超高压对乳清分离蛋白结构和抗氧化活性的影响

Effects of ultra-high pressure on structure and antioxidant activity of whey protein isolates

为了研究超高压处理对乳清分离蛋白结构的影响,该研究对乳清分离蛋白进行了不同条件的超高压处理,之后测定表面疏水性、傅里叶变换红外光谱、自由巯基含量和内源荧光光谱分析乳清分离蛋白的结构变化。与未经处理的乳清分离蛋白相比,200 MPa及以上压力显著提高了乳清分离蛋白的表面疏水性,在400 MPa-30min时达到最大值。超高压处理使乳清分离蛋白的α-螺旋、β-折叠含量发生明显变化,证明了其对乳清分离蛋白二级结构的影响。超高压处理增加了蛋白自由巯基含量,在400 MPa-30 min时增加49%,并且超高压处理也引起了乳清分离蛋白内源荧光强度的显著变化。在所有的超高压处理条件中,400 MPa-30 min对乳清分离蛋白结构的影响最为显著,并显示出了最高的抗氧化活性。研究表明,超高压处理能显著改变乳清分离蛋白的二、三级结构,暴露出疏水基团等活性基团,从而对抗氧化活性产生影响。

The study aimed to investigate the effects of ultra-high pressure(UHP)on the structure of whey protein isolates.To this end,whey protein isolates were treated with ultra-high pressure under different conditions,and any structural changes were analyzed by surface hydrophobicity,Fourier transform infrared spectrum,free sulfhydryl group content,and endogenous fluorescence spectra.Compared to the control group,the surface hydrophobicity of whey protein isolates significantly improved at 200 MPa and above,reaching a maximum value of 400 MPa-30 min.The content of theα-helix andβ-sheet was found to change significantly,which proved its influence on the secondary structure of the whey protein isolates.UHP treatment increased the content of the protein-free sulfhydryl group by 49%at 400 MPa-30 min,and UHP treatment also caused significant changes in the endogenous fluorescence intensity of the whey protein isolates.Among all the UHP treatment conditions,the 400 MPa-30 min value had the most significant effect on structure and showed the highest antioxidant activity.The results confirm that UHP treatment can significantly change the secondary and tertiary structures of whey protein isolates,exposing active groups like hydrophobic groups,thereby affecting antioxidant activity.