超高压处理对乳清分离蛋白结构及致敏蛋白含量的影响

以乳清分离蛋白为研究对象,通过测定圆二色性光谱、巯基含量以及内源性荧光光谱等研究了不同超高压水平(100、200、400和600 MPa)对其二级、三级结构的影响,并采用水解度测定、十二烷基硫酸钠-聚丙烯酰胺凝胶电泳以及2个标志性致敏蛋白(β-乳球蛋白和 α-乳白蛋白)含量的检测来解析超高压对乳清分离蛋白致敏性的影响....

Effects of ultra-high pressure on the structure of whey protein isolate and the content of allergenic protein

In this study,whey protein isolate(WPI)was subjected to ultra-high pressure(UHP)at different treatments(100、200、400 and 600 MPa).The secondary and tertiary structures of WPI was studied by measuring circular dichroism(CD),sulfhydryl groups content,and endogenous fluorescence spectroscopy.The degree of hydrolysis(DH),sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-page),and the contents of two marker sensitizing proteins,β-lactoglobulin(β-LG)andα-lactalbumin(α-LA),were used to analyze the effect of UHP on the sensitization of WPI.The results showed that the UHP treatment transformed theα-helix andβ-turn of WPI into aβ-sheet and random coil.And it also enhanced the sulfhydryl contents of WPI.At 400 MPa,the surface sulfhydryl content increased by 104.82%.The UHP treatment also caused a significant change in the endogenous fluorescence intensity of WPI and red shift of maximum absorption wavelength.The SDS-page pattern and degree of hydrolysis of the samples treated with UHP did not show significant differences.Furthermore,ELISA detection found that UHP could significantly reduce the content ofα-LA,however,the UHP treatment at 400MPa increased the content ofβ-LG.These results indicate that UHP can significantly alter the secondary and tertiary structure of WPI,expose the hydrophobic groups inside the structure,and influence its allergenic protein.