Dextrose equivalent (DE) is a measure of the amount of reducing sugars present in a sugar product, expressed as a percentage on a dry basis relative to dextrose.
The dextrose equivalent gives an indication of the average degree of polymerisation (DP) for starch sugars.
In all glucose polymers, from the native starch to glucose syrup, the molecular chain ends with a reducing sugar, containing a free aldehyde in its linear form.
As the starch is hydrolysed, the molecules become shorter and more reducing sugars are present.
The standard method of determining the dextrose equivalent is the Lane-Eynon titration, based on the reduction of copper(II) sulfate in an alkaline tartrate solution,[1] an application of Fehling's test.