Yang Yang, Zhang Can, Ma Chun-Min, Bian Xin, Zou Ling, Fu Yu, Shi Yan-Guo, Wu Yan, Zhang Na
College of Food Engineering, Harbin University of Commerce, Harbin, China.
College of Food Science, Southwest University, Chongqing, China.
J Sci Food Agric. 2024 Aug 30;104(11):6778-6786. doi: 10.1002/jsfa.13505. Epub 2024 Apr 17.
This study explored the denaturation of 11S globulin, a protein known for its diverse functional properties in soy protein applications, at pH 3.0 and pH 10.0, followed by a gradual return to pH 7.0 to facilitate renaturation. It investigated the structural and functional changes during renaturation induced by a change in pH, revealing the stabilization mechanism of 11S globulin.
The findings revealed that during pH adjustment to neutral, the denatured soybean 11S globulin - resulting from alkaline (pH 10.0) or acidic (pH 3.0) treatments - experienced a refolding of its extended tertiary structure to varying extents. The particle size and the proportions of α-helix and β-sheet in the secondary structure aligned progressively with those of the natural-state protein. However, for the alkali-denatured 11S, the β-sheet content decreased upon adjustment to neutral, whereas an increase was observed for the acid-denatured 11S. In terms of functional properties, after alkaline denaturation, the foaming capacity (FC) and emulsifying activity index (EAI) of 11S increased by 1.4 and 1.2 times, respectively, in comparison with its native state. The solubility, foamability, and emulsifiability of the alkali-denatured 11S gradually diminished during renaturation but remained superior to those of the native state. Conversely, these properties showed an initial decline, followed by an increase during renaturation triggered by pH neutralization.
This research contributes to the enhancement of protein functionality, offering a theoretical foundation for the development of functional soy protein products and expanding their potential applications. © 2024 Society of Chemical Industry.
本研究探讨了11S球蛋白（一种在大豆蛋白应用中因其多样功能特性而闻名的蛋白质）在pH 3.0和pH 10.0条件下的变性情况，随后逐渐恢复至pH 7.0以促进复性。研究了pH变化诱导复性过程中的结构和功能变化，揭示了11S球蛋白的稳定机制。
研究结果表明，在将pH调节至中性的过程中，经碱性（pH 10.0）或酸性（pH 3.0）处理而变性的大豆11S球蛋白，其伸展的三级结构会不同程度地重新折叠。二级结构中的粒径以及α-螺旋和β-折叠的比例逐渐与天然状态蛋白质的相应比例趋于一致。然而，对于碱变性的11S，调节至中性时β-折叠含量降低，而酸变性的11S则观察到β-折叠含量增加。在功能特性方面，碱性变性后，11S的发泡能力（FC）和乳化活性指数（EAI）分别比其天然状态增加了1.4倍和1.2倍。碱变性11S在复性过程中的溶解度、发泡性和乳化性逐渐降低，但仍优于天然状态。相反，这些特性在pH中和引发的复性过程中先下降，随后增加。
本研究有助于提高蛋白质的功能特性，为功能性大豆蛋白产品的开发提供理论基础，并拓展其潜在应用。© 2024化学工业协会。
