{{Short description|Polysaccharide that is a sulfated galactan}} {{refimprove|date=October 2017}} {{Chembox <!-- Images --> | ImageFile = Agaropectin v2.svg | ImageSize = 250px | ImageCaption = Chemical structure of agaropectin, where R is a predominantly H or SO<sub>3</sub>H | ImageAlt = <!-- Names --> | IUPACName = | OtherNames = <!-- Sections --> | Section1 = {{Chembox Identifiers | CASNo = 9046-34-8 | PubChem = <!-- six hits for "Agaropectin", three solely that name, but none seem authoritative --> | SMILES = }} | Section2 = {{Chembox Properties | Formula = | MolarMass = | Appearance = | Density = | MeltingPt = | BoilingPt = | Solubility = }} | Section3 = {{Chembox Hazards | MainHazards = | FlashPt = | AutoignitionPt = }} }}
'''Agaropectin''' is one of the two main components of agar.
==Structure==
Agaropectin is a sulfated galactan mixture which composes agar by 30% composition.<ref>{{cite book |last1=Zeece |first1=Michael |title=Introduction to the Chemistry of Food |chapter=Food additives |date=2020 |pages=251–311 |doi=10.1016/B978-0-12-809434-1.00007-4 |isbn=978-0-12-809434-1 }}</ref> It is composed of varying percentages of organosulfates (sulfate esters), <small>D</small>-glucuronic acid and small amounts of pyruvic acid. It is made up of alternating units of <small>D</small>-galactose and <small>L</small>-galactose heavily modified with acidic side-groups which are usually sulfate, glucuronate, and pyruvate.<ref>{{cite web |access-date=2023-03-21 |url=https://water.lsbu.ac.uk/water/agar.html |title=Agar |archive-url=https://web.archive.org/web/20220926200632/https://water.lsbu.ac.uk/water/agar.html |archive-date=2022-09-26 |website=London South Bank University}}</ref><ref name=FAO3>{{cite book|chapter-url=http://www.fao.org/docrep/field/003/AB730E/AB730E03.htm |title=Training manual on Gracilaria culture and seaweed processing in China |chapter=III: Properties, Manufacture, and Application of Seaweed Polysaccharides – Agar, Carageenan, and Algin |publisher=Food and Agriculture Organization, United Nations|date=August 1990 |access-date=2011-04-27}}</ref><ref name=FAO1>{{cite book|chapter-url=http://www.fao.org/docrep/x5822e/x5822e03.htm |title=Production and Utilization of Products from Commercial Seaweeds|chapter=Chapter 1 – Production, Properties and Uses of Agar |author1=Rafael Armisen |author2=Fernando Galatas |publisher=Food and Agriculture Organization, United Nations |date=1987 |editor=McHugh DJ |isbn=92-5-102612-2}}</ref> Pyruvic acid is possibly attached in an acetal form to the <small>D</small>-galactose residues of the agarobiose skeleton. The sulfate content of the agar depends on the source of the raw material from which it is derived. Acetylation of agaropectin yields the chloroform-insoluble agaropectin acetate, as opposed to agarose acetate. This process can be used to separate the two polysaccharides via fractionation.<ref name="ThainHickman2001">{{cite book |last1=Thain |first1=Michael |last2=Hickman |first2=Michael |title=The Penguin Dictionary of Biology |date=2000 |publisher=Penguin Books |isbn=978-0-606-20848-2 }}{{pn|date=December 2025}}</ref>
==Use== Agaropectin has no commercial value and is discarded during the commercial processing of agar, and food grade agar is mainly composed of agarose with a molecular weight of about 120 kDa.<ref name="Nussinovitch2012">{{cite book |last1=Nussinovitch |first1=A. |title=Hydrocolloid Applications |chapter=Agar |date=1997 |pages=1–18 |doi=10.1007/978-1-4615-6385-3_1 |isbn=978-1-4613-7933-1 }}</ref>
==References== {{Reflist}}
Category:Polysaccharides Category:Organosulfates