Improving Foaming Properties of Yolk-Contaminated Egg Albumen by Basic Soy Protein

Mechanism of enhancing foaming properties of egg white by super critical carbon dioxide treatment

The effect of supercritical carbon dioxide (SCCD) treatment at varying processing time (30-90 min) on foaming and structure properties of egg white protein (EWP) were studied in this paper. The highest foaming ability (107.7%) was obtained after 60 min SCCD treatment, which was 3.6-fold to the control group. Foaming stability kept stable under the processing time of 75 min. Results of surface tension, surface hydrophobicity, rheological properties and particle size indicated that protein was easier to spread to the gas-liquid interface and generate molecular rearrangement. Circular dichroism (CD) and Endogenous fluorescence spectrum showed that there were slight changes on the secondary structure of EWP. The α-helical structure of the protein was destroyed and the particle size became uneven, which indicated that the protein structure became more flexible and loose. The results of this study indicate that SCCD treatment had a potential to be implemented to enhance foaming properties of EWP.

Using modified soy protein to enhance foaming of egg white protein

BACKGROUND

It is well known that the foaming properties of egg white protein are significantly reduced when a small amount of yolk is mixed in the white. To improve foaming properties of yolk-contaminated egg white protein, soy protein isolate (SPI) and egg proteins were modified to make basic proteins, and effects of these modified proteins on egg white foaming were evaluated in a model and an angel cake system.

RESULTS

SPI and egg yolk proteins were modified to have an isoelectric point of 10, and sonication was used to increase protein dispersibility after the ethyl esterification reaction. However, only the addition of sonicated and modified SPI (SMSPI) showed improvement of foaming in the 5% egg protein model system with 0.4% yolk addition. SMSPI was then used in making angel food cake to examine whether the cake performance reduction due to yolk contamination of the white would be restored by such alkaline protein. Cake performance was improved when cream of tartar was used together with SMSPI.

CONCLUSION

Basic soy protein can be made and used to improve egg white foaming properties and cake performance.