Overview
ISO 12872:2022 - "Olive oils and olive-pomace oils - Determination of the 2‑glyceryl monopalmitate content" specifies an analytical procedure to determine the percentage mass fraction of 2‑glyceryl monopalmitate in olive oils and olive‑pomace oils that are liquid at ambient temperature (20 °C). The method is based on an International Olive Council (IOC) procedure and was revised to include solvent alternatives (e.g., iso‑octane) and updated precision data.
Key topics and technical requirements
- Scope and purpose: Quantifies 2‑glyceryl monopalmitate in the monoacylglycerol fraction to support quality assessment and classification of olive oils and pomace oils.
- Analytical principle: Partial hydrolysis with pancreatic lipase (specific for sn‑1 and sn‑3 positions) yields 2‑monoacylglycerols; after silylation, these are separated and quantified by capillary gas chromatography (GC).
- Sample preparation:
- Follow ISO 661 for test‑sample preparation.
- Oils with free acidity > 3 % require neutralization and washing steps to reduce acidity below 0.5 % before analysis.
- Recommended sampling reference: ISO 5555.
- Chromatography and instrumentation:
- Silica gel column chromatography or ready‑to‑use 500 mg SPE cartridges to isolate monoacylglycerols.
- GC with cold on‑column injector and flame ionization detector (FID).
- Fused silica capillary column (8–12 m; 0.25–0.32 mm i.d.; methylpolysiloxane or 5% phenyl methylpolysiloxane; film 0.10–0.30 µm).
- Carrier gas: hydrogen or helium; specified auxiliary gases for FID.
- Reagents: silica gel, n‑hexane (iso‑octane allowed as alternative), isopropanol, pancreatic lipase (activity 2–10 U/mg), silylation reagents (e.g., HMDS/TMCS/pyridine).
- Procedure highlights:
- Silica gel column or SPE for fraction isolation.
- Hydrolysis with pancreatic lipase.
- Preparation of silylated derivatives and GC analysis.
- Quality control and precision:
- Precision data and interlaboratory study results are provided (see Annex B).
- Annex C covers lipase preparation/activity guidance.
Practical applications and users
This standard is intended for:
- Food chemistry and analytical laboratories performing olive oil analysis and quality control.
- Regulatory and conformity assessment bodies checking composition for trade standards.
- Olive oil producers and certification schemes needing precise monoacylglycerol profiling.
- Research groups studying oil processing, adulteration, or classification (e.g., distinguishing lampante virgin vs. crude olive‑pomace oils).
Keywords: ISO 12872:2022, 2-glyceryl monopalmitate, olive oil analysis, olive-pomace oil, pancreatic lipase, gas chromatography, monoacylglycerol, SPE, silica gel chromatography.
Related standards
- ISO 661 - Preparation of test sample (referenced for sample prep)
- ISO 5555 - Recommended sampling methods (sampling guidance)
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