161 Determination of the "Stirring Number" using the Newport Rapid Visco Analyser, as a measure of the degree of alpha-amylase activity in grain and flour

Methods Type: Generic Methods
Key data
Number: 161
Analyte: Alpha-Amylase (Newport Rapid Visco Analyser)
Matrix: Wheat and Rye Flours
Year of Approval: 1996
Scope: This standard specifies a method, using the Rapid Visco Analyser (RVA), developed and supplied by Newport Scientific, Warriewood, NSW Australia, for rapid determination of the pasting properties of starch, indicated by the viscosity of a flour-water suspension at high temperature and as influenced by the alpha-amylase activity present in flour. The method is applicable to wheat and rye flours. This method is also applicable to wheat and rye meals and grain, the latter after appropriate grinding. See 9.1. In this standard the word "flour" also means meals and ground grain (wholemeal).

References

  • ICC-Standard No. 101/1, Sampling of grains;
  • ICC-Standard No. 130, Sampling of milling products (semolina, flours, agglomerated flours, and by-products);
  • ICC-Standard No. 107/1, Determination of the "Falling Number" according to Hagberg-Perten as a measure of the degree of alpha-amylase activity in grain and flour;
  • ICC-Standard No. 110/1, Determination of moisture content of cereals and cereal products (practical method);
  • ISO 3696, Water for analytical laboratory use - specification and test methods.

Definition

The viscosity of the gelatinised starch undergoing liquefaction in the flour-water suspension, simultaneously heated to 95 °C in the Rapid Visco Analyser, is measured as the current necessary to rotate the stirrer at constant speed after three minutes of test (in the 180th second) and expressed in arbitrary units as "Stirring Number".

 

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