Cristina Soares

Determination of acrylamide in coffee and coffee products by GC-MS using an improved SPE clean-up

An improved gas chromatography-mass spectrometry (GC-MS) method to determine acrylamide (AA) in coffee and coffee products was developed. The method was based on two main purification steps: the first with ethanol and Carrez solutions in order to precipitate polysaccharides and proteins, respectively; and the second with a layered solid-phase extraction (SPE) column which proved to be efficient in the elimination of the main chromatographic interferences. The method is applicable to a wide range of coffee products. Twenty-six samples of different coffee products were analysed. The levels of AA were in the range 11.4–36.2 µg l−1 for ‘espresso coffee’ and 200.8–229.4 µg l−1 for coffee blends with cereals. The results indicate that the presence of cereals significantly increased the levels of AA.

Development and Validation of a Matrix Solid-Phase Dispersion Method to Determine Acrylamide in Coffee and Coffee Substitutes

The present study describes the development and validation of a new method based on a matrix solid-phase dispersion (MSPD) sample preparation procedure followed by GC-MS for determination of acrylamide levels in coffee (ground coffee and brewed coffee) and coffee substitute samples. Samples were dispersed in C(18) sorbent and the mixture was further packed into a preconditioned custom-made ISOLUTE bilayered SPE column (C(18)/Multimode; 1 g + 1 g). Acrylamide was subsequently eluted with water, and then derivatized with bromine and quantified by GC-MS in SIM mode. The MSPD/GC-MS method presented a LOD of 5 microg/kg and a LOQ of 10 microg/kg. Intra and interday precisions ranged from 2% to 4% and 4% to 10%, respectively. To evaluate the performance of the method, 11 samples of ground and brewed coffee and coffee substitutes were simultaneously analyzed by the developed method and also by a previously validated method based in a liquid-extraction (LE) procedure, and the results were compared showing a high correlation between them.

Polycyclic aromatic hydrocarbons bioaccessibility in seafood: Culinary practices effects on dietary exposure

&NA; This work aimed to determine the effect of culinary practices on the contamination level and bioaccessibility of polycyclic aromatic hydrocarbons (PAHs) in seafood. The selected farmed seafood species (marine shrimp, clams and seaweed) were commercially available in Portugal. The mean concentrations of PAHs varied between 0.23 and 51.8 &mgr;g kg−1, with the lowest value being observed in raw shrimp and the highest in dried seaweed. The number of compounds detected in seaweed and clams (naphthalene, acenaphthene, fluorene, phenanthrene, benzo(b)fluoranthene and benzo(j)fluoranthene) were higher than in shrimp (fluorene and pyrene). Among the PAHs measured, fluorene was the predominant one. There was a significant interaction effect between species and culinary treatment (p < 0.05), thus boiled and dried seaweed samples presented the lowest and the highest levels of fluorene (0.13 and 1.8 &mgr;g kg−1), respectively. The daily intake of PAHs decreased with bioaccessibility, varying from 22% for benzo(k)fluoranthene (in raw clam) to 84% for phenanthrene (in steamed clam). According to the potency equivalent concentrations, screening values and bioaccessibility of PAHs, the consumption of marine shrimp, clam and seaweed is considered as safe for consumers. HighlightsPAHs bioaccessibility in seafood was assessed.Raw shrimp present the lowest and dried seaweed the highest content of PAH.There was a significant interaction effect between species and culinary treatment.

Factors Affecting Acrylamide Levels in Coffee Beverages

Abstract Acrylamide is a heat-generated food toxicant formed via the Maillard reaction between asparagine and reducing sugars during food processing. In coffee, acrylamide is intensively formed during the early stages of roasting, but its content tends to diminish with increasing temperature and time of roasting. The acrylamide content in coffee is dependent on the coffee species, degree of roast, and storage conditions. Different methods of brew preparation, according to regional and personal preferences, lead to different amounts of acrylamide in coffee brews and, consequently, to different exposures to this compound.

Seaweeds from the Portuguese coast as a source of proteinaceous material: Total and free amino acid composition profile

The total protein content and the (total and free) amino acid composition of nine edible species of red, brown and green seaweeds collected in the Portuguese North-Central coast were quantified to assess their potential contribution to the recommended dietary intake. Whenever possible, the protein and amino acid composition was compared with that of commercial European seaweeds. The protein content was the highest (P < 0.05) in red species (19.1-28.2 g/100 g dw), followed by the green seaweed Ulva spp. (20.5-23.3 g/100 g dw), with the lowest content found in brown seaweeds (6.90-19.5 g/100 g dw). Brown seaweeds presented the lowest mean contents of essential amino acids (EAAs) (41.0% protein) but significantly (P < 0.05) higher concentrations of non-essential amino acids (36.1% protein) and free amino acids (6.47-24.0% protein). Tryptophan, methionine and leucine were the limiting EAAs in all species. In contrast, lysine was found in high concentrations, especially in red (2.71-3.85% protein) and green (2.84-4.24% protein) seaweeds.

Seaweeds from the Portuguese coast: A potential food resource?

The Portuguese coast presents a large amount of potentially edible seaweeds that are underexploited. The identification of different macroalgae species and their availability in the northern and central coast of the continental territory was assessed. The nutritional value of seaweeds is discussed based on a literature review (when available) focused on data for species collected in Portugal with the aim to define the most important nutritional parameters that should be characterized in the samples. Possible health concerns related with the presence of contaminants are also considered.

Acrylamide in Coffee: Influence of Processing

Abstract Acrylamide is a heat-generated food toxicant, usually found in processed carbohydrate-rich foods, that represents a potential health hazard for humans. It is formed via the Maillard reaction between asparagine and reducing sugars during food processing. In coffee, acrylamide is formed during the early stages of bean roasting and, after that, its content tends to diminish. The acrylamide levels decrease with lower concentrations of asparagine and with increasing temperature and time of roasting. For a similar roast degree, Robusta coffee contains higher acrylamide levels than Arabica species, probably due to a higher initial amount of asparagine in the former. The level of this amino acid becomes relevant when considering immature beans due to the high concentration in these. The depulping of green coffee fruits enables a reduction in the levels of asparagine. Another factor that contributes to the acrylamide intake is the way in which the coffee beverage is prepared.