I need a method on how I can hydrolyze the dextrin and measure the total glucose content as well as the method to measure the glucose content in those mixture.
If the mixture contains only glucose and starch dextrin, then you can first measure glucose content by the Glucose Oxidase method or the Hexokinase method (kits are available from Megazyme). You can then measure the total carbohydrate content using the phenol-sulfuric acid method, and calculate dextrin content by difference.
You can convert the dextrin (a form of starch) to glucose using amylase and determine the glucose content by titrating with Fehlings A and B. Use the AOAC tables to convert mL titrant to mass of glucose.