Which of the following is an example of an emulsifier used in food products?

Lecithin, found in egg yolks, is well known for its ability to act as an emulsifier in food products. Emulsifiers are substances that help to stabilize mixtures of water and fats by reducing surface tension, allowing them to blend together smoothly. Lecithin contains phospholipids, which have both hydrophilic (water-attracting) and hydrophobic (water-repelling) properties, making it particularly effective in creating stable emulsions. This quality makes lecithin a common ingredient in products like mayonnaise, dressings, and chocolates, where it helps to maintain a consistent texture and appearance.

Other options, such as water, butter, and gelatin, do not function as effective emulsifiers in the same way that lecithin does. Water, while necessary in many food formulations, does not have emulsifying properties. Butter contains both fat and water, but it does not serve as an emulsifier on its own. Gelatin, though useful as a gelling agent, does not have the dual affinity for water and fat that characterizes emulsifiers, making lecithin the right choice in this context.