Overview
ISO 23065:2009 (IDF 211:2009) defines a standardized laboratory method for the determination of omega‑3 (ω−3) and omega‑6 (ω−6) fatty acid content in anhydrous milk fat extracted from dairy products that are supplemented or naturally enriched. The method uses preparation of fatty acid methyl esters (FAMEs) and separation/quantification by gas‑liquid chromatography (GLC / GC) with an internal standard. Key analytes include linoleic acid (LA), α‑linolenic acid (α‑LNA), EPA, DPA and DHA.
Key Topics
- Scope and purpose: Quantitative determination of the most important ω−3 and ω−6 fatty acids in milk fat from enriched dairy products.
- Principle: Addition of an internal standard (C23:0), transesterification of lipids to FAMEs, and separation by capillary GC with flame ionization detection (FID).
- Reagents and standards: n‑hexane, high‑purity FAME standards (C23:0 internal standard, EPA, DHA, LA and others), and calibrated standard solutions.
- Apparatus: Analytical balance, volumetric glassware, GC with capillary column and FID, high‑purity carrier gas (helium or hydrogen), split or on‑column injection and computerized integration.
- Chromatographic considerations: Recommended capillary columns (polyethylene glycol or cyanosilicone phases), example conditions provided for helium isothermal or hydrogen temperature‑programmed runs to ensure separation (e.g., separation of C18:4ω−3 from conjugated linoleic acid and DPA from DHA).
- Procedure overview: Extraction of anhydrous milk fat (ISO 14156/IDF 172), methylation (ISO 15884/IDF 182), calibration with EPA/DHA/LA and internal standard, qualitative and quantitative GC analysis, and calculation of mass fraction expressed in mg per 100 g fat.
- Precision and reporting: Includes sections on repeatability, reproducibility and required content for the test report.
Applications and Users
- Who uses it: Dairy laboratories, food testing laboratories, quality control teams in dairy and infant formula manufacturing, regulatory agencies and certification bodies assessing nutritional labeling claims for omega‑3/omega‑6 content.
- Practical uses: Verifying enrichment claims, product development (fortified milks, yogurts, spreads), compliance testing for nutrition labeling, and research on fatty acid profiles in dairy products.
Related Standards
- ISO 14156 / IDF 172 - Lipid extraction from milk and milk products
- ISO 15884 / IDF 182 - Preparation of fatty acid methyl esters (FAMEs)
- ISO 707 / IDF 50 - Recommended sampling of milk (sampling is not part of ISO 23065)
Keywords: ISO 23065:2009, milk fat, omega‑3, omega‑6, gas‑liquid chromatography, FAME, EPA, DHA, linoleic acid, anhydrous milk fat, dairy analysis.
Open preview (PDF)Milk fat from enriched dairy products — Determination of omega-3 and omega-6 fatty acid content by gas-liquid chromatography