Galactan (galactosan) is a polysaccharide consisting of polymerized galactose.
[1] In general, galactans in natural sources contain a core of galactose units connected by α(1→3) or α(1→6), with structures containing other monosaccharides as side-chains.
[3] Halymenia durvillei is a red seaweed (algae) that produces a sulfated galactan.
[6] Galactan is found in the side chains of rhamnogalacturonan I (RG-I) and is needed for gel formation in the cell walls of organisms.
[7] It was observed there was less of the gelling characteristic (as well as the polymeric chains being more likely to degrade) when fewer galactans were present in the polymeric side chains.