Editing Disaccharide (section)

==Classification==
There are two functionally different classes of disaccharides: 
*'''Reducing disaccharides''', in which one monosaccharide, the [[reducing sugar]] of the pair, still has a free [[hemiacetal]] unit that can perform as a reducing [[aldehyde]] group; [[lactose]], [[maltose]] and [[cellobiose]] are examples of reducing disaccharides, each with one hemiacetal unit, the other occupied by the [[glycosidic bond]], which prevents it from acting as a [[reducing agent]]. They can easily be detected by the Woehlk test or Fearon's test on [[methylamine]].<ref>{{Cite journal|title=How to visualize the different lactose content of dairy products by Fearon's test and Woehlk test in classroom experiments and a new approach to the mechanisms and formulae of the mysterious red dyes|journal = [[Chemistry Teacher International]]|language=en|doi = 10.1515/cti-2019-0008|year = 2019|last1 = Ruppersberg|first1 = Klaus|last2 = Herzog|first2 = Stefanie|last3 = Kussler|first3 = Manfred W.|last4 = Parchmann|first4 = Ilka| volume=2 | issue=2 |doi-access = free}}</ref>
*'''Non-reducing disaccharides''', in which the component monosaccharides bond through an [[acetal]] linkage between their [[anomer]]ic centers. This results in neither monosaccharide being left with a hemiacetal unit that is free to act as a reducing agent. [[Sucrose]] and [[trehalose]] are examples of non-reducing disaccharides because their glycosidic bond is between their respective hemiacetal carbon atoms. The reduced chemical reactivity of the non-reducing sugars, in comparison to reducing sugars, may be an advantage where stability in storage is important.<ref>{{cite web |title=Nomenclature of Carbohydrates (Recommendations 1996): 2-Carb-36 |url=http://www.chem.qmul.ac.uk/iupac/2carb/36.html |url-status=dead |archive-url=https://web.archive.org/web/20170826141346/http://www.chem.qmul.ac.uk/iupac/2carb/36.html |archive-date=2017-08-26 |access-date=2010-07-21 |website=chem.qmul.ac.uk}}</ref><ref>{{cite web |title=Disaccharides and Oligosaccharides |url=http://faculty.virginia.edu/mcgarveylab/Carbsyn/Carblist/html/disacch.html |access-date=2008-01-29 |website=University of Virginia Faculty and Lab Site |archive-date=2018-11-18 |archive-url=https://web.archive.org/web/20181118183515/http://faculty.virginia.edu/mcgarveylab/Carbsyn/Carblist/html/disacch.html |url-status=dead }}</ref>