pectins

https://doi.org/10.1351/goldbook.P04467
Polyuronic acids mostly derived from d-galacturonic acid (abundant in some fruits).
See also:
uronic acids
Source:
PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1356 [Terms] [Paper]