Overview
EN ISO 6885:2016 (ISO 6885:2016) specifies a standardized chemical method for the determination of the anisidine value in animal and vegetable fats and oils. The anisidine value quantifies aldehydes (principally α,β‑unsaturated aldehydes) formed during lipid oxidation and is reported as 100 times the increase in absorbance at 350 nm (10 mm cell) for a defined test solution. Milk and milk products (and fats from milk) are explicitly excluded from the scope.
Key topics and technical requirements
- Principle: Reaction of the oil/fat test solution in isooctane with p‑anisidine (in glacial acetic acid) and measurement of the increase in absorbance at 350 nm.
- Reagents & safety: Use analytical‑grade reagents; p‑anisidine is toxic and must be handled with appropriate precautions and stored refrigerated in the dark. Isooctane with low UV absorbance is required.
- Apparatus: Single‑ or double‑beam spectrometer capable of 350 nm measurements using 10 mm cells; matched cells recommended for double‑beam.
- Sample preparation: Follow ISO 661 for preparation of test sample; dry samples >0.10% moisture with anhydrous sodium sulfate. Typical test portions range 0.4 g to 4.0 g in a 25 ml volumetric flask.
- Procedure controls: Reaction times and temperatures are specified (reaction ~10 min at (23 ± 3) °C); blank and unreacted controls are required. The anisidine value calculation and expression are standardized.
- Precision and validation: The standard includes repeatability/reproducibility data from interlaboratory testing and reporting requirements.
- Normative references: ISO 661, ISO 3696 and (sampling guidance) ISO 5555 are referenced.
Applications and users
- Quality control in edible oil, fat and oilseed processing: monitor secondary oxidation products and rancidity.
- Shelf‑life and storage testing: assess accumulation of aldehydes during storage or processing.
- Regulatory and compliance testing: standardized reporting for trade and certification in the food industry.
- Research and formulation: evaluate antioxidant performance, refining processes, and product stability.
- Typical users: food testing laboratories, oil refiners, edible oil manufacturers, certification bodies, and academic researchers.
Related standards
- ISO 661 - Preparation of test sample (fats & oils)
- ISO 3696 - Water for analytical laboratory use
- ISO 5555 - Sampling of animal and vegetable fats and oils (recommended)
- Supersedes: EN ISO 6885:2007 (updated technically in 2016)
This standard is essential for consistent, comparable measurement of aldehyde content in fats and oils and is frequently referenced in oil quality assessment, rancidity monitoring and product specification testing.