Othmeni Ines, Blecker Christophe, Karoui Romdhane
Univ. Artois, Univ. Lille, Univ. Littoral Côte d'Opale, Univ. Picardie Jules Verne, Univ. Liège, INRAE, Junia, UMR-T 1158, BioEcoAgro, F-62300 Lens, France; Gembloux Agro-Bio Tech, Department of Food Science and Formulation, University of Liège, B-5030 Gembloux, Belgium; Cosucra Groupe Warcoing S.A., B-7040 Warcoing, Belgium.
Gembloux Agro-Bio Tech, Department of Food Science and Formulation, University of Liège, B-5030 Gembloux, Belgium.
Int J Biol Macromol. 2025 Feb;290:139105. doi: 10.1016/j.ijbiomac.2024.139105. Epub 2024 Dec 22.
This study investigated the relationship between pea protein isolates (PPI) emulsifying properties and their structural, interfacial, and physicochemical characteristics at various pH values (native pH, 7, 5, and 3). Emulsion characteristics including emulsifying activity and stability, droplet size, flocculation index (FI) and coalescence index (CI) were examined. Additionally, physicochemical properties such as solubility, zeta potential, surface hydrophobicity, interfacial protein adsorption and protein conformation were analyzed. Results revealed significant pH-dependent variations in emulsifying performance. The poorest emulsifying performance was observed at pH 5, with the largest droplet size (28.84 μm) and highest CI (38.94 %). Optimal emulsifying properties were noticed at native pH, with the smallest droplet size (7.73 μm) and lowest CI (4.69). At pH 3, good emulsifying ability with the highest physical stability (5.43) were observed, associated with increased surface hydrophobicity and the presence of some aggregates contributing to the formation of cohesive interfacial film. Structural elements, particularly β-sheets and random coils, were positively correlated with emulsifying activity and stability, while β-turns had a negative impact. These findings provide insights into the pH-dependent emulsifying behavior of PPI, highlighting the complex relationship between protein structure and functionality, enabling the optimization of the use of PPI as an emulsifier in food applications.
本研究调查了不同pH值（天然pH值、7、5和3）下豌豆分离蛋白（PPI）的乳化特性与其结构、界面和物理化学特性之间的关系。检测了包括乳化活性和稳定性、液滴大小、絮凝指数（FI）和聚并指数（CI）在内的乳液特性。此外，还分析了诸如溶解度、ζ电位、表面疏水性、界面蛋白吸附和蛋白质构象等物理化学性质。结果显示，乳化性能存在显著的pH依赖性变化。在pH值为5时观察到最差的乳化性能，液滴尺寸最大（28.84μm），CI最高（38.94%）。在天然pH值下观察到最佳乳化性能，液滴尺寸最小（7.73μm），CI最低（4.69）。在pH值为3时，观察到具有最高物理稳定性（5.43）的良好乳化能力，这与表面疏水性增加以及一些聚集体的存在有关，这些聚集体有助于形成粘性界面膜。结构元件，特别是β-折叠和无规卷曲，与乳化活性和稳定性呈正相关，而β-转角则有负面影响。这些发现为PPI的pH依赖性乳化行为提供了见解，突出了蛋白质结构与功能之间的复杂关系，有助于优化PPI在食品应用中作为乳化剂的使用。
