Scope: The method can be used for all products containing starch (e.g. cereals, flour, semolinas, bran flakes, germs, gluten, etc.), but not if the sample contains glycogen. According to the method described below, the starch content is that portion of the sample that can be determined as glucose after enzymatic decomposition with amyloglucosidase, the sample being previously extracted, where necessary, with 40% ethanol.
Principle: The starch contained in the sample is dispersed with water. The dispersion is autoclaved. Subsequently the starch is hydrolysed with amyloglucosidase and the glucose formed is determined photometrically with glucose oxidase and peroxidase in the presence of ABTS (( 2,2' -azino-bis-(3-ethyl benzthiazoline)-6-sulphonate)) as chromogenic reagent. The colour intensities measured are proportional to the amount of glucose. If the sample contains glucose and oligosaccharides, these have to be extracted beforehand with a mixture of ethanol and water.