Pectin

Vegetable gums are carbohydrates that consist of molecules in long chains, somewhat like starches. They can absorb a great deal of water, which makes them useful for thickening or gelling liquids.

Pectin is extracted from fruits and used to thicken or gel fruit preserves, jams, and jellies. It can also be used to make fruit glazes, because the pectin thickens or sets fruit juices and purées. An important advantage of pectin over an ingredient such as cornstarch is that it makes a clear, not cloudy, gel.