Overview
ISO 665:2020, "Oilseeds - Determination of moisture and volatile matter content," specifies a standardized laboratory method for measuring the moisture and volatile matter content of oilseeds. The method is a gravimetric drying procedure in which a test portion is dried at 103 °C ± 2 °C to constant mass and the loss in mass is reported as a percentage. This third edition (2020) updates references and replaces the 2000 edition with minor revisions.
Key topics and requirements
- Scope: Applicable to moisture/volatile-matter determination of oilseeds, either as received (including impurities) or on cleaned/pure seed.
- Principle: Gravimetric determination by oven drying at 103 °C ± 2 °C until practically constant mass.
- Apparatus:
- Analytical balance (readability 0.001 g)
- Mechanical mill or grater (for sample preparation without heating)
- Flat-bottomed metal or glass vessels with lids
- Thermostatically-controlled electric oven with good ventilation
- Desiccator with effective desiccant
- Sample preparation: Reduce laboratory sample per ISO 664; grind or grate depending on seed type (guidance provided for copra, medium and small seeds).
- Test portion and drying times:
- Typical test portion: ~5 g (5–10 g for certain whole seeds)
- Dry for 3 h (longer 12–16 h for cottonseed with adherent linters) then reweigh until mass change ≤ 0.005 g for a 5 g portion between successive weighings.
- Expression of results: Loss in mass expressed as % (mass fraction) of initial sample; arithmetic mean of two determinations (rules for repeats if results diverge).
- Precision:
- Repeatability limits (absolute): rapeseed 0.2%, soya beans 0.4%, sunflower seeds 0.2%
- Reproducibility limits (absolute): rapeseed 0.4%, soya beans 2.0%, sunflower seeds 0.4%
- Test report: Must identify sample, sampling method (if known), method reference (ISO 665), operating conditions, result (noting whether it is for product as received or pure seed), and date.
Applications and users
ISO 665:2020 is used by:
- Laboratory analysts and QA/QC teams in seed processing and edible oil production
- Seed traders and commodity inspectors for contract compliance and quality control
- Regulatory bodies and standards organizations monitoring food/feed safety and storage parameters
- Research institutions studying seed moisture, storage stability, and handling
Practical uses include moisture-based grading, drying/conditioning process control, storage risk assessment (mould/spoilage), and contract verification.
Related standards
- ISO 664 - Reduction of laboratory sample to test sample (referenced for sample preparation)
- ISO 21294 - Recommended sampling methods for oilseeds (sampling guidance referenced)
Keywords: ISO 665:2020, oilseeds, moisture determination, volatile matter, drying method, laboratory procedure, moisture content, oven drying, seed quality, ISO standard.
