What is the process of adding an ingredient that allows two immiscible liquids to mix?

Emulsification is the process of adding an ingredient known as an emulsifier, which enables two immiscible liquids, such as oil and water, to blend together more seamlessly. Emulsifiers contain both hydrophilic (water-attracting) and hydrophobic (water-repelling) properties, allowing them to reduce the surface tension between the liquids, thus stabilizing the mixture. This process is essential in a variety of culinary applications, such as making mayonnaise or salad dressings, where a stable blend of oil and water is desired.

In contrast, other options provided refer to different processes. Colouring is the addition of pigments or dyes to enhance the appearance of food without impacting the mixing of liquids. Coagulation involves the transformation of a liquid into a solid or semi-solid state, often seen in protein-rich foods like eggs or cheese, and does not relate to the mixing of immiscible liquids. Bulking refers to increasing the volume of food without significantly increasing calories, which does not involve the interaction between two immiscible liquids.