What is the difference between a reducing sugar and a non-reducing sugar?

Question

Paisley Boney · Accepted Answer

Reducing Sugars are those which are easily oxidized by mild oxidizing agent like ferric Fe^(2+) or cupric Cu^(2+) ions

Basically, the reduding effect is due to the free anomeric carbon in sugar. Glucose, maltose, and other sugars capable of reducing ferric and cupric ions are reducing sugars, and this is the basis of Fehling's reaction. The sugar's carbonyl carbon is oxidized to a carboxylic group.

Zoe Alexander · Answer

A reducing sugar, as the name suggests is any sugar that is capable of acting as a reducing agent because it has a free aldehyde group or a free ketone group.

Any carbohydrate that can be oxidized and cause the reduction of other substances without first needing to be hydrolyzed is referred to as a reducing sugar. Reducing sugars also oxidize themselves, converting their carbonyl carbon to a carboxyl group. The cyclic hemiacetal forms of aldoses can open to reveal an aldehyde, and certain ketoses can undergo tautomerization to become aldoses; however, acetals, including those found in polysaccharide linkages, cannot easily become free aldehydes. The aldehyde functional group allows the sugar to act as a reducing agent, for example in the Tollens' test or Benedict's test. Sugars that reduce include glucose, fructose, lactose, and so on. Sugars that do not reduce include sucrose.

Madison Anderson · Answer

undefined Reducing sugars can donate electrons to other molecules, while non-reducing sugars cannot. This ability is due to the presence of a free aldehyde or ketone group in reducing sugars, which can undergo oxidation reactions. Non-reducing sugars lack such functional groups and therefore cannot undergo oxidation reactions.