Flavor and Structural Regulation of Fermented Egg White: The Improving Effect of Delactosed Whey Permeate on Metabolic Behavior.

Fermented egg white is often hindered by inherent nutritional limitations, leading to poor fermentation kinetics, undesirable textures, and unbalanced flavors-related chemical profiles (such as the accumulation of harsh aldehydes). To address these challenges, this study investigated the modulatory effect of milk-derived components on the structural regulation and metabolic behavior of fermented egg white. Biophysical and rheological analyses revealed that specifically delactosed whey permeate (DLP) restructured the protein network, inducing the formation of a finely dispersed weak gel characterized by smaller particle sizes, elevated surface hydrophobicity, and pronounced shear-thinning behavior. Chemical profiling demonstrated that DLP effectively modified the flavor potential and volatile composition: It maximized the proportion of umami-associated amino acids and key dairy volatiles (e.g., diacetyl) while eliminating aldehydes associated with off-flavors. Furthermore, untargeted metabolomics provided insights into the biochemical shifts associated with these modifications. DLP was associated with the modulation of metabolic pathways by significantly enriching central carbon metabolism and amino acid biosynthesis, potentially contributing to an abundant supply of flavor precursors. Concurrently, DLP reduced the accumulation of hydrophobic peptides typically associated with bitterness (e.g., leucyl-leucine) and downregulated undesirable secondary metabolic pathways, such as alkaloid biosynthesis. Ultimately, this study shows that DLP from milk synergistically modulates the texture and flavor potential of fermented egg white by restructuring its protein network and influencing metabolic pathways to promote the accumulation of desirable aroma precursors while reducing compounds linked to off-flavors, providing a novel strategy for protein matrix engineering.