Study On Phosphorylated Modification And Properties Of Pasteurized Egg White

In this paper,the phosphorylation of egg serum was studied by using complex phosphate,and the modification process was studied.On the basis of these,the effects of phosphorylation on the functional and structural properties of egg serum were studied.The further application of the liquid in the food industry provides a theoretical basis.The main findings are as follows:The effects of the addition of sodium tripolyphosphate(STP),the amount of sodium pyrophosphate(SAP)and the amount of sodium hexametaphosphate(HMP)on the phosphorylation of egg white protein were studied.Based on the orthogonal test,The optimum ratio of compound phosphate in the modified reaction was:STP:SAP:HMP = 2:1.5:1,and the reaction conditions were carried out at the reaction pH = 8,temperature of 40 ?,reaction time of 6 h And the degree of phosphorylation on the egg white protein was 26.40 mg/g.The effects of compound phosphate addition,pH,reaction temperature and reaction time on the phosphorylation of egg white protein were studied by single factor test.On the basis of these,the four-factor three-level response surface was designed according to Box-Benhnken center combination experiment design principle.The optimal conditions for the modification of phosphorylated egg white protein were as follows:the dosage of compound phosphate was 4%,pH 8.5,reaction temperature was 40 ?,reaction time was 8 h,and the phosphorylation degree of egg white protein was 27.46 mg/g.The solubility of the modified egg white protein was the lowest at pH = 5.0,and the solubility of the unmodified albume was the lowest at pH = 4.0,indicating that the isoelectric point was changed after modification.The change trend of egg foaming after modification was consistent with the solubility,emulsifying property and foam stability were improved slightly,and the water holding capacity and oil holding capacity were improved to a great extent.The modified phosphates showed a sharp peak at 976.04 cm-1,and the STP?SAP?HMP modification were in the range of 973.31 cm-1,107.82 cm-1,973.31 cm-1,suggesting that these peaks are due to PO43-produced.At the absorption peak of 1598.5 cm-1,the transmittance of the unmodified sample was 36.44,and the transmittance of the modified sample increased,indicating that the amino group(-NH2)in the modified protein was reduced,It is inferred that the active group.?-NH2,which may be the lysine residue,reacts with the phosphate.The content of sulfhydryl(-SH)in the sample was decreased and the content of disulfide bond(-S-S-)was increased after the phosphorylation of egg white protein was carried out by using complex phosphate,STP,SAP and HMP.The egg white was modified by the complex phosphate,then the highest-S-S-content in the sample was 2.46 ?mol/g.And the hydrophobicity index of the modified phosphate was higher than that of the modified phosphate.Therefore,compared with other modified samples,the solubility was the best.The thermo gravimetric temperature of the protein was increased by 5.05 J/g after the modification of SAP,and the enthalpy of the composite was 4.59 J/g,but the difference between the two gap is small.The maximum absorbance of all the samples was near 280 nm,but the maximum absorbance of the modified samples was changed.The results of LF-NMR analysis showed that the water retention of the complex phosphate-modified egg white protein was improved.