Thursday, 17 December 2015

Forecasting Olea Airborne Pollen Concentrations by Means of Artificial Intelligence

Fresenius Environmental Bulletin, (2015) 24, 4574-4580


A model based in an Artificial Neural Network was de- veloped in order to forecast the Olea airborne pollen concen- tration due to the allergenic power of its pollen grains. Daily data for Olea pollen and the meteorological variables docu- mented in the period 1993-2008, were used. All developed models had five input variables; i) Julian day, ii) precipita- tion, iii) humidity value, and iv) insolation hours. The model was carried out with data collected in the city of Ourense, North West of Spain. The developed model predicts the at- mospheric concentration of Olea pollen one day ahead. The model was tested with data from 2009 and 2010. The devel- oped model could be employed in allergology and health sci- ences in order to prevent effect of pollinosis. It is due the ability of obtain good predictions of threshold pollen con- centration values, which are important to take preventive measures by Health Systems. The time-lag observed in pre- diction phase may be due to the influence of other meteoro- logical parameters which have not been taken into account in the beginning, this fact is reaffirmed by studying the simi- larity between the different pollen seasons and the year 2010 (Mann-Whitney U Test with p<0.031), or due the low concen- trations of Olea pollen during the MPS (≈ 14 grains·m-3).

Thursday, 10 December 2015

Organic pollutants profiling of wood ashes from biomass power plants linked to the ash characteristics

Science of the Total Environment, 544 (2016) 535-543
doi:10.1016/j.scitotenv.2015.11.134



Wood ash, characterized by high content of certain nutrients and charcoal, can be applied to soils as a means of managing this waste product improving the soil quality. The associated environmental risk must be assessed. The objective of this study was to characterize the bottom and fly ash collected from 15 biomass power plants in Spain by determining the benzene, toluene, ethylbenzene, xylene and styrene (BTEX + S), PAHs and aliphatic hydrocarbon contents of both types of ash. Biochar was also used for comparison purposes.

Wednesday, 9 December 2015

As(V) and P Competitive Sorption on Soils, By-Products and Waste Materials

Int. J. Environ. Res. Public Health 2015, 12(12), 15706-15715
doi:10.3390/ijerph121215016


Batch-type experiments were used to study competitive As(V) and P sorption on various soils and sorbent materials. The materials assayed were a forest soil, a vineyard soil, pyritic material, granitic material, coarsely and finely ground mussel shell, calcinated mussel shell ash, pine sawdust and slate processing fines. Competition between As(V) and P was pronounced in the case of both soils, granitic material, slate fines, both shells and pine sawdust, showing more affinity for P. Contrary, the pyritic material and mussel shell ash showed high and similar affinity for As(V) and P. These results could be useful to make a correct use of the soils and materials assayed when focusing on As and P removal in solid or liquid media, in circumstances where both pollutants may compete for sorption sites.

Monday, 7 December 2015

Electrical Percolation of AOT-based Microemulsions with n-Alcohols

Journal of Molecular Liquids
DOI: 10.1016/j.molliq.2015.12.021


Percolative behaviour of w/o AOT/iC8/H2O microemulsions added with different n-alkanols is reported. 1-n-alcohols and 2-n-alkanols presented dissimilarities affecting percolation. Smaller alcohols ease percolation, especially at low concentrations. Greater molecules implied a reinforcement of the surfactant film that delayed percolation threshold. Also, a neural network based simulation model of the phenomenon has been developed. This single model has only five input variables and can estimate percolation temperature of microemulsions added with the two types of alcohols studied, with an RMSE of 0.98oC and R2=0.9740 (validation dataset values). This is considered a successful prediction rate, following previous developments with other families of additives, that confirms neural networks as reliable tools for percolative behaviour modelling.

Thursday, 3 December 2015

A palla de cereal reinvéntase como material de última xeración para producir nanofibras de celulosa


  • Investigadores das universidades de Córdoba e Vigo desenvolven novos usos para estes residuos a través de novas novas técnicas de separación ambientalmente favorables.


A industria agroalimentaria enfróntase ao reto de xestionar os seus residuos e faino, entre outras liñas de actuación, buscando a través da I+D novos usos para os subprodutos que xera. É o caso da palla de cereal. Os cambios nos usos dos terreos agrícolas, máis orientados actualmente á obtención de alimentos e de biocombustible, traen consigo a necesidade e a oportunidade de aproveitar os residuos de cultivos de cereais como o trigo, a cebada ou a avea. Investigadores da Universidade de Vigo colaboran nun proxecto da Universidade de Córdoba que traballa na obtención de nanofibras de celulosa, actualmente obtidas principalmente de especies madereiras, destes residuos agrícolas. 

Os resultados desta investigación conxunta veñen de ser publicados na revista Bioresource Technology, nun artigo titulado Agricultural residue valorization using a hydrothermal process for second generation bioethanol and oligosaccharides production e asinado por F. Vargas, E. Domínguez, C. Vila, A. Rodríguez Pascual e Gil Garrote, investigador este último da Facultade de Ciencias do campus de Ourense. Segundo explican os científicos do equipo de investigación Biorrefinería de Materiais Lignocelulósicos da Industria Agroalimentaria da Universidade de Córdoba, liderado por Alejandro Rodríguez, a celulosa é un dos polímeros máis dispoñibles do planeta pola súa presenza nos vexetais. Este grupo ten unha ampla bagaxe na obtención de papel e cartón a partir da celulosa, buscando agora novos procedementos químicos para obter máis produtos e de maior valor engadido, como hidroxeles ou compoñentes para a formulación de cemento.


Obtención de azucres e biocombustible

Entre estes procedementos está a biorrefinería de materiais lignocelulosos, que permite separar nos residuos agrícolas como a palla de cereal a celulosa, a hemicelulosa e a lignina. O primeiro material é aproveitable directamente para facer papel desde a celulosa chamada nobre, mentres que coas hemicelulosas obtéñense compostos de interese industrial, como por exemplo xilitol. Por último, está a lignina, que está presente na chamada lixivia negra ou licor residual. A colaboración coa Universidade de Vigo permitiu desenvolver novas técnicas na separación da celulosa e a lignina. O proceso, de carácter innovador, disolve a materia prima cun catalizador ácido, obtendo unha fracción rica en hemicelulosas e outra rica en celulosa e lignina. A partir desta fracción líquida caracterizáronse azucres interesantes para a industria alimentaria, como xilitol. A fracción sólida, rica en celulosa, púidose fermentar para a obtención de biocombustibles. 

Segundo comenta Rodríguez Pascual, “a palla do cereal ata o de agora empregábase para alimentar o gando ou se desbotaba no campo, en ocasións por medio de pequenos lumes controlados”. O procedemento desenvolvido durante a investigación parte dun proceso ambientalmente favorable, ao empregar sosa a presión atmosférica. Así obtéñense fibras celulósicas por un lado, que se utilizarán para a obtención de lignonanofibras de celulosa (con aparencia de xel), e o licor negro, rico en lignina, por outro. Os investigadores están obtendo lignonanofibras de celulosa mediante procedementos mecánicos, enzimáticos e por oxidación TEMPO, partindo da pasta celulósica sen branquexar, o que implica un menor custe económico e ambiental respecto a outras nanofibras que se obteñen mediante un proceso previo de blanqueamiento.

Fuente: DUVI

Wednesday, 25 November 2015

Influence Prediction of Alkylamines Upon Electrical Percolation of AOT-based Microemulsions Using Artificial Neural Networks

Tenside Surfactants Detergents, 52, 473-476 (2015)


Simulations for the electrical percolation of AOT/iC8/H2O w/o microemulsions added with alkylamines have been carried out by means of multilayer perceptron. Five variables have been elected as inputs: amine concentration, molecular weight, log P, hydrocarbon chain length (as number of carbons), and pKa. As a result, a neural model consisting in five input neurons, two middle layers (with fifteen and ten neurons respectively) and one output neuron was chosen because of its better performance, with a RMSE of 0.54 °C for the prediction set, with R2 = 0.9976.




Sunday, 22 November 2015

Metales pesados en suelos de pradera de A Pastoriza (NO España) tratados con purín de vacuno y fertilizantes NPK

Spanish Journal of Soil Science, 5 (2015) 154-164


En Galicia las praderas ocupan una gran extensión, siendo utilizadas principalmente para la alimentación del ganado vacuno destinado tanto a la producción de leche como de carne. Las granjas se manejan de manera intensiva, utilizando fertilizantes inorgánicos y purín de vacuno para aumentar la producción de pastos. Esta práctica puede aumentar el contenido de metales pesados en el suelo. En este trabajo se estudian las concentraciones totales y la distribución en profundidad de metales pesados y elementos afines (As, Cd, Cr, Cu, Mn, Ni, Pb y Zn) en dos suelos forestales (SN1, SN2) y en cinco praderas (P1-P5) fertilizadas con purín de vacuno y NPK en una zona con una gran vocación ganadera (A Pastoriza, Lugo). Se pretende conocer el grado de influencia de la fertilización sobre los niveles de estos elementos. Los suelos elegidos se desarrollaron a partir de pizarras (SN2, P4) y de cuarcitas de la Serie de Cándana (SN1, P1, P2, P3, P5). Los suelos forestales presentaron pH ácido (4,58-4,68), elevada saturación del complejo de cambio por Al (75-90%) y baja concentración de P disponible (4,78-11,96 mg kg-1); estos parámetros mejoran en los suelos de pradera como consecuencia de las enmiendas y fertilizantes aplicados, presentando un pH entre 5,17 y 7,02, una saturación de Al que varía entre 0,58-59,24% y P disponible entre 5,24 y 42,07 mg kg-1.En relación con los metales pesados, la profundidad de la muestra no afecta de modo significativo a su concentración total, pero sí el material de partida, presentando concentraciones más elevadas de Fe, As, Cu y Ni los suelos desarrollados sobre pizarras, posiblemente debido a la presencia de materiales piríticos. En la mayoría de los casos, los metales pesados estudiados presentan concentraciones totales inferiores a las establecidas como genéricas para suelos desarrollados sobre los respectivos materiales geológicos, y siempre son menores que los límites considerados fitotóxicos. La fertilización aplicada no parece tener una influencia significativa sobre los contenidos totales de estos elementos, con la excepción del Zn en la pradera P4, ya que los suelos naturales en muchos casos presentan valores similares e incluso superiores a los obtenidos en las parcelas fertilizadas.

Wednesday, 18 November 2015

Dissipation kinetics of pre-plant pesticides in greenhouse-devoted soils

Science of the Total Environment, 543 (A) (2016) 1-8


This work was conducted to study the distribution of methyl isothiocyanate (MITC) in greenhouse soils treated with the fumigant dazomet (DZ) from the formulated product “Basamid Granular®”, but also of 1,3-dichloropropene (1,3-D) and chloropicrin (CP) from the fumigant “Agrocelhone NE®”. In order to achieve this aim, several methods for the determination of fumigants residues in soils, but also pepper fruits were optimized and characterized. With independence of the soil depth, no residues of MITC, 1,3-D and CP above the detection limits were observed in soils covered with a polyethylene (PE) film (0.04 mm thick) after 27, 13 and 8 days of treatment, respectively. Liberation and dissipation curves of MITC in soil in presence of a PE film (0.04 mm) used to limit volatilization losses were also obtained. According to the results, the rate of decomposition of DZ into MITC have a half-life of 3.7 days in the surface horizon (5–10 cm) of the soil while in the subsurface horizon (15–20 cm), MITC formation rate is slightly slow (half-life of 3.2 days). With respect to the dissipation process, half-lives lower than 1 day were obtained for both depths (0.8 and 0.9 for the surface and the subsurface horizon, respectively). In the case of 1,3-D and CP in soil, the dissipation half-life of 1,3-D on soils was a bit higher than for CP (2 days vs. 1). In addition, the presence of residues of the fumigants on green pepper fruits grown on the treated soils was not detected as expected.


Sunday, 15 November 2015

Voltammetric analysis of mancozeb and its degradation product ethylenethiourea

Journal of Electroanalytical Chemistry, 758 (2015) 54-58


The purpose of this work was to develop a reliable alternative method for the determination of the dithiocarbamate pesticide mancozeb (MCZ) in formulations. Furthermore, a method for the analysis of MCZ's major degradation product, ethylenethiourea (ETU), was also proposed. Cyclic voltammetry was used to characterize the electrochemical behavior of MCZ and ETU, and square-wave adsorptive stripping voltammetry (SWAdSV) was employed for MCZ quantification in commercial formulations.

It was found that both MCZ and ETU are irreversibly reduced (− 0.6 V and − 0.5 V vs Ag/AgCl, respectively) at the surface of a glassy carbon electrode in a mainly diffusion-controlled process, presenting maximum peak current intensities at pH 7.0 (in phosphate buffered saline electrolyte).

Several parameters of the SWAdSV technique were optimized and linear relationships between concentration and peak current intensity were established between 10–90 μmol L− 1 and 10–110 μmol L− 1 for MCZ and ETU, respectively. The limits of detection were 7.0 μmol L− 1 for MCZ and 7.8 μmol L− 1 for ETU. The optimized method for MCZ was successfully applied to the quantification of this pesticide in two commercial formulations. The developed procedures provided accurate and precise results and could be interesting alternatives to the established methods for quality control of the studied products, as well as for analysis of MCZ and ETU in environmental samples.

Friday, 6 November 2015

“Nun churrasco, hai máis risco de cancro co sol que coa carne”


Fonte: GCiencia

A decisión da OMS de declarar canceríxena a carne procesada debe entenderse en relación á cantidade e o tempo, segundo Jesús Simal, catedrático da Universidade de Vigo.

Desterrar o touciño das nosas comidas? Renunciar ao xamón ou non comelo tanto como nos gustaría? O churrasco, perigoso? Poucas veces unha declaración da Organización Mundial da Saúde (OMS), apoiada polos científicos da Axencia Internacional para a Investigación en Cancro (IARC), é capaz de xerar tanta alarma e discordia. A carne procesada – sometida a procesos de salgadura, como o lacón, ou curada, como o tótem da gastronomía ibérica que é o xamón, pero tamén hamburguesas ou salchichas- entran no grupo 1 de alimentos carcinóxenos. A carne vermella queda baixo sospeita, nun grupo 2A que a sitúa como “probablemente” carcinóxena. Que o tabaco e o lacón estean segundo a OMS no mesmo grupo de produtos canceríxenos fai  tentadora a comparación entre o cigarro e os banquetes carnívoros, máis os científicos que traballan para botar luz sobre a relación entre o consumo de carne e o cancro colorrectal relaxan a alarma. Tamén a propia OMS o fai: é cuestión de cantidades e de tempo.

Jesús Simal é catedrático da área de Coñecemento de Nutrición dirixe o Departamento de Química Analítica e Alimentaria da Universidade de Vigo, no campus de Ourense. As súas investigacións máis recentes versan sobre o factor cárnico no risco de padecer un cancro. Ante a alarma, lembra que é importante ter en conta o tipo de consumo. “O que vén dicir a Axencia Internacional para a Investigación en Cancro”,  interpreta o investigador, “é que altos consumos diarios de carnes procesadas, especialmente as tratadas a altas temperaturas, con procesos de fritura ou á grella, contribúen a un maior risco de cancro colorrectal”. Con todo, o científico lembra que para avaliar o risco real convén agardar o informe da Autoridade Europea de Seguridade Alimentaria. “Os seus ditames serven para analizar a relación entre risco e beneficio derivado do consumo dos alimentos, para así emitir recomendacións en función desta avaliación dunha maneira prudente”, asegura. Ademais, hai detalles sobre o traballo que só se coñecerán cando o IARC publique o estudo monográfico completo nuns meses.

Ao alarmismo xerado pola decisión da OMS Simal recéitalle decisións informadas. “Hai que ter en conta que o risco cero non existe; trátase de minimizalo no posible. Vivir significa precisamente tomar decisións poñendo na balanza vantaxes e inconvenientes. O que si é adecuado é estar informado sobre a magnitude do perigo para calibrar o risco asociado. Son moitos os factores de risco, así que non ten moito sentido atribuílo a un único factor”, opina Simal. Así, na análise dos perigos hai tamén algún paradoxo. “Por exemplo”,  segue o investigador, “no consumo de carne á grella o maior risco de cancro estaría en non usar protector solar mentres se prepara ou mesmo na inhalación de partículas finas de carbón transportados polo fume”.

O cancro é unha sorte de tómbola na que se entra a xogar con máis ou menos papeletas. “Por razóns de tipo xenético, unhas persoas están máis predispostas que outras a padecer un ou outro tipo de enfermidades. Ademais, os nosos hábitos, como a dieta, o exercicio físico, o fumar, o beber alcohol ou a exposición a contaminantes poden condicionar a expresión ou non de xenes que desencadean este tipo de patoloxías. É por iso que é moi importante un equilibrio na dieta de acordo coa pirámide de alimentos saudables: moderar as carnes vermellas procesadas a altas temperaturas e soster un consumo regular dos alimentos recomendados a diario, na súa maioría produtos hortofrutícolas con ingredientes antioxidantes, que reducen o dano oxidativo a nivel celular”. As recomendacións existentes sobre hábitos de vida saudables xa situaban a carne vermella e os seus subprodutos no cumio da pirámide, a dos alimentos ocasionais.

Simal estudou en 2014 xunto a un equipo das universidades de Vigo e Porto os compoñentes canceríxenos da carne á grella e como reducir o seu impacto ao cociñalos. Para entender o aviso da OMS hai que ter en conta que ao asar carne de porco, por exemplo, se están formando uns compoñentes canceríxenos, os hidrocarburos aromáticos policíclicos. “Fórmanse ao contacto directo da carne coa chama, ou con superficies metálicas quentes, pero tamén ao gotear os mollos cárnicos, graxas sobre todo, sobre as brasas. O fume con estes compostos deposítase sobre a superficie da carne, de aí o interese en reducir e limitar estes compostos a doses seguras. Nós estudamos se o marinado previo con cervexas de distinta actividade antioxidante podía reducir os niveis destes compostos. Atopamos que a cervexa negra, de maior actividade antioxidante, reducía os seus niveis nun 60%. A capacidade de inhibición da súa formación aumentou coa capacidade antioxidante da cervexa, o que abre a porta ao estudo do marinado con produtos ricos en antioxidantes, como o viño tinto ou o té, ademais de allos e cebolas unidos a adobos de vinagre ou limón. Contribúen a cambiar a acidez na superficie da carne e preveñen que se fixen a ela os compostos canceríxenos do fume”,explica o catedrático da Universidade de Vigo.

O equilibrio na dieta e manter algúns bos hábitos á hora de cociñar parecen mellor resposta que a de declararlle guerra aberta á churrascada ou ao xamón. Simal recomenda, por exemplo, ter ben limpas as grellas antes de usalas para evitar o contacto da carne con restos xa carbonizados, ou envolver as pezas de carne en papel aluminio para que non haxa contacto directo coa chama ou con superficies metálicas quentes.  Engadir á carne asada algunha hortaliza aporta antioxidantes ao prato.

Algúns trucos e sentido común na dieta, pero tamén a ciencia debería poder reducir os compoñentes canceríxenos das carnes procesadas, lembra Simal. “Os embutidos e o lacón, así como o outros produtos crus curados a base de carnes vermellas obtidas por salgadura, curado, fermentación e afumado, conteñen na súa composición nitratos e nitritos como conservantes para evitar a proliferación de microorganismos patóxenos ou manter a cor vermella das carnes. Poden formar derivados nitrosados como nitrosaminas e nitrosamidas canceríxenas. Por iso se limitan as doses residuais destes compostos a niveis seguros para os consumidores. Ademais estase investigando a substitución parcial ou total destes aditivos con extractos de plantas con propiedades antimicrobianas e antioxidantes. Malia este coñecemento, aínda non se comprende completamente como se incrementa o risco de cancro pola carne vermella ou procesada”.

O ditame da OMS alarma a sociedades consumidoras de carne e confirma o que o coñecemento científico – “sempre suxeito a revisión, estudo e modificación”, matiza Simal- xa advertía: que un consumo excesivo de carne –máis de 500 gramos á semana xa  é demasiado-  aumenta o risco dun cancro colorrectal. Pero dentro dunha dieta equilibrada non hai razóns para desterrar as carnes nin os seus nutrintes. “O problema é que cada vez somos máis carnívoros, e consómese carne case a diario, máis en homes que en mulleres, e esta tendencia é peor nas xeracións máis novas. Ademais, a nosa maior lonxevidade fai que aumente o risco de enfermidades crónicas e dexenerativas, e de aí a conveniencia duns hábitos de vida saudables”.

A súa presenza varía en distintas rexións do mundo porque no que respecta á comida hai hábitos para describir até cansar. “Non existen patróns nutricionais bioloxicamente determinados, senón hábitos alimentarios culturalmente herdados”, lembra Simal, que lembra que o omnívoro ser humano pode apreciar “dende a termita até a balea e hai pobos como os inuit, que consomen sobre todo carne e peixe e outros que se alimentan case unicamente de cereais”.

Friday, 23 October 2015

O aceite galego, saudable e con valor diferencial


A produción de aceite en Galicia como actividade xeralizada é historicamente constatable ata o século XVIII. A partir dese momento comeza o seu declive ata case a súa desaparición. Foi a partir de ben entrada a década dos 90 cando se comezou a producir un tímido auxe da actividade oliveira na comunidade. Na actualidade por unha banda estase a fomentar a plantación de variedades principais, a arbequina e/ou picual, coa finalidade de alcanzar unha produción oleícola intensiva a curto prazo, e, doutra banda, estase a recuperar oliveiras centenarias das variedades coñecidas polos olivicultores locais como brava e mansa para elaborar aceites únicos. Para protexer e garantir este valor diferencial dos aceites elaborados con exemplares de oliveiras centenarias, a investigadora Patricia Reboredo abordou na súa tese de doutoramento unha profunda análise das súas características.

A tese, titulada Caracterización aromática e fenólica de olivas e aceites de oliva producidos en Galicia, foi realizada na Facultade de Ciencias do campus de Ourense baixo a dirección de Jesús Simal, Beatriz Cancho e Carmen González, da Área de Nutrición e Bromatoloxía do Departamento de Química Analítica e Alimentaria da Universidade de Vigo. “En primeiro lugar, o noso obxectivo foi identificar correctamente este material vexetal mediante técnicas moleculares para demostrar que non se trata de variedades de oliveiras rexistradas no Banco de Germoplasma Mundial da Oliveira (BGMO) da Universidade de Córdoba”. Como resultado, detectouse que o perfil molecular das 20 mostras avaliadas coincidiu co da variedade brava, actualmente en fase de rexistro. Unicamente o perfil de dúas mostras non puido asociarse a ningunha das variedades incluídas en devandito BGMO. "Este feito pode deberse a que sexan variedades autóctonas descoñecidas ata o momento ou ben variedades sen introducir aínda no BGMO", comenta a investigadora.

Características aromáticas
Centrándose na análise das características dos aceites galegos, Reboredo sinala que “a calidade sensorial dos aceites elaborados con variedades principais está amplamente avaliada e recoñecida. Con todo, os aceites de oliva virxe obtidos a partir de variedades non clasificadas ata o momento, como os galegos, poderían presentar características diferentes e mesmo superiores a estes”. Se esto se demostra, engade, non só se podería potenciar a elaboración de aceites monovarietais destas variedades minoritarias senón que ademais se poderían deseñar novos aceites resultantes de procesos de moenda ou mestura con outras variedades. 

Na avaliación sensorial realizada durante a investigación, feita unicamente nos aceites elaborados con olivas brava e mansa en diferentes proporcións, os atributos "amargo" e "picante" destacan sobre todo no aceite elaborado cunha maior proporción de brava, mentres que os atributos "doce", "afroitado maduro" e "folla verde" son moi similares en ambos aceites. No desenvolvemento destes novos aceites, a comoenda ou mestura de olivas brava/mansa con arbequina ou picual aumentaron significativamente as series odorantes principais que conforman o perfil sensorial dos aceites e, ao mesmo tempo, a súa funcionalidade debido ao incremento dos compostos fenólicos. 

Na categoría de saudable
En relación á funcionalidade dos aceites, Patricia Reboredo recalca que a Comisión Europea aprobou recentemente a alegación de propiedade saudable para aqueles aceites que conteñan polo menos cinco mg de hidroxitirosol e os seus derivados/por 20 gr de aceite de oliva virxe, tendo en conta que os polifenoles do aceite de oliva contribúen á protección dos lípidos fronte ao dano oxidativo. Segundo apunta a xa doutora ourensá, “os resultados obtidos a partir dun protocolo analítico sinxelo e validado demostraron que os aceites elaborados a partir das olivas brava/mansa satisfán os requisitos esixidos no marco da Unión Europea para poder indicar na etiquetaxe a declaración de propiedade saudable, superando incluso o limiar establecido na lexislación”. 

Perfil aromático non extrapolable da oliva ao aceite
Durante a tese, Reboredo Rodríguez tamén analizou se era posible extrapolar este perfil aromático único das olivas galegas ao aceite. “O aceite de oliva virxe caracterízase, entre outros atributos, polo seu aroma asociado á presenza minoritaria de compostos volátiles que se transfiren ao aceite, en gran medida, desde a moenda do froito. Comprobar se o perfil aromático das olivas se pode extrapolar ao seu correspondente aceite permitiría avaliar o potencial aromático de cada variedade previamente á elaboración do aceite”, comenta a investigadora. 

En base aos resultados obtidos, demostrouse que o perfil aromático das olivas non é extrapolable posto que a actividade das encimas endóxenas ao longo do proceso de elaboración é o principal factor que determina a síntese dos compostos volátiles máis relevantes do aroma do aceite. Na investigación, demostrou que a actividade destas encimas pódese modular variando distintos parámetros durante o proceso de elaboración, sendo a temperatura e o tempo da etapa de batido os máis importantes. “A elección da combinación temperatura/tempo de batido dependerá de se se prioriza a súa funcionalidade ou o seu aroma, ademais de estar supeditada ao rendemento da extracción”, afirma por último.

Fonte: DUvi

Thursday, 22 October 2015

Postdoctoral position - Design of new polyurethane-based hydrogels


Topic:
Hydrogels find numerous applications in medicine. The goal of this project is to develop together with an industrial partner, new functional pre-polymers systems as a component of polyurethane based hydrogels. The project will be constituted of the synthesis and characterization of pre-polymers, the synthesis and preparation of hydrogels based on these polymers and finally by evaluation of physico-chemical, physical and mechanical properties of the resulting materials (swelling ratio, wettability, rheology, flexibility, mechanical properties, roughness of the surface, etc…)

The laboratory and the team:
This postdoctoral position will be carried out in the frame of an industrial cooperation at the laboratory of Photochemistry and Macromolecular Engineering (LPIM) in Mulhouse. The project will be held within the team Chemistry and Physico-Chemistry of Polymers under the supervision of Professors Sophie BISTAC and Jean-François STUMBE 

Profile of the applicant:
The applicant must have strong competencies in the area of synthesis and characterisation of polymers as well as in physico-chemistry of polymeric material. An experience in the specific area of complex macromolecular architectures and / or of polyurethanes (chemistry and physico-chemistry) is a must. In addition, experience in the domain of hydrogels will be strongly appreciated. Finally, the applicant should have a strong ability in French and/ or in English (spoken and written). 

For more information and for application, please contact:

Pr. Jean-François STUMBE 
Tel. ++33 (0)3 89 33 67 59

A detailed CV, plus motivation letter and reference letter(s) from the PhD supervisor and last(s) postdoc(s) supervisor are required for evaluation of the application.

Université de  Haute-Alsace
Laboratoire de Photochimie et d’Ingénierie Macromoléculaires
3 rue Alfred Werner - 68093 MULHOUSE CEDEX - FRANCE
Tél. +33 (0)389 335 025 - Fax +33 (0)389 335 014


Wednesday, 21 October 2015

A Critical Review on the Applications of Artificial Neural Networks in Winemaking Technology

Critical Reviews in Food Science and Nutrition


Since their development in 1943, artificial neural networks were extended into applications in many fields. Last twenty years have brought their introduction into winery, where they were applied following four basic purposes: authenticity assurance systems, electronic sensory devices, production optimization methods, and artificial vision in image treatment tools, with successful and promising results. This work reviews the most significant approaches for neural networks in winemaking technologies with the aim of producing a clear and useful review document.



Friday, 16 October 2015

Characterization of Xanthophyll Pigments, Photosynthetic Performance, Photon Energy Dissipation, Reactive Oxygen Species Generation and Carbon Isotope Discrimination during Artemisinin-Induced Stress in Arabidopsis thaliana

PLOS ONE
DOI:10.1371/journal.pone.0114826


Artemisinin, a potent antimalarial drug, is phytotoxic to many crops and weeds. The effects of artemisinin on stress markers, including fluorescence parameters, photosystem II photochemistry, photon energy dissipation, lipid peroxidation, reactive oxygen species generation and carbon isotope discrimination in Arabidopsis thaliana were studied. Arabidopsis ecotype Columbia (Col-0) seedlings were grown in perlite and watered with 50%Hoagland nutrient solution. Adult plants of Arabidopsis were treated with artemisinin at 0, 40, 80, 160 μM for one week. Artemisinin, in the range 40–160 μM, decreased the fresh biomass, chl a, b and leafmineral contents. Photosynthetic efficiency, yield and electron transport rate in Arabidopsis were also reduced following exposure to 80 and 160 μM artemisinin. The ΦNPQ and NPQ were less than control. Artemisinin treatment caused an increase in root oxidizability and lipid peroxidation (MDA contents) of Arabidopsis. Calcium and nitrogen contents decreased after 80 and 160 μM artemisinin treatment compared to control. δ13C values were less negative following treatment with artemisinin as compared to the control. Artemisinin also decreased leaf protein contents in Arabidopsis. Taken together, these data suggest that artemisinin inhibits many physiological and biochemical processes in Arabidopsis.

Thursday, 15 October 2015

Identification of Relevant Phytochemical Constituents for Characterization and Authentication of Tomatoes by General Linear Model Linked to Automatic Interaction Detection (GLM-AID) and Artificial Neural Network Models (ANNs)

PLOS ONE
DOI: 10.1371/journal.pone.0128566


There are a large number of tomato cultivars with a wide range of morphological, chemical, nutritional and sensorial characteristics. Many factors are known to affect the nutrient content of tomato cultivars. A complete understanding of the effect of these factors would require an exhaustive experimental design, multidisciplinary scientific approach and a suitable statistical method. Some multivariate analytical techniques such as Principal Component Analysis (PCA) or Factor Analysis (FA) have been widely applied in order to search for patterns in the behaviour and reduce the dimensionality of a data set by a new set of uncorrelated latent variables. However, in some cases it is not useful to replace the original variables with these latent variables. In this study, Automatic Interaction Detection (AID) algorithm and Artificial Neural Network (ANN) models were applied as alternative to the PCA, AF and other multivariate analytical techniques in order to identify the relevant phytochemical constituents for characterization and authentication of tomatoes. To prove the feasibility of AID algorithm and ANN models to achieve the purpose of this study, both methods were applied on a data set with twenty five chemical parameters analysed on 167 tomato samples from Tenerife (Spain). Each tomato sample was defined by three factors: cultivar, agricultural practice and harvest date. General Linear Model linked to AID (GLM-AID) tree-structured was organized into 3 levels according to the number of factors. p-Coumaric acid was the compound the allowed to distinguish the tomato samples according to the day of harvest. More than one chemical parameter was necessary to distinguish among different agricultural practices and among the tomato cultivars. Several ANN models, with 25 and 10 input variables, for the prediction of cultivar, agricultural practice and harvest date, were developed. Finally, the models with 10 input variables were chosen with fit’s goodness between 44 and 100%. The lowest fits were for the cultivar classification, this low percentage suggests that other kind of chemical parameter should be used to identify tomato cultivars.

Wednesday, 14 October 2015

El campus crea nuevos productos para el consumo humano y animal


El campus crea nuevos productos para el consumo humano y animal


En el apartado de calidad y seguridad alimentaria el CIA desarrolló en el último lustro cinco proyectos publicó más de 35 artículos en revistas de prestigio internacional. Uno de sus estudios actuales es comparar la riqueza en compuestos polifenólicos antioxidantes y compuestos volátiles aromáticos de productos hortofrutícolas nativos y de las variedades comerciales. La uva es protagonista de una parte de ese trabajo, que también estudia el efecto en el contenido y actividad aromática y funcional del producto de los tratamientos de conservación tras la cosecha y de los procesos de transformación de la industria. En el ámbito de la producción sostenible, este centro estudia los efectos de la actividad humana sobre el entorno natural en el que desarrolla la actividad agraria. Uno de sus proyectos es la interacción de los contaminantes agrarios y ambientales (plaguicidas, por ejemplo) con el sistema suelo-agua-cultivo-alimento. Los investigadores evalúan también la persistencia de estos residuos en los productos que consumimos. Doce proyectos y más de 50 artículos son el fruto directo del trabajo en los últimos 5 años en ese terreno. El tercer eje estratégico es el desarrollo de nuevos productos para la alimentación humana y animal, por ejemplo, presentaciones tipo surimi a partir de especies de pescado de baja demanda o recuperación de componentes bioactivos usando subproductos como sueros de leche.

Tuesday, 13 October 2015

La investigación universitaria impulsa la economía rural


El CIA desarrolló en 5 años 22 proyectos agroambientales y alimentarios.


La investigación universitaria se está convirtiendo en un elemento dinamizador del desarrollo rural sostenible, favoreciendo la revalorización de los recursos del territorio por su contribución a las diferentes actividades de las industrias agroalimentarias.

Esta repercusión socioeconómica en una provincia desangrada demográficamente es una de las consideraciones de la última memoria del Centro de Investigacións Agroambientais e Alimentarias (CIA), una agrupación estratégica de investigación universitaria -la única gallega en un campus periférico- que cuenta con financiación de la Consellería de Cultura, Educación e Ordenación Universitaria.

De las ocho agrupaciones estratégicas de investigación con financiación autonómica, tres versan sobre nuevas tecnologías; dos sobre medicina; una sobre química y otra sobre el mar. La ourensana, dirigida por Jesús Simal, es la única que vincula los ámbitos ambiental, agrario y alimentario en la cadena de producción de alimentos. Es en ese terreno en el que está llamada a ser «unha peza chave para o futuro exitoso do sector agroalimentario» y un apoyo para proyectos económicos de éxito que asienten población en la geografía rural gallega.

Constituido por grupos de investigación del CITI (Centro de Investigación, Transferencia e Innovación, de la Tecnópole), la Facultad de Ciencias de Ourense y la Facultad de Bioloxía de Vigo, el CIA reúne a varias decenas de investigadores. Trabajan en torno a tres ejes: la producción primaria sostenible, el desarrollo de nuevos productos y la calidad y seguridad alimentaria.

Su participación en programas de formación y la investigación cooperativa y multidisciplinar son dos de sus fortalezas. Incrementar la transferencia de los resultados de sus investigaciones al sector público y al privado, y aumentar su presencia en proyectos internacionales, son sus retos.

Colaboración con empresas

La repercusión de sus investigaciones queda patente con los programas de colaboración con 38 empresas alimentarias con interés en productos como aceite, agua, pescado, aves, galletas, bebidas alcohólicas, lácteos, carnes, platos preparados, pan o surimi. Esa colaboración con el sector empresarial ha dado lugar a numerosos proyectos de investigación y ha supuesto una fuente de financiación a mayores, ya que el 34% de los fondos del centro entre 2012 y 2014 procedía de firmas privadas.

Los acuerdos de transferencia y explotación de las investigaciones han dado resultados concretos, como el diseño de procedimientos para obtener aguardiente de castañas y el de un extracto gelificable de proteínas a partir del agua de cocción de pescado, así como la composición para aumentar el contenido proteico en carne de pescado y el procedimiento para su aplicación.

Monday, 12 October 2015

Manufacture of furfural in biphasic media made up of an ionic liquid and a co-solvent

Industrial Crops and Products, 77, 163-166 (2015)
DOI: 10.1016/j.indcrop.2015.08.048


Xylose was converted into furfural operating in a medium containing the acidic ionic liquid (AIL) 1-butyl-3-methylimidazolium hydrogen sulfate, in the presence of toluene as a co-solvent. No catalytic species different from the AIL were needed for furfural production from xylose. Operating at 100-140. °C for 15-480. min in media containing 10. g xylose/100. g AIL and 2-4. g toluene/g (AIL. +. xylose), most furfural generated in the AIL phase was transferred to the co-solvent, limiting the losses caused by undesired side reactions. Operating under optimal conditions (140. °C for 240. min using 4.4. g toluene/g initial AIL phase), xylose was almost completely consumed, and furfural was obtained at 73.8% of the stoichiometric yield.

Sunday, 11 October 2015

Agricultural residue valorization using a hydrothermal process for second generation bioethanol and oligosaccharides production

Bioresource Technology, 191, 263-270 (2015)
DOI: 10.1016/j.biortech.2015.05.035


In the present work, the hydrothermal valorization of an abundant agricultural residue has been studied in order to look for high added value applications by means of hydrothermal pretreatment followed by fed-batch simultaneous saccharification and fermentation, to obtain oligomers and sugars from autohydrolysis liquors and bioethanol from the solid phase. Non-isothermal autohydrolysis was applied to barley straw, leading to a solid phase with about a 90% of glucan and lignin and a liquid phase with up to 168gkg-1 raw material valuable hemicellulose-derived compounds. The solid phase showed a high enzymatic susceptibility (up to 95%). It was employed in the optimization study of the fed-batch simultaneous saccharification and fermentation, carried out at high solids loading, led up to 52gethanol/L (6.5% v/v). 

Saturday, 10 October 2015

Simple and efficient furfural production from xylose in media containing 1-butyl-3-methylimidazolium hydrogen sulfate

Industrial and Engineering Chemistry Research, 54, 8368-8373 (2015)
DOI: 10.1021/acs.iecr.5b01771


The acidic 1-butyl-3-methylimidazolium hydrogen sulfate ([bmim][HSO4]) ionic liquid was explored as both a reaction medium and a catalyst in the furfural production from xylose. Preliminary experiments were carried out at 100-140 °C for 15-480 min in systems containing just xylose dissolved in [bmim][HSO4] in the absence of externally added catalysts. More than 95% xylose conversion was achieved when operating at 120 or 140 °C for 300 and 90 min, respectively; but just 36.7% of the initial xylose was converted to furfural. Operation in biphasic reaction systems (in the presence of toluene, methyl-isobutyl ketone or dioxane as extraction solvents) at 140 °C under selected conditions resulted in improved furfural production (73.8%, 80.3%, and 82.2% xylose conversion to furfural for the cited extraction solvents, respectively). 

Friday, 9 October 2015

Biomass, sugar, and bioethanol potential of sweet corn

GCB Bioenergy, 7, 153-160 (2015)
DOI: 10.1111/gcbb.12136


Sweet corn is a widely distributed crop that generates agricultural waste without significant commercial value. In this study, we show that sweet corn varieties produce large amounts of residual biomass (10 t ha-1) with high content of soluble sugars (25% of dry matter) in a short growing season (3 months). The potential ethanol production from structural and soluble sugars extracted from sweet corn stover reached up to 4400 l ha-1 in the most productive hybrids, 33% of which (1500 l ha-1) were obtained by direct fermentation of free sugars. We found wide genetic variation for biomass yield and soluble sugars content suggesting that those traits can be included as complementary traits in sweet corn breeding programs. Dual-purpose sweet corn hybrids can have an added value for the farmers contributing to energy generation without affecting food supply or the environment.

Thursday, 8 October 2015

Barley straw (Hordeum vulgare) as a supplementary raw material for Eucalyptus camaldulensis and Pinus sylvestris kraft pulp in the paper industry

BioResources, 10 (2) 3682-3693 (2015)
DOI: 10.15376/biores.10.2.3682-3693


The present study shows that barley straw (Hordeum vulgare) can be a supplementary raw material of softwoods and hardwoods such as Pinus sylvestris and Eucalyptus camaldulensis, respectively, for the production of cellulose and paper, reducing an agricultural residue that has no added value. Barley straw has a lower content of cellulose at 36.4% than P. sylvestris and E. camaldulensis, but it contains a lower quantity of lignin, 15.9%. After pulping with soda anthraquinone (AQ), high contents of cellulose (56.5 to 67.5%) and holocellulose (>80%) were attained. Paper sheet properties were able to reach, and even improve upon, those of wood species (Pinus and Eucalyptus) pulped with kraft. Better values of total yield (56.5%), Kappa number (8.9), and ISO brightness (36.4%), were attained for paper sheets from barley straw pulp versus E. camaldulensis and P. sylvestris, respectively, and comparable values for viscosity, tensile, and burst index were obtained.

Wednesday, 7 October 2015

A new method for determining the sources of airborne particles

Journal of Environmental Management
DOI: 10.1016/j.jenvman.2015.03.037


Air quality is a major issue for humans owing to the fact that the content of particles in the atmosphere has multiple implications for life quality, ecosystem dynamics and environment. Scientists are therefore particularly interested in discovering the origin of airborne particles. A new method has been developed to model the relationship between the emission surface and the total amount of airborne particles at a given distance, employing olive pollen and olive groves as examples. A third-degree polynomial relationship between the air particles at a particular point and the distance from the source was observed, signifying that the nearest area to a point is not that which is most correlated with its air features. This work allows the origin of airborne particles to be discovered and could be implemented in different disciplines related to atmospheric aerosol, thus providing a new approach with which to discover the dynamics of airborne particles.

Tuesday, 6 October 2015

Voltammetric analysis of mancozeb and its degradation product ethylenethiourea

Journal of Electroanalytical Chemistry


The purpose of this work was to develop a reliable alternative method for the determination of the dithiocarbamate pesticide mancozeb (MCZ) in formulations. Furthermore, a method for the analysis of MCZ's major degradation product, ethylenethiourea (ETU), was also proposed. Cyclic voltammetry was used to characterize the electrochemical behaviour of MCZ and ETU, and square-wave adsorptive stripping voltammetry (SWAdSV) was employed for MCZ quantification in commercial formulations.

It was found that both MCZ and ETU are irreversibly reduced (−0.6 V and −0.5 V vs Ag/AgCl, respectively) at the surface of a glassy carbon electrode in a mainly diffusion-controlled processes, presenting maximum peak current intensities at pH 7.0 (in phosphate buffered saline electrolyte).

Several parameters of the SWAdSV technique were optimized and linear relationships between concentration and peak current intensity were established between 10–90 μmol L-1 and 10–110 μmol L-1 for MCZ and ETU, respectively. The limits of detection were 7.0 μmol L-1 for MCZ and 7.8 μmol L-1 for ETU. The optimized method for MCZ was successfully applied to the quantification of this pesticide in two commercial formulations. The developed procedures provided accurate and precise results and could be interesting alternatives to the established methods for quality control of the studied products, as well as for analysis of MCZ and ETU in environmental samples.

Sunday, 4 October 2015

High-throughput HPLC–MS/MS determination of the persistence of neonicotinoid insecticide residues of regulatory interest in dietary bee pollen

Analytical and Bioanalytical Chemistry


The aim of this work is the development of a simple, fast, quantitative, and economic method for the determination of neonicotinoid insecticide residues in dietary bee pollen. Several parameters of the method, such as extraction solvent, extraction time, and solid-phase extraction sorbents for purification [silica, C18, primary–secondary amine (PSA), and Envi-Carb II/PSA], were studied. The final proposed method based on solid–liquid extraction with hexane, cleanup with Supelclean™ Envi-Carb II/PSA cartridges, and subsequent analysis by high-performance liquid chromatography with tandem mass spectrometry was validated and applied to the analysis of commercial bee pollen samples from different geographical zones. Method performance was assessed by the evaluation of several quality parameters of the method, such as recovery values, repeatability, reproducibility, linearity, and limits of detection and quantification. Matrix effects on the chromatographic signal were also studied. The quality parameters of the method were equivalent to or better than those obtained with previously published methods, with recoveries between 81 and 99 % and repeatabilities lower than 8.8 %. The detection and quantification limits were in the ranges 0.2-2.2 μg kg-1 and 0.4-4.3 μg kg-1, respectively.

Saturday, 3 October 2015

Thirty-four identifiable airborne fungal spores in Havana, Cuba

Annals of Agricultural and Environmental Medicine
DOI: 10.5604/12321966.1152068



The airborne fungal spore content in Havana, Cuba, collected by means a non-viable volumetric methodology, was studied from November 2010 – October 2011. The study, from a qualitative point of view, allowed the characterization of 29 genera and 5 fungal types, described following the Saccardo´s morphotypes, as well as their morphobiometrical characteristics. In the amerospores morphotype, the conidia of 7 genera (with ascospores, basidiospores and uredospores) and 5 fungal types were included. Among phragmospores morphotype, the ascospores and conidia of 12 different genera were identified. The dictyospores morphotype only included conidial forms from 6 genera. Finally, the less frequent morphotypes were staurospores, didymospores and distosepted spores. In general, the main worldwide spread mitosporic fungi also predominated in the Havana atmosphere, accompanied by some ascospores and basidiospores. Cladosporium cladosporioides type was the most abundant with a total of 148,717 spores, followed by Leptosphaeria, Coprinus and the Aspergillus-Penicillium type spores, all of them with total values ranging from 20,591 – 16,392 spores. The higher monthly concentrations were registered in January (31,663 spores) and the lowest in December (7,314 spores). Generally, the average quantity of spores recorded during the months of the dry season (20,599 spores) was higher compared with that observed during the rainy season (17,460 spores).

Friday, 2 October 2015

Challenges in Relating Concentrations of Aromas and Tastes with Flavour Features of Foods

Critical Reviews in Food Science and Nutrition


Flavour sensations in food are highly influenced by the aroma and taste compounds. Reviewing the extensive literature of recent years in this field has shown that the reconstitution of flavour based on aroma and taste compounds poses numerous problems. These are of different nature and include among others (a) chemical transformations among these compounds, (b) changes in the concentrations of the compounds responsible for the perceived flavour, (c) interactions among the chemical compounds that enhance or reduce a specific flavour sensation, and finally, (d) the complexity of the different food matrices and its influence in the flavour perception. Another difficulty that flavour scientists must face is how to properly model and visualize the complex relationships existing between the chemical composition of foods and the flavour perception. These problems have repercussions on the reconstitution of the flavour signature of food based on the natural concentrations of its key aroma and taste compounds. Therefore, the main aim of this review is to deal with all these issues to propose potential solutions for a robust transformation in a science-based quality approach.

Thursday, 1 October 2015

Linear Polyethers as Additives for AOT-Based Microemulsions: Prediction of Percolation Temperature Changes Using Artificial Neural Networks

Tenside Surfactants Detergents: 52 (2015) 264-270.
doi: 10.3139/113.110374
 
Predictive models based on artificial neural networks have been developed for the percolation threshold of AOT based microemulsions with addition of either glymes or polyethylene glycols. Models have been built according to the multilayer perceptron architecture, with five input variables (concentration, molecular mass, log P, number of C and O of the additive). Best model for glymes has a topology of five input neurons, five neurons in a single hidden layer and one output neuron. Polyethylene glycol model's architecture consists in five input neurons, three hidden layers with eight neurons in both first two and five in the last, and a neuron in the last output layer. All of them have a good predictive power according to several quality parameters.

Sunday, 30 August 2015

Higher peroxidase activity, leaf nutrient contents and carbon isotope composition changes in Arabidopsis thaliana are related to rutin stress

Journal of Plant Physiology
DOI: 10.1016/j.jplph.2014.05.009


Rutin, a plant secondary metabolite that is used in cosmetics and food additive and has known medicinal properties, protects plants from UV-B radiation and diseases. Rutin has been suggested to have potential in weed management, but its mode of action at physiological level is unknown. Here, we report the biochemical, physiological and oxidative response of Arabidopsis thaliana to rutin at micromolar concentrations. It was found that fresh weight; leaf mineral contents (nitrogen, sodium, potassium, copper and aluminum) were decreased following 1 week exposure to rutin. Arabidopsis roots generate significant amounts of reactive oxygen species after rutin treatment, consequently increasing membrane lipid peroxidation, decreasing leaf Ca2+, Mg2+, Zn2+, Fe2+ contents and losing root viability. Carbon isotope composition in A. thaliana leaves was less negative after rutin application than the control. Carbon isotope discrimination values were decreased following rutin treatment, with the highest reduction compared to the control at 750μM rutin. Rutin also inhibited the ratio of CO2 from leaf to air (ci/ca) at all concentrations. Total protein contents in A. thaliana leaves were decreased following rutin treatment. It was concluded carbon isotope discrimination coincided with protein degradation, increase lipid peroxidation and a decrease in ci/ca values may be the primary action site of rutin. The present results suggest that rutin possesses allelopathic potential and could be used as a candidate to develop environment friendly natural herbicide.



Thursday, 20 August 2015

Modeling the batch bacteriocin production system by lactic acid bacteria by using modified three-dimensional Lotka-Volterra equations

Biochemical Engineering Journal
DOI: 10.1016/j.bej.2014.04.010


Different batch cultures of Lactococcus lactis CECT 539, a nisin-producing strain, were carried out in culture media prepared with whey and mussel processing wastes. From these cultures, a reasonable system of differential equations, similar to the three-dimensional Lotka-Volterra two predators-one prey model, was set up to describe, for the first time, the relationship between the absolute rates of growth, pH drop and nisin production.Thus, the nisin production system was described as a three-species (pH, biomass and nisin) ecosystem. In this case, both nisin and biomass production were considered as two pH-dependent species that compete for the nitrogen source. Excellent agreement (R2 values ≥0.9885) resulted between model predictions and the experimental data, and significant values for all the model parameters were obtained. The developed model was demonstrated (R2 values ≥0.9874) for five batch cultivations of the strains L. lactis CECT 539 in MRS broth and Lactobacillus sakei LB 706 (sakacin A producer), Pediococcus acidilactici LB42-923 (pediocin AcH producer), L. lactis ATCC 11454 (nisin producer) and Leuconostoc carnosum Lm1 (leuconocin Lcm1 producer) in TGE broth. These results suggest that the batch bacteriocin production system in these culture media can be successfully described by using the Lotka-Volterra approach.

Saturday, 15 August 2015

Assessment of potential probiotic properties and multiple bacteriocin encoding-genes of the technological performing strain Enterococcus faecium MMRA

Food Control
DOI: 10.1016/j.foodcont.2013.09.044


In the present study, Enterococcus faecium MMRA, a safety and technological performing strain, previously isolated from a well-known fermented dairy product of Tunisia, was evaluated for certain properties relevant to probiotic including acid and bile tolerance, gastrointestinal juice resistance and adhesive properties. Acidic pH (2.0-5.0) and bile salt concentrations of 0.3% were used as stress conditions. The adhesive properties were assessed by determination of bacterial hydrophobicity. The strain MMRA showed interesting features such as high tolerance to gastrointestinal tract transit, an extremely high survival rates under stress caused by acidic pHs or bile salts, and a high adhesive potential linked to the elevated percentage of hydrophobicity. Furthermore, the genome of this strain was examined for the occurrence of known enterocin (enterococcal bacteriocins) genes by means of specific PCR assays and this study revealed the genes coding for enterocins A, B, P and X. Although the joint production of these bacteriocins has not been verified, producers of multiple enterocins could have a great technological potential as protective and/or probiotic cultures in the food industry. The results suggested that E.faecium MMRA should be considered as a potential probiotic which meets the criteria to enhance healthy attributes of fermented dairy product besides both of hygienic and sensory aspects.

Wednesday, 22 July 2015

Cr(VI) sorption/desorption on pine sawdust and oak wood ash

International Journal of Environmental Research and Public Health
DOI: 10.3390/ijerph120808849


The objective of this work was to study Cr(VI) sorption/desorption on two by-products from the wood industry: pine sawdust and oak wood ash. The retention/release experiments were carried out using standard batch-type trials. In the sorption-phase experiments, pine sawdust showed 23% sorption when a concentration of 100 mg Cr(VI)·L-1 was added, whereas sorption on oak wood ash was 17%. In the desorption-phase, chromium release was clearly higher from pine sawdust than from oak wood ash (98% and 66%, respectively). Sorption curves were well fitted to the Freundlich and Lineal models. In view of the results, both materials can be considered of very limited value to remove Cr from polluted soil and water, which can be of relevance regarding its appropriate use as biosorbents and recycled by-products.




Monday, 20 July 2015

Metalaxyl mobility in acid soils: Evaluation using different methods

International Journal of Environmental Science and Technology 
DOI: 10.1007/s13762-014-0612-1


In the present work, different methods were tested to evaluate the adsorption and desorption of metalaxyl in two acid soils with different organic carbon and clay contents. The three methods (batch, stirred flow chamber and column) that were examined produced similar findings when the two soils were compared: (a) the metalaxyl adsorption capacity was higher in the soil with higher organic matter and clay content, and (b) the soil with the lower organic matter and clay contents provided higher adsorption rate constants. In the two soils tested, the metalaxyl adsorbed in the soil was highly reversible. When only one soil was considered, the different methods yielded different results. The metalaxyl adsorption and its rate were higher with the stirred flow chamber than in the column experiments, and in the column experiments, the total metalaxyl adsorption and the rate of adsorption were higher than in the batch experiments. The percentages of metalaxyl desorbed from the soil were similar in the stirred flow chamber and column experiments, but in the batch experiments, the percentages were significantly lower. In the stirred flow chamber experiments, the desorption processes were faster than the adsorption processes, while in the column experiments, the adsorption and desorption processes exhibited similar rates.

Thursday, 16 July 2015

Time evolution of the general characteristics and Cu retention capacity in an acid soil amended with a bentonite winery waste

Journal of Environmental Management
DOI: 10.1016/j.jenvman.2014.12.024


The effect of bentonite waste added to a "poor" soil on its general characteristic and copper adsorption capacity was assessed. The soil was amended with different bentonite waste concentrations (0, 10, 20, 40 and 80Mgha-1) in laboratory pots, and different times of incubation of samples were tested (one day and one, four and eight months). The addition of bentonite waste increased the pH, organic matter content and phosphorus and potassium concentrations in the soil, being stable for P and K, whereas the organic matter decreased with time. Additionally, the copper sorption capacity of the soil and the energy of the Cu bonds increased with bentonite waste additions. However, the use of this type of waste in soil presented important drawbacks for waste dosages higher than 20Mgha-1, such as an excessive increase of the soil pH and an increase of copper in the soil solution.

Wednesday, 15 July 2015

Heavy metals in pastureland soils situated in A Pastoriza (NW Spain) treated with cattle slurry and NPK fertilizers

Spanish Journal of Soil Science, 5, 154-164 (2015)
DOI: 10.3232/SJSS.2015.V5.N2.05


In Galicia (NW Spain), pasturelands cover a broad extension and are mainly used to feed cattle. Farms are managed in an intensive manner, using cattle slurry and inorganic fertilizers to increase pasture production, but also increasing risks of heavy metal pollution. In this work we studied the influence of fertilization practices on total concentrations and in-depth distribution of heavy metals and related elements (As, Cd, Cr, Cu, Mn, Ni, Pb and Zn) in two forest soils (SN1, SN2) and five pastureland soils (P1-P5) fertilized with cattle slurry and NPK, in a broadly exploded farmland area (A Pastoriza, Lugo). Soils SN2 and P4 were developed over slate, whereas soils SN1, P1, P2, P3 and P5 evolved on Candana quartzite. Forest soils presented acid pH (4.58-4.68), high Al saturation (75-90%), and low available P concentration (4.78-11.96 mg kg-1), whereas those parameters exhibited better scores in the pastureland soils, due to previous amendment and fertilization practices, thus giving pH 5.17-7.02, Al saturation 0.58-59.24%, and available P 5.24-42.07 mg kg-1. Regarding heavy metals, soil depth did not affect significantly to total concentrations, contrary to that happening with parent material, with higher As, Cu, Fe, and Ni concentrations found in soils over slate (possibly due to the presence of pyritic materials). In most cases, heavy metal total concentrations were lower than that considered as reference background levels for soils developed over each of the parent materials, and were always lower than that considered phyto-toxic. In this study, natural soils usually presented heavy metal total contents similar or even higher than that of the fertilized soils (unless Zn in the P4 pastureland), thus indicating that the spread doses of fertilizers did not influence significantly their concentration levels.

Tuesday, 14 July 2015

Profiling, distribution and levels of carcinogenic polycyclic aromatic hydrocarbons in traditional smoked plant and animal foods

Food Control, 59 (2016) 581–590


The purpose of this study was to evaluate the concentration of polycyclic aromatic hydrocarbons (PAH8 plus fluoranthene and pyrene) in “Pan de Cea” bread, “Pimentón de La Vera” paprika, “San Simón da Costa”, “Idiazábal” and “Humus” cheeses, and “Chorizo” garlic pork sausage. Results obtained showed that harmless low molecular weight compounds (Fluoranthene and Pyrene) represented the major contribution to the total PAHs. The most important PAHs according to the levels found were those in the 4 PAHs group (the rest of PAHs to add a total of 8 were contributing at very low levels). PAH4 and PAH8 levels showed percentages ranging from 6.0 to 7.0 % in bread, 16–17 % in paprika, 23–28 % in cheese and 20–24 % in meat sausages, respectively. B(a)P did not exceed the imposed limits in the EU. Bread showed the lower PAH concentration (3.4 μg/kg) followed by cheese (88 μg/kg), smoked sausage (1779 μg/kg) and paprika (9937 μg/kg). “Pimentón de la Vera” paprika is a condiment consumed in small quantities. The PAH profile had in common the decrease in PAH content as their molecular weight increased. These results showed that the contamination detected in “Pan de Cea” bread samples was very low, so that the consumption of this product does not pose a health risk. In cheese samples, the PAH contamination was detected meanly in rind, that accounted around the 100% of the total contamination. In meat sausages samples, the 90% of the total PAHs determined were accumulated in the casing. Considering the edible part, the PAH4 and B(a)P mean contents were below the limit established. Although, the highest PAH levels were detected in “Pimentón de la Vera” paprika, it should be pointed out that this product is a condiment consumed in small quantities and not in an everyday basis, it does not represent a risk for consumers. In cheese and meat sausage, according our estimates, the removal of the external part can be considered a good consumer practices to reduce the ingestion of PAHs.

Sunday, 14 June 2015

A critical review about human exposure to Polychlorinated Dibenzo-p-Dioxins (PCDDs), Polychlorinated Dibenzofurans (PCDFs) and Polychlorinated Biphenyls (PCBs) through foods

Critical Reviews in Food Science and Nutrition, 55 (11), 2015, 1590-1617


Dioxins include polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and part of polychlorinated biphenyls (PCBs). Only the compounds that are chlorinated at the 2,3,7, and 8 positions have characteristic dioxin toxicity. PCDDs, PCDFs and PCBs accumulate in the food chain due to their high lipophilicity, high stability, and low vapor pressure. They are not metabolized easily; however their hydroxylated metabolites are detected in feces. They cause a wide range of endocrine disrupting effects in experimental animals, wildlife, and humans. Endocrine related effects of PCDDs, PCDFs and PCBs on thyroid hormones, neurodevelopment and reproductive development were referenced. In addition, some studies of contamination of foods, bioaccumulation, dietary exposure assessment, as well as challenges of scientific research in these compounds were reviewed.

Saturday, 13 June 2015

A critical review about the health risk assessment of PAHs and their metabolites in foods

Critical Reviews in food science and nutrition, 55 (10), 2015, 1383-1405


Polycyclic aromatic hydrocarbons (PAHs) are a family of toxicants that are ubiquitous in the environment. These contaminants generate considerable interest, because some of them are highly carcinogenic in laboratory animals and have been implicated in breast, lung, and colon cancers in humans. Dietary intake of PAHs constitutes a major source of exposure in humans. Factors affecting the accumulation of PAHs in the diet, their absorption following ingestion, and strategies to assess risk from exposure to these hydrocarbons following ingestion have received very little attention. This review, therefore, focuses on concentrations of PAHs in widely consumed dietary ingredients along with gastrointestinal absorption rates in humans. Metabolism and bioavailability of PAHs in animal models and the processes, which influence the disposition of these chemicals, are discussed. Finally, based on intake, disposition, and tumorigenesis data, the exposure risk to PAHs from diet is presented. This information is expected to provide a framework for refinements in risk assessment of PAHs.

Friday, 12 June 2015

Toxicity evaluation of new agricultural fungicides in primary cultured cortical neurons

Environmental Research, 140, 2015, 37-44


Fungicides are crucial for food protection as well as for the production of crops of suitable quality and quantity to provide a viable economic return. Like other pesticides, fungicides are widely sprayed on agricultural land, especially in wine-growing areas, from where they can move-off after application. Furthermore, residues of these agrochemicals can remain on crops after harvest and even after some food processing operations, being a major exposure pathway. Although a relatively low toxicity has been claimed for this kind of compounds, information about their neurotoxicity is still scarce.

In the present study, nine fungicides recently approved for agricultural uses in the EU ― ametoctradin, boscalid, cyazofamid, dimethomorph, fenhexamid, kresoxim-methyl, mepanipyrim, metrafenone and pyraclostrobin ― have been evaluated for their toxicity in primary cultured mouse cortical neurons. Exposure to 0.1–100 µM for 7 days in vitro resulted in a dose-dependent toxicity in the MTT cell viability assay. Strobilurin fungicides kresoxim-methyl (KR) and pyraclostrobin (PY) were the most neurotoxic compounds (lethal concentration 50 were in the low micromolar and nanomolar levels, respectively) causing a rapid raise in intracellular calcium [Ca2+]i and strong depolarization of mitochondrial membrane potential. KR- and PY-induced cell death was reversed by the calcium channels blockers MK-801 and verapamil, suggesting that calcium entry through NMDA receptors and voltage-operated calcium channels are involved in KR- and PY-induced neurotoxicity. These results highlight the need for further evaluation of their neurotoxic effects in vivo.

Tuesday, 9 June 2015

Effects of sugar concentration processes in grapes and wine aging on aroma compounds of sweet wines—a review

Critical Reviews in Food Science and Nutrition, 55(8), 2015, 1053-1073


Dessert sweet wines from Europe and North America are described in this review from two points of view: both their aroma profile and also their sensorial description. There are growing literature data about the chemical composition and sensory properties of these wines. Wines were grouped according to the production method (concentration of sugars in grapes) and to the aging process of wine (oxidative, biological, or a combination of both and aging in the bottle). It was found that wines natively sweets and wines fortified with liquors differ in their volatile compounds. Sensory properties of these wines include those of dried fruit (raisins), red berries, honey, chocolate and vanilla, which is contributing to their growing sales. However, there is still a need for scientific research on the understanding of the mechanisms for wine flavor enhancement.
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