Pectin is a plant polysaccharide (more precisely: polyuronide), which primarily consists of a 1.4-glycosidically linked D-galacturonic unit. Nutritionally speaking, pectin is a dietary fiber for humans. However, many microorganisms are able to convert pectin.

In the industry, pectin is mainly used as a gelling agent. Pectin can be found in all higher terrestrial plants. It occurs in all the firmer components, for example in the stems, blossoms and leaves. It is found in the central lamellas and primary cell walls, where they have a strengthening and water-regulating function. The composition of pectin not only differs depending on the plant species, but also depends on the type and age of the plant tissue. Plant parts with relatively tough or hard components, e.g. citrus fruits or the infructescence (fruit head) of sunflowers are particularly rich in pectin. However, there are only small amounts of pectin in soft fruits such as strawberries.