Construction and characterization of egg white protein-gallic acid-xanthan gum-based emulsion and oleogel

In this work, the egg white protein-gallic acid-xanthan gum covalent complexes were used to construct emulsions and oleogels and the effects of different concentrations of the complexes on the properties of emulsions and oleogels were investigated. The results showed that the values of emulsion D[4,3] and zeta-potential decreased with increasing complex concentration, while the emulsion stability index increased. The emulsions exhibited good centrifugal stability against changes in temperature, salt ion concentration and pH value. The emulsions prepared with high concentrations of the complexes (0.6-1.0%, wt) showed good viscoelasticity and gelation properties. The oil binding capacity increased from 75.86% to 98.04% as the concentration of oleogel increased from 0.2% to 0.4% (wt), and all the oleogels exhibited a strong gel network structure (G'>G"). Compared with the bulk oil, the oleogel had a stronger antioxidant capacity, and with increasing the concentration of the complexes, the antioxidant ability of the produced oleogel enhanced. This study may provide a theoretical basis for the preparation of protein-polysaccharide-polyphenol based oleogels and their application as solid fat substitutes in the food industry.