2.3.4. Determination of fatty acid composition of oils
The fatty acid composition of the RBO before and after heating and frying was analysed as their methyl esters by using Gas Chromatograph (AOCS, 2002) (model GC-15A, Shimadzu Corporation, Kyoto, Japan) equipped with flame ionization detector (FID) and a data processor (model CR-4A). The GC was fitted with a stainless steel column (3 m length × 0.5 mm i.d.) packed with 15% diethylene glycol succinate (DEGS) supported on 60–80 mesh Chromosorb WAW. The operating conditions were: column temperature 180 °C, injector temperature 220 °C, detector temperature 230 °C, with a nitrogen flow of 40 ml/min; hydrogen flow 40 ml/min, air flow 300 ml/min. The major fatty acids were identified by comparison to the retention times of standard fatty acid methyl esters.