Sains Malaysiana 43(12)(2014): 1937–1942

Quantitative Gas Chromatographic Method for the Analysis of cis and trans

Fatty Acid in Margarines

(Kaedah Kuantitatif Gas Kromatograpi untuk Analisis Asid Lemak cis dan trans

dalam Sampel Margarin)

JUMAT SALIMON*, TALAL AHMED & NADIA SALIH

School of Chemical Sciences & Food Technology, Faculty of Science and Technology

Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia

Received: 11 January 2013/Accepted: 17 April 2014

ABSTRACT

Fats and oils in human diets are the main sources of essential fatty acids for the body. However, there is a mounting concern about the intake of foods containing trans fatty acids (TFAs) due to their deleterious effects on human. Thus, the accurate detection of fatty acids (FAs) and TFAs is needed to control and correct nutrition labeling in dietary fat samples. Accordingly, a method for the identification and quantification of FAs and TFAs in food fats by gas chromatography (GC) based on the extraction of lipids and derivatization using base catalyzed followed by trimethylsilyl-diazomethane (TMS-DM) was developed. The proposed method was evaluated to standard mixture of oleic acid (OA) (C18:1cis 9) and Elaidic acid (EA) (C18:1 trans 9) and its application to three samples of commercial margarines was demonstrated. Based on the results obtained, recovery values (R) from all the samples were close to 100%. Repeatability (RSD) values ranged between 0.78 and 2.47%, while Reproducibility (RSD) values ranged between 1.14 and 3.65%. Consequently, the proposed method is sensitive, accurate and suitable for FAs and TFAs analysis of food fats and oils and can be applied to nutritional, medicine and food studies.

Keywords: Derivatization; food fats; quantitative analyses; trans fatty acids

ABSTRAK

Minyak dan lemak dalam pemakanan harian merupakan sumber utama asid lemak yang diperlukan dalam tubuh manusia. Namun begitu, kesedaran yang tinggi terhadap pengambilan makanan yang mengandungi asid lemak trans (TFAs) wujud disebabkan oleh kesan buruk terhadap manusia. Oleh itu, kaedah penentuan secara tepat kandungan asid lemak (FAs) dan TFAs amat diperlukan bagi tujuan pengawalan dan perlabelan kandungan nutrien dalam sampel makanan berlemak. Suatu kaedah pengenalpastian dan penentu ukuran kandungan FAs and TFAs dalam sampel makanan berlemak secara gas kromatograpi (GC) berasaskan kepada pengekstrakan lipid dan penterbitan menggunakan mangkin bes diikuti oleh trimetilsilil-diazometana (TMS-DM) telah dibangunkan. Kaedah cadangan telah dinilai dan diuji menggunakan sampel campuran piawai asid oleik (OA; C18:1cis 9) dan asid elaidik (EA; C18:1 trans 9) dan penggunaannya terhadap tiga sampel margarin dagangan telah ditunjukkan. Hasil kajian menunjukkan bahawa nilai kebolehdapatan (R) daripada setiap sampel kajian adalah menghampiri 100%. Nilai kebolehulangan RSD adalah dalam julat 0.78 hingga 2.47%, sementara nilai kebolehhasilan RSD adalah dalam julat 1.14 hingga 3.65%. Oleh itu kaedah cadangan terbukti merupakan suatu kaedah yang sensitif, tepat dan sesuai untuk penganalisaan kandungan FAs and TFAs dalam sampel makanan berlemak dan boleh digunakan dalam bidang pemakanan, perubatan dan kajian makanan.

Kata kunci: Analisis kuantitatif; asid lemak trans; makanan berlemak; penterbitan

REFERENCES

Ackman, R. 1998. Remarks on official methods employing boron trifluoride in the preparation of methyl esters of the fatty acids of fish oils. Journal of the American Oil Chemists’ Society 75(4): 541-545.

Aldai, N., Murray, B.E., Nájera, A.I., Troy, D.J. & Osoro, K. 2005. Derivatization of fatty acids and its application for conjugated linoleic acid studies in ruminant meat lipids. Journal of the Science of Food and Agriculture 85(7): 1073-1083.

Backholer, K. & Peeters, A. 2012. Reduction of trans-fatty acids from food. The Journal of the American Medical Association 308(18): 1858-1859.

Berger, K. & Idris, N.A. 2005. Formulation of zero-trans acid shortenings and margarines and other food fats with products of the oil palm. Journal of the American Oil Chemists’ Society 82(11): 775-782.

Bhanger, M.I. & Anwar, F. 2004. Fatty acid (FA) composition and contents of trans unsaturated FA in hydrogenated vegetable oils and blended fats from Pakistan. Journal of the American Oil Chemists’ Society 81(2): 129-134.

Buchgraber, M. & Ulberth, F. 2002. Determination of low level trans unsaturation in physically refined vegetable oils by capillary GLC-Results of 3 intercomparison studies. European Journal of Lipid Science and Technology 104(12): 792-799.

Christie, W.W. 1993. Preparation of ester derivatives of fatty acids for chromatographic analysis. Advances in Lipid Methodology 2: 69-111.

Delmonte, P. & Rader, J.I. 2007. Evaluation of gas chromatographic methods for the determination of trans fat. Analytical and Bioanalytical Chemistry 389(1): 77-85.

Harmanescu, M. 2012. Comparative researches on two direct transmethylation without prior extraction methods for fatty acids analysis in vegetal matrix with low fat content. Chemistry Central Journal 6: 8.

Juárez, M., Polvillo, O., Contò, M., Ficco, A., Ballico, S. & Failla, S. 2008. Comparison of four extraction/methylation analytical methods to measure fatty acid composition by gas chromatography in meat. Journal of Chromatography A1190(1): 327-332.

Jumat, S., Mamot, S., Suria, R. & Mohamad, A.S.M.L. 2006. Oil and Fat Analysis. Bangi: Penerbit UKM.

Mossoba, M., Kramer, J.K.G., Milosevic, V., Milosevic, M. & Azizian, H. 2007. Interference of saturated fats in the determination of low levels of trans fats (below 0.5%) by infrared spectroscopy. Journal of the American Oil Chemists’ Society 84(4): 339-342.

Mozaffarian, D., Katan, M.B., Ascherio, A., Stampfer, M.J. & Willett, W.C. 2006. Trans fatty acids and cardiovascular disease. New England Journal of Medicine 354(15): 1601- 1613.

Murrieta, C., Hess, B. & Rule, D. 2003. Comparison of acidic and alkaline catalysts for preparation of fatty acid methyl esters from ovine muscle with emphasis on conjugated linoleic acid. Meat Science 65(1): 523-529.

Neo, Y.P., Tan, C.H. & Ariffin, A. 2007. Fatty acid composition of five Malaysian biscuits (cream crackers) with special reference to trans-fatty acids. ASEAN Food Journal 14(3): 197-204.

Nimal Ratnayake, W. 2004. Overview of methods for the determination of trans fatty acids by gas chromatography, silver-ion thin-layer chromatography, silver-ion liquid chromatography, and gas chromatography/mass spectrometry. Journal of AOAC International 87(2): 523-539.

Phillips, K.M., Ruggio, D.M. & Amanna, K.R. 2010. Optimization of standard gas chromatographic methodology for the determination of trans fat in unlabeled bakery products. Food Analytical Methods 3(4): 277-294.

Pierluigi, D. & Jeanne, I.R. 2007. Evaluation of gas chromatographic methods for the determination of trans fat. Anal. Bioanal. Chem. 389: 77-85.

Tang, T. 2002. Fatty acid composition of edible oils in the Malaysian market, with special reference to the trans-fatty acids. Journal of Oil Palm Research 14(1): 1-8.

Tarrago-Trani, M.T., Phillips, K.M., Lemar, L.E. & Holden, J.M. 2006. New and existing oils and fats used in products with reduced trans-fatty acid content. J. Am. Diet Assoc. 106(6): 867-880.

Taverniers, I., De Loose, M. & Van Bockstaele, E. 2004. Trends in quality in the analytical laboratory. II. Analytical method validation and quality assurance. TrAC Trends in Analytical Chemistry 23(8): 535-552.

Wassell, P. & Young, N.W.G. 2007. Food applications of trans fatty acid substitutes. International Journal of Food Science & Technology 42(5): 503-517.

*Corresponding author; email: jumat@ukm.edu.my