Flour protein is the total protein content of flour, measured by the Kjeldahl or Dumas method and reported as a percentage on a dry-matter basis, guiding selection for bread, pastry or biscuit applications.
In trade practice
Laboratories test each production lot using Kjeldahl or Dumas combustion analysis; results appear on the mill quality certificate alongside moisture and ash. Buyers specify a minimum protein level in the purchase contract and verify it against the certificate of analysis on arrival. A frequent dispute arises when protein is declared on an as-is rather than dry-matter basis, producing apparent discrepancies between supplier and receiver results. For wheat flour, protein level is cross-checked against wet gluten and falling number to confirm functional performance.
In a specification
A contract specification states the minimum flour protein percentage on a dry-matter basis, the analytical method to be used, and the tolerance permitted before a claim is raised.