2.8.2. Determination of fatty acid profiles
Fatty acid profiles were determined by Gas Chromatography,
using a 6890 Hewlett Packard Gas Chromatograph with flame ionisation
detector, equipped with a SPB™ PUFA fused silica capillary
column, 30 m 0.25 mm inner diameter, 0.20 lm film thickness
S. Karnjanapratum et al. / Food Chemistry 141 (2013) 4138–4145 4139
(Supelco Inc., Bellefonte, PA, USA). Prior to analysis, fatty acid
methyl esters (FAMEs) were prepared according to the method of
AOAC (2000). Briefly, the extracted lipid (25 mg) was heated at
100 C for 30 min in the presence of 0.5 N NaOH and 14% boron tri-
fluoride in methanol. After heating, the mixture was allowed to
separate into layers. The upper layer containing FAMEs was collected
and used for analysis. The analytical conditions were
250 C injection port temperature and 270 C detector temperature.
The oven was programmed from 170 to 225 C at a rate of
1 C/min (no initial or final hold). Retention times of FAME standard
were used to identify chromatographic peak of the samples.
Fatty acid content was calculated, based on the peak area ratio
and expressed as % of total fatty acids .