Development of silver based antimicrobial films for coating and food packaging applications

Aunque la plata se usa como componente clave en el control microbiano en incontables aplicaciones, las tecnologías basadas en plata disponibles son escasas. Esto radica en la dificultad para evaluar su eficacia debido a problemas de estabilidad y de especiación. En la presente tesis, iones de plata fueron incorporados en matrices biopoliméricas para obtener materiales de prolongada capacidad antimicrobiana basados en su liberación sostenida. Se realizó un estudio profundo de las interacciones químicas entre las especies activas de plata, las bacterias, y posibles ligandos presentes en el medio de acción. En condiciones óptimas, la plata demostró ser eficaz en el rango de los nanomoles. Sin embargo, interacciones químicas con varios ligandos afectaron drásticamente tanto su eficacia como la evaluación de la viabilidad bacteriana. La incorporación de iones de plata en películas de EVOH no alteró las propiedades físico-químicas de los materiales que mostraron una rápida liberación del contenido de plata al entrar en contacto con la humedad. Esto se reflejó en la inactivación de las bacterias a concentraciones muy bajas (0.0001wt.%) en condiciones óptimas. Cuando se incorporaron iones de plata en PLA por casting o mezclado-fundido, la liberación y el rendimiento antimicrobiano se prolongaron de días a meses, dependiendo del contenido, el método de incorporación, la humedad o el pH del medio de liberación. Una etapa inicial de liberación mayor pudo ser atenuada gracias a la aplicación de una capa de cera de abejas, lo que permitió adaptar los perfiles de liberación a demanda y cumplir con la legislación vigente en diversas condiciones de liberación. Las películas demostraron un alto efecto antibacteriano y antiviral contra los patógenos transmitidos por los alimentos más comunes en medios sintéticos, en superficie y en alimentos líquidos y sólidos. Este estudio representa un avance en la comprensión de la eficacia antimicrobiana de la plata y destaca su posible idoneidad para la fabricación de materiales de envasado de alimentos, de contacto con alimentos u otras aplicaciones.Martínez Abad, A. (2014). Development of silver based antimicrobial films for coating and food packaging applications [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/36738TESISPremios Extraordinarios de tesis doctorale

Differences in the Long-term Progression Course of Two Cases of Pellucid-like Keratoconus: Are they the Same Condition with Different Phenotypic Presentation?

We report the long-term follow-up of two cases of untreated corneal ectasia presenting a crab claw-like sagittal and tangential topographic pattern at baseline, but without peripheral thinning. Currently, according to clinical examination, these two cases are diagnosed as pellucid-like keratoconus (PLK). The first case was a 58-year-old male who developed a true pellucid marginal degeneration (PMD) in one eye and with a nonprogressive PLK in the other eye. The second case presented was a 19-year-old male without clinical signs of ectasia at baseline that progressed to PLK with evident changes in topographic and pachymetric maps but maintaining the point of minimum corneal thickness (MCT) in the central area. The presence of two different conditions in the same patient (case 1) and the progression from inferosuperior asymmetry to the development of a crab claw-pattern (case 2) suggest that PMD, PLK, and keratoconus may be different phenotypic presentations of the same pathophysiological condition.The author David P Piñero has been supported by the Ministry of Economy, Industry and Competitiveness of Spain within the program Ramón y Cajal, RYC-2016-20471

Condado y Ducado de Benavente : adictamiento... executado por Sebastian Antonio de Medina y Truxillo: sobre la nulidad de un censo, impuesto el año de 1533 por el ... Conde Duque Don Antonio Sexto de la Casa ... y pretende cobrar Don Fernando de Escovar y Lizana ...

Copia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 2011Sign.: A-O4, P2Port. con orla tip.Texto con apostillas marginale

Biodegradable poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/thermoplastic polyurethane blends with improved mechanical and barrier performance

Papers presented at 5th International Conference on Bio-based and Biodegradable Polymers (BIOPOL-2015)Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) polymers pose a green alternative to fossil-fuel derived polymers, as they exhibit good biocompatibility, biodegradability and outstanding barrier performance compared to other biopolyesters. However, their excessive brittleness has not yet been overcome without compromising barrier performance. In this work, a native ester-based thermoplastic polyurethane (TPU) not stabilised against hydrolysis, has been thoroughly assessed for the first time as an additive in melt blends with PHBV. Phase segregation in scanning electron microscopy (SEM) confirmed the immiscibility of the two polymers, however a degree of interaction has been found. Wide-angle X-ray scattering and differential scanning calorimetry revealed no major effect of the TPU on the crystallinity of the PHBV phase. The onset and kinetics of thermal degradation was not altered by the presence of the TPU up to 50 wt% content. Blends with increasing TPU contents showed a gradual decrease in the modulus of elasticity and tensile strength, while a substantial increase in elongation at break has been found for contents of TPU above 20 wt%, which resulted an improvement in the overall toughness of the blends. The excellent barrier performance of the PHBV against water vapour and aroma compounds was shown to be unaffected by TPU loads of ≤30 wt%. Full decomposition of neat PHBV and PHBV/TPU blends below 50 wt% TPU content was achieved after 40 days according to biodisintegration standards (ISO 20200). The study puts forward the potential use of TPU to improve the mechanical performance of these natural biopolyesters without compromising the barrier properties or the biodisintegratibility of the melt blends.The authors wish to thank the European project ECOBIOCAP and the Ministry of Economy and Competitiveness under project MAT2012-38947-C02 for financial support. Jennifer Gonzalez-Ausejo gratefully acknowledges financial support under grant “Pla de promoció de la investigació en la Universitat Jaume I” Predoc/2012/32

Diagnosis of a Chopper Controlled DC Motor by Boosting

This paper proposes a methodology to diagnose a transient state of a dynamic system using boosting. The methodology is composed by two steps: one off-line process and another on-line process. The off-line phase begins gathering data from the system, both when it is running free of fault and when the system is running in each fault mode. A segmentation and normalization algorithm is used to reduce the large amount of gathered data. The final step is the generation of a decision tree by a classification tool. The boosting technique is used with the aim of improving the classification results. The on-line process of the methodology consists of evaluating a new reading of the system sensors with the generated decision trees. The diagnosis of the system is the result of this evaluation which has very low computational cost due to the simplicity of the decision trees. Also, the implementation cost is very low due to this simplicity.Ministerio de Ciencia y Tecnología DPI2003-07146-C02-0

Alginate industrial waste streams as a promising source of value-added compounds valorization

[EN] The alginate industry processes more than hundred thousand tons per year of algae in Europe, discarding around 80% of the algae biomass as different solid/liquid residual streams. In this work, Saccharina latissima and Ascophyllum nodosum, their generated alginates and all residual fractions generated in the process were characterized in terms of lipid, ash, protein content, and the carbohydrate composition and antioxidant capacities analyzed. The first fraction after acid treatment (ca. 50% of the initial dry biomass) was rich in phlorotannins (15 mg GAE/g) and bioactive fucoidans (15-70%), with a high sulfation degree in A. nodosum. Two fractions generated from the solid residue, one soluble and another insoluble (Ra and Rb, respectively), constituted 9% and 5-8% of the initial biomass and showed great potential as a source of soluble protein (30% for S. latissima), and cellulose (70%) or fucoidan, respec-tively. Valorization strategies are suggested for these waste streams, evidencing their high potential as bioactive, tex-turizing or nutritional added-value ingredients for cosmetic, food, feed or pharmaceutical applications.This work acknowledges financial support from the Spanish Research agency (Ministry of Science and Innovation) through projects RTI-2018-094268-B-C22 and PID2020-117744RJ-I00. H. Bojorges acknowledges fi-nancial support from the Generalitat Valenciana for the award of a Santiago Grisol?a grant (GRISOLIAP/2019/007).Bojorges, H.; Fabra, MJ.; López-Rubio, A.; Martínez-Abad, A. (2022). Alginate industrial waste streams as a promising source of value-added compounds valorization. Science of The Total Environment. 838:1-11. https://doi.org/10.1016/j.scitotenv.2022.15639411183

Tailoring structural, rheological and gelling properties of watermelon rind pectin by enzymatic treatments

[EN] In this work, pectin extracts from watermelon rind (WRP) were enzymatically treated to evaluate their potential for preparing hydrogels with the addition of CaCl2. Based on a previous work, two different conditions were selected to obtain WRP extracts according to the 1) highest yield (OP) or 2) highest yield without negatively affecting the branching and native structure of pectin (OPA). Firstly, both WRP extracts were enzymatically modified using different treatments (de-esterification and/or de-branching of galacturonic and arabinose side chains, and deproteinization), and their impact on the esterification degree, monosaccharide composition and changes on their structural properties (linearity and branching degree) were analysed. Then, the effect of the structural properties of the resulting pectin on the rheological behaviour and nanostructure of the hydrogels was investigated. The presence of long branched side chains and high methyl-esterified galacturonic acid chains promoted the formation of weaker hydrogels whereas de-esterification of the original pectin enabled intermolecular association giving rise to stronger hydrogels with the formation of ordered and densely packed structures (as deduced from SAXS results). However, the presence of small arabinogalactans side chains in the de-branched and de-esterified pectin extracts acted as reinforcement agents, inducing the formation of more densely packed networks and stronger hydrogels than their less-branched counterpart. These results demonstrated the impact of the pectin structure on the hydrogel-forming capacity.Grant RTI-2018-094268-B-C22 funded by MCIN/AEI/10.13039/501100011033 and by "ERDF A way of making Europe". This work was also funded by the grant INNVAL10-19-009 -CA8250 from Agencia Valenciana d'Innovacio (AVI). D.A. M ' endez. is supported by the Administrative Department of Science, Technology and Innovation (Colciencias) of the Colombian Government (783-2017). This research is part of the CSIC program for the Spanish Recovery, Transformation and Resilience Plan funded by the Recovery and Resilience Facility of the European Union, established by the Regulation (EU) 2020/2094. Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy+. (PTI-SusPlast+) is also acknowledged for financial support.Mendez-Reyes, DA.; Martínez-Abad, A.; Martínez-Sanz, M.; López-Rubio, A.; Fabra Rovira, MJ. (2022). Tailoring structural, rheological and gelling properties of watermelon rind pectin by enzymatic treatments. Food Hydrocolloids. 135. https://doi.org/10.1016/j.foodhyd.2022.10811913

Superabsorbent food packaging bioactive cellulose-based aerogels from Arundo donax waste biomass

A. donax waste biomass has been valorized for the extraction of cellulosic fractions with different purification degrees, as well as aqueous bioactive extracts, which were then combined to develop superabsorbent bioactive aerogels. All the developed aerogels presented excellent water and oil sorption capacities; however, the presence of hemicelluloses yielded more porous and hydrophilic aerogels, capable of absorbing more water. With regards to the aqueous extracts, the hot water treatment (HW) of A. donax stems promoted the extraction of polysaccharides and polyphenols, producing the extract (S-HW) with the highest antioxidant capacity. This extract was then incorporated into the aerogels produced from the less purified stem fractions (F2A and F3A), which were chosen due to their good water sorption capacity, higher antioxidant potential and lower production costs and environmental impact. The hybrid aerogels showed a great potential to be used as bioactive pads for food packaging. In particular, the F2A + S-HW aerogel would be the most optimum choice since it provides a complete release of the extract in hydrophilic media, as demonstrated by in-vitro release and β-carotene bleaching inhibition studies, and it is able to reduce the colour loss and lipid oxidation in red meat upon refrigerated storage to a greater extent.Marta Martinez-Sanz is recipient of a Juan de la Cierva (IJCI-2015-23389) contract from the Spanish Ministry of Economy, Industry and Competitiveness. Cynthia Fontes-Candia is recipient of a pre-doctoral grant from CONACYT (MEX/Ref. 306680)

Bioethanol Production and Alkali Pulp Processes as Sources of Anionic Lignin Surfactants

Lignin is an abundant biopolymer with potential value-added applications that depend on biomass source and fractioning method. This work explores the use as emulsifiers of three native lignin-rich product coming from industrial bioethanol production and alkali or Kraft pulping. In addition to their distinctive characteristics, the different molecular organization induced by emulsification pH is expected to interact in various ways at the water-oil interface of the emulsion droplets. Initially, model oil-in-water (O/W) emulsions of a silicone oil will be studied as a function of lignin source, disperse phase concentration and emulsification pH. Once stablished the effect of such variables, emulsion formulations of three potential bitumen rejuvenators (waste vegetable cooking oil, recycled lubricating oil and a 160/220 penetration range soft bitumen). Droplet size distribution, Z-potential and viscous tests conducted on model emulsions have shown that emulsification pH strongly affects stabilization ability of the lignins tested. Regarding bitumen rejuvenators, lignin emulsification capability will be affected by surfactant source, pH and, additionally, by the dispersed phase characteristics. Lower Z-potential values shown by KL at pH 9 and 11 seem to facilitate emulsification of the less polar disperse phases formed by RLUB and bitumen. In any case, lower particle size and higher yield stress values were found for both bioethanol-derived lignins emulsifying RVO and RLUB at pH 13, which are expected to exhibit a longer stabilit

High pressure treatment and green tea extract synergistically control enteric virus contamination in beverages

Consumers are driving food production toward the use of natural preservatives and minimal processing technologies. Green tea extract (GTE) at low concentration could be combined with high pressure processing (HPP) for reduced treatment times and quality impact on foods in a hurdle concept for synergistic effects on foodborne viral pathogens, specifically human norovirus and hepatitis A virus (HAV). Viral inactivation by HPP (at 300, 400, and 500 MPa for 5 min) combined with 3.3 mg/mL aged-GTE was initially evaluated in buffer (PBS) against murine norovirus (MNV), a culturable human norovirus surrogate, and HAV. Furthermore, human norovirus inactivation was evaluated by the novel human intestinal enteroid system (HIE) and a capsid integrity binding assay (ISC-RT-qPCR). HPP treatment completely inhibits human norovirus GII.4 infectivity when applied at 500 MPa alone and at 400 MPa combined with aged-GTE. Additional experiments investigated the reduction of MNV and HAV infectivity in apple and horchata juices exposed to combined aged-GTE and HPP treatments. Results demonstrated that the addition of aged-GTE to the juices exposed to HPP significantly inactivated MNV and HAV at reduced holding pressure time. This synergistic effect of aged-GTE combined with HPP treatments represents a hurdle technology that could be exploited as a control measure to improve the food safety of beverages