Host: The Japan Society of Cookery Science
Name : 2022Annual Meeting of the Japan Society of Cookery Science
Location : [in Japanese]
Date : September 02, 2022 - September 03, 2022
Purpose
Egg whites are divided into two types: thick albumen and thin albumen. Compared to thin albumen, thick albumen contains more mucin’s content, and it is thought that the mucin forms a network that makes the egg white gelatinous, thus maintaining its high viscosity. In addition, there is much interest in the condition of concentrated egg white because its viscosity decreases as time passes after laying. However, there are few examples of studies on the properties of thick albumens, especially their effects on cooking. The purpose of this study was to compare aqueous egg white and thick albumen and to clarify the differences in their characteristics.
Material and Methods
Commercial eggs were cracked and the yolks and carruthers were removed using a separator. The egg whites were placed on a 20-mesh strainer, and the egg whites that passed through the strainer were considered thin albumens, and the egg whites remaining on the mesh were considered thick albumens. The structure of each egg white in its raw state was observed by scanning electron microscopy using a sample of each egg white fixed with glutaraldehyde and osmamic acid and dehydrated with ethanol. Dynamic viscoelasticity was measured for viscosity change, gel properties were measured for properties at break, and foaming height and stability were measured for foaming power.
Result
In structural observation, the thin albumens were structureless, whereas the thick albumens were observed to be layered. Next, in viscosity when the egg whites were heated, not much change was observed up to 60°C. However, there was a temperature at which viscosity increased rapidly. Thin albumens rose near 65°C, dropped once, and then rose again. When the egg whites were heated at 80°C to gelatinize firmly, there was little difference in rupture strength, but the compressive distance to rupture was greater for the thick albumens. The foaming power of the aqueous egg whites was higher than that of the thick albumens. When the foam was left to stand, the amount of water release was lower for the thick albumen.
