Editing Reducing sugar (section)

===Aldoses and ketoses===
[[Monosaccharide]]s which contain an aldehyde group are known as [[aldoses]], and those with a ketone group are known as [[ketoses]]. The aldehyde can be oxidized via a [[redox reaction]] in which another compound is reduced. Thus, aldoses are reducing sugars. Sugars with [[ketone]] groups in their open chain form are capable of isomerizing via a series of [[tautomerism|tautomeric]] shifts to produce an aldehyde group in solution. Therefore, ketones like [[fructose]] are considered reducing sugars but it is the isomer containing an aldehyde group which is reducing since ketones cannot be oxidized without decomposition of the sugar. This type of isomerization is catalyzed by the base present in solutions which test for the presence of reducing sugars.<ref name=Campbell/>