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Rodriguez-Naranjo M.I.,Area de Nutricion y Bromatologia | Gil-Izquierdo A.,CSIC - Center of Edafology and Applied Biology of the Segura | Troncoso A.M.,Area de Nutricion y Bromatologia | Cantos-Villar E.,Institute Investigacion y Formacion Agraria y Pesquera IFAPA | Garcia-Parrilla M.C.,Area de Nutricion y Bromatologia
Food Chemistry | Year: 2011

Melatonin (N-acetyl-5-methoxytryptamine) is a neurohormone produced in the pineal gland. Its biological properties are related to the circadian rhythm. Recently, the European Food Safety Authority (EFSA) accepted the health claim related to melatonin and the alleviation of subjective feelings of jet lag. This molecule has been detected in some foods. In this work, 13 grape varieties were studied; 7 monovarietal wines were produced in an experimental winery under strictly controlled conditions and were sampled in different steps. The grape varieties used to make the wines were: Cabernet Sauvignon, Merlot, Syrah, Tempranillo, Tintilla de Rota, Palomino Fino and Alpha red. Liquid chromatography tandem mass spectrometry (LC-MS/MS) unequivocally confirmed the presence of melatonin in wines. The main contribution of this paper is the results that clearly show that melatonin is synthesised during the winemaking process, specifically after the alcoholic fermentation. Indeed, melatonin is absent in grapes and musts and is formed during alcoholic fermentation. © 2010 Elsevier Ltd. All rights reserved. Source


Rodriguez-Naranjo M.I.,Area de Nutricion y Bromatologia | Gil-Izquierdo A.,CSIC - Center of Edafology and Applied Biology of the Segura | Troncoso A.M.,Area de Nutricion y Bromatologia | Cantos E.,Institute Investigacion y Formacion Agraria y Pesquera IFAPA | Garcia-Parrilla M.C.,Area de Nutricion y Bromatologia
Journal of Food Composition and Analysis | Year: 2011

Melatonin (N-acetyl-3-(2-aminoethyl)-5-methoxyindole) is biologically active as a neurohormone and a chronobiotic and antioxidant agent. Its concentration in plant material and foods is usually determined by ELISA. However, commercial ELISA kits are not validated for those matrixes. This paper aims to accurately detect melatonin in wines. The advantages and pitfalls of the methods currently used to assay melatonin in wines (ELISA, LC-fluorescence and LC-ESI-MS/MS) are presented. The LC-FL method was validated as reliable for the quantitative analysis of MEL in wine samples that met AOAC requirements: LOD. =51.72. ng/mL; LOQ. =172.39. ng/mL; intraday accuracy as RSD. =0.35% and interday accuracy as RSD. =13.46%. The linearity showed a correlation coefficient of 0.9999, and peak resolution ranged from 0.96 to 1.52. Melatonin in wines was identified by LC-ESI-MS/MS, comparing its MS and MS2 spectra with its corresponding authentic commercial marker. LC-ESI-MS/MS revealed another compound with an identical fragment pattern (positive-mode ESI) but a different retention time as melatonin. Major mass fragmentation ions were (m/. z) 216 and 174, tentatively identified as a melatonin isomer not previously described in wines. This compound appears in certain monovarietal wines (Jaen Tinto, Merlot and Palomino Negro). Only melatonin is present in others (Petit Verdot and Syrah), and a third group contains both melatonin and the new compound (Cabernet Sauvignon, Prieto Picudo and Tempranillo). © 2011 Elsevier Inc. Source


Rios V.,Area de Nutricion y Bromatologia | Moreno I.,Area de Nutricion y Bromatologia | Prieto A.I.,Area de Nutricion y Bromatologia | Frias J.E.,University of Seville | Camean A.M.,Area de Nutricion y Bromatologia
Journal of Water and Health | Year: 2014

Cyanobacteria are able to produce several metabolites that have toxic effects on humans and animals. Among these cyanotoxins, the hepatotoxic microcystins (MC) occur frequently. The intracellular MC content produced by two strains of Microcystis aeruginosa, PCC7806 and PCC7820, and its production kinetics during the culture time were studied in order to elucidate the conditions that favour the growth and proliferation of these toxic strains. Intracellular MC concentrations measured by liquid chromatography (LC) coupled to electrospray ionization mass spectrometer (MS) were compared with those obtained by enzyme-linked immunosorbent assay (ELISA) anti-Adda and protein phosphatase 2A (PP2A) inhibition assays. It has been demonstrated there are discrepancies in the quantification of MC content when comparing ELISA and LC-MS results. However, a good correlation has been obtained between PP2A inhibition assay and LC-MS. Three MC were identified using LC-MS in the PCC7806 strain: MC-LR, demethylated MC-LR and a new variant detected for the first time in this strain, [L-MeSer7] MC-LR. In PCC7820, MC-LR, D-Asp3-MCLR, Dglu(OCH3)-MCLR, MC-LY, MC-LW and MC-LF were identificated. The major one was MC-LR in both strains, representing 81 and 79% of total MC, respectively. The total MC content in M. aeruginosa PCC7820 was almost three-fold higher than in PCC7806 extracts. © IWA Publishing 2014. Source


Garcia-Parrilla M.C.,Area de Nutricion y Bromatologia | Cerezo A.B.,Area de Nutricion y Bromatologia | Tesfaye W.,Area de Nutricion y Bromatologia | Troncoso A.M.,Area de Nutricion y Bromatologia
ACS Symposium Series | Year: 2011

Sherry vinegars are appreciated products reaching higher prices in the market than Sherry wine. Actually, the Protection of Designations of Origin is recognized since 1995. Their elaboration encompasses the acetification process to reach the required acetic degree and aging in wood. Phenolic compounds proved to be valid markers to differentiate vinegars according to their origin and elaboration process. Multivariate analysis of phenolic composition data including Linear Discriminant Analysis (LDA) and Artificial Neural Networks trained by Backpropagation (BPANN) classifies correctly vinegar according to the acetification process (LDA=92.5, BPANN =99.6) and origin (LDA=88, BPANN= 96.5). Good recalling classification rates were also obtained for aging periods. Indeed, phenolic aldehydes as syringaldehyde, vanillin, coniferaldehyde increase their concentration during aging. New trends in Sherry vinegars elaboration intends to shorten the production time. This is achieved by obtaining the acetic degree with submerged culture or by accelerating aging with chips. This communication presents the impact of both strategies on phenolic profile. Nowadays certain innovations to produce high quality vinegars include the type of wood used. Compounds released from it as (+)-taxifolin in the case of cherry wood or (+)-dihydrorobinetin for acacia wood are suitable chemical markers to characterize vinegars aged in these woods. © 2011 American Chemical Society. Source


Martinez O.,Area de Nutricion y Bromatologia | Salmeron J.,Area de Nutricion y Bromatologia | Guillen M.D.,Area de Nutricion y Bromatologia | Casas C.,Area de Nutricion y Bromatologia
LWT - Food Science and Technology | Year: 2010

This study reports the effect of different refrigeration/freezing treatments on the physicochemical, textural and sensorial properties of farmed Atlantic salmon (Salmo salar) treated with a commercial liquid smoke flavouring. Observations were made on three groups of fillets - group RFS: salted, smoked and stored at 4 °C; group BFS: frozen at -25 °C for 24 h, thawed, salted, smoked and stored at 4 °C; and group AFS: salted, smoked and frozen at -25 °C for 24 h and stored at -18 °C - over a period of 45 days. Scores (on a scale of 1-9) were provided for different sensorial attributes by a panel of 10 trained tasters. Sixty percent of the panellists consistently preferred the AFS fillets. The maximum shelf life associated with each treatment was defined as the last sampling day on which a mean score of ≤5 was awarded for the fillet sensorial attributes by ≥50% of the panellists. Freezing the salmon for 24 h before smoking (BFS) did not increase its shelf life (30 days) over that of refrigerated smoked salmon (RFS). In addition, the former treatment had a negative effect on the adhesiveness, cohesiveness, smoke odour intensity and colour intensity of the flesh. However, maintaining the fish frozen at -18 °C (AFS) increased its shelf life (>45 days) and invested the flesh with greater firmness, cohesiveness and colour intensity. © 2010 Elsevier Ltd. All rights reserved. Source

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