Overview
EN ISO 11746:2022 (ISO 11746:2020) specifies a standardized laboratory method for determining the biometric characteristics of husked or milled rice kernels. Endorsed by CEN, this standard defines how to measure kernel length, width, thickness and the length/width ratio, and how to report results to ensure consistency and comparability across laboratories and industry users.
Key topics and technical requirements
- Scope: Measurement of biometric characteristics of individual rice kernels (husked or milled).
- Sample preparation: Reduce an aggregate sample using a sample divider to obtain a test sample of about 50 g; remove extraneous matter, immature, malformed or broken kernels.
- Measurement procedure:
- Randomly draw two sets of 100 kernels each from the test sample.
- Maintain each kernel in the correct orientation (see Annex A) and measure with a micrometer (or equivalent) readable to 0.01 mm without deforming the kernel.
- Record values to the nearest 0.01 mm.
- Quality check of random selection: Compare arithmetic means of the two 100-kernel sets using the specified formula; if the calculated percentage exceeds 2%, re-sample and repeat.
- Calculations and reporting:
- Report arithmetic means for length (l), width (b) and thickness (δ).
- Compute length/width ratio (l/b) using the averaged values.
- Report results to 0.01 mm.
- Precision data (from the interlaboratory study):
- Repeatability limits: r(l)=0.125 mm, r(b)=0.049 mm, r(δ)=0.040 mm.
- Reproducibility limits: R(l)=0.337 mm, R(b)=0.163 mm, R(δ)=0.092 mm.
- Annexes: Annex A-kernel measurement orientation; Annex B-interlaboratory precision results.
Practical applications and who uses it
- Rice breeders and geneticists - characterizing varietal kernel size and shape.
- Quality control laboratories in milling and processing - verifying product specifications.
- Grain traders and commodity analysts - classifying rice quality for grading and pricing.
- Regulatory bodies and standards organizations - harmonizing testing and labelling requirements.
- Research institutions studying rice morphology, processing behavior or consumer preferences.
Using EN ISO 11746:2022 ensures repeatable, comparable biometric data for decision-making in breeding, milling, trading and research.
Related standards
- ISO 24333 - Cereals and cereal products - Sampling (recommended sampling method).
- ISO 7301 - Rice - Specification.
- ISO 5725-1 - Accuracy (trueness and precision) of measurement methods and results.
Keywords: EN ISO 11746:2022, ISO 11746:2020, rice biometric characteristics, kernel length, kernel width, kernel thickness, length/width ratio, micrometer measurement, repeatability, reproducibility.