Comprehensive identification and hydrophobic analysis of key proteins affecting foam capacity and stability during the evolution of egg white foam

Each protein in a multiprotein system assumed a different role at the colloidal interface. To determine exactly which proteins played a key role in the evolution of egg white foam, label-free quantitative proteomics tech-niques were employed to detect key proteins associated with egg white foam properties. There were 35 (14 up -regulated and 21 down-regulated) and 25 (13 up-regulated and 12 down-regulated) key proteins related to egg white foam capacity and stability, respectively. The hydrophobicity prediction results revealed that the hydro-phobicity of the amino acid sites, the grand average of hydropathicity (GRAVY) of the whole molecule and the spatial arrangement of the hydrophobic domain all influenced the air-water interface properties of these key proteins. Among the high abundance proteins in egg white, ovalbumin was identified as a key protein associated with superior foam capacity, and ovostatin, although a trace protein, could not be ignored for the role it assumed in foam formation. Meanwhile, ovomucoid and lysozyme could result in excellent foam stability. This study was integral to the ensuing discussion of the air-water interface behavior of single or multiple key protein systems.