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探究了拉曼光谱应用于黑豆蛋白结构变化研究的可行性,研究了黑豆蛋白溶液在低频超声处理在不同超声强度、不同处理时间下的结构变化,并进行了热力学特性分析。低、中超声处理强度下TD的降低表明蛋白质分子的内部疏水作用被破坏,使黑豆蛋白不稳定的聚集体解聚为小分子可溶性聚集物,而在高超声处理强度下TD的增高表明聚集体重聚。拉曼光谱分析表明超声处理下除了E样品(300 W,24 min)所有黑豆蛋白均发生了α-螺旋结构含量降低和β-折叠结构含量增高。聚集体的聚合/解聚导致黑豆蛋白二级结构的重组,尤其是β-折叠。超声处理使拉曼光谱在760 cm~(-1)的色氨酸归属谱线强度降低表明超声处理使黑豆蛋白发生了部分的解折叠。超声处理下酪氨酸归属谱线强度变化不显著,表明超声处理并未显著改变黑豆蛋白酪氨酸的微环境。1 450 cm~(-1)拉曼归属谱带随着超声处理强度和时间的增加而增大,但随着功率及处理时间的进一步增大此值有所降低。在超声处理下聚集体的形成使二硫键的g-g-t构型转变为t-g-t构型。尽管黑豆蛋白聚集体重组的机理仍有待研究,但拉曼光谱是一种研究超声处理黑豆蛋白结构变化的可行方法,也可为蛋白质结构研究提供一种新的研究思路。
The feasibility of applying Raman spectroscopy to the study of the structure change of black soybean protein was explored. The structure changes of black soybean protein solution under different ultrasonic intensities and different treatment time were studied. The thermodynamic properties of black soybean protein solution were also studied. The decrease in TD at low and medium sonication intensities indicates that the internal hydrophobic interactions of the protein molecules are disrupted, depolymerizing the unstable aggregates of black bean proteins into small molecule soluble aggregates, whereas the increase in TD at high sonication intensities indicates that aggregate weight Poly. Raman spectroscopy analysis showed that the content of α-helical structure and the content of β-sheet structure increased in all the black soy protein except for the E sample (300 W, 24 min) under the ultrasonic treatment. Aggregation / disaggregation of aggregates results in the recombination of the secondary structure of the black bean protein, especially the [beta] -sheet. Sonication reduced the intensity of the tryptophan attributable spectrum at 760 cm -1 in Raman spectrum, indicating that the sonication partially unfolded the black bean protein. The intensity of attribution of tyrosine under sonication did not change significantly, indicating that sonication did not significantly change the microenvironment of black protein tyrosine. The Raman at 1 450 cm -1 increased with the increase of ultrasonic treatment intensity and time, but decreased with the increase of power and treatment time. Formation of aggregates under sonication converts the g-g-t configuration of disulfide bonds to the t-g-t configuration. Although the mechanism of aggregation of black bean protein aggregates remains to be studied, Raman spectroscopy is a feasible method to study the structure changes of black bean protein by sonication. It can also provide a new research idea for protein structure research.