Rice Glutelins and β-Conglycinin or Glycinin Forming Binary Structures with Different Structural and Functional Properties

Design of binary proteins based on protein–protein interactions has proven to be a facile approach to improve such functional properties as foaming and emulsifying properties of individual proteins. In this study, novel binary protein complexes were fabricated which was performed by co-dissolving glutelins of rice proteins (RGs) with β-conglycinin (7S) or glycinin (11S) of soybean proteins at pH 12 prior to neutralization. Fluorescence spectra, far-ultraviolet circular dichroism, dynamic light scattering and morphological characterizations revealed that either 7S or 11S formed shared conformations with RGs by hydrophobicity, leading to the formation of nanoscale (80–120 nm), water-dispersible complexes, i.e., RG-7S or RG-11S, respectively. The functionalities of both binary structures, e.g., foaming properties and emulsifying properties, were profoundly enhanced as compared to their individual components. Specifically, the foaming stability of RG-11S was four times that of 11S. Moreover, RG-7S or RG-11S had varied performance in emulsifying capacity due to varied structural flexibility. Thus, this study provided a feasible approach utilizing protein–protein interactions as a tool for enhancing the functional properties of individual proteins, especially foaming and emulsifying properties.