Effect of ultrasound-irradiation combined pretreatment on the foamability of liquid egg white

Simple Method to Assess Foam Structure and Stability using Hydrophobin and BSA as Model Systems

The properties and arrangement of surface-active molecules at air-water interfaces influence foam stability and bubble shape. Such multiscale-relationships necessitate a well-conducted analysis of mesoscopic foam properties. We introduce a novel automated and precise method to characterize bubble growth, size distribution and shape based on image analysis and using the machine learning algorithm Cellpose. Studying the temporal evolution of bubble size and shape facilitates conclusions on foam stability. The addition of two sets of masks, for tiny bubbles and large bubbles, provides for a high precision of analysis. A python script for analysis of the evolution of bubble diameter, circularity and dispersity is provided in the Supporting Information. Using foams stabilized by bovine serum albumin (BSA), hydrophobin (HP), and blends thereof, we show how this technique can be used to precisely characterize foam structures. Foams stabilized by HP show a significantly increased foam stability and rounder bubble shape than BSA-stabilized foams. These differences are induced by the different molecular structure of the two proteins. Our study shows that the proposed method provides an efficient way to analyze relevant foam properties in detail and at low cost, with higher precision than conventional methods of image analysis.

Effect of electron beam irradiation on the structural characteristics and functional properties of goat's milk casein

The effects of electron beam irradiation (EBI) at different doses (0, 2, 4, 6, 8, and 10 kGy) were investigated on the structural and functional properties of casein, including their interrelationship. A gradual reduction in the α-helix content of the secondary structure (as a stable structure) indicates that casein under EBI treatment mainly undergoes fragmentation and aggregation from a structural perspective. Furthermore, the hydrophobic group and tryptophan in the tertiary structure were exposed, which opened up the internal structure of the protein. In addition, a continuously increasing irradiation dose led to casein aggregation, as confirmed by electron microscopy. The structural changes affected its functional properties, such as solubility, emulsification, foaming, and rheological properties, all of which increased first and subsequently decreased. Finally, at irradiation doses of 4-6 kGy, casein was modified to exhibit optimal functional properties, which enhanced its food processing value and performance.

Inhibition of water-diluted precipitate formation from egg whites by ultrasonic pretreatment: Insights from quantitative proteomics analysis

The formation of the egg white precipitate (EWP) during dilution poses challenges in food processing. In this paper, the effects of 90 W and 360 W ultrasonic intensities on the inhibition of EWP formation were investigated. The findings revealed that 360 W sonication effectively disrupted protein aggregates, decreasing the dry matter of EWP by 5.24 %, particle size by 57.86 %, and viscosity by 82.28 %. Furthermore, the ultrasonic pretreatment unfolded protein structures and increased the content of β-sheet structures. Combined with quantitative proteomics and intermolecular forces analysis, the mechanism by which ultrasonic pretreatment inhibited water-diluted EWP formation by altering protein interactions was proposed: ultrasonic pretreatment disrupted electrostatic interactions centered on lysozyme, as well as hydrogen-bonding interactions between ovomucin and water. In conclusion, our research provides valuable insights into the application of ultrasonic pretreatment as a means to control and improve the quality of egg white-based products.

Quantitative proteomic analysis of chicken egg white and its components

The protein profiles and properties of chicken egg white and its three components (thick egg white, TKEW; thin egg white, TNEW; and chalaza, CLZ) were comprehensively compared. The proteomes of TNEW and TKEW are relatively similar, but the abundance of mucin-5B and mucin-6 (the two subunits of ovomucin) is significantly higher in TKEW than in TNEW (42.97% and 870.04%, respectively), while the lysozymes in TKEW are 32.57% higher (p < 0.05) than those in TNEW. Meanwhile, the properties (including the spectroscopy, viscosity, and turbidity) of TKEW and TNEW are significantly different. Comprehensively, it is speculated that the electrostatic interactions between lysozyme and ovomucin are the main reason for the high viscosity and turbidity of TKEW. Compared with egg white sample (EW), CLZ has a higher abundance of insoluble proteins (mucin-5B, 4.23-fold; mucin-6, 6.89-fold) and a lower abundance of soluble proteins (ovalbumin-related protein X, 89.35% lower than EW; ovalbumin-related protein Y, 78.51% lower; ovoinhibitor, 62.08% lower; riboflavin-binding protein, 93.67% lower). These compositional differences should explain the insolubility of CLZ. These findings are important references for deepening the research and development of egg white in the future, such as the thinning of egg white, the molecular basis of changes in egg white properties, and the differential application of TKEW and TNEW.