Effect Of Low Temperature Heat Treatment On Properties Of Compound Egg White And Its Mechanism

Egg white is widely used in the food industry.In order to improve the foaming of egg white,this study aims to improve the physical and chemical properties of egg white by studying the effect of heat treatment on the foaming of compound egg white liquid and its influencing mechanism.Firstly,poly glutamic acid was selected as an additive of egg white liquid by using foaming property and foam stability as indicators.On the basis of adding polyglutamic acid,the compound egg white liquid was heated for 3 min and the heating temperature was 30?,40?,50?,60?,room temperature 20? as a control,heating temperature of 50? heating time of 0 min,1 min,2 min,3 min,4 min,5 min heat treatment,study heating temperature and heating time influence on the indexes of foaming,surface tension,surface hydrophobicity,viscosity,solubility,etc,through the determination of free sulfhydryl content and scanning of microstructure,further study the effect of heat treatment on the microscopic and secondary structure of egg white modified liquid,and Source fluorescence,UV absorption spectroscopy,Fourier infrared spectroscopy and other spectroscopy techniques were used to study the effect of heat treatment on egg white modified solution.The experimental results show that moderate heat treatment plays a positive role in the foaming of the compound egg white liquid.When the heating temperature is 50? and the heating time is 3 min,the foaming performance of the compound egg white liquid is 60.53%,and the foam stability is 95.61%;heat treatment causes the surface tension of the protein to decrease first and then increase.At 50?,the surface tension is at least 64.10 mN/m2.When the heating time is 2 min and 3 min,the surface tension of the protein is low.60.60 mN/m2 and 64.10 mN/m2 respectively;the lowest surface hydrophobicity of the protein is 197.05 when the heating temperature is 50? and the surface hydrophobicity of the protein is 197.05 when the heating time is 3 min.The compound egg white liquid after heat treatment at 50?,the content of ?-sheet in the content of the structural unit is increased,which makes the molecular structure of the protein more stable and is beneficial to the stability of the foam.Proper application of heat-treated the compound egg white liquid in sponge cake improved the texture and sensory score of sponge cake.The compound egg white liquid before heat treatment was applied to the sponge cake.The hardness of the sponge cake was 5.36,and the sensory score was 57.After the heat treatment of 50?,3 min,the compound egg white liquid was applied to the sponge cake.The hardness of the sponge cake was 4.28,and the sensory score was 79.The sensory score was significantly improved compared with the no heat treatment.In summary,proper heat treatment improves the functional properties of the compound egg white liquid,and egg white is applied to the sponge cake in which the sensory score and texture of the sponge cake are better than those of the untreated cake.