Overview
ISO 15788-2:2003 specifies a rapid screening method for the determination of stigmastadienes (and other steradienes) in vegetable oils using high-performance liquid chromatography (HPLC). Steradienes form by dehydration of sterols during refining steps such as bleaching, steam washing and deodorization. This HPLC method is intended primarily as a fast screening technique to detect the presence of refined vegetable oils in virgin oils (for example, virgin olive oil). ISO 15788-1 (GC method) remains the reference method for definitive analysis.
Key topics and technical requirements
- Scope: Quantification of stigmastadienes/steradienes in edible fats and vegetable oils as an indicator of refining.
- Sample preparation:
- Initial cleanup on a silica-gel column to separate non-polar steradienes (elution with petroleum ether).
- Concentration of eluate and reconstitution in acetonitrile/tert‑butyl methyl ether (50:50).
- Options for external or internal standard quantification using Δ3,5‑cholestadiene.
- HPLC conditions (validated conditions provided in the standard):
- Stationary phase: RP‑18 (reverse phase), 5 µm, 250 mm × 4.0–4.6 mm column.
- Mobile phase: acetonitrile/tert‑butyl methyl ether, 70:30 (v/v), degassed.
- Flow rate: 1.0 ml/min; injection volume: 20–100 µl (depending on expected level).
- Detection: UV at 235 nm.
- Identification: Peak assignment by relative retention times against cholestadiene (RRTs provided for stigmastadiene, campestadiene, stigmastatriene).
- Quantification: External or internal standard methods with prepared stock and working solutions; cholestane used to check standard purity.
- Precision and limitations: Standard is suitable as a rapid screening tool; samples close to regulatory limits should be confirmed by the reference GC method (ISO 15788‑1).
Applications and users
- Food quality laboratories performing routine screening of edible oils.
- Olive oil producers and inspectors verifying authenticity of virgin olive oil and detecting adulteration with refined oils.
- Regulatory agencies enforcing labeling and compositional standards.
- Industrial quality control in edible oil refining to monitor steradiene formation during processing (bleaching, deodorization).
Related standards
- ISO 15788-1 - Reference method: capillary-column gas chromatography (GC) for stigmastadienes.
- ISO 12228 - Determination of sterols by gas chromatography.
- ISO 3696 - Water for analytical use (reagents).
- ISO 5555 - Recommended sampling methods for oils (sampling guidance).
Keywords: ISO 15788-2, stigmastadienes, HPLC, vegetable oils, refined oil detection, virgin olive oil screening, steradienes, ISO standard.
Open preview (PDF)Animal and vegetable fats and oils — Determination of stigmastadienes in vegetable oils — Part 2: Method using high-performance liquid chromatography (HPLC)