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Abstract The foaming characteristics (foam ability, foam stability and foam microstructure) of fresh foams based on egg white protein, and with the addition of different proportions of egg yolk and yolk fractions (plasma and granules) were analyzed in this research. The relationships between foaming properties and addition of yolk fractions were carried out via surface tension, surface hydrophobicity, apparent viscosity and zeta potential. The results showed that charge properties of yolk fraction dispersions were considered to have positive correlations with their foam stability to egg white. The foam abilities might possibly be determined by their particular structure and interactions with egg white protein. Besides, their interactions could also be represented by surface tension and surface hydrophobicity. Therefore, this study provides a new insight for determining the relationship between foaming properties of egg white contaminated by proportions of egg yolk fractions and the physicochemical properties of egg white/yolk or yolk fractions dispersions. Graphical abstract Image 1 Highlights • Foaming properties of egg white-yolk/fractions were studied. • Components and Structures in yolk/fractions influenced foaming characterization. • Surface indexes dominated foam properties of egg white-yolk/fractions dispersions. • Surface charge resulted in high foam stability of egg white/granules bubbles. [ABSTRACT FROM AUTHOR]

Abstract Egg gel is the combined gelation of egg white (EW) and egg yolk (EY); its properties depend on the fixed ratio of EW and EY in shell egg. This study investigated the gelation properties of egg mixtures in artificial blends to explore innovative egg solutions catering to the market demands and provide guidance for the production of creative egg products. Results showed that solubility of samples decreased with the increase of EY proportion while solid content increased. More surface hydrophobicity and total SH group increases were observed with higher EY proportion. Rheological tests suggested that adding EY decreased samples' initial G' values. Egg gel containing 20% EY presented the largest hardness value, which seems to be related to the fine gel network microstructure. Besides, the springiness and water-holding capacity of gels gradually increased with EY addition, which may be the result of dense microstructure and high solid content of EY. Highlights • Gelling properties of egg white and yolk were dependent on the proteins. • Water-holding capacity of egg gels was closely related to gels' microstructure. • Yolk filled the cavities existing in egg white gels, making microstructure denser. [ABSTRACT FROM AUTHOR]

The effects of NaCl addition on the gelling and water holding properties of egg white/yolk gels were studied via solubility, surface hydrophobicity, reduced sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), Fourier transform infrared spectra (FTIR), textural analysis, low-field nuclear magnetic resonance (LF-NMR) and centrifugation. Results showed that more solubility and surface hydrophobicity increase of egg yolk dispersions were observed than that of egg white dispersions. SDS-PAGE results indicated that the different change trend of surface hydrophobicity between two egg proteins was closely related with the dissociation of egg yolk granule proteins. NaCl-induced protein heat denaturation will result in the decrease of ordered secondary structure (α-helix and β-sheet) by breaking hydrogen bond for both egg protein gels. A rapid decrease ( p < 0.05) in fracture strength/strain of egg white gels was found as the NaCl increased, while the fracture strength/strain of egg yolk gels first rose and then descended, indicating that the significant increases of solubility and hydrophobicity of egg yolk dispersions at a certain NaCl concentration (≤1.8%) were benefit to the formation of strong molecule interaction among gel network. Results from LF-NMR and centrifugation water holding capacity (WHC) tests revealed that NaCl addition affected the WHC of egg white gels by increasing the mobility and distribution of free water, and had a complex influence on proton mobility and relaxation peak changeability of egg yolk gels due to the interaction among lipid, protein and water. [ABSTRACT FROM AUTHOR]