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 (https://doi.org/10.1351/pac199567081307)