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.