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Composición de tocoferoles en aceite de semilla de sésamo: indicativo de adulteración Este trabajo examina la importancia de los tocoferoles en la detección de la adulteración del aceite de sésamo comercializado en Brasil. Se analizaron cinco muestras a las que se le determinaron su composición en ácidos grasos, esteroles y tocoferoles. Una de las muestras se reveló puro aceite de semilla de sésamo; en otra, todos los parámetros estaban en desacuerdo. En las demás, el perfil de ácidos grasos caracterizaba el aceite de sésamo, sin embargo los tocoferoles y esteroles permanecieron en desacuerdo. Los resultados indican adulteración con otros aceites vegetales como soja, aceites láuricos y maíz.

An alternative method for determination of total trans fatty acids expressed as elaidic acid by capillary zone electrophoresis (CZE) under indirect UV detection at 224 nm within an analysis time of 7.5 min was developed. The optimized running electrolyte includes 15.0 mmol L(-1) KH(2)PO(4)/Na(2)HPO(4) buffer (pH approximately 7.0), 4.0 mmol L(-1) SDBS, 8.0 mmol L(-1) Brij35, 45%v/v ACN, 8% methanol, and 1.5% v/v n-octanol. Baseline separation of the critical pair C18-9cis/C18:1-9t with a resolution higher than 1.5 was achieved using C15:0 as the internal standard. The optimum capillary electrophoresis (CE) conditions for the background electrolyte were established with the aid of Raman spectroscopy and experiments of a 3(2) factorial design. After response factor (R(F)) calculations, the CE method was applied to total trans fatty acid (TTFA) analysis in a hydrogenated vegetable fat (HVF) sample, and compared with the American Oil Chemists' Society (AOCS) official method by gas chromatography (GC). The methods were compared with an independent sample t test, and no significant difference was found between CE and GC methods within the 95% confidence interval for six genuine replicates of TTFA analysis (p-value > 0.05). The CE method was applied to TTFA analysis in a spreadable cheese sample. Satisfactory results were obtained, indicating that the optimized methodology can be used for trans fatty acid determination for these samples.

Neste trabalho foi avaliado e otimizado um método para extração e quantificação de benzo [a]pireno (B[a]P) em amostras de café das espécies conillon (Coffea canephora) e arabica (Coffea arabica), verde e torrado em pó. A influência do processo de torração na formação do B[a]P também foi estudada. Estas amostras foram extraídas com acetona, seguidas por saponificação, extração com ciclohexano e purificação em coluna de silica-gel. A quantificação foi feita por CLAE por eluição isocrática em fase reversa com detector de fluorescência. Os limites de detecção e quantificação foram de 0,03 e 0,10 μg kg -1 respectivamente. O intervalo de recuperação foi de 76 a 116% para concentrações entre 1,00 e 3,00 μg kg -1. Os resultados obtidos para o B[a]P foram de 0,47 a 12,5 μg kg -1 para amostras de café em pó torradas, e não foi detectado a presença de B[a]P em amostras de café verde. Portanto, o controle dos parâmetros de torração é fundamental na obtenção de um produto de boa qualidade, sem prejuízos à saúde da população. A method for extracting and quantifying benzo[a]pyrene (B[a]P) was evaluated and improved for samples of green and roasted ground Arabica (Coffea arabica) and Conillon (Coffea canephora)Brazilian coffees. The influence of the roasting process in B[a]P formation was considered too. These samples were extracted with acetone, followed by saponification and cyclohexane extraction. The extracts were cleaned by chromatography on a silica-gel. The quantification was done by HPLC with reversed-phase and fluorescence detection under isocratic conditions. The detection and quantification limits were 0.03 μg kg -1 and 0.10 μg kg -1, respectively. The recovery ranged from 76 to 116% for concentrations between 1.00 and 3.00 μg kg -1. The values obtained for B[a]P concentrations were from 0.47 to 12.5 μg kg -1 for samples of ground roasted coffee. B[a]P was absent in the green coffee samples. The control of the roasting parameters is fundamental for obtaining a good quality product.

The aim of this study was to characterize the Bombacopis glabra nut oil (Malvaceae-Bombacoideae) by the determination of its lipid content and fatty acid composition with emphasis on the cyclopropenoid fatty acids (CPFA). The lipids were obtained by five different extraction conditions:[raw almonds: maceration with ethyl ether (I-MA) and n-hexane (II-MA), both at room temperature, and Soxhlet extraction with hexane for 6 (III-MA) and 12 h (IV-MA) and toasted almond: maceration with hexane at room temperature (V-MA)]. Additionally, the oxidation stability of oil by the Rancimat test and the boiling point by thermal analysis (technical TG / DTG) were evaluated. The oil content ranged from 34.99 (I-MA) to 47.36% (IV-MA); oxidation stability was 4.18 h and the boiling point was 373.37 ℃. It should be noted that results about thermal and oxidative stability are been reported for the first time with respect to Bombacopis glabra nut oil. The major oil constituents were palmitic acid (56.06%) and estercúlico (24.83%). The high percentage of CPFA oil, determined by NMR 1 H (26.2 to 30.9%) and GC-FID (26.5%), reinforce that the kernels of this species are not suitable for human consumption.

Recebido em 4/1/09; aceito em 19/7/09; publicado na web em 25/11/09 Different methods to determine total fat (TF) and fatty acids (FA), including trans fatty acids (TFA), in diverse foodstuffs were evaluated, incorporating gravimetric methods and gas chromatography with flame ionization detector (GC/FID), in accordance with a modified AOAC 996.06 method. Concentrations of TF and FA obtained through these different procedures diverged (p< 0.05) and TFA concentrations varied beyond 20 % of the reference values. The modified AOAC 996.06 method satisfied both accuracy and precision, was fast and employed small amounts of low toxicity solvents. Therefore, the results showed that this methodology is viable to be adopted in Brazil for nutritional labeling purposes.Keywords: total fat; fatty acids; nutritional labeling. INTRODUCTIONNutritional labeling information is one of the employed strategies by the World Health Organization to avoid chronic disease.1,2 Since inadequate ingestion of both saturated and trans fatty acids increases cardiovascular diseases risk, 3 the attention to dietary fat has increased either in health aspects and in analytical determination. Brazilian legislation demands the declaration of total fat (TF), saturated (SFA) and trans fatty acid (TFA), among other nutrients, on the label of packed foods (RDC 360/03 ANVISA/MS). 4 To commit to such legislation, laboratories must be able to verify, by means of analysis, the contents declared on labels. 5Total fat and fatty acid determination in food products comprises several steps and, depending on the type of food, laws and analysis procedures, different results should be generated. 6,7 Food lipids are constituted mainly, more than 90%, by triacylglycerol (TAG), which are esters of fatty acids and glycerol. Phospho-and glycolipids, sterols, waxes and free fatty acids are minor components of food fat. When not free, fatty acids are linked in such compounds by ester or amide bonds to other molecules but glycerol. 8 Total fat determination requires a quantitative extraction of all lipid compound classes and the breakage of bonds and interactions with nonfat compounds. As various energy amounts are involved (interactions range from van der Waals to ionic forces), appropriate solvents should be chosen for each case. The fat content of food has traditionally been determined by extraction with organic solvents, followed by extract drying and gravimetric determination. Non-polar organic solvents such as chloroform and n-hexane are used for disrupting hydrophobic and ion-dipole interactions (e.g. lipid hydrophobic chain and non-polar amino acids) whereas polar organic solvents with high dielectric constant, such as methanol, for breaking hydrogen bonds (e.g. non-lipid compounds and lipid hydroxyl, carboxyl or amino groups). [6][7][8] Several methods have been reported in the literature and are indicated for specific food matrices. Fat extraction based on Soxhlet method (reflux with diethyl ether, petroleum ether or n-hexane) extracts neutral lipid, such as t...