Alginic acid, also called algin, is a naturally occurring, edible polysaccharide found in brown algae. It is hydrophilic and forms a viscous gum when hydrated. With metals such as sodium and calcium, its salts are known as alginates. Its colour ranges from white to yellowish-brown. It is sold in filamentous, granular, or powdered forms.

Alginic acid

Names
Other names Alginic acid; E400; [D-ManA(β1→4)L-GulA(α1→4)]n
Identifiers
CAS Number	9005-32-7 Y
ChemSpider	None
ECHA InfoCard	100.029.697
EC Number	232-680-1
E number	E400 (thickeners, ...)
UNII	8C3Z4148WZ N
CompTox Dashboard (EPA)	DTXSID601010868
Properties
Chemical formula	(C6H8O6)n
Molar mass	10,000 – 600,000
Appearance	White to yellow, fibrous powder
Density	1.601 g/cm3
Acidity (pKa)	1.5–3.5
Pharmacology
ATC code	A02BX13 (WHO)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

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