Unveiling the binding mechanism between egg white proteins and wheat glutens during the dough mixing process

Abstract

Hen egg white is mainly composed of ovalbumin (OVA), ovomucoid (OVO), and lysozyme (Lys), all of which impact the gluten network in wheat products. This research explored the effects of these proteins on the gluten network from both structural and molecular interaction perspectives. The addition of OVA, OVO and Lys did not enhance the network structure of gliadin groups (Gli), while Lys promoted a denser and more uniform network structure for glutenin groups (Glu). A higher Lys ratio led to a transition of Glu from β-sheet to α-helix, accompanied by an increase in disulfide bonds, which rose from 52.07 to 82.43 μmol/g, especially in the high molecular weight glutenin subunit (HMW). Such transition then caused a denser sponge-like network along with a higher molecular chain height maximum (8.5 nm) of HMW, likely driven by the stronger molecular affinity between Lys and HMW. The HMW-Lys complex exhibits the higher binding energy and unbinding force than that LMW-Lys group due to the contributions of hydrogen bonds and van der Waals forces, hence providing fundamental support for the gluten development. These findings clarify the contribution of egg white proteins in the dough formation process and may guide future improvements in dough quality.