Proteomics revealed regulatory mechanisms of pickling alkalinity on yellow preserved egg white gel properties.

Background: Yellow preserved eggs (YPE) require precise pickling conditions to achieve their unique color and texture. The alkalinity of the pickling solution significantly affects the gel properties of the egg whites, but its underlying mechanism remains unclear. This study systematically investigated the effects of varying alkaline concentrations on the gel characteristics of yellow preserved egg whites (YPEW) through integrated proteomic and physicochemical characterization techniques.

Results: The results indicated that the textural properties of YPEW gels first increased and then decreased with increasing alkaline concentration, reaching their peak at 60 g kg^-1 sodium hydroxide (NaOH) (PEW-60). Both the PEW-60 group and PEW-45 (45 g kg^-1 NaOH) group exhibited larger particle sizes and higher absolute zeta potential than fresh egg white, with PEW-60 showing greater values than PEW-45. Fourier-transform infrared (FTIR) spectroscopy analysis indicated reduced proportions of α-helix and random coil structures, while β-sheet and β-turn conformations increased to 22.39% and 36.46%, respectively. The enhanced hydrophobic interactions and disulfide bond crosslinking collectively contributed to the formation of a reinforced gel network. Proteomic analysis identified 329 proteins, with 21 differentially expressed proteins between the group of PEW-45 and PEW-60, 17 showing decreased abundance and four exhibiting increased levels. Notably, the reduced abundance of key proteins including ovalbumin, lysozyme and ovomucin played a pivotal regulatory role in gel network formation.

Conclusion: These findings further revealed the mechanistic basis of alkaline concentration in governing gel quality through structural protein modification, intermolecular interaction regulation, and functional protein expression modulation, providing theoretical guidance for optimizing YPE processing technology. © 2025 Society of Chemical Industry.