Browsing by Author "Shrestha, Kshitij"

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    Development and Validation of a Gas Chromatography−Flame Ionization Detection Method for the Determination of Epoxy Fatty Acids in Food Matrices
    (Journal of Agricultural and food chemistry, 2014) Mubiru, Edward; Shrestha, Kshitij; Papastergiadis, Antonios; Meulenaer, Bruno De
    A reliable and suitable method for the determination of epoxy fatty acids in various food matrices based on the Bligh and Dyer lipid extraction procedure was developed and validated. The method involves the use of a methylated epoxy fatty acid as internal standard (IS), extraction of the analytes from the matrices followed by room temperature methylation, a three- step solid phase extraction (SPE) separation of the fatty acid methyl esters (FAMEs), and detection with gas chromatography− flame ionization detection (GC-FID). The method was validated in four different food matrices chosen as model systems, namely, vegetable oils, unprocessed pork, fried potato crisps, and infant formula. The extraction technique allows the method to be applied for routine analysis of a large amount of samples. Intraday repeatability ranged from 1 to 19%, and interday reproducibility ranged from 2 to 9%. The limit of quantification (LOQ) ranged from 3.32 to 20.47 μg g−1 of sample with recoveries ranging from 94 to 115%. The results verify the accuracy and reproducibility of the analytical technique and its ability to provide reliable quantification of epoxy fatty acids. Finally, levels of epoxy fatty acids in several food products on the Belgian market were screened and are presented.
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    Exposure assessment of epoxy fatty acids through consumption of specific foods available in Belgium
    (Food Additives & Contaminants, 2017) Mubiru, Edward; Jacxsens, Liesbeth; Papastergiadis, Antonios; Lachat, Carl; Shrestha, Kshitij; Mozumder, N. H. M. Rubel; De Meulenaer, Bruno
    Epoxy fatty acids (EFAs) are secondary oxidation products formed from unsaturated fatty acid hydroperoxides. Seventeen food categories were analysed for C18 monoEFAs of food products available on the Belgian market. A quantitative exposure assessment was performed based on deterministic and probabilistic approaches combining these concentration data with consump- tion data obtained from the Belgian National Food Consumption Survey of 2004. A preliminary evaluation of any potential risk related to the intake of the studied EFAs through the studied foods was performed by applying the threshold of toxicological concern (TTC) concept. Three food categories out of 17 foods, mayonnaise, butter–margarine and ready-to-eat meals were found to contribute most to the intake of EFAs. According to probabilistic determination, these foods had P50 intakes of 0.4085, 0.3328 and 0.2997 mg kg–1 bw day–1 respectively. They had P99.5 intakes of 3.7183, 2.7921 and 38.6068 mg kg–1 bw day–1 respectively. The intake below the TTC was from the consumption of cooked meat, smoked salmon and raw cured ham, with P50 intakes of 0.0006, 0.0007 and 0.0011 mg kg–1 bw day–1 respectively, and the other foods were above the TTC. Based on the TTC concept, a risk to human health could be identified related to the consumption of cheese, snacks foods, plant oils, French fries, dry nuts, chips, cured minced raw meat, cookies, fresh and frozen salmon and bacon.
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    Improved gas chromatography-flame ionization detector analytical method for the analysis of epoxy fatty acids
    (Clinical and Vaccine Immunolog, 2014) Mubiru, Edward; Shrestha, Kshitij; Papastergiadis, Antonios; De Meulenaer, Bruno
    In this study an improved method for analysis of epoxy fatty acids is reported. Data obtained from analysis of polar fatty acids has previously been presented, but due to the high number of compounds that co- elute in the polar fraction, the resultant chromatograms are complex which may lead to compromising the accuracy of the data. A three steps separation of fatty acid methyl esters (FAMEs) by solid-phase extraction (SPE) on a silica gel column to remove hydroxy fatty acid interferences was proposed. This approach is opposed to a two step separation procedure that has been often used to prevent analytical interferences caused by non-altered fatty acids. A gas chromatograph with a flame ionization detector (GC-FID) equipped with a polar CP-Sil 88TM column was used. Quantification was based on the use of methyl nonadecanoate (C19:0), as an internal standard. Individual mono epoxy fatty acids were well separated without co-eluting compounds. The optimized method was finally applied to screen epoxy fatty acids in 37 fresh oil samples. Results obtained for the total epoxy fatty acids were in the range 0.03–2 mg g−1 of oil with repeatability coefficient of variation (CV) ranging from 2.8 to 9.9% for duplicate analysis showing that the results obtained are repeatable.