Biodegradable Multilayer Films for Active Food Packaging, Based on Starch and Polyesters with Phenolic Acids

Tesis por compendio[ES] Se han desarrollado mediante termoprocesado películas multicapa biodegradables activas para el envasado de alimentos, combinando películas de almidón mejoradas y de una mezcla de poliésteres (PLA-PHBV), con diferentes ácidos fenólicos (ferúlico, p-cumárico y protocatecuico). En las películas almidón de yuca o de maíz se incorporaron gomas de origen microbiano (xantana y gelano) (10%) para mejorar sus propiedades funcionales. Las gomas mejoraron las propiedades mecánicas y de barrera al vapor de agua y al oxígeno de los films de almidón. Estos films se combinaron con films mezcla de PLA:PHBV en bicapas almidón-poliésteres por termocompresión. Las bicapas presentaron una alta capacidad barrera al oxígeno y al vapor de agua comparado con sus respectivas monocapas. La capa de poliéster contribuyó al refuerzo mecánico de la bicapa, aportando alta capacidad de barrera al vapor de agua, mientras que la capa de almidón aportó alta capacidad de barrera al oxígeno a la bicapa. La bicapa con almidón de yuca y goma gelano presentó la mejor adhesión entre capas, con propiedades funcionales adecuadas para el envasado de alimentos. Los ácidos ferúlico, p-cumárico y protocatecuico, con propiedades antimicrobianas y antioxidantes, se incorporaron (2%) en los films mezcla de PLA:PHBV para obtener films activos. Los ácidos fenólicos modificaron positivamente las propiedades de la mezcla de poliésteres, incrementando su módulo de elasticidad y resistencia a la fractura y su capacidad de barrera al vapor de agua y al oxígeno, al tiempo que aumentaron levemente la Tg del material. El ácido protocatecuico provocó los mayores efectos, afectando a la cristalización del PHBV. La liberación de estos compuestos en diferentes simulantes alimentarios (con polaridad alta e intermedia) fue muy limitada en cuanto a velocidad y cantidad liberada, lo que disminuyó la capacidad de las películas para inhibir de forma significativa el crecimiento de Listeria innocua inoculada en medio de cultivo. Estos films, con y sin compuestos activos, se desintegraron en condiciones de compostaje, sin efecto significativo de los ácidos fenólicos. Los films sin activos y con ácido ferúlico se biodegradaron completamente después de 20 días de compostaje, mientras que los films que contenían ácido p-cumárico y protocatecuico lo hicieron en 21 y 26 días, respectivamente. Por lo tanto, ninguno de los ácidos fenólicos incorporados inhibió el proceso de biodegradación, pero se retardó el proceso, dependiendo del grado de retención del compuesto en la matriz polimérica. Los films bicapa biodegradables constituidos por una capa de almidón-gelano y otra de PLA:PHBV, con y sin ácidos fenólicos, se caracterizaron en sus propiedades mecánicas y de barrera al vapor de agua y al oxígeno y se utilizaron para el envasado de carne de cerdo, evaluando su calidad durante el almacenamiento a 5 °C. La presencia de ácidos fenólicos disminuyó el módulo elástico y la tensión de fractura de las bicapas y mejoró su capacidad de barrera al vapor de agua y al oxígeno. Esto último, junto al efecto activo de los ácidos, contribuyó a mejorar la conservación de la carne durante el almacenamiento, reduciendo los niveles de oxidación lipídica, cambios de pH y pérdidas de peso de las muestras envasadas, así como el crecimiento microbiano, especialmente coliformes totales y bacterias ácido-lácticas. Los films bicapa biodegradables con ácidos fenólicos, a base de almidón y poliésteres, se muestran como una estrategia adecuada para obtener materiales de envasado activo, con propiedades funcionales próximas a las de algunos plásticos sintéticos comúnmente utilizados en el envasado de alimentos. Estos materiales pueden alargar la vida útil de los alimentos, mitigando el impacto ambiental de los envases plásticos ya que pueden ser compostados.[CA] S'han desenvolupat, mitjançant termoprocesat, pel·lícules multicapa biodegradables actives per a l'envasament d'aliments, combinant pel·lícules de midó millorades i d'una mescla de polièsters (PLA-PHBV), amb diferents àcids fenòlics (ferúlic, p-cumàric i protocatecuic). En les pel·lícules midó de iuca o de dacsa es van incorporar gomes d'origen microbià (xantana i gellan) (10%) per a millorar les seues propietats funcionals. Les gomes van millorar les propietats mecàniques i de barrera al vapor d'aigua i a l'oxigen dels films de midó. Aquests films es van combinar amb films mescla de PLA:PHBV en bicapes midó-polièsters per termocompresió. Les bicapes van presentar una alta capacitat barrera a l'oxigen i al vapor d'aigua comparat amb les respectives monocapes. La capa de polièster va contribuir al reforç mecànic de la bicapa, aportant alta capacitat de barrera al vapor d'aigua, mentre que la capa de midó va aportar alta capacitat de barrera a l'oxigen a la bicapa. La bicapa amb midó de iuca i goma gellan va presentar la millor adhesió entre capes, amb propietats funcionals adequades per a l'envasament d'aliments. Els àcids ferúlic, p-cumàric i protocatecuic, amb propietats antimicrobianes i antioxidants, es van incorporar (2%) en els films mescla de PLA:PHBV per a obtindre films actius. Els àcids fenòlics van modificar positivament les propietats de la mescla de polièsters, incrementant el seu mòdul d'elasticitat i resistència a la fractura i la seua capacitat de barrera al vapor d'aigua i a l'oxigen, al mateix temps que van augmentar lleument la Tg del material. L'àcid protocatecuic va provocar els majors efectes, afectant la cristal·lització del PHBV. L'alliberament d'aquests compostos en diferents simulants alimentaris (amb polaritat alta i intermèdia) va ser molt limitada en quant a velocitat i quantitat alliberada, la qual cosa va disminuir la capacitat de les pel·lícules per a inhibir de manera significativa el creixement de Listeria innocua inoculada en medi de cultiu. Aquests films, amb i sense compostos actius, es van desintegrar en condicions de compostatge, sense efecte significatiu dels àcids fenòlics. Els films sense actius i amb àcid ferúlic es biodegradaren completament després de 20 dies de compostatge, mentre que els films que contenien àcid p-cumàric i protocatecuic ho van fer en 21 i 26 dies, respectivament. Per tant, cap dels àcids fenòlics incorporats va inhibir el procés de biodegradació, però es va retardar el procés, depenent del grau de retenció del compost en la matriu polimèrica. Els films bicapa biodegradables constituïts per una capa de midó-gellan i una altra de PLA:PHBV, amb i sense àcids fenòlics es van caracteritzar en les seues propietats mecàniques i de barrera al vapor d'aigua i a l'oxigen i es van utilitzar per a l'envasament de carn de porc, avaluant la qualitat a llarg del emmagatzematge a 5 °C. La presència d'àcids fenòlics va disminuir el mòdul elàstic i la tensió de fractura de les bicapes i va millorar la seua capacitat de barrera al vapor d'aigua i a l'oxigen. Això últim, junt a l'efecte actiu dels àcids, va contribuir a millorar la conservació de la carn durant l'emmagatzematge, reduint els nivells d'oxidació lipídica, canvis de pH i pèrdues de pes de les mostres envasades, així com el creixement microbià, especialment coliformes totals i bacteris àcid-làctics. Els films bicapa biodegradables amb àcids fenòlics, a base de midó i polièsters, es mostren com una estratègia adequada per a obtindre materials d'envasament actiu, amb propietats funcionals pròximes a les d'alguns plàstics sintètics comunament utilitzats en l'envasament d'aliments. Aquests materials poden allargar la vida útil dels aliments, mitigant l'impacte ambiental dels envasos plàstics ja que poden ser compostats.[EN] Active biodegradable multilayer films have been developed by thermoprocessing for food packaging purposes, combining improved starch films and a blend of polyesters (PLA-PHBV), with different phenolic acids (ferulic, p-coumaric and protocatechuic). Into the cassava or maize starch films, gums of microbial origin (xanthan and gellan) were incorporated (10%) to improve their functional properties. The gums improved the mechanical and barrier properties to water vapor and oxygen of the starch films. These films were combined with PLA:PHBV blend films in starch-polyester bilayers by thermocompression. The bilayers exhibited high barrier capacity to oxygen and water vapor compared to their respective monolayers. The polyester layer contributes to the mechanical reinforcement of the bilayer, providing high water vapor barrier capacity, while the starch layer provided high oxygen barrier capacity to the bilayer. The bilayer with cassava starch and gellan gum showed the best interlayer adhesion, with adequate functional properties for food packaging applications. Ferulic, p-coumaric and protocatechuic acids, with antimicrobial and antioxidant properties, were incorporated (2%) in the PLA: PHBV blend films to obtain active films. Phenolic acids positively modified the properties of the polyester blend, increasing its elastic modulus and resistance to break and its barrier capacity to water vapor and oxygen, while slightly increasing the Tg of the material. Protocatechuic acid caused the greatest effects, affecting the crystallization of PHBV. The release of these compounds in different food simulants (with high and intermediate polarity) was very limited in terms of release rate and released amount, which reduced the ability of the films to significantly inhibit the growth of Listeria innocua inoculated in culture medium. These films, with and without active compounds, disintegrated under composting conditions, without significant effect of phenolic acids. Films without active compounds and with ferulic acid biodegraded completely after 20 days of composting, whereas films containing p-coumaric and protocatechuic acids did so in 21 and 26 days, respectively. Therefore, none of the incorporated phenolic acids inhibited the biodegradation process, but the process was delayed, depending on the degree of retention of the compound in the polymeric matrix. The biodegradable bilayer films with a layer of starch-gellan and another of PLA: PHBV, with and without phenolic acids, were characterized as to their mechanical properties and barrier capacity to water vapor and oxygen and were used for packaging of pork meat whose quality development was analysed throughout storage time at 5 °C. The presence of phenolic acids decreased the elastic modulus and resistance to break of the bilayers and improved their barrier capacity to water vapor and oxygen. The latter, together with the active effect of the acids, contributed to improving the preservation of the meat during storage, reducing the levels of lipid oxidation, changes in pH and weight losses of the packed samples, as well as microbial growth, especially total coliforms and lactic acid bacteria. Biodegradable bilayer films with phenolic acids, based on starch and polyesters, appeared as a suitable strategy to obtain active packaging materials, with functional properties close to those of some synthetic plastics commonly used in food packaging. These materials can extend the shelf-life of foods, mitigating the environmental impact of plastic packaging since they can be composted.The authors would like to thank the Ministerio de Ciencia e Innovación of Spain, for funding this study through the Project AGL2016-76699-R and PID2019-105207RB-I00, and the predoctoral research grant # BES-2017-082040Hernández García, E. (2022). Biodegradable Multilayer Films for Active Food Packaging, Based on Starch and Polyesters with Phenolic Acids [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/181473TESISCompendi

Novel antimicrobial formulations based on plant extracts for agroforestry applications

In the current context, characterized by the increasing global population and climate change, the priority of ensuring productivity and quality in agricultural crops has been widely recognized internationally, particularly through Sustainable Development Goal (SDG) 2 of the 2030 Agenda. However, it is crucial to address this challenge responsibly and sustainably, as emphasized by SDG 12, especially regarding the substitution of conventional phytosanitary products. This Doctoral Thesis focuses on the application of natural extracts for the control of phytopathogens, both in the pre-harvest and post-harvest phases. The emphasis is on the extraction and physicochemical characterization of a variety of extracts, including plants such as Limonium binervosum, Hibiscus syriacus, Punica granatum var. nana, Quercus suber, Sambucus nigra, Quercus ilex subsp. ballota, Tamarix gallica, Taxus baccata, Ginkgo biloba, Euphorbia serrata, Uncaria tomentosa, Armeria maritima, Silene uniflora, Helichrysum stoechas, residues like Allium sativum peels, fungi such as Ganoderma lucidum, secondary metabolites from Streptomyces spp., and purified natural products like methylxanthines. The efficacy of these extracts was assessed against pathogens affecting woody, extensive (cereals), and horticultural crops, as well as post-harvest pathogens, through in vitro, in vivo, and ex-situ trials. The results obtained reveal that the efficacy of these extracts is comparable or even superior to conventional phytosanitary products such as strobilurins or phosphonates. This approach not only proves promising in terms of pest control but also underscores the feasibility of adopting more sustainable and environmentally friendly agricultural practices, aligning with the principles outlined in the 2030 Agenda.En el contexto actual, caracterizado por el aumento de la población mundial y el cambio climático, la prioridad de asegurar la productividad y calidad de los cultivos agrícolas ha sido ampliamente reconocida a nivel internacional, especialmente a través del Objetivo de Desarrollo Sostenible (ODS) 2 de la Agenda 2030. No obstante, es crucial abordar este desafío de manera responsable y sostenible, como subraya el ODS 12, particularmente en lo que respecta a la substitución de productos fitosanitarios convencionales. La presente Tesis Doctoral se centra en la aplicación de extractos naturales para el control de fitopatógenos, tanto en la fase de precosecha como en la de postcosecha. El énfasis recae en la extracción y caracterización físicoquímica de una variedad de extractos, abarcando plantas como Limonium binervosum, Hibiscus syriacus, Punica granatum var. nana, Quercus suber, Sambucus nigra, Quercus ilex subsp. ballota, Tamarix gallica, Taxus baccata, Ginkgo biloba, Euphorbia serrata, Uncaria tomentosa, Armeria maritima, Silene uniflora, Helichrysum stoechas, residuos como las pieles de Allium sativum, hongos como Ganoderma lucidum, metabolitos secundarios de Streptomyces spp., y productos naturales purificados como las metilxantinas. La eficacia de estos extractos se evaluó frente a patógenos que afectan a cultivos leñosos, extensivos (cereales) y hortícolas, así como patógenos postcosecha, mediante ensayos in vitro, in vivo y ex situ. Los resultados obtenidos revelan que las eficacias de estos extractos son comparables o incluso superiores a las de fitosanitarios convencionales como las estrobirulinas o los fosfonatos. Este enfoque no solo demuestra ser prometedor en términos de control de plagas, sino que también resalta la viabilidad de adoptar prácticas agrícolas más sostenibles y respetuosas con el medio ambiente, alineándose con los principios establecidos en la Agenda 2030.Escuela de DoctoradoDoctorado en Ciencia e Ingeniería Agroalimentaria y de Biosistema

Development of an environmental narrative in a video game made in Unreal Engine

Treball final de Grau en Disseny i Desenvolupament de Videojocs. Codi: VJ1241. Curs acadèmic: 2021/2022This document represents the memory of Eva María Garzón Hernández’s Final Degree Project in Video Game Design and Development. This work consists of a video game that shows a story that takes place in a house. During the video game, the player will be able to explore the house, investigate and collect objects that will lead to unlocking new areas, which will change as time goes by. With simple graphic adventure mechanics, which any video game enthusiast or not is familiar with and can handle, the video game focuses on a journey where the environmental narrative is the key point. The story can have different interpretations, depending on the person and the amount of exploration and details to be taken into account. The development has been carried out in Unreal Engine and has been handled as well as possible within the initial unfamiliarity with the engine and the continuous learning from the beginning of the project to the end

Pragmatic gains in the study abroad context: Learners' experiences and recognition of pragmatic routines

The present study investigates second language (L2) learners' pragmatic development during study abroad (SA) programs by focusing on the recognition of pragmatic routines, and how sociocultural adaptation and intensity of interaction influence pragmatic gains. It is a longitudinal investigation that employed a mixed-method approach. Thirty-one Brazilian students in their first semester of study in a US university completed a pretest and posttest version of a sociocultural adaptation questionnaire, a language contact survey, and a routine recognition test. Quantitative data were complemented with qualitative information from semi-structured interviews with 2 of the participants, who provided details about the nature of their adaptation experiences and the patterns of interaction they held during the sojourn. Findings revealed that the recognition of pragmatic routines significantly increased during a semester abroad, and that this development was influenced by both sociocultural adaptation and intensity of interaction, interaction being the main predictor of pragmatic gains. Results from this study emphasize the importance of SA programs for the acquisition of pragmatic routines, and suggest that learners' willingness to acculturate in the SA environment, and exposure to recurrent situations outside of the classroom are determinant aspects for routine recognition

IMPACT OF INSTRUCTION ON THE USE OF L2 DISCOURSE MARKERS

The present study compares the acquisition of L2 Spanish discourse markers under explicit and implicit learning conditions. Subjects were fifth-semester Spanish students assigned to one of three groups: an explicit instruction combined with input flood group, an input flood alone group, or a control group. The explicit instruction combined with input flood group was provided with explicit information about discourse markers. The group then received a flood of written input containing the target forms. Learners were also provided with communicative practice and feedback. The input flood group did not receive explicit instruction on discourse markers. The group received the same flood of input as the other experimental group. The input flood group was presented with communicative practice although there was no feedback. Prior to instruction, a questionnaire was administered to assess learners’ previous knowledge and use of Spanish discourse markers. In addition, a speaking task was administered as a pretest, immediate posttest, and delayed posttest. Their results indicated that both experimental treatments had a positive impact on learners’ overall use of discourse markers. No significant differences were found between the two groups on the posttests. Quantitative and qualitative data, however, revealed that the explicit instruction combined with input flood group was more effective than the input flood group in employing new discourse markers to structure their narratives. Taken together, these results confirm the positive impact of instruction on the use of L2 Spanish discourse markers

Flavonoids in Agriculture

Flavonoids are compounds that are secondary metabolites, but which play an important role in the biological activities of plants. They can be responsible for the color of flowers and fruits and for the attraction of pollinators. They also participate in plant-microorganism symbiosis. These relationships can be used to naturally control weeds and insect pests and reduce stress and diseases in order to increase crop yield. To improve the understanding of the different biological systems where flavonoids are involved in their symbiotic relationships and in plant physiology, tools such as metabolomics are used, which give a broader picture and allow to search for strategies to solve problems specific to the agricultural sector

Doctoral education in the EEES context. A competence base-training

Este artículo analiza algunos aspectos relacionados con la formación de doctores en el contexto del EEES. La reforma de la formación de doctores ha experimentado un cambio muy sustancial a lo largo de las últimas décadas. Se destaca la importancia de la formación doctoral para el ejercicio profesional dentro y fuera de las instituciones universitarias. El nuevo concepto de formación se basa en competencias y no sólo en la realización de la tesis doctoral. Son numerosas las propuestas sobre las competencias en las que deben formarse los doctorandos, centrándose en las transferibles. En nuestro contexto, el proyecto de Real Decreto que regula las enseñanzas oficiales de Doctorado completará el cuadro de cualificaciones del sistema universitario.This paper analyses some of the aspects related to doctoral training within the ESHE context. In the last two decades there have been dramatic changes in doctoral training and particular importance is placed on this kind of training in the workplace both at University and elsewhere. The new concept of training is based on competences and not merely on the writing of a doctoral thesis. Prospective doctors are expected to develop a number of competences, of which transferable competences are the most outstanding ones. In our Spanish context, the final qualification structure of university studies will be completed after the inclusion of the Royal Decree project that regulates official teaching of PhD degrees

International benchmark and best practices on national infrastructure plans. Application to Spanish strategic planning

[EN] The need for planning regarding investment in infrastructures is recognised and supported by most governments around the world. Planning helps to take effective and correct decisions, provides a basis for monitoring its impacts and also facilitates further developments. However it requires a high level of organization, coordination among stakeholders and anticipation of transport needs. There are some different methodological approaches for strategic planning. This paper examines the importance of infrastructure planning and how it is undertaken in different countries from Europe and other continents. It is based on a benchmarking about planning procedures of 7 reference countries (UK, France, the Netherlands, Poland, Germany, Japan and USA), in addition to others whose strategic plans are being developed at the present moment such as Croatia or Romania. This benchmarking aims to extract and compare best practices carried out in this field and to define the optimal formulation of strategic planning. In this regard, the benchmarking is focused on some key aspects: firstly, on the plan structure and its main contents. There are a lot of differences about how each country defines the future needs for transport and how it establishes the objectives and the strategies to be followed. Secondly, on the characterisation of the authorities which are responsible of the plan development (level of dependence from the government, know-how…) along with the time frame and final validity of the plans. And finally, the level of detail of the proposed actions and budgetary commitments provided by the strategic plans. Throughout the comparative analysis, the knowledge generated by this benchmarking has allowed setting a series of specific recommendations in strategic planning which can be applied as innovative solutions and best practices in future planning processes in Spain.Pino Hernández, E.; Delgado Quiralte, C. (2016). International benchmark and best practices on national infrastructure plans. Application to Spanish strategic planning. En XII Congreso de ingeniería del transporte. 7, 8 y 9 de Junio, Valencia (España). Editorial Universitat Politècnica de València. 1358-1365. https://doi.org/10.4995/CIT2016.2015.3459OCS1358136

Urban Agriculture: Models-in-Circulation from a Critical Transnational Perspective

Urban Agriculture (UA) is practiced around the globe (Biel, 2016), supported and advocated by a diversity of actors ranging from local neighbourhood groups to supra-national bodies (e.g. FAO, 2014; Mougeot, 2006; UN Habitat, 2014). As such, UA must be understood as one of planning’s current “models-in-circulation” (Roy and Ong, 2011), characterised by the traveling of ideas and policies in a globalised world (Healey, 2013). UA operates at a diversity of scales and engages a variety of actors. Yet, as a model-in-circulation, only some of the ways in which UA is practiced are promoted globally and influence the way UA is perceived, thus disregarding UA’s highly specific manifestations in different social/economic/political contexts around the world. We use a critical transnational perspective for a qualitative analysis of collective (rather than individual) UA practices happening in small-scale, left-over public spaces in three very different locations in Latin America and Europe (Bogotá and Medellin in Colombia, and Vienna in Austria) to gain insights into how policies and initiatives inspired by typical models-in-circulation affect the situation on ground. The analysis shows that the reliance on such models can act like a filter impeding the acknowledgment that actors, objectives and barriers for UA practices are more complex, nuanced and multifaceted than those that a simple model can contain. As a result the benefits UA can yield are only partially attained. The conceptual device of translocal is subsequently formulated as one conveying the traveling of ideas locally, which can enrich and root models-in-circulation