不同pH对马铃薯蛋白理化性质的影响

Effects of different pH on the physicochemical properties of Solanum tuberosum L. protein

中文关键词:  马铃薯蛋白  pH  疏水性  聚集  亚基组成

英文关键词:Solanum tuberosum L. protein  pH  hydrophobicity  aggregation  subunit composition

中文摘要:

      目的 探究pH处理对马铃薯蛋白结构和功能特性的影响。方法 以马铃薯蛋白为研究对象, 通过荧光光谱、傅里叶变换红外光谱、粒径和电位、扫描电镜等方法分析pH对其物化性质、结构和构象的影响。结果 不同pH处理后的蛋白质亚基组成、粒径分布、电位值等所得结果有显著差异。与pH 7相比, pH 10条件下增强了马铃薯蛋白质的静电斥力, 蛋白溶解度和黏度显著提高, 分别为89.2%、19625.0 mPa·s; 蛋白内源荧光光谱中λmax红移至343 nm, 暴露了更多的疏水基团; 蛋白分子的粒径减小为123.2 nm, Zeta电位绝对值增大至41.3 mV, 蛋白质分子形成分子内二硫键从而使得变性温度增加至82.22 ℃。而pH 2条件下, 蛋白在去折叠的同时发生聚集并形成可溶性聚集体, 但黏度下降为1860.6 mPa·s, 蛋白荧光光谱中λmax蓝移至341 nm, 粒径增加至369.3 nm, Zeta电位绝对值减小到8.97 mV, 二硫键数量未有显著性改变, 这使得酸性条件下马铃薯蛋白的稳定性不足且有聚集趋势。结论 不同pH处理均会改善马铃薯蛋白的理化性质, 本研究以期为马铃薯蛋白在食品加工中的应用提供科学指导。

英文摘要:

      Objective To elucidate the influence of pH treatment on the structural and functional properties of Solanum tuberosum L. protein. Methods Solanum tuberosum L. protein was selected as the research subject, and the effects of pH on its physical and chemical properties, structure, and conformation were analyzed by fluorescence spectroscopy, Fourier transform infrared spectroscopy, particle size and potential analysis, and scanning electron microscopy. Results Significant differences were observed in the protein subunit composition, particle size distribution, and potential values following treatments at different pH levels. Compared to pH 7, pH 10 enhanced the electrostatic repulsion of Solanum tuberosum L. proteins, significantly increasing protein solubility and viscosity to 89.2% and 19625.0 mPa·s, respectively. Additionally, λmax in the endogenous fluorescence spectra of the proteins shifted to 343 nm, exposing more hydrophobic groups. The particle size of protein molecules decreased to 123.2 nm, while the absolute value of the Zeta potential increased to 41.3 mV. Protein molecules formed intramolecular disulfide bonds, leading to an increase in the denaturation temperature to 82.22 ℃. At pH 2, the protein aggregated and formed soluble aggregates while unfolding. However, viscosity decreased to 1860.6 mPa·s, λmax in the fluorescence spectrum shifted to 341 nm, particle size increased to 369.3 nm, the absolute value of the Zeta potential decreased to 8.97 mV, and the number of disulfide bonds did not change significantly. This resulted in insufficient stability of Solanum tuberosum L. protein under acidic conditions, with a tendency for aggregation. Conclusion Different pH treatments can enhance the physicochemical properties of Solanum tuberosum L. protein, and this study aims to offer scientific guidance for its application in food processing.