Agar: Difference between revisions

'''Agar''' ({{IPAc-en|ˈ|eɪ|ɡ|ɑːr}} or {{IPAc-en|ˈ|ɑː|g|ər}}), or '''agar-agar''', is a [[gelling agent|jelly-like substance]] consisting of [[polysaccharides]] obtained from the cell walls of some species of [[red algae]], primarily from "ogonori" (''[[Gracilaria]]'') and "tengusa" ([[Gelidiaceae]]).<ref>{{cite web|last1=Shimamura |first1=Natsu |title=Agar |url=http://www.tokyofoundation.org/en/topics/japanese-traditional-foods/vol.-4-agar |website=The Tokyo Foundation |access-date=19 December 2016 |date=August 4, 2010}}</ref><ref>{{cite book|title=Oxford Dictionary of English |edition=2nd |year=2005 |title-link=Oxford Dictionary of English}}</ref> As found in nature, agar is a mixture of two components, the linear [[polysaccharide]] [[agarose]] and a heterogeneous mixture of smaller molecules called [[agaropectin]].<ref name="Williams2000">{{cite book |last1=Williams |first1=Peter W. |last2=Phillips |first2=Glyn O. |title=Handbook of hydrocolloids |chapter-url=https://books.google.com/books?id=dXS7qnh-ZOEC&pg=PA28 |chapter=Chapter 2: Agar |publisher=Woodhead |location=Cambridge |year=2000 |page= 91 |isbn=1-85573-501-6 |quote= Agar is made from seaweed and it is attracted to bacteria.}}</ref> It forms the supporting structure in the cell walls of certain species of algae and is released on boiling. These algae are known as [[agarophyte]]s, belonging to the [[Rhodophyta]] (red algae) phylum.<ref>{{cite book|last1=Balfour |first1= Edward Green |author-link = Edward Balfour |chapter= agar |title = Cyclopædia of India and of eastern and southern Asia, commercial, industrial and scientific: products of the mineral, vegetable and animal kingdoms, useful arts and manufactures |chapter-url = https://archive.org/details/cyclopdiaindiaa00unkngoog/page/n63 |year = 1871| publisher = Scottish and Adelphi Presses |page = 50}}</ref><ref name="oxford">{{cite book|last1= Davidson |first1= Alan |title = The Oxford Companion to Food |url = https://books.google.com/books?id=JTr-ouCbL2AC |date = 2006 |publisher = Oxford University Press |isbn = 978-0-19-280681-9 }}</ref> The processing of food-grade agar removes the agaropectin, and the commercial product is essentially pure agarose.