动态超高压微射流对卵清蛋白微观结构的影响

Effect of Dynamic High Pressure Microfluidization Treatment on the Microstructure of Ovalbumin

采用圆二色谱(CD)、X射线衍射(XRD)、ANS荧光探针和紫外(UV)光谱研究了动态超高压微射流对卵清蛋白微观结构的影响。结果表明:卵清蛋白的微观结构的变化与处理压力有关,CD显示不同压力处理的卵清蛋白二级结构中的α-螺旋,β-折叠,β-转角和无规卷曲之间发生相互转化,二级结构的有序性提高;X射线衍射图谱直观显示不同压力处理的卵清蛋白晶体结构增加,160 MPa处理下结晶区最大,说明蛋白结构的有序性提高,与CD分析结果相似;ANS荧光探针光谱显示卵清蛋白的表面疏水性随着处理压力的增大而提高,120 MPa处理下达到最大;紫外光谱显示随着处理压力的增大,卵清蛋白最大紫外吸光值下降,卵清蛋白分子表面的具有紫外吸收的芳香氨基酸残基被包埋于分子内部,卵清蛋白的三维结构发生改变。

The effect of dynamic high pressure microfluidization on the microstructure of ovalbumin was studied by CD spectra, XRD spectra, ANS fluorescence probe emission spectra and UV absorption spectra. The results indicated that the changes in the microstructure were dependent on the pressure. CD spectra were used to examine the changes in the secondary structure of the ovalbumin treated by different pressures. When the pressure increased, the mutual transformation between a-helix, /？-sheet, /？-turn and the random coil was observed. The orderliness of the secondary structure was increased with increasing the pressure. XRD spectra analysis showed that the crystal structure content of the ovalbumin treated increased with increasing the pressure and the largest data was observed at 160 MPa, indicating that the orderliness of the secondary structure was increased. The re- sults were similar to CD spectra analysis. The iNS fluorescence probe emission spectra analysis demonstrated that the dynamic high pressure microfluidization induced an increase in surface hydrophobicity following high pressure treatment, while the largest data was observed at 120 MPa. In addition, UV absorption spectra analysis indicated that dynamic high pressure microfluidiza- tion treatment also resulted in a decrease in the UV-absorption maximum wavelength with increasing the pressure, indicating that the aromatic amino acid was buried in the molecular interior and the three dimensional structure of ovalbumin was changed.