The Gluten Index method

Overview

Wet Gluten is prepared from whole meal or flour by the Glutomatic® 2200 gluten washer. Gluten Index Centrifuge 2015 is used to force the wet gluten through a specially designed sieve cassette. The relative amount of gluten passing through the sieve indicates the gluten characteristics.The wet gluten is further dried in the Glutork 2020 for dry gluten content and water binding in the wet gluten calculation.

 

The steps in detail

The steps are illustrated in the picture above. Click the picture to enlarge it.

  1. Weighing
    10.0 g ± 0.01 g of whole meal or flour is weighed and put into the Glutomatic® wash chamber with an 88 micron polyester sieve. When vital wheat gluten is measured, 1.5 ± 0.01 g is weighed.
  2. Dispensing
    4.8 ml of salt solution is added to the meal or flour samples. No salt solution is added to vital wheat gluten samples.
  3. Mixing
    Meal or flour and the salt solution are mixed to form a dough during 20 seconds.
  4. Washing
    After termination of the mixing phase, the washing automatically starts and continues for five minutes. For wheat meal the sample is transferred to a chamber equipped with a coarse 840 micron sieve allowing bran particules to be washed out.
  5. Centrifuging
    Exactly 30 seconds after completed washing, the undivided wet gluten piece is transferred to the special sieve cassette and centrifuged one minute at 6000 ± 5 rpm in Centrifuge 2015.
  6. Weighing
    The fraction passed through the sieves is scraped off with a spatula and weighed. The fraction remaining on the inside of the sieve is collected and added to the balance. The total wet gluten weight is obtained.
  7. Drying
    The total wet gluten piece is dried at min. 150°C during four minutes in the Glutork 2020. After drying the gluten is weighed on the balance.
  8. Calculation
    The amount of gluten remaining on the centrifuge sieve in relation to total wet gluten weight is the Gluten Index.