Benedict's tests are chemical procedures used to test whether a solution contains reducing or non-reducing sugars. These tests are called Benedict's tests because they use Benedict's solution as the primary reagent for the chemical processes that produce the test results.
Reducing sugars are simple types of sugars, including monosaccharides and many disaccharides. These sugars contain aldehyde groups or form aldehyde groups through isomerization. These aldehyde groups produce special characteristics in these sugars, such as the Maillard reaction, which causes foods with simple sugars to brown when cooked.
When a Benedict's test for reducing sugar is used in a solution that contains a reducing sugar, the sugar interacts with copper in the Benedict's solution. This leads to oxidation and a precipitation of the oxidized copper in the solution. As the copper reacts with the solution, the solution changes color, providing evidence of the presence of a reducing sugar.
Other tests for reducing sugars are sometimes used, especially Fehling's test. However, Benedict's test is more sensitive to very low concentrations of reducing sugars, and it involves only a single solution; to conduct a Fehling's test, two separate solutions are needed, and these can only be combined at the time of the test.