Protein denaturation is defined as the destruction of its spatial structures while retaining the primary structure. Globular proteins, such as egg white and soybean protein, are able to form gels upon heating (Doi, 1993). For a coagulum to form it is important that the functional groups (e.g. hydrophobic groups) within the protein are exposed. This makes it easier for the groups to interact and form a three dimensional network. Coagulum formation is complicated, and affected by the concentration of protein, amount of water, ionic strength, time and temperature as well as pH and interaction with other components in the food system (Raikos et al., 2007). The process for gelation in short, is: The heat will make the native protein to denature, and during the denaturation disulfide bonds will be formed and hydrophobic amino acid residues are exposed (Shimada and Matsushita, 1980). After denaturation and further heating, the proteins will aggregate and interact with other proteins and form a coagulum. The type that is formed depends on conditions like molecular weight, heating time and protein concentration (Raikos et al., 2007; Shimada and Matsushita, 1980). The gel structure is a more structured network compared to the coagulum that is a disorganized aggregation (Raikos et al., 2007).
In this experiment, an egg white solution with distilled water in the ratio of 1:3 was prepared. There is no observable change in egg white solution when distilled water is added to it. As