Effects of pH and Temperature on the Structure and Function of Pea Albumin

Pea albumin is a high-quality plant-based protein with growing relevance in food applications, yet the effects of pH and thermal treatment on its structural and functional properties remain insufficiently understood. This study investigated the effects of environmental factors, namely pH (3, 5, 7, 9) and temperature (40, 60, 80, 100 °C), on the structural behavior and functionality of pea albumin. Structural changes were characterized through particle size, Zeta potential, surface hydrophobicity, and intrinsic fluorescence. Functional properties, including solubility, foaming ability, and emulsifying capacity, were evaluated and compared with untreated controls. Under alkaline conditions (pH 9), stronger electrostatic repulsion led to a 29.5% reduction in particle size, a 76.47% increase in Zeta potential, enhanced protein unfolding, and a 19.06% increase in surface hydrophobicity. At this pH, solubility increased by 24.8%, accompanied by notable improvements in foaming and emulsifying performance. Moderate heating (40, 60 °C) induced partial unfolding, resulting in decreased particle size and enhanced solubility, which further contributed to improved functional behavior. Pearson correlation analysis demonstrated significant associations between structural indicators (particle size, Zeta potential, surface hydrophobicity) and functional properties, highlighting the structure–function relationship of pea albumin. This work provides a comprehensive understanding of environmental factor-induced changes in pea albumin and offers valuable insights for its optimized application in plant-based foods.