree.After maillard reaction between BSA and lactose,not only some beneficial substances were formed,but also generated some harmful substances.This thesis mainly studied the content of melanoidin,fructosamine,carboxymethyl lysine(CML)and HMF.The results showed that compared with the traditional heating,the content of melanoidin,fructosamine,carboxymethyl lysine(CML)and HMF were less higher under ultrasonic pre-treatment.