Study On The Mechanism Of Irradiation Treatment On The Functional Properties Of Egg White Protein

Egg white proteins are known to have excellent functional properties such as foaming,emulsifying,and gelling properties.Compared with other plant proteins,egg white protein has better nutritional value and is more beneficial to human body absorption.Irradiation technology has a long history of application in egg whites,and irradiation is mainly used in the preservation and sterilization of egg products.With the increasing application of egg white in food processing,the use of irradiation technology to improve the functional properties of egg white has attracted wide interest among researchers.In this paper,egg white liquid was used as raw material to study the effects of different irradiation dose treatments on the foaming,emulsifying and gelling properties of egg white.The changes of egg white foaming power and foam stability,viscosity,surface hydrophobicity and protein content under different irradiation doses were observed to study the relationship between different irradiation doses and egg white foaming during storage.The relationship between different irradiation dose treatment and egg white emulsification characteristics was studied by using particle size,zeta potential,emulsion droplet microstructure,emulsification index,interfacial tension,protein secondary structure and microrheology.Finally,the relationship between the different irradiation dose treatment and the gel properties of egg white was analyzed,and the changes of water holding capacity,thermal properties and rheological properties of the gel were studied.Through the above measurement,the application of irradiation technology in the processing of egg products lays a foundation,and the application range of egg white liquid in the neighborhood of food processing is broadened.The main findings are as follows:(1)Effect of irradiation treatment on the foaming property of egg white protein.The results showed that under irradiation treatment,the foaming ability of egg white increased significantly with the increase of irradiation dose(P<0.05).The foam stability of all irradiated samples was significantly reduced(P<0.05)compared to the control samples.However,the reduction of 1 k Gy irradiated samples was larger,while the reduction of 3k Gy and 5 k Gy irradiated samples was smaller.In addition,irradiated egg whites had higher surface hydrophobicity,lower viscosity and surface tension than unirradiated egg whites.At the same time,the content of free sulfhydryl groups did not change significantly after irradiation treatment(P>0.05).Finally,SDS-PAGE data showed that irradiation caused ovarian mucin degradation.(2)The results of irradiation treatment on egg white protein emulsification characteristics showed that the average egg size of the irradiated egg white protein emulsion was smaller and showed lower interfacial tension than the natural egg white protein emulsion.After irradiation,the two-phase separation time of the emulsion was prolonged,and the zeta potential value of the emulsion increased as the irradiation dose level increased.In addition,the experimental results also indicated that the irradiation treatment can change the secondary structure of the egg white protein,resulting in the conversion of the ?-helix and the ?-sheet structure into a ?-turn and a random coil structure.In this study,the microstructure of the emulsion was observed by optical microscopy and confocal laser scanning microscopy(CLSM).The droplets of the natural egg white protein emulsion were severely flocculated and the dispersion of the emulsion was poor.As the irradiation dose increases,the dispersion of the emulsion droplets was better and the droplet size was significantly reduced.The microfluidic results of the emulsion showed that as the irradiation dose increased,the fluidity of the egg white protein emulsion droplets increased,and the elasticity and viscosity of the emulsion decreased.(3)The effect of irradiation treatment on the gelatinity of egg white protein.The results showed that the brightness value(L*)of the egg white gel after irradiation treatment decreased with the increase of the irradiation dose,and the redness value(a*)increased remarkably(P<0.05);the egg white gel after irradiation treatment Adhesion,cohesion and viscosity showed a downward trend.The elasticity and chewiness of egg white gel increased with the increase of irradiation dose.The degree of swelling of the egg white gel of the 1 k Gy irradiation group was significantly lower than that of the other groups.Correspondingly,the thermal enthalpy of the respective endothermic peaks also decreased with the increase of the irradiation dose value.Irradiation treatment did not impart any crystal structure to the egg white gel and results in a decrease in the gel hydroxyl content.Finally,the microfluidic results showed that the EI value of the irradiated egg white gel increased,there was no significant difference in the macroscopic viscosity value,and there was no significant difference in the microstructure results.