冷等离子体处理改性大豆分离蛋白及改善其界面性能

Modification of Soybean Protein Isolate by Cold Plasma Treatment and Improvement of Its Interface Properties

摘要:

该研究探讨了大豆分离蛋白（SPI）作为植物蛋白，在食品中应用广泛，但其界面性能较差，影响其在乳液食品中应用。该研究利用冷等离子体技术处理大豆分离蛋白（SPI），研究其对SPI蛋白结构影响及其界面性能改善作用。结果表明，经冷等离子体处理60 s后，大豆分离蛋白的α-螺旋含量从31.93%下降到23.56%，其三级构象变的更为紧凑。大豆分离蛋白的表面性能、持水能力（WHC）和持油能力（FHC）均显著提高。同时，经冷等离子体处理后的蛋白溶液粒径分布逐渐变窄，ζ-电位绝对值显著增加。此外，随着冷等离子体处理时间的增加，大豆分离蛋白分散体的游离巯基含量从9.77 μmol/g蛋白（未处理SPI）增加到17.76 μmol/g蛋白（50 W，60 s）。经过冷等离子体处理后，大豆分离蛋白分散体的表面疏水性从2 330.9增加到3 680.7。利用冷等离子体处理的大豆分离蛋白的微观结构呈现更均匀的聚集。总之，该研究显示利用冷等离子体可以改变SPI蛋白结构及其物理特性并显著增强SPI界面性能，可以拓展SPI在食品中应用。

Abstract:

As a plant-sourced protein, soy protein isolate (SPI) is widely used in food. However, interface properties of SPI are poor, which affects its application in emulsion food. In this study, SPI is treated with cold plasma to investigate the changes in its structure and improvement of its interface properties. The results showed that the α-helix contents of SPI decreased from 31.93% to 23.56% after treatment with cold plasma for 60 s, and its tertiary conformations changed to a more compact structure. The emulsifying properties of SPI, including the surface properties, water-holding capacity (WHC), and fat-holding capacity (FHC), were also improved significantly. The particle size distribution of the cold plasma-treated protein solutions gradually narrowed, and the absolute value of ζ-potential also changed. Moreover, free sulfhydryl content increased from 9.77 μmol/g protein (untreated SPI) to 17.76 μmol/g protein (50 W, 60 s) with the increase in cold-plasma treatment duration. The surface hydrophobicity of SPI dispersions increased from 2,330.9 to 3,680.7 after treatment with cold plasma. The microstructures of SPI treated with cold plasma exhibited a more uniform aggregation. Conclusively, this study showed that cold plasma treatment could modify the protein structure and physical properties of SPI and enhance its interface properties, which could expand the application of SPI in food. Key words: