Overview
EN ISO 6886:2016 - Animal and vegetable fats and oils: Determination of oxidative stability (accelerated oxidation test) specifies an accelerated laboratory method to measure the oxidative stability (induction period) of virgin and refined animal and vegetable fats and oils. The test exposes samples to high temperature and high air flow to induce rapid oxidation and records the time until volatile acidic oxidation products cause a rapid rise in water conductivity. The method is intended for comparing antioxidant efficacy and product quality; it is not a measure of stability at ambient temperatures. Milk fats and milk-derived products are excluded.
Key topics and technical requirements
- Principle: Heated sample is aerated; oxidation volatiles are swept into demineralized water and detected by a conductivity electrode. The end of the induction period is when conductivity rises sharply.
- Temperature: Typical test temperatures are 100 °C to 120 °C. Optimal induction period is 6–24 hours. A 10 °C change roughly halves or doubles the induction period.
- Air flow: Air flow is typically 10 L/h, with a maximum permitted deviation of ±1.0 L/h (or equivalent pressure for specific instruments).
- Apparatus: Commercial instruments (e.g., Rancimat or equivalent) include:
- Air filter with molecular sieve (beads ≈1 mm, pore size 0.3 nm; dried at 150 °C)
- Gas diaphragm pump and flow controller
- Aeration vessels and sealed measurement cells
- Conductivity electrodes (measuring range ~0–300 µS/cm)
- Heating block (up to 150 °C ±0.1 °C) and temperature control
- Reagents & sample prep: Use analytical-grade reagents and demineralized/distilled water. ISO 661 is referenced for test-sample preparation.
- Limitations: Presence of volatile fatty acids or volatile acidic oxidation products can interfere and prevent accurate measurement.
Applications
- Comparing antioxidant efficacy in edible oils, frying fats, and oleochemical products
- Quality control in edible oil refining and storage studies
- Product development and shelf-life screening under accelerated conditions
- Research on oxidative behavior of new oil blends, seed oils, and animal fats
Who uses this standard
- Food and oil industry QC laboratories
- R&D teams in edible oils, margarine, and fat-based ingredient manufacturers
- Certification and regulatory laboratories performing method validation or comparative testing
- Instrument manufacturers and service providers supplying Rancimat/OSI-type equipment
Related standards
- ISO 661 - Preparation of test sample (normative reference for sample preparation)
- ISO/TC 34 (Food products) provides the technical committee context for fats and oils methods
Keywords: EN ISO 6886:2016, oxidative stability, accelerated oxidation test, fats and oils, Rancimat, induction period, conductivity, antioxidants, animal and vegetable fats and oils.