Abstract: Fatty acids in pomegranate seed oil were methyl esterified,identified by GC-MS,and five fatty acids in the oil were quantitatively determined by GC.The effects of methyl esterification methods,esterification agents,and extraction times on the assay were examined.The results showed that when 0.5 mol/L sodium hydroxide methanol solution was chosen as a methyl esterifying agent and the reaction was maintained at 70 ℃ for 5 min,followed by the addition of internal standard of n-capric acid methyl ester,fatty acid methyl esters were recovered completely by being extracted with n-hexane for three times.The method was accurate with good repeatability.The fatty acid contents in pomegranate seed oils from five manufactures were determined by this approach.Cluster analysis of the manufactures was conducted based on the fatty acid concentrations.It divided the manufactures into two groups,including high and low content of punicic acid,respectively.The study indicated that fatty acids in plant oils can be accurately measured if internal standard was introduced before methyl ester extraction,along with three repeated extraction.

Key words: pomegranate seed oil, fatty acid, methyl esterification, GC, determination