Pectin is an extremely complex and structurally diverse galacturonan with a molecular weight of up to 130 000 g/mol.
The molecule's backbone consists of a linear chain of
alpha-(1-4)-linked galacturonic acid units, which are partially interrupted by (1-2)-linked L-rhamnose units, where side branches with neutral sugars branch off. The occurrence and distribution of the L-rhamnose, as well as the composition of the side branches, is dependent on the fruit or vegetable variety. This explains why pectin from different sources can have quite different properties. Xylose, arabinose, and galactose are the most frequent examples of neutral sugars, which can be found at about 10 to 15% in our pectin types.