128/1 Procedure for the Determination of Starch after Enzymatic Decomposition

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Methods Type: Generic Methods
Key data
Number: 128/1
Analyte: Starch (Enzymatic Decomposition)
Matrix: Cereals, flour, semolinas, bran flakes, germs, gluten
Year of Approval: 1986
Year of Last Revision: 1998
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.

References

  • ICC Standard No. 101/1, Sampling of Grain
  • ICC Standard No. 110/1, Determination of the Moisture Content of Cereals and Cereal Products (Practical Method)
  • ICC Standard No. 120, Mechanical Sampling of Grain
  • ICC Standard No. 130, Sampling of Milling Products (semolina, flours, agglomerated flours and by-products)
  • ICC Standard No. 138, Mechanical Sampling of Milled Cereal Products

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