Complexation of nanofibrillated egg white protein and low methoxy pectin improves microstructure, stability, and rheology of oil-in-water emulsions

Structured emulsions (40-70% oil) were designed through complexation between nanofibrillated egg white protein (FEWP) and pectin and emulsion properties were then evaluated at different pHs and biopolymer concentrations. While native egg white protein (NEWP) and pectin formed insoluble complexes, TEM observation the FEWP and pectin complexes consisted of unpacked supramolecular network. The rheological properties of these protein-pectin complexes were significantly influenced by pH, protein-to-pectin ratio, and biopolymer concentration. While pectin addition had no significant influence on the rheological properties of emulsions made by NEWP at oil contents between 40 and 50%, pectin significantly improved the viscosity and elastic modulus of the emulsions prepared by FEWP. This effect was optimized at a protein-to-pectin ratio of 10:1 and pH 3.7. Furthermore, the elastic module was enhanced for the FEWP/pectin complex (FEWP/P) emulsions by increasing the total biopolymer concentration. The capability of FEWP-pectin complexes to make emulsions with enhanced elastic modulus and stability could be ascribed to the fibrillar structure of nanofibrils, enabling them to create a solid network at the continuous phase of the emulsions by complexation with pectin. This study demonstrates the potential of nanofibrillar EWP/pectin complexes for fabricating structured O/W emulsions at reduced fat content. This may contribute to formulations for healthier emulsion-based food products with an improved texture such as sauces, mayonnaises, dressings, and dips.