Db 23 capillary column

An automated Soxhlet apparatus (Soctec Avanti 2055, Foss, Sweden) was used to extract the fat from MNM as described by the Association of Official Analytical Chemists (AOAC, 2006 , method number 920.39). The methyl ethers were analyzed using gas chromatography as described by Christopherson and Glass, (1969) . Briefly, the fat extracts were trans-methylated with 2 M methanol-sodium hydroxide. Heptane was used to extract the fatty acid methyl esters which were then filtered and dried under nitrogen. The fatty acids were separated by a temperature gradient over 45 min on gas chromatography with nitrogen as carrier gas on a DB-23 capillary column (90  cm  ×  250 μm   ×   0.25 μm) (Supelco, Sigma-Aldrich). The chromatograph consisted of an HP6890 gas chromatograph (Hewlett Packard, Bristol, United Kingdom) with a flame ionization detector (FID). Both the detector and injector temperatures were set at 300 °C. A PC equipped with Chemstation software was used for quantification. Nonadecanoic acid (C19:0) was used as an internal standard.

The Soxhlet Apparatus was used to extract the oil from the breast muscle sample as described by the Association of Analytical Chemists (AOAC, 2006 ; method number: 920.39). The fatty acid profiles of the oil extracted from the meat were determined as described by Christopherson & Glass, (1969) . Briefly, the oil extracts were trans-methylated with 2 mol/L methanol sodium hydroxide. The resulting fatty acid methyl esters were extracted in heptane, filtered (Nylon syringe filters, pore size: 0.45 µm, diameter: 13 mm with a glass fibre prefilter, Membrane Solutions) and dried under nitrogen after which they were separated by a temperature gradient over 45 min on a gas chromatograph with nitrogen as carrier gas on a DB-23 capillary column (90  cm  ×  250 μm  ×  0.25 μm; Supelco, Sigma-Aldrich). The gas chromatograph consisted of an HP6890 GC (Hewlett Packard, Bristol, UK) with a flame ionisation detector. Both the detector and injector temperatures were set at 300 °C. A personal computer equipped with Chemstation software (Agilent Technologies Inc., Santa Clara, CA, USA) was used for quantification. Nonadecanoic acid (C19:0) was used as an internal standard.