Background: One of the useful factors in research and application in food industry is the functional properties of proteins, as egg protein contains a variety of functional properties that can be improved using multiple modification methods, including ultrasonic modification and phenolic compounds known for their antioxidant effect, giving flavor to the product, and their chemical interaction with proteins. Therefore, this study investigated the synergistic effect of polyphenols and ultrasonic on functional properties and structural composition of egg white proteins.
Methods: The synergistic effect of ultrasound for 5 minutes and phenols provided from aqueous plant extract of black seed (Nigella sativa) at 0.1% (T1) and 0.2% (T2) concentrations and cardamom (Elettaria cardamomumate) at 0.2% (T3) and 0.4% (T4) concentrations, as well as a control treatment (T5) was evaluated on egg white proteins. The chemical contents of egg whites were estimated, and the functional properties (solubility, foaming, emulsification and water binding) of the modified proteins were studied. For structural changes resulting from the modification, they were assessed by Fourier Transforms Infrared Spectrometer (FTIR), Fluorescence Measurement techniques and Scanning Electron Microscopy (SEM).
Results: A significant difference was noticed between the treatments (p≤0.05) revealing an improved functional properties. The treatment illustrated the highest digestibility in T4, while the digestibility decreased in T1 and the lowest digestibility in T5.
Conclusion: Ultrasonic treatment for 5 minutes and the phenolic compounds of the black seed at 0.2% showed the best results in improving functional properties, digestibility, and change in the secondary structure of egg white protein. The α-helix content decreased and the β-turn increased when treated with phenolic compounds at different concentrations when compared to the control group.