Comparative N-Glycoproteomic Analysis of Transparent and Opaque Pigeon Egg Albumen

Albumen transparency is an important quality trait of pigeon eggs that directly influences consumer preference and market value; however, its molecular basis remains unclear. This study aimed to characterize the key molecular differences between transparent and opaque pigeon egg albumen from an N-glycoproteomic perspective and to explore their associations with macroscopic textural properties. Transparent and opaque pigeon eggs were selected, and N-glycoproteomic analysis combined with texture profile analysis was conducted to compare glycosylation modifications and textural characteristics between the two groups. The results showed that transparent pigeon egg albumen exhibited significantly lower hardness, fracturability, gumminess, and chewiness than opaque albumen. Comparative glycoproteomic analysis revealed that the abundance of 122 glycopeptides was significantly lower in the transparent group, primarily originating from ovalbumin-related proteins and transferrin. Functional enrichment and protein-protein interaction analyses indicated that these proteins are closely associated with the extracellular space and serine-type endopeptidase inhibitor activity, and form a functional interaction module dominated by ovalbumin family proteins and transferrin. Overall, reduced N-glycosylation of key egg white proteins may influence protein aggregation behavior and gel network formation during heating, thereby contributing to differences in albumen textural properties and transparency. These findings provide glycoproteomic insights into the molecular mechanisms underlying transparency differences in pigeon egg albumen and identify specific glycosylation-related targets that may be exploited to modulate gel properties during thermal processing. This knowledge may support precision quality control of pigeon eggs and facilitate the development of transparent protein-based foods and functional gel products in the food industry.