Overview
EN ISO 21415-1:2007 (identical to ISO 21415-1:2006) defines a manual washing‑out method for determining the wet gluten content of wheat and wheat flour (Triticum aestivum L. and Triticum durum Desf.). The method is directly applicable to wheat flour and can be applied to semolina and ground wheat provided the particle size distribution meets the specification given in the standard (Annex B). This European Standard was adopted by CEN and is part of the ISO 21415 series on gluten content.
Key topics and technical requirements
- Principle: Prepare a dough from a measured test portion and 20 g/L sodium chloride solution; allow the dough to rest so gluten structure develops; separate wet gluten by manual washing and remove excess solution; weigh the wet gluten residue.
- Test portion & dosing: Typical test portion ~24 g; add ~12 ml sodium chloride solution dropwise; dough preparation should not exceed 3 minutes.
- Resting time: Dough is covered and left to rest for 30 minutes to allow gluten development (important for reproducible results).
- Washing procedure: Manual hand‑washing over a gauze frame using NaCl solution; specified flow rate example: 750 ml per 8 min during washing (standard details methods for starch detection using Lugol’s reagent).
- Reagents & apparatus: Uses analytical reagents (20 g/L NaCl, Lugol’s iodine solution) and typical lab apparatus (mortar/vessel, burette, balance to 0.01 g, gluten press, gauze, small‑scale mill for sample preparation).
- Precision and reporting: Standard includes sections on repeatability, reproducibility, sampling, calculation and test reporting. The report should note the technique used (manual washing vs mechanical), since methods may yield different values.
- Scope limits: Applicable to flour directly; semolina and ground wheat only if particle size distribution meets Table B.1.
Applications
- Routine gluten content testing in flour mills, quality control laboratories, cereal research institutes and food testing labs.
- Compliance testing for product labeling, baking performance assessment, and raw material specification (wheat, semolina, re‑ground samples).
- Comparative evaluation against mechanical methods (ISO 21415‑2) and conversion to dry gluten results (ISO 21415‑3/4).
Who should use it
- Quality assurance scientists in milling and baking industries
- Analytical chemists and food laboratories performing gluten tests
- Standards and regulatory bodies assessing cereal product specifications
Related standards
- ISO 21415 series (Part 2: mechanical method; Parts 3–4: dry gluten determination)
- ISO 712 (moisture content of cereals and cereal products)
- ISO 6644 / ISO 13690 (recommended sampling methods)
Keywords: EN ISO 21415-1:2007, ISO 21415-1:2006, wet gluten, wheat flour, gluten content determination, manual washing method, semolina testing, ground wheat.
