Overview
EN ISO 21415-3:2007 (ISO 21415-3:2006) specifies a laboratory method for determining dry gluten content by drying a ball of wet gluten in an oven. Adopted by CEN as EN ISO 21415-3:2007, this standard is part of the ISO 21415 series on wheat and wheat flour - gluten content and is intended for routine quality control and testing in cereal and flour laboratories. The method can also be used to determine the moisture content of wet gluten.
Key topics and requirements
- Scope: Converts wet gluten (obtained according to ISO 21415-1 or ISO 21415-2) to dry gluten by oven drying and expresses results as percent of the original sample.
- Apparatus: Typical lab equipment including scalpel/knife, metal or glass plate (5 cm × 5 cm), oven controllable at 130 °C ± 2 °C, desiccator with desiccant, and a balance accurate to 0.01 g.
- Procedure essentials:
- Weigh plate and wet gluten (to 0.01 g).
- Dry in oven at 130 °C: initial 2 h, make several deep incisions, then continue for another 4 h (total 6 h).
- Cool in a desiccator, reweigh and calculate dry gluten and water content.
- Calculations: Dry gluten content is reported as a mass fraction (%) of the original flour/sample. The method also includes formulae to correct results on a dry-matter basis and to calculate water content of the wet gluten.
- Precision:
- Repeatability: typical limit r ≈ 0.6 g/100 g (two single tests in same lab).
- Reproducibility: R ≈ 3.1 g/100 g (starting from manual wet gluten) or R ≈ 2.3 g/100 g (starting from mechanical wet gluten).
- Precision results are supported by an interlaboratory study cited in the standard.
Applications and users
- Who uses it: cereal and flour testing laboratories, milling and baking industry QC teams, ingredient suppliers, research labs, regulatory and conformity assessment bodies.
- Practical uses:
- Quantifying gluten for product specification, quality grading and process control.
- Supporting labeling and regulatory compliance where gluten content or gluten-related moisture data are required.
- Correlating wet-gluten measurements (from ISO 21415-1/2) with dry gluten for formulation and ingredient management.
- Determining moisture content of wet gluten as part of ingredient quality checks.
Related standards
- ISO 21415-1 - Determination of wet gluten by a manual method
- ISO 21415-2 - Determination of wet gluten by mechanical means
- ISO 21415-4 - Rapid drying method for dry gluten determination
- ISO 712 - Determination of moisture in cereal products (referenced for dry-matter correction)
- ISO 5725 - Precision of measurement methods (interlaboratory/statistics)
Keywords: EN ISO 21415-3:2007, ISO 21415-3:2006, dry gluten, wet gluten, oven drying method, wheat, wheat flour, gluten content, moisture content, CEN, laboratory method.
