Egg white ovomucin (OVM) has properties highly similar to intestinal mucin and is considered to have a protective effect on probiotics, but this remains to be confirmed. This study evaluated the effect of OVM on the probiotic viability and functionality of Lactobacillus plantarum Lp90 and explored the mechanism by which OVM affects Lp90 using proteomics. The results indicated that OVM treatment showed no adverse effects on Lp90 viability, but concentration-dependently enhanced its self-aggregation ability, with the H-OVM group (10 mg/mL) reaching up to 39.6%. Quantitative proteomic analysis revealed that L-OVM (3 mg/mL) and H-OVM treatments resulted in the differential expression of only 79 (4.42%) and 173 (9.68%) proteins, respectively, indicating OVM exerted a weak overall effect on Lp90. Analysis of the differentially expressed proteins revealed that L-OVM enhanced the environmental adaptability of Lp90 by regulating cell wall synthesis and modification and promoting the expression of various nutrient transport systems. This study clarified that OVM is beneficial to the self-aggregation and environmental adaptability of Lp90, demonstrating that OVM has potential as a probiotic protectant.

The primary proteins in chicken egg white are glycoproteins, which generate substantial glycopeptides in the digestive tract following gastrointestinal digestion. The structures of the glycopeptides have yet to be identified and elucidated. In this study, chicken egg white was digested by trypsin, and N-glycopeptides were enriched from the hydrolysate by hydrophilic interaction chromatography and O-glycopeptides by Retain AX chromatography combined with AminoLink resin adsorption. The structures of these glycopeptides were analyzed by liquid chromatography-mass spectrometry (LC-MS), and their potential intestinal effects were explored by bioinformatics analysis. Mass spectrometry analysis identifeid 1720 N-glycopeptides from 49 N-glycoproteins and 565 O-glycopeptides from 29 O-glycoproteins. Glycopeptides derived from ovomucin were the most diverse, including 490 N-glycopeptides and 216 O-glycopeptides. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed that sialylated N-glycoproteins were mainly involved in interleukin-17 signaling pathway and ferroptosis, while sialylated O-glycoproteins were mainly involved in cholesterol metabolism, vitamin digestion and absorption, the hypoxia-inducible factor-1 signaling pathway and the renin-angiotensin system. This study provides crucial structural information for further research on the potential effects of egg white glycopeptides on the intestinal tract.