Final answer:
Egg yolk would not make a stable foam with a high volume because it contains fats and emulsifiers that are less effective at stabilizing foam compared to the proteins present in egg whites, gelatin, and heavy whipping cream.
Step-by-step explanation:
The ingredient that would not make a stable foam with a high volume is egg yolk. Foams are generally created by incorporating air into a system that can trap the air, which is typically done by proteins that can unfold and create a network to trap the air, such as the protein albumin found in egg whites. Egg whites can be whipped into a stable, high-volume foam. This process is known as denaturation, where protein molecules unfold and form a structure that can trap air bubbles, creating a stable foam in the process. Similarly, gelatin can also trap water and air, forming a gel-like structure that can support a foam. Heavy whipping cream contains proteins and fat, which helps stabilize the air bubbles when whipped, creating a foam. On the other hand, egg yolk contains fats and emulsifiers which are not as effective at stabilizing foam as the proteins found in egg whites.
From a chemical perspective, an egg is a heterogeneous mixture with diverse components in both the yolk and the white. The major protein in egg white, albumin, creates a stable foam when agitated as the protein network traps air. In contrast, egg yolk's composition is better suited to act as an emulsifying agent, interacting with both polar and nonpolar substances, but it does not form a high-volume foam when whipped.