Which substance is a type of polysaccharide found in brown algae that serves as a thickener in food products?

Alginate is a type of polysaccharide derived from the cell walls of brown algae, such as kelp. It is composed of two types of monomer units: mannuronic acid and guluronic acid. In the food industry, alginate is widely used as a thickening agent, emulsifier, and stabilizer due to its ability to form gels in the presence of calcium ions. This property makes it particularly valuable in various food applications, including sauces, dressings, and dairy products, where viscosity and texture enhancement are desired.

The effectiveness of alginate as a thickening agent stems from its unique molecular structure, which allows it to interact with water and form viscous solutions or gels under certain conditions. This behavior is especially useful in creating products with desirable mouthfeel and consistency.