Ultrasound-assisted covalent cross-linking of egg white protein with ferulic acid: Structure, foaming, and application in chiffon cake

Egg white protein is one of the most important functional proteins in daily life; however, owing to its slow foaming, small volume and easy instability, EWP foam has limited application in the food industry, and its foaming performance needs to be further improved. However, its foaming performance still needs further improvement due to its instability mechanism. In this study, egg white protein and ferulic acid were combined via ultrasound-assisted covalent cross-linking methods, and their structure, foaming performance, and application were studied. The results showed that the composite prepared via ultrasound-assisted covalent cross-linking methods presented an increased foaming capacity of 94 % and foaming stability of 81.6 %. The Fourier transform infrared (FTIR) spectroscopy and circular dichroism (CD) spectroscopy results revealed that the secondary structure of the composite changed with increasing α-helices and β-folds and the transformation of the β-turn angle and random coil. In particular, cakes prepared with FA–EWP covalent complexes have uniform and dense bubble pore sizes. Hence, this study provides new strategic information for ultrasound-assisted covalent crosslinking of polyphenols to improve the foaming performance of egg white protein.