Final answer:
A gelling agent is a material that thickens a liquid and provides stability by forming a gel. Examples of gelling agents include starch, agar, pectin, and gelatin.
Step-by-step explanation:
A gelling agent, also known as a thickening agent, is a material that thickens a liquid and provides stability. It forms a gel, which is a colloidal dispersion of a liquid phase throughout a solid phase. The interstices of the solid phase are filled with the liquid medium or a dilute solution of the dispersing medium. Examples of gelling agents include starch, agar, pectin, and gelatin.