Effect of NaCl concentration on the interfacial and foaming properties of wheat aqueous phase protein

Abstract

In this study, the structure, foaming properties, and air-water interfacial behavior of wheat aqueous phase protein (WAP) with different NaCl concentrations were investigated. With the addition of NaCl, the particle size and the β-sheet content increased, indicating the formation of larger aggregates. In the FT-IR spectrum NaCl also increased the peak intensity for WAP, this peak often associated with C-O and C-N stretching vibrations, indicating that NaCl may induce conformational changes, such as protein unfolding. As NaCl concentration increased, the foam capacity of WAP increased from 106.25 ± 1.41% to 142.38 ± 15.73%, while native WAP exhibited higher foam stability. Interfacial adsorption kinetics revealed that NaCl favored WAP adsorption at the air-water interface. The interfacial viscoelasticity modulus of all samples increased over time, forming an interfacial layer primarily characterized by elastic behavior. Native WAP exhibited a stronger viscoelasticity modulus, forming a stable adsorption layer at the air-water interface, which contributed to enhanced foam stability. This study provides valuable insights into the regulation of WAP structure and foaming properties by salt ions, which may offer a new strategy for improving the interfacial properties of wheat-based food products.