AOAC GFA Stakeholder Program Meeting Book (August 27, 2023)

ANNEX B ANNEX B

PREPARATION OF MATERIALS FOR GLUTEN METHOD VALIDATION As an example, a barley flour is tested and found to have a Dumas nitrogen level of 1.5%. This is multiplied by 5.83 to attain a crude protein level of 8.75%. Using the conversion factor for barley, the 8.75% crude protein is multiplied by 0.78 to obtain the gluten percent of 6.83%. This percent value is then multiplied by 10,000 to estimate the mg/kg (ppm) value at 68,300. This is equivalent to 68.3 mg of gluten per gram of flour. In the example provided to determine the gluten content in a barley flour, the conversion factor used 0.75 is not the conversion factor of the above list for barley (0.78). As a consequence the rest of calculations seem to be wrong.