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

Diserahkan: 11 Januari 2013/Diterima: 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 penentuukuran 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

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*Pengarang untuk surat-menyurat; email: jumat@ukm.edu.my