Comparison of porous starches obtained from different enzyme types and levels

The objective was to compare the action of different hydrolases for producing porous corn starches. Amyloglucosidase (AMG), α-amylase (AM), cyclodextrin-glycosyltransferase (CGTase) and branching enzyme (BE) were tested using a range of concentrations. Microstructure, adsorptive capacity, pasting and thermal properties were assessed on the porous starches. SEM micrographs showed porous structures with diverse pore size distribution and pore area depending on the enzyme type and its level; AMG promoted the largest holes. Adsorptive capacity was significantly affected by enzymatic modification being greater influenced by AMG activity. Unexpectedly, amylose content increased in the starch treated with AMG and BE, and the opposite trend was observed in AM and CGTase treated samples, suggesting different mode of action. A heatmap illustrated the diverse pasting properties of the different porous starches, which also showed significant different thermal properties, with lower To and Tp. Porous starch properties could be modulated by using different enzymes and concentrations.Financial support of the Spanish Ministry of Economy and Competitiveness (Project AGL2014-52928-C2-1-R) and the European Regional Development Fund (FEDER). Y. Benavent-Gil would like to thank predoctoral fellowship from Spanish Ministry of Economy and Competitiveness.Peer reviewe

Enzymatic modification of starches to improve their technological and functional properties

En la última década, los polímeros porosos han atraído la atención de las industrias alimentarias y no alimentarias principalmente por su gran capacidad absorbente, la cual está determinada por el número y tamaño de poros. En este tipo de materiales se han integrado biopolímeros como los almidones tras ser sometidos a tratamientos físicos, químicos o enzimáticos. Estos últimos, son los que se consideran más prometedores al originar biopolímeros etiqueta limpia. Sin embargo, los estudios realizados no permiten un control de la porosidad de los almidones. El objetivo de esta tesis doctoral fue el estudio integral de la producción de almidones porosos mediante tratamientos enzimáticos que permitieran modular las propiedades estructurales y tecnológicas de los almidones. Para conseguir dicho objetivo se utilizaron almidones nativos de distintos orígenes (maíz, trigo, arroz, patata, tapioca) y distintas enzimas hidrolíticas (amiloglucosidasa, alfa amilasa, ciclodextrin glicosil transferasa, enzima ramificante) para la obtención de almidones porosos, los cuales se caracterizaron atendiendo a sus propiedades estructurales, tecnológicas y digestibilidad in vitro. Asimismo, se determinó su viabilidad como vehículos de probióticos. El análisis de superficie de los gránulos de almidón realizado mediante microscopía electrónica de barrido (SEM) indicó que la porosidad de los almidones se puede modular utilizando diversas estrategias como el empleo de enzimas con diferente actividad hidrolítica, variando la concentración de estas enzimas o utilizando almidones de distinto origen botánico. La amiloglucosidasa fue la hidrolasa que originó poros de mayor tamaño, los cuales fueron más profundos en los almidones de cereales. Además, el control de la porosidad permitió modificar la funcionalidad de los almidones, afectándose significativamente su capacidad de retener agua y aceite, su capacidad de formación de pasta, propiedades térmicas, e incluso su digestibilidad in vitro. Los almidones de maíz y arroz porosos obtenidos con alfa amilasas se aplicaron como vehículos de probióticos, observándose un incremento de la estabilidad térmica de Lactobacillus plantarum, sobre todo tras ser recubiertos con almidón gelatinizado. Además, el estudio realizado con los almidones porosos tras su gelatinización abre la posibilidad de obtener hidrogeles con propiedades estructurales y funcionales diversas.In the last decade, porous polymers have attracted the attention of the food and non-food industries owing their great absorption capacity, which is dependent on the number and sizes of the pores. In this type of materials have been incorporated diverse polymers like starches after being subjected to physical,\ud chemical or enzymatical treatments. The latter are considered the most promising due to the resulting materials are clean label polymers. However, up to now, the reported studies do not allow controlling the starch porosity. The objective of this doctoral thesis was the integral study of the production of porous starches by enzymatic treatment in order to modulate their structural and technological properties. With that purpose, native starches from different origin (corn, wheat, rice, potato and cassava) and diverse amylases (amyloglucosidase, alpha amylase, cyclodextrin-glycosyltransferase, branching enzyme) were used for producing porous starches, which were then characterized according to their structural and technological properties, as well as their in vitro digestibility. In addition, their viability as probiotic carriers was evaluated. The surface analysis of the starch granules, carried out by scanning electronic microscopy (SEM) indicated that the porosity of the starches could be modulated by either using enzymes with different hydrolytic activity, changing of enzymatic levels, or employing starches from diverse botanical origin. The amyloglucosidase led to porous starches with bigger pore sizes, and those were deeper in the case of cereal starches. Moreover, the control of starch porosity allowed changing the functionality of the starches, significantly affecting the water and oil holding capacities, the pasting and thermal properties and even their behavior during in vitro digestibility. Porous starches obtained from corn or rice after treated with alpha amylase were tested as probiotic carriers, yielding an increase of the thermal stability of Lactobacillus plantarum, especially after being coated with gelatinized starch. Additionally, the study carried out with the porous starches after being subjected to gelatinization opens new opportunities to obtain hydrogels with diverse structural and functional properties

Experimental study on the effective width of flat slab structures under dynamic seismic loading

This paper investigates the effective width of reinforced concrete flat slab structures subjected to seismic loading on the basis of dynamic shaking table tests. The study is focussed on the behavior of corner slab? column connections with structural steel I- or channel-shaped sections (shearheads) as shear punching reinforcement. To this end, a 1/2 scale test model consisting of a flat slab supported on four box-type steel columns was subjected to several seismic simulations of increasing intensity. It is found from the test results that the effective width tends to increase with the intensity of the seismic simulation, and this increase is limited by the degradation of adherence between reinforcing steel and concrete induced by the strain reversals caused by the earthquake. Also, significant differences are found between the effective width obtained from the tests and the values predicted by formula proposed in the literature. These differences are attributed to the stiffening effect provided by the steel profiles that constitute the punching shear reinforcement

Métodos para el estudio de la actividad académica y científica de investigadores singulares

Este trabajo se enmarca dentro del proyecto Biblioteca Digital de Científicos y Humanistas Valencianos del siglo XX, que tiene como objetivo recuperar el patrimonio científico y humanista reciente de la Comunidad Valenciana y difundirlo a través de una plataforma digital interoperable en Internet. En los estudios históricos y documentales sobre la ciencia tienen una importancia especial los destinados al conocimiento de las aportaciones de los profesores universitarios e investigadores, campo muy cultivado en el que se aplican técnicas actuales que se han impuesto en las investigaciones sobre historia social de la administración, la política o la ciencia. Otra línea de estudios procede de la documentación científica, que mediante la aplicación de técnicas bibliométricas y el análisis de redes sociales permite obtener indicadores de la actividad científica y repercusión de los personajes estudiados. La información procedente de todos ellos, convenientemente integrada, proporciona una perspectivade conjunto o perfil colectivo de los científicos y humanistas de una época determinada.Este trabajo tiene como objetivo describir la metodología empleada para la recolección, análisis y evaluación de la información de los principales científicos y humanistas valencianos del siglo XX que formarán parte de la biblioteca digital VESTIGIUM

Datos abiertos de investigación. Camino recorrido y cuestiones pendientes

Los aspectos profesionales y técnicos de la gestión de datos de investigación han avanzado, sin embargo otras cuestiones necesitan ser investigadas, y más ahora en que los datos han de estar disponibles en abierto. Este trabajo efectúa una revisión bibliográfica y de sitios de web de referencia que permite identificar los últimos avances producidos y las tendencias de investigación en temas relacionados con los datos científicos. La publicación de datos en revistas, el estudio del comportamiento de los autores o los métodos para medir el impacto de los datos son aspectos que necesitan ser abordados con urgencia. El objetivo de este trabajo es resaltar los retos pendientes en este momento en que se está produciendo un cambio disruptivo en su intercambio, dada la cantidad de datos disponibles en abierto, reflexión que nos permitimos desde nuestra experiencia en este campo

Analysis of web-based information architecture using a combination of navigation stress test, usability testing and eye tracking

Evaluating the Information Architecture in an already deployed website is not an easy task. Most evaluation techniques are focused on examining system usability, but this is not the only factor that influences IA. The main technique that deals with IA in already deployed web environments is the Navigation Stress Test (NST). A new methodology makes this technique more informative by taking NST beyond simple notation on paper. This work proposes the use of NST combined with other usability testing techniques such as Thinking Aloud and a usability questionnaire. Eye tracking also has been used to supplement the information obtained from applied techniques. This new methodology has been tested by analyzing a series of websites belonging to Spanish public university libraries. The results of this study show the validity of the approach used, as well as the value that this approach and the use of Eye tracking bring to the analysis of IA compared to traditional NST

Comparative study of Spanish norms used to quantify gypsum content in civil and building construction

The "Pliego de Prescripciones Técnicas Generales para Obras de Carreteras y Puentes (PG3)" is the Spanish's Government Technical Instruction that stablishes the properties that materials used in road and bridge construction must accomplish, and includes the corresponding standardized norms to test these properties

Gut Microbiota Cannot Compensate the Impact of (quasi) Aposymbiosis in Blattella germanica

The German cockroach Blattella germanica is a good model to study complex symbiotic relationships because the following two symbiotic systems coexist in a single individual: the endosymbiont Blattabacterium (living inside specialized cells called bacteriocytes) and the gut microbiota. Although the role of the endosymbiont has been fully elucidated, the function of the gut microbiota remains unclear. The study of the gut microbiota will benefit from the availability of insects deprived of Blattabacterium. Our goal is to determine the effect of the removal (or, at least, the reduction) of the endosymbiont population on the cockroach's fitness, in a normal gut microbiota community. For this purpose, we treated our cockroach population with rifampicin to decrease the amount of endosymbiont in the following generation. As the treatment also affects rifampicin-sensitive gut bacteria, we allowed it to recover for at least 20 days before sampling. We found that after this antibiotic treatment, the endosymbiont population remained extremely reduced and only the microbiota were able to recover, although it could not compensate for the endosymbiont role, and the host's fitness was drastically affected. This accomplished reduction, however, is not homogenous and requires further study to develop stable quasi-aposymbiotic cockroaches

Viticulture and oenology scientific research: The Old World versus the new World wine-producing countries

[EN] The main aim of this study was to analyze the scientific productivity and collaboration between Old World wine-producing countries (Austria, Bulgaria, France, Germany, Greece, Hungary, Italy, Portugal, Romania, Spain, Switzerland) and New World wine-producing countries (Argentina, Australia, Brazil, Canada, Chile, Mexico, New Zealand, Peru, South Africa, United Sates, Uruguay) in viticulture and oenology through bibliometric analyses of articles included in the Science Citation Index Expanded database for the period 1994-2013. A number of 1527 research articles were published in 563 journals. The results highlight an important growth in the collaboration between countries during the second decade (2004-2013). Papers have been published in numerous journals belonging to several subject areas. Food Science and Technology, Horticulture and Biotechnology and Applied Microbiology appeared as the most productive research areas. A social network analysis of collaboration between these countries was also performed in order to analyze the most powerful scientific cooperation. (C) 2016 Elsevier Ltd. All rights reserved.Aleixandre Benavent, JL.; Aleixandre Tudó, JL.; Bolaños-Pizarro, M.; Aleixandre Benavent, R. (2016). Viticulture and oenology scientific research: The Old World versus the new World wine-producing countries. International Journal of Information Management. 36(3):389-396. https://doi.org/10.1016/j.ijinfomgt.2016.01.003S38939636