Validation and Application of a Gas Chromatographic Method for the Determination of Fatty Acids and Sterols in the Total Diet

Fatty acids (FAs) and sterols represent the most important fraction of edible oils and fats, which play a significant role in human nutrition and health. A gas chromatographic method for the identification and quantification of FAs and sterols based on the extraction of lipids by accelerated solvent extraction (ASE), saponification of the obtained extract, and direct determination of the isolated FAs and sterols without derivatization, was developed and validated. The proposed method was accurate and precise (mean recovery in the range 80.8% to 98.2%, precision with RSD < 8.6%; LOQ < 0.86 mg/kg; measurement uncertainty < 14.8%). This method was applied for the determination of the most abundant FAs and sterols in the total diet. The obtained results showed that the most abundant FA in the total diet is monounsaturated C18:1 with 34.5% of the total FAs. The lowest presence was observed for the short chain FAs: C4:0 – C12:0 (6.4%). Cholesterol was found to be the most abundant sterol in the diet (57.5%). The total amount of the plant sterols in the diet was found to be 42.5%.