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ABSTRACT: Alheiras are a traditional, smoked, fermented meat sausage, produced in Portugal, with an undeniable cultural and gastronomic legacy. In this study, we assessed the nutritional value of this product, as well as the influence of different types of thermal processing. Alheiras from Mirandela were submitted to six different procedures: microwave, skillet, oven, charcoal grill, electric fryer and electric grill. Protein, fat, carbohydrate, minerals, NaCl, and cholesterol contents, as well as fatty acid profile were evaluated. The results show that alheiras are not hypercaloric but an unbalanced foodstuff (high levels of proteins and lipids) and the type of processing has a major impact on their nutritional value. Charcoal grill is the healthiest option: less fat (12.5g/100g) and cholesterol (29.3mg/100g), corresponding to a lower caloric intake (231.8kcal, less 13% than the raw ones). Inversely, fried alheiras presented the worst nutritional profile, with the highest levels of fat (18.1g/100g) and cholesterol (76.0g/100g).
Meat Science 10/2012; · 2.28 Impact Factor
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ABSTRACT: This work reports the composition of arabica and robusta coffees in terms of biogenic amines. The analyses were conducted before and after acid hydrolysis with the aim of the determining both free and conjugated forms in green and roasted coffee beans. The amines (putrescine, cadaverine, serotonin, tyramine, spermidine, and spermine) were determined by reverse-phase high-performance liquid chromatography (RP-HPLC) after derivatization with dansyl chloride. Multivariate analyses were applied in order to evaluate the possible use of these amines as chemical descriptors for arabica and robusta coffees. It was found that putrescine, the main biogenic amine present in the green beans, could be used in the discrimination of the referred species. There is also some evidence that these compounds can be used for discrimination between green coffees subjected to different postharvest processes and that tyramine can be considered a chemical marker for Angolan robustas. The variations in biogenic amine levels after roasts is also discussed, but the statistical significance for species discrimination is reduced.
Journal of Agricultural and Food Chemistry 11/2004; 52(20):6188-92. · 2.82 Impact Factor
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ABSTRACT: This work reports the results for the composition of robusta and arabica coffee species in terms of their amino acid enantiomers in the green and roasted states. The analyses were conducted for the free amino acids, as well as for the amino acids obtained after acid hydrolysis. The amino acids were extracted/hydrolyzed and isolated by SPE on strong cation exchange columns, derivatized to their N-ethoxycarbonylheptafluorobutyl esters, and analyzed by gas chromatography/FID on a Chirasil l-Val column. Multivariate analyses applied to the results showed that the free amino acids can be used as a tool for discrimination between coffee species, with a special reference to l-glutamic acid, l-tryptophan, and pipecolic acid. There is also some evidence that these compounds can be used for discrimination between green coffees subjected to different postharvest processes. It is also shown that the amino acid levels observed after acid hydrolysis can be used for the same purposes, although displaying less discriminatory power.
Journal of Agricultural and Food Chemistry 11/2003; 51(22):6495-501. · 2.82 Impact Factor
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ABSTRACT: Norharman and harman are two neuroactive β-carbolines present in several plants and thermally processed foods, including roasted coffee. The objective of this study was to evaluate their amounts in commercial instant coffee-based and coffee substitute beverages (n = 48), with variable amounts of coffee, chicory, barley, malt, and rye. All samples contained variable amounts of both β-carbolines, always with a higher proportion of norharman than harman. The highest levels (p < 0.01) were found in 100% instant coffees, with mean amounts of 3.8 μg/g and 1.5 μg/g for NH and H, respectively, followed by plain chicory. The lowest amounts were found in 100% barley, with 1.1 μg/g for NH and 0.3 μg/g for H. The NH and H content was statistically higher (p < 0.01) in all mixtures with coffee when compared to those without it. Nevertheless, and except for 100% barley, the amounts provided by beverages based on coffee substitutes are within those reported for standard coffee brews.
Food Chemistry.
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ABSTRACT: An isocratic HPLC technique is described for the determination of benzoic acid and sorbic acid in industrial quince jam. The preparation procedure was optimized. Precipitation of proteins and fat by the addition of methanol, followed by centrifugation and/or filtration provided an extract suitable for chromatographic analysis. The chromatographic separation was achieved with a C18 column and acetate buffer (pH=4.4) - methanol (65:35) as the mobile phase. The effluent was monitored at 235 nm. Effective separation and quantification was achieved in less than 7 min. Specificity of the method was checked against common food additives added to industrial quince jam, such as l-ascorbic acid and citric acid. Diode array detection was used for confirmation of the preservatives. Mean recoveries of 95–104% were obtained with a precision less than 2.6%, detection limits of 25 and 6.25 mg/kg were obtained for benzoic and sorbic acids, respectively. Results were in good agreement with the reference methods. The presence of benzoic and sorbic acids in quince jams available on the Portuguese market, was also determined. Eleven commercial brands of quince jam were analysed. All contained benzoic acid. The concentration ranged from 413.9±10.4 to 1501±4.2 mg of benzoic acid/kg of quince jam. Only two brands also contained sorbic acid. The concentrations were 515.0±7.0 and 908.3±5.3 mg of sorbic acid/kg of quince jam.
Food Research International.
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ABSTRACT: A method for the determination of adenosine, cytidine, uridine, guanosine and inosine 5′-monophosphates in milk and dairy products was optimized and its performance evaluated. The technique was based on ion-pair reversed-phase HPLC separation of the nucleotides and diode array detection. The chromatographic separation was achieved using a C18 column and a gradient elution with a mixture of two solvents: solvent A, water/glacial acetic acid/tetrabutilammonium hydrogensulphate (TBAHS) and solvent B, methanol/glacial acetic acid/TBAHS. The effluent was monitored using a Diode Array detector set at 260 nm. Validation of the proposed method was carried out by standard additions method, with recoveries of 98.3%. The precision of the method was also evaluated and reported a coefficient of variation (CV) as less than 3.2. Upon development the technique was applied on different dairy products in order to study the distribution of nucleotides therein. The samples included bovine, ovine and caprine milks, the corresponding manually manufactured cheeses, whey cheese and whey. Three commercial cheeses made from bovine, ovine and caprine milks, respectively, and 20 infant formulae were also analysed. In contrast to their absence in cheese upon preparation nucleotides were present in cheese at the end of ripening; this observation led to the extraction of DNA in order to evaluate whether nucleotides were released from degradation of nucleoproteins.
Food Chemistry.
