Study On Determination Of Polyunsaturated Fatty Acids In Functional Food By Gas Chromatography Mass Spectrograph

With development of people's consciousness of health,healthy products graduate into one of the most important parts in our daily life.Fish oil and liver oil have occupied a majority of health market,because of its sky-high content of polyunsaterated fatty acid.Many companies are competing the market of milk powder for infant and young children,alleging their products' high content of DHA and EPA. In this condition,identification of healthy foods becomes a emergent problem.In this experiment,mothod of determination of the content of polyunsaterated fatty acids in milk powder and oil bought from market and the comparison of decrease of polyunsaterated fatty acids in different conditions were studied.Mothod of simultaneous determination of DHA,EPA,AA,α-linolenic acid,γ-linolenic acid and linoleic acid by gas chromatography-mass spectrometry(GC-MS) with internal standard.Based on the developed method,determination of DHA,EPA,AA,α-linolenic acid,γ-linolenic acid and linoleic acid in milk powder and oil was done.The results showed that more double-bonds the fatty acid had,faster the content of the fatty acid decreased,because of rupture and polymerization between double-bonds.Similarly, less double-bond the fatty acid had,more slowly the content decreased.In addition,comparison of content of DHA and EPA in 4 oil samples was studied after their three-month storage in condition of 4℃and room temperature without sunlight. The results showed that diffirence of change of content of polyunsaturated fatty acids in oil samples stored in the two conditions was not very obviously.Based on the results above,oil samples that were stored in condition of room temperature could remain the content of their functional components.Recovery of the six targets was all between 90～110%with RSD all under 2%. Method detection limit of six targets was between 2.4～4.8 mg/kg in milk powder and 0.9～2.4 mg/kg in oil.