Yuan Bingbing, Zhao Hekai, Xu Xinru, Zhang Haomiao, Yan Shizhang, Li Yang
College of Food Science, Northeast Agricultural University, Harbin, Heilongjiang 150030, China.
Daqing No. 1Middle School Cambridge International Center, Daqing, Heilongjiang 163000, China.
Food Chem. 2025 Apr 1;470:142707. doi: 10.1016/j.foodchem.2024.142707. Epub 2024 Dec 31.
Protein fibrillation has great potential for enhancing the emulsification, foaming, and gelling properties of proteins. However, its effects on protein film-forming properties are less well understood. In this study, soy protein isolate (SPI) was subjected to fibrillation at pH 2.0 and 85 °C to prepare films plasticized with glycerol (2 %). Mature fibrils formed at 12 h, as confirmed by thioflavin T fluorescence assay, circular dichroism spectroscopy, and atomic force microscopy. Moreover, the structural changes of the fibrillar SPI were related to the resulting film characteristics. Rheological analysis confirmed that a dense gel network was formed during fibrillation. In addition, particle size increased, while the free sulfhydryl content and surface hydrophobicity decreased. Fourier transform infrared spectroscopy revealed strong hydrogen-bonded β-sheets were dominant in the fibrillar SPI film. The dense network and exposed amino acids in the fibrillar SPI film resulted in high tensile strength (4.91 MPa) and good ultraviolet-blocking properties.
蛋白质纤维化在增强蛋白质的乳化、发泡和凝胶化特性方面具有巨大潜力。然而，其对蛋白质成膜特性的影响却鲜为人知。在本研究中，大豆分离蛋白（SPI）在pH 2.0和85°C条件下进行纤维化处理，以制备用甘油（2%）增塑的薄膜。通过硫黄素T荧光测定、圆二色光谱和原子力显微镜证实，在12小时时形成了成熟的纤维。此外，纤维状SPI的结构变化与所得薄膜特性相关。流变学分析证实，在纤维化过程中形成了致密的凝胶网络。此外，粒径增大，而游离巯基含量和表面疏水性降低。傅里叶变换红外光谱显示，强氢键结合的β-折叠在纤维状SPI薄膜中占主导地位。纤维状SPI薄膜中的致密网络和暴露的氨基酸导致了高拉伸强度（4.91MPa）和良好的紫外线阻隔性能。
