Validation of a Simple, Colorimetric, Microplate Assay using Amplex Red for the Determination of Glucose and Sucrose in Potato Tubers and other Vegetables

Accurate quantification of tuber glucose and sucrose content is important for scientific as well as commercial purposes. High pressure liquid chromatography and enzyme coupled assays are accepted methods for determining sugar concentrations. A method is presented here for a reliable, cost-effective, 96-well microplate enzymatic assay that allows one to determine quickly sugar concentrations in tuber samples and in other vegetables. Sample size can be less than 1 g of fresh material. This colorometric assay utilizes coupled reactions of glucose oxidase and peroxidase to accurately measure glucose concentrations. Sucrose content is determined by using invertase in an additional enzyme mediated step. Data from this improved enzymatic assay compare favorably with other methods, with the added benefits of lower capital outlay and fast sample turn around times.