Comparative study on the foam and air-water interface properties of ethanol-soluble and non-ethanol components in wheat aqueous phase protein

Abstract

We conducted an investigation into the foam and interface properties of wheat aqueous phase protein (WAP) along with its ethanol-soluble fraction (ES) and non-ethanol-soluble fraction (NES). The results reveal that the ES component exhibits exceptional foamability at both pH 5 and 7, whereas the NES component demonstrates relatively lower foamability but excels in foam stability at pH 5 and 7. The ES component shows a higher initial surface pressure, indicating stronger surface activity and, consequently, superior foamability. In contrast, the NES component exhibits a faster adsorption rate. The surface dilatational modulus of all three proteins increases over time and with varying frequencies, forming an interface layer primarily characterized by elastic behavior. Notably, the NES component displays heightened sensitivity to oscillations, suggesting its enhanced capacity to form a stable adsorption layer at the interface, thereby contributing to foam stability. Within WAP, the combined interactions of the ES and NES components dictate its foam properties, with the ES component primarily influencing foamability and the NES component playing a more significant role in foam stability. This study offers valuable insights into the intricate behavior of wheat proteins at gas-liquid interfaces, thereby enhancing our comprehension of the formation and stability mechanisms of dough aqueous phase foams.