The fatty acids profile of oils, fats and lipids extracted from
foods were determined by capillary gas chromatography as fatty
acid methyl esters (FAMEs) according the IUPAC method 2.301
(IUPAC, 1987). The principle of IUPAC method is based on the preparation
of FAMEs by transesterification with methanolic potassium
hydroxide. The FAMEs were automatically injected (Agilent technologies
7683B series Injector) into a capillary gas chromatography
instrument (Agilent technologies 7890A) fitted with a CP-Sil88
fused capillary column (100 m long, ID 0.25 mm, thickness
0.25 lm) and flame ionisation detector (GC/FID). Oxygen-free
nitrogen gas used as mobile phase at a flow rate of 1 mL/min. Oven
temperature was programmed as following: the column held
initially at 60 C for 5 min after injection increased to 165 C with
15 C/min heating holding for 1 min and increased to 225 C with
2 C/min heating holding for 17 min; injector temperature,
260 C; detector (FID) temperature, 300 C; split ratio, 30:1;
injected volume, 1 lL. The determination of fatty acids profiles
were carried out using Supelco 37 FAMEs reference standard mixture
(Sigma–Aldrich, Buchs, Switzerland). The quantification of
fatty acids profiles were carried out using methyl tridecanoate as
internal standard (Dieffenbacher & Dysseler, 1997). The GC/FID
method shows repeatability and reproducibility at 95% of confidence
interval of 0.1 g FFAs/100 g of fat and 0.2 g FFAs/100 g of
fat, respectively.