Quantitative N-glycoproteomic analyses provide insights into the effects of thermal processes on egg white functional properties

• Pasteurization caused disintegration of natural protein aggregates in egg white. • P-EW has a smaller particle size and a “block-like structure” gel microstructure. • SD caused aggregation and a better EAI, FC, gel cohesiveness, but a weaker WHC. • N-glycoproteome profiles of SD-EW and F-EW was significantly different. • N-glycans of EW proteins were likely to be covalently cross-linked during SD. This study tries to elucidate the different mechanisms of functional properties among pasteurized egg white (P-EW), spray-dried egg white (SD-EW) and fresh egg white (F-EW) via quantitative N-glycoproteomic analyses. The results showed that spray-drying increased the surface hydrophobicity (181.4%) and zeta potential (25.6%) of egg white, which contributed to the enhancement of emulsifying activity index (20.1%) and foaming capacity (35.2%). Pasteurization caused the disintegration of natural protein aggregates in F-EW and resulted in a “block-like” P-EW gel and higher water holding capacity (6.2%). Spray-drying caused formation of thermal aggregates and led to a “mesh-like” SD-EW gel and better cohesiveness (3.6%). Quantitative N-glycoproteomic analysis showed that the abundance of 32 N-glycosites from 18 N-glycoproteins (such as Mucin 5B) of SD-EW was significantly reduced comparing to F-EW, indicated that the N-glycans of egg white protein are likely to be covalently cross-linked during spray-drying and are involved in thermal aggregation.