Overview
ISO 6885:2016 - Animal and vegetable fats and oils - Determination of anisidine value - specifies a standardized photometric method to quantify the anisidine value (AV) of animal and vegetable fats and oils. The anisidine value measures the amount of aldehydes (principally α,β‑unsaturated aldehydes) formed during oxidation and is used alongside peroxide value (PV) to assess oil deterioration. Milk and milk‑derived fats are explicitly excluded.
Key topics and technical requirements
- Test principle: Reaction of a fat/oil solution (in isooctane) with p‑anisidine in glacial acetic acid and measurement of the increase in absorbance at 350 nm in a 10 mm cell.
- Reagents & safety: Use analytical‑grade reagents and water per ISO 3696. p‑Anisidine is toxic - store cold, protect from light, and prepare fresh anisidine reagent on the day of use.
- Sample preparation: Prepare samples according to ISO 661; dry if moisture > 0.10% using anhydrous sodium sulfate. Typical test portion is 0.4–4.0 g dissolved to 25 ml (Q = 0.01 g/ml).
- Procedure essentials: Measure three absorbances - unreacted test solution, reacted test solution, and blank (anisidine + isooctane). Ensure reacted absorbance falls in 0.20–0.80; blank absorbance must not exceed 0.20.
- Calculation & reporting: AV is calculated from the increase in absorbance (350 nm), corrected for dilution and sample mass; report to 1 decimal place. The standard also references the totox value (TV = 2×PV + AV) for combined oxidation assessment.
- Precision: Repeatability and reproducibility limits are provided (see Table 1, ISO 6885:2016), and interlaboratory test results are summarized (Annex A).
Applications and users
ISO 6885:2016 is primarily used by:
- Food and edible‑oil testing laboratories performing quality control and shelf‑life studies.
- Edible oil processors, refiners, and packers monitoring oxidative deterioration.
- Regulatory bodies and standards organizations assessing compliance and safety.
- Research institutions studying fatty‑acid oxidation, rancidity, and formulation stability.
Practical uses include routine quality checks, incoming raw material inspection, finished product release, and comparative studies of antioxidant effectiveness.
Related standards
- ISO 661 - Preparation of test sample for animal and vegetable fats and oils
- ISO 3696 - Water for analytical laboratory use
- ISO 5555 - Recommended sampling methods (referred)
- ISO 5725‑2 - Accuracy (used for interlaboratory precision analysis)
Keywords: ISO 6885:2016, anisidine value, animal and vegetable fats and oils, p‑anisidine, anisidine reagent, oxidation testing, peroxide value, totox value, oil quality control, spectrometric measurement.