Starch is a complex carbohydrate that provides a ready source of energy and is commonly used as a thickener in foods. Here are some of the functional properties of starch:

• Swelling power: Starch granules have the ability to absorb water and swell, which is important for many food applications.

• Starch solubility: Starch is not soluble in cold water, but can be dissolved in hot water.

• Gelatinization: When starch is heated in water, it undergoes a process called gelatinization, which results in the swelling and thickening of the starch granules.

• Retrogradation: After gelatinization, starch can undergo retrogradation, which is the process of the re-association of the starch molecules. This can lead to the formation of a gel or a hard, gritty texture.

• Syneresis: Syneresis is the separation of liquid from a gel or a paste, which can occur when starch is heated and then cooled.

• Rheological behavior: Starch has unique rheological properties, which means it can change the flow and deformation of a food product.

Overall, the functional properties of starch are important for many food applications, including thickening, gelling, and modifying texture.