Determination of trichothecenes and zearalenones in grain cereal, flour and bread by liquid chromatography tandem mass spectrometry

Although analytical methods have been already reported for legislated mycotoxins as trichothecenes and zearalenone (ZON) separately, we describe the optimization of a simple and rapid multimycotoxin method for the determination of a total of 12 mycotoxins simultaneously, nine trichothecenes (NIV, DON, FUS-X, DAS, 15-AcDON, 3-AcDON, NEO, HT-2, T-2 T2), and zearalenone and its metabolites (ZON, a-ZOL, b-ZOL), of different origin (wheat, oat, barley and spelt) and in three different products where these substance can be present (grain, flour and bread) reach the food chain and cause toxic effect either in humans or animals. The extraction procedure was based on a mixture of acetonitrile/water (84/16, v/ v), which provided the highest recoveries and the lowest matrix effect. DON-d1 was used as internal standard (I.S.) which helped to compensate the significant matrix effect observed for some matrices, and to obtain high success in the method validation and to reach the parameters compiled in Commission Decision, 2002/657/EC. Analytes were determinate by liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS). Relative recoveries obtained were higher than 70% for the studied mycotoxins the four cereal. Good linearity (r2 > 0.992) was obtained and quantification limits (2.5–25 ng/g) were below European regulatory levels. Repeatability, expressed as relative standard deviation, was always lower than 11%, whereas interday precision was lower than 11% for the developed method

Existence and topological stability of Fermi points in multilayered graphene

We study the existence and topological stability of Fermi points in a graphene layer and stacks with many layers. We show that the discrete symmetries (spacetime inversion) stabilize the Fermi points in monolayer, bilayer and multilayer graphene with orthorhombic stacking. The bands near $k=0$ and $\epsilon=0$ in multilayers with the Bernal stacking depend on the parity of the number of layers, and Fermi points are unstable when the number of layers is odd. The low energy changes in the electronic structure induced by commensurate perturbations which mix the two Dirac points are also investigated.Comment: 6 pages, 6 figures. Expanded version as will appear in PR

Bioaccessibility of Deoxynivalenol and its natural co-occurrence, with Ochratoxin A and Aflatoxin B1 in italian commercial pasta

Cereals products for direct human consumption are rarely contaminated by moulds, unlike raw materials, which are often infected, either in the field or during storage. In this study, 27 samples of dried pasta characterised by size, packaging and marketing intended for young children consumption were collected and analysed by liquid chromatography (LC) and liquid chromatography– tandem mass spectrometry (LC–MS/MS) for Deoxynivalenol (DON), Ochratoxin A (OTA) and Aflatoxin B1 (AFB1) determination. The samples that showed the highest amounts of one of the mycotoxins were cooked for 10 min, digested with an in vitro gastrointestinal protocol and bioaccessibility values were calculated. Seven of the 27 samples exceeded from 120% to 225% the legal limit of 200 lg/kg for DON fixed for processed cereal-based baby foods by an European Regulation; all the collected samples were under the OTA legal limit (0.05 lg/kg) fixed by the European Regulation and no sample was contaminated by AFB1 over the instrumental limit of detection of 0.10 lg/kg. The mean value of gastric bioaccessibility verified for the DON resulted of 23.1%, whereas mean duodenal bioaccessibility was 12.1%

Reduction in vitro of the minor Fusarium mycotoxin beauvericin employing different strains of probiotic bacteria

The interaction between the minor Fusarium mycotoxins BEA and 13 bacterial strains characteristic of the gastrointestinal tract as Bifidobacterium longum, Bifidobacterium bifidum, Bifidobacterium breve, Bifidobacterium adolescentes, Lactobacillus rhamnosus, Lactobacillus casei-casei, Lactobacillus plantarum, Eubacterium crispatus, Salmonella fecalis, Salmonella termofilus, Lactobacillus ruminis, Lactobacillus casei and Lactobacillus animalis was studied. The fermentations were carried out in the liquid medium of MRS during 4, 12, 16, 24 and 48 h at 37 C, under anaerobic conditions. Levels of BEA in the fermentation liquid, on the cell walls and on the internal part of the cells were determined using liquid chromatography coupled to the mass spectrometry detector (LC-MS/MS). Results showed that the bacteria reduced the concentration of the BEA present in the medium, part of the mycotoxin was adsorbed by cell wall and part internalized by the bacteria. All the bacteria analyzed in this study showed a significant BEA reduction during the fermentation process, in particular the mean diminution resulted variable from 66 to the 83%

Influence of the heat treatment on the degradation of the minor Fusarium mycotoxin beauvericin

Beauvericin (BEA) is a bioactive compound produced by the secondary metabolism of several Fusarium strains and known to have various biological activities. This study investigated the degradation of the minor Fusarium mycotoxin BEA present in the concentration of 5 mg/kg in a model solution and in different crispy breads produced with different flours typologies (corn, hole, wheat, durum wheat, soy and rice) during the heat treatment carried out in an oven at three different temperatures of 160, 180 and 200 C and at 3, 6, 10, 15 and 20 min incubation. The concentration of the bioactive compound studied, analyzed with the technique of the liquid chromatography tandem mass spectrometry (LCeMS/MS), decreased in the experiment carried out in the model solution from 2.89 0.13 mg/kg of the assay at 160 C for 3 min until the complete degradation at 200 C during 20 min incubation. In the experiments carried out using the crispy breads prepared with different kind of flours, as system to simulate a food preparation, the percentage of BEA degradation, resulted variable from 20 to 90%, with no a significative differences showed in the use of the different flour matrices. Also a metabolite of the thermical degradation of the mycotoxins BEA was identified using the LCeMS in the full scan mode

Tomás Rico, Víctor Beltrí and Cartagena´s Gran Hotel

El Gran Hotel fue la obra más significativa de la Cartagena de principios de siglo XX, una obra compartida por los dos arquitectos más destacados de la ciudad. Tomás Rico, arquitecto municipal, realizó el proyecto original y dirigió la obra hasta su muerte en 1912. Fue entonces cuando Víctor Beltrí, el proyectista más popular entre la burguesía cartagenera, continuó la obra. Este hecho lanza uno de los mayores interrogantes de la arquitectura modernista cartagenera. ¿Hasta qué punto Beltrí fue fiel al proyecto original del Gran Hotel? ¿Cuál fue su grado de aportación a la obra finalizada? Dado que los planos originales del proyecto no nos brindan suficiente información al respecto, se inicia un estudio sobre la trayectoria profesional de ambos arquitectos, para así poder ver que grado de actuación tuvieron cada uno en la obra finalizada, la cual también será analizada en profundidad

Barrio de peral (Cartagena) orígenes y transformación urbana

Esta investigación, publicada en Junio de 2014 con la colaboración del Ayuntamiento de Cartagena y el Colegio de Arquitectos de la Región de Murcia, se basa en la información documental de más de ochenta viviendas construidas a finales del S. XIX y principios del S.XX, y de algunos planos históricos de la ciudad de Cartagena, analizando el desarrollo urbano de esta área de la periferia cartagenera. Desde su origen, en el que simplemente consistía en una agrupación de viviendas, a lo largo de un camino, llamada Los Molinos, hasta su consolidación como barrio, con iglesia, comercios, casino y escuelas. También se desarrolla un estudio tipológico de las viviendas, medianeras y aisladas, según fueran para la clase obrera o burguesa, y de las dotaciones. Los ornamentos eclécticos y modernistas que inundan sus fachadas también son descritos, así como las conexiones compositivas que se establecen con Cartagena e incluso de Europa

Symmetry-based approach to electron-phonon interactions in graphene

We use the symmetries of monolayer graphene to write a set of constraints that must be satisfied by any electron-phonon interaction hamiltonian. The explicit solution as a series expansion in the momenta gives the most general, model-independent couplings between electrons and long wavelength acoustic and optical phonons. As an application, the possibility of describing elastic strains in terms of effective electromagnetic fields is considered in detail, with an emphasis on group theory conditions and the role of time reversal symmetry.Comment: 11 pages, 1 figure. Treatment of ripples in suspended graphene sheets included. Revised journal version with improved presentation and two new appendice

Influence of different soluble dietary fibers on the bioaccessibility of the minor Fusarium mycotoxin beauvericin

Beauvericin (BEA) is a bioactive compound produced by the secondary metabolism of several Fusarium strains and is known to have various biological activities. This study investigated the bioaccessibility of the BEA tested in concentrations of 5 and 25 mg/L, in a model solution and in wheat crispy breads elaborated with different natural binding compounds as the soluble alimentary dietary fibers b-1,3 glucan, chitosan low molecular weight (L.M.W.), chitosan medium molecular weight (M.M.W.), fructooligosaccharides (FOS), galattomannan, inulin and pectin, added at concentrations of 1% and 5%. The bioaccessibility was determinated by employing a simulated gastrointestinal digestion that simulates the physiologic conditions of the digestive tract until the colonic compartment. The determination of BEA in the intestinal fluids was carried out by liquid chromatography– mass spectrometry detection (LC–MS). The mean BEA bioaccessibility data in the model solutions ranged from 31.8% of the samples treated with only the duodenal digestion until 54.0% of the samples processed including the colonic fermentation, whereas in the alimentary system composed by the wheat crispy breads produced with different fiber concentration the duodenal and the duodenal + colonic BEA bioaccessibility resulted in 1.9% and 27.0% respectively

Whey fermented by using Lactobacillus plantarum strains: A promising approach to increase the shelf life of pita bread

Nowadays, there is an increasing concern regarding the shelf life of food products, leading producers to research natural antimicrobial agents to use in food preparation. In this study, we evaluated the antifungal activity of Lactobacillus plantarum fermented whey and then added the whey during preparation of pita bread to study shelf-life improvement. The fermented whey showed a satisfactory inhibitory (antifungal) effect against Penicillium expansum and Penicillium brevicompactum strains: the minimum inhibitory and minimum fungicidal concentrations ranged from 3.9 to 39.0 g/L and from 62.5 to 250 g/L, respectively. Addition of fermented whey increased the shelf life of the pita bread. After inoculation of the bread surface with Penicillium, an increase in shelf life until d 8 was achieved compared with the positive control, whereas under natural contamination conditions, an extension of shelf life until d 19 was observed. In terms of antimicrobial activity, the greatest reduction (100%) in fungal growth was achieved when all of the water in the dough was replaced with fermented whey. An untrained sensory panel could not identify differences between bread produced with fermented whey and control pita breads. These results suggest the possibility of using fermented whey in food preservation