活性氧对牛乳β-乳球蛋白结构、功能特性和致敏性的影响

Effects of Reactive Oxygen Species on Structure,Functional Properties and Sensitization of Bovine Milk β-Lactoglobulin

为分析牛乳加工过程中活性氧氧化对牛乳β-乳球蛋白(β-lactoglobulin,β-LG)结构、功能特性和致敏性的影响,以牛乳β-LG为研究对象,利用圆二色谱、表面疏水性和内源荧光光谱分析活性氧氧化前后β-LG结构的变化,同时测定其功能特性的变化,通过酶联免疫试验(enzyme linked immunosorbent assay,ELISA)和大鼠嗜碱性细胞白血病细胞(rat basophilic leukemia cells,RBL-2H3)评价其致敏性的变化。结果表明:活性氧氧化后,β-LG的α-螺旋含量降低,二级结构更无序,表面疏水性升高,内源荧光强度降低,起泡能力和起泡稳定性增加,乳化活性降低,但乳化稳定性升高。β-LG的免疫球蛋白E结合能力和RBL-2H3中β-已糖苷酶释放率和组胺的释放量降低。表明加工过程中适当氧化可以改变牛乳β-LG构象结构,从而显著改善功能特性与降低潜在致敏性。该研究为探究食品加工过程中牛乳蛋白功能特性及其致敏性的变化规律提供参考。

To analyze the effects of reactive oxygen species oxidation on the structure,functional properties,and sensitization of bovine milk β-lactoglobulin(β-LG)during bovine milk processing,β-LG was studied,and the changes in the structure of β-LG before and after reactive oxygen species oxidation were analyzed using circular dichroism,surface hydrophobicity,and endogenous fluorescence spectroscopy.In addition,the changes in functional properties were determined,while the changes in sensitization were evaluated by enzyme linked immunosorbent assay(ELISA)and rat basophilic leukemia cells(RBL-2H3).The results showed that after reactive oxygen speciesoxidation,the α-helix content of β-LG was reduced;the secondary structure was more disordered;the surface hydrophobicity was elevated;the intensity of endogenous fluorescence was reduced;the foaming ability and stability were increased;the emulsion activity was reduced,but the emulsion stability was elevated.β-LG's immunoglobulin E-binding ability and the content of β-hexosidase and histamine in RBL-2H3 were reduced.It was shown that proper oxidation during processing could alter the conformational structure of bovine milk β-LG,resulting in a significant improvement of functional properties with a reduction of potential sensitization.This study provided a reference for exploring the changing patterns of functional properties and sensitization of bovine milk proteins during food processing.