Assessment of the bioavailability of toxic and non-toxic arsenic species in seafood samples

Bioavailability of total arsenic, toxic (arsenite, As(III); and arsenate, As(V)), and non-toxic (monomethylarsonic acid, MA; dimethylarsonic acid, DMA; arsenobetaine, AB; and arsenocholine, AC) arsenic species has been assessed in different raw seafood samples (white fish, cold water fish and molluscs) by using an in vitro model that combines simulated gastric and intestinal digestion/dialysis methods. Correlations between arsenic species bioavailability and seafood nutrient contents (fat and protein) have also been established. Total arsenic content in seafood samples, and dialyzable and non-dialyzable fractions, were analyzed by inductively coupled plasma – mass spectrometry (ICP–MS) after a microwave-assisted acid digestion treatment. The determination of the different arsenic species concentrations in the samples (after an optimised matrix solid phase dispersion (MSPD) approach) and in the dialyzable fraction was done by high performance liquid chromatography (HPLC) coupled to ICP-MS as a selective detector. Accuracy of the procedure (total arsenic determination) was assessed by analyzing DORM-2 and BCR-627 certified reference materials. The accuracy of the in vitro procedure was established through a mass-balance study. After statistical evaluation (95% confidence interval), good accuracy of the whole in vitro process, for total arsenic and for arsenic speciation, was observed. High dialyzability percentages for total arsenic and for arsenic species were found (i.e. from 84.6 ± 1.7% to 106 ± 2.6%). Bioavailability of arsenic exhibits a negative correlation with the fat content of the seafood. However, no correlation was observed between the bioavailable fraction of total arsenic and arsenic species and the protein content of the seafood studied.     

Analysis of Water-Soluble Vitamins in Honey by Isocratic RP-HPLC

An isocratic RP-HPLC method has been developed for the identification and quantification of water-soluble vitamins in honey. The mobile phase tested was an aqueous solution of sulphuric acid and the detection was carried out simultaneously by UV and fluorescence. The separation of vitamins C (l-ascorbic acid), B₁ (thiamine), B₃N (nicotinamide), B₃H (nicotinic acid), B₅ (d-pantothenic acid) and B₆ (pyridoxine) is achieved in these conditions in 15 min. The addition to the mobile phase of methanol 2 %?v/v reduced significantly the analysis time in the separation of these vitamins up to 10 min. Moreover, in presence of a cationic surfactant hexadecyltrimethylammonium bromide (CTAB) in the mobile phase, the separation of vitamin C, B₁, B₃N, B₃H, B₂ (riboflavin) and B₆ is possible in 6 min. The combination of both mobile phases, H₂SO₄/methanol and H₂SO₄/methanol/CTAB, has been applied to the analysis, in isocratic mode, of several monofloral honeys (rosemary, thyme, lavender, chestnut, echium) and a honeydew honey in a short time analysis.     

Browning Inhibition in Fresh-cut'Fuji'Apple Slices by Natural Antibrowning Agents

ABSTRACT Response surface methodology was used to study the effect of antibrowning agents (4‐hexylresorci‐nol, glutathione, N‐acetylcysteine, and ascorbic acid) and storage time (14 d) on the color of minimally processed Fuji apples. The selected color parameters were L*,a*, b*, hue angle (h*), and color difference (ΔE*). Storage time had a significant effect on all the studied color parameters (P± 0.05). 4‐hexylresorcinol showed the most effective individual effect on keeping constant a*values (P± 0.0001). Besides, the interaction of N‐acetylcysteine/ glutathione was found to have a significant effect (P± 0.05) on maintaining a* values over time. On the other hand, individual treatment with N‐acetylcysteine in concentrations higher than 0.75% w/v may be used to preserve a*and h*.According to the F‐test, 4‐hexylresorcinol and N‐acetylcysteine (P± 0.05) displayed a significant individual effect on ΔE*, indicating that ΔE* decreased when increasing the concentration of these antibrowning agents. Nevertheless, color difference went down when 4‐hexylresorcinol concentration increased up to 0.5%, but higher concentrations of this agent led to an increase in ΔE* that indicates browning.     

Free amino acids and biogenic amines in Alicante Monastrell wines

The simultaneous determination of 17 free amino acids and 8 biogenic amines in Alicante Monastrell wines was investigated for the first time. The quantification was carried out by using a RP-HPLC method, based on a pre-column derivatization with o-phthaldialdehyde (OPA) and fluorescence detection. From the results obtained it may be concluded that the most abundant free amino acids were Glu, Arg, Ala Asp, and Lys. None of the wine samples analysed had histamine (HIM) or Tyramine (TYM) levels above the limits considered as a possible toxic risk for healthy individuals. No measurable amounts of cadaverine (CAD) or methylamine (MEA) were found, showing no spoilage symptoms of sensory properties of the wines. Tryptamine (TRM) content was significantly higher in aged wines compared to young wines. However ethanolamine (ETA) content was lower. These data were used to make a preliminary classification of the samples using cluster analysis.     

Micro-oxygenation and oak chip treatments of red wines: Effects on colour-related phenolics,volatile composition and sensory characteristics. Part I: Petit Verdot wines

In this paper, the effects of micro-oxygenation before malolactic fermentation and oak chip treatments on Petit Verdot red wines have been evaluated. Our attention was focused on the colour characteristics, the phenolic compounds related to the colour of red wine, the volatile compounds, and the sensory characteristics of the wines. The micro-oxygenation treatment promoted the stabilisation of red wine colour by increasing the formation of colour-related phenolic compounds (higher concentrations of pyranoanthocyanins and anthocyanin-ethyl-flavan-3-ol adducts). Red wine aroma quality was improved with the addition of oak chips (eugenol and 4-vinyl-guaiacol concentration increased). Micro-oxygenation treatment resulted in higher scores for the plum/currant and spicy attributes, as well as the appearance of tobacco and nutty notes which were absent in the non-treated wines. Nevertheless, the typical oak chip aromas (vanilla and woody) were observed to a lesser extent in wines obtained by micro-oxygenation.     

The acerola fruit: composition, productive characteristics and economic importance

The acerola (Malpighia emarginata Sessé y Moci?o ex DC) is a wild plant grown in zones of tropical and subtropical climate. Acerola is origin from South of Mexico, Central America and Septentrional area of South America. Its scientific name was adopted in 1986 by the International Council of Vegetable Genetic Resources. Malpighia emarginata has a subglobulose drupa fruit with three seeds which account between the 19 - 25% of the total weight. The diameter and weight of the fruit varies between 1 - 4 cm and 2 - 15 g, respectively. The fruit shows green color when it is developing, which changes to yellow and red tones when it is mature. Each plant produces annually 20 - 30 kg of fruits. This fruit contents macro and micronutrients: proteins (0.21-0.80 g/100 g), fats (0.23-0.80 g/100 g), carbohydrates (3.6-7.80 g/100 g), mineral salts (iron 0.24, calcium 11.7, phosphorus 17.1 mg/100 g) and vitamins (thiamine 0.02, riboflavine 0.07, piridoxine 8.7 mg/100 g). Its high content in vitamin C (695 a 4827 mg/100 g) is remarkable, therefore acerola has an increasing economic value by its great consume during last years. Acerola also presents carotenoids and bioflavonoids which provide important nutritive value and its potential use as antioxidant. Brazil has a climate and soil appropriate for the culture of acerola, thus this country is the main mundial productor. Acerola is commercialised as juices, jams, ices, gelatins, sweets or liquors. Bibliographical data have been mainly supplied by Electronic Resources of the University of Seville and the University do Vale do Itajaí (Santa Catarina, Brazil).     

Tetrabutylammonium-induced coacervation in vesicular solutions of alkyl carboxylic acids for the extraction of organic compounds

The potential of the tetrabutylammonium-induced liquid-liquid-phase separation in alkyl carboxylic acid vesicular solutions for the extraction of organic compounds prior to liquid chromatography was examined for the first time. The behavior of the coacervates yielded from octanoic to oleic acids as a function of the pH and salts was investigated. The time required for phase separation depended on the length of the carboxylic acid alkyl chain and the experimental procedure (i.e., standing, sonication, centrifugation, stirring, etc.). Theoretical preconcentration factors were a function of both surfactant concentration and the length of the alkyl chain, and they greatly surpassed those obtained with other surfactant-mediated separations (e.g., surfactant-rich phases from dodecanesulfonic acid or Triton X-114). Parameters affecting the extraction efficiency were assessed. Analytes in a wide polarity/charge range, (e.g., PAHs, surfactants, chlorophenols, bisphenols, phthalates, herbicides, amines, dyes, and photographic developers) were extracted with high efficiencies on the basis of the different types of interactions that the vesicular coacervates can establish (i.e., hydrophobic and ionic interactions, hydrogen bonds, and formation of mixed aggregates). The coacervates were compatible with the chromatographic determination of analytes following UV or MS detection. Their suitability for working under real conditions was checked by applying them to the extraction of nonionic surfactants [alkylphenol ethoxylates (octyl and nonyl) and alcohol ethoxylates (C12-C16)] from raw and treated sewage and to river water samples. Analytes in the coacervate were separated and quantified by liquid chromatography-ion trap mass spectrometry. No cleanup steps were necessary. Recoveries of the target compounds in the environmental water samples ranged from 89 to 103%.     

Direct coupling of ionic liquid based single-drop microextraction and GC/MS

The use of ionic liquids as extracting media in single-drop liquid-phase microextraction (SDME) and its direct coupling to gas chromatography/mass spectrometry (GC/MS) is presented. For this purpose, a new removable interface that enables the introduction of the extracted analytes into the GC system, while preventing the ionic liquid from entering the column, has been developed. The determination of three representative pollutants in water samples has been used as a model analytical problem in order to demonstrate the feasibility of the proposed interface. The analytes (dichloromethane, p-xylene, and n-undecane) were coextracted from the aqueous sample in a 2-microL drop of 1-butyl-3-methylimidazolium hexaflourophosphate. Then, the syringe used to perform the SDME was directly introduced into the interface, which was held at 140 degrees C in order to achieve a complete volatilization of the target compounds. After the injection, the ionic liquid was retained in the interface, while a carrier gas transferred the volatilized analytes into the GC inlet. The optimization of the operational variables affecting the new interface (temperature, carrier flow rate, sample volume and injection technique) was accomplished. The analytes could be determined with detection limits in the low-nanogram per milliliter concentration range, and the relative standard deviations were between 3.3 and 4.4%.