Abstract: In this study,the purified triacylglycerols(TAG) of some edible oils were subjected to stereospecific hydrolysis by an sn-1,3-specific lipase(pancreatic lipase) which cleaves selectively the sn-1 and sn-3 position ester bonds of TAG yielding to 2-monoglycerides(2-MAG) and free fatty acids(FFA).After lipase hydrolysis,the released free fatty acids and 2-MAG were isolated by thin-layer chromatography(TLC) and were converted to fatty acid methyl esters,and then analyzed by gas-liquid chromatography.The method was applied for stereospecific analyses of peanut,soyabean,maize,rapeseed and camellia oil.And the fatty acids in the TAG were also determined.Results showed that vegetable oils are made up of unsaturated fatty acids mainly accounting for 80%,and at the sn-2-position unsaturated fatty acids are the primary constituents,whose percentage is more than 90%.And saturated fatty acids mainly distribute at the position of sn-1,3.

Key words: fatty acids, pancreatic lipase, thin-layer chromatography, gas-liquid chromatography