Egg Protein Denaturation

Sample

Egg white of a hen's egg

Conditions

Measuring cell: DSC20

Pan: Aluminum standard 40 µl, hermetically closed

Reference: Approximately the same amount of water

Sample preparation: Egg white was separated and stirred for 2 min. Content of dry substance: DS = 11.6%. Sample mass 32.9 mg

DSC measurement: Heating from 30 °C to 110 °C at 10 K/min

Interpretation

Heating up the egg white of a fresh hen’s egg shows two main endothermic peaks at 70 °C and at 87 °C (double peak). The first peak relates to the denaturation of the conalbumin fraction (13.8% of the total protein, heat of denaturation 19.8 J/g[1]), the second peak represents the denaturation of the ovalbumin fraction (65% of the total protein, heat of denaturation 28.9 J/g[1]). Since the lysozyme fraction (3.4% of the total protein [1]) denatures between the two main peaks, the first peak is not completely separated from the second peak.

Evaluation

Conclusion

The typical denaturation peaks can be used for identification purposes.

[1] Donovan, J.W. et al.: A differential scanning calorimetric study of the stability of egg white to heat denaturation, J.Sci. Fd. Agric. 26: 73, 1975

_{Egg Protein Denaturation | Thermal Analysis Application No. HB1004 | Application published in METTLER TOLEDO TA Application Handbook Food}