Modificación superficial de membranas de celulosa bacteriana

La celulosa es uno de los biopolímeros más abundantes en la naturaleza y cuenta con características deseables como alta disponibilidad, origen renovable, bajo costo y excelentes propiedades mecánicas, por lo que se presenta como una alternativa económica y ambientalmente sostenible para sustituir fibras sintéticas en la producción de materiales compuestos [1]. Esta puede ser producida por microorganismos [2,3] o también puede ser extraída a partir de fuentes vegetales. Para incrementar la estabilidad de la celulosa a ambientes húmedos y favorecer su dispersión en matrices hidrofóbicas, es necesario modificarla a partir de tratamientos químicos o físicos específicos siendo uno de los más utilizados la acetilación [1,3] la cual es una de las metodologías de modificación más simples en la cual los grupos hidroxilo (-OH), en los cuales la celulosa es rica son reemplazados parcialmente por grupos acetilo (-COCH3)Fil: Marin Quintero, Diana Catalina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Zuluaga, Robin. Universidad Pontificia Bolivariana; ColombiaFil: Gañan, Piedad. Universidad Pontificia Bolivariana; ColombiaFil: Stefani, Pablo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

Caracterización físico-química y microbiológica de la miel de Apis mellifera sp. del Suroeste de Antioquia, Colombia

Characterizations of Apis mellifera honey produced in Southwest of Antioquia, an important coffee region of Colombia, have not been published in recent years. In the present work, seven samples of honey collected in the mentioned region, were physically (refractive index, specific rotation, density), chemically (moisture content, water activity, pH, free acidity, carbohydrates) and microbiologically (Clostridium, fungi and yeast) analyzed. The results show that the analyzed honeys meet both national (Resolución 1057 of 2010) and International (Codex-Stan 12 of 1981) standards for moisture content, free acidity, sucrose content and microbiological parameters, indicating their good quality. Fructose/glucose ratio, pH and specific rotation values indicate that the samples are blossom honeys.Caracterizaciones de miel de Apis mellifera producida en el Suroeste de Antioquia, una región cafetera de Colombia, no se han publicado recientemente. En el presente trabajo, siete muestras de miel recolectadas en la región mencionada, fueron físicamente (índice de refracción, rotación específica, densidad), químicamente (contenido de humedad, actividad acuosa, pH, acidez libre, carbohidratos), y microbiológicamente (Clostridium, hongos y levaduras) analizadas. Los resultados muestran que las mieles analizadas cumplen tanto los estándares nacionales (Resolución 1057 de 2010) como internacionales (Codex-Stan 12 de 1981) para contenido de humedad, acidez libre, contenido de sacarosa y los parámetros microbiológicos, indicando su buena calidad. Los valores de relación fructosa/glucosa, pH y rotación específica indican que las muestras son mieles florales

Caracterización físico-química y microbiológica de la miel de Apis mellifera sp. del Suroeste de Antioquia, Colombia

Characterizations of Apis mellifera honey produced in Southwest of Antioquia, an important coffee region of Colombia, have not been published in recent years. In the present work, seven samples of honey collected in the mentioned region, were physically (refractive index, specific rotation, density), chemically (moisture content, water activity, pH, free acidity, carbohydrates) and microbiologically (Clostridium, fungi and yeast) analyzed. The results show that the analyzed honeys meet both national (Resolución 1057 of 2010) and International (Codex-Stan 12 of 1981) standards for moisture content, free acidity, sucrose content and microbiological parameters, indicating their good quality. Fructose/glucose ratio, pH and specific rotation values indicate that the samples are blossom honeys.Las caracterizaciones de la miel de Apis mellifera producida en el suroeste de Antioquia, una importante región cafetera de Colombia, no se han publicado en los últimos años. En el presente trabajo, siete muestras de miel recolectadas en la región mencionada fueron física (índice de refracción, rotación específica, densidad), químicamente (contenido de humedad, actividad del agua, pH, acidez libre, carbohidratos) y microbiológicamente (Clostridium, hongos y levaduras ) analizado. Los resultados muestran que las mieles analizadas cumplen con los estándares nacionales (Resolución 1057 de 2010) e internacionales (Codex-Stan 12 de 1981) para el contenido de humedad, acidez libre, contenido de sacarosa y parámetros microbiológicos, lo que indica su buena calidad. La relación fructosa / glucosa, el pH y los valores de rotación específicos indican que las muestras son mieles en flor

Starch and Starch/Bacterial Nanocellulose Films as Alternatives for the Management of Minimally Processed Mangoes

Improving the storage of minimally processed mangoes represents a substantial challenge for packaging. For this purpose, thermoplastic starch (TPS) and its composites with bacterial cellulose nanoribbons (TPS/BC) are used as wrapping materials to prolong the shelf life of minimally processed mangoes. Commercial polyvinyl chloride stretch (PVC) films and unwrapped mangoes are used as the controls. The samples were stored at 75% RH and 5 °C for five and ten days. The films are removed after storage and subjected to mechanical tests and physical evaluation. The weight loss, firmness, total soluble solids, and total titratable acidity in the mangoes are tested to monitor fruit ripening. ATR-FTIR is used as an alternative nondestructive technique to examine fruit quality through changes in the sugar and organic acid contents. The results showed that TPS films reduced mango weight loss until the fifth day (2.84%), whereas the reduction in weight loss seen in mangoes wrapped with TPS/BC is even lower (13.18%). Therefore, even though both TPS and TPS/BC films can be used to prolong the fruit shelf life for five days, the latter is more effective. The elongations at break of both film samples remained constant over time, which means that these films can be used under stress conditions.Fil: Montoya Rojo, Ursula Maria. Universidad Pontificia Bolivariana; Colombia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; ArgentinaFil: Zuluaga, Robin. Universidad Pontificia Bolivariana; ColombiaFil: Castro, Cristina. Universidad Pontificia Bolivariana; ColombiaFil: Velez, Lina. Universidad Pontificia Bolivariana; ColombiaFil: Gañán, Piedad. Universidad Pontificia Bolivariana; Colombi

The Evolution and Future Trends of Unsaturated Polyester Biocomposites: A Bibliometric Analysis

Unsaturated polyester resin (UPR) is one of the first commercialized polymer matrices for composites reinforced with glass fibers, but has remained popular to this day. To reduce their environmental impact, natural fibers have been used as reinforcements. Researchers all over the world are still interested in these composites, and numerous papers have been published in the last four decades. Using bibliometric analysis, this work provides compiled, structured, and relevant information about the evolution and current state of these materials. This first study on UPR biocomposites based on bibliometric analysis examined 531 published papers identified in the Scopus database from 1982 to July 2022. An analysis of the most active states, leading institutions, and leading authors is followed by the identification of key areas such as the most common natural fibers used as reinforcements, fiber treatments, and composite design parameters such as processing techniques; recently, composite testing; and technological applications. The findings emphasize the importance of staying active in this global field and provide information on novel promising topics for future research.This research was funded by Universidad Pontificia Bolivariana, grant number “692C-09/21-25” and “The Ministerio de Ciencia y Tecnología de Colombia” proyect name “Desarrollo de aplicaciones a partir del aprovechamiento de los subproductos de la cadena productiva del fique para la industria de alimentos, fitoterapeútica y cosmética.”, grant number 1210-903-86606

Transcriptome responses to Ralstonia solanacearum infection in the roots of the wild potato Solanum commersonii

Background: Solanum commersonii is a wild potato species that exhibits high tolerance to both biotic and abiotic stresses and has been used as a source of genes for introgression into cultivated potato. Among the interesting features of S. commersonii is resistance to the bacterial wilt caused by Ralstonia solanacearum, one of the most devastating bacterial diseases of crops. - Results: In this study, we used deep sequencing of S. commersonii RNA (RNA-seq) to analyze the below-ground plant transcriptional responses to R. solanacearum. While a majority of S. commersonii RNA-seq reads could be aligned to the Solanum tuberosum Group Phureja DM reference genome sequence, we identified 2,978 S. commersonii novel transcripts through assembly of unaligned S. commersonii RNA-seq reads. We also used RNA-seq to study gene expression in pathogen-challenged roots of S. commersonii accessions resistant (F118) and susceptible (F97) to the pathogen. Expression profiles obtained from read mapping to the S. tuberosum reference genome and the S. commersonii novel transcripts revealed a differential response to the pathogen in the two accessions, with 221 (F118) and 644 (F97) differentially expressed genes including S. commersonii novel transcripts in the resistant and susceptible genotypes. Interestingly, 22.6% of the F118 and 12.8% of the F97 differentially expressed genes had been previously identified as responsive to biotic stresses and half of those up-regulated in both accessions had been involved in plant pathogen responses. Finally, we compared two different methods to eliminate ribosomal RNA from the plant RNA samples in order to allow dual mapping of RNAseq reads to the host and pathogen genomes and provide insights on the advantages and limitations of each technique. - Conclusions: Our work catalogues the S. commersonii transcriptome and strengthens the notion that this species encodes specific genes that are differentially expressed to respond to bacterial wilt. In addition, a high proportion of S. commersonii-specific transcripts were altered by R. solanacearum only in F118 accession, while phythormone-related genes were highly induced in F97, suggesting a markedly different response to the pathogen in the two plant accessions studied

Effect of molecular weight reduction by gamma irradiation on the antioxidant capacity of chitosan from lobster shells

AbstractThis study assessed the effect of molecular weight (MW) reduction by gamma irradiation on the antioxidant capacity of chitosan with potential application in the preservation of foodstuffs. Two batches of chitosan were obtained by heterogeneous chemical N-deacetylation of chitin from common lobster (Panulirus argus). Irradiation of chitosan was performed using a 60Co source and applying doses of 5, 10, 20 and 50 kGy with a dose rate of 10 kGy/h. Attenuated Total Reflection Fourier Transform Infrared Spectroscopy was used to identify main chemical features of chitosan. The average viscosimetric MW was determined by the viscosimetric method while the deacetylation degree by a potentiometric method. Thermogravimetric analysis and differential scanning calorimetry were conducted to evaluate the thermal degradation behavior of the chitosan samples, both under nitrogen flow. The antioxidant activity of chitosan solutions at 1% (w/v) in lactic acid at 1% (v/v) and Tween 80 at 0.1% (v/v) was evaluated through the ABTS assay and scavenging of DPPH radical by chitosan. The increase of irradiation dose with 60Co until 50 kGy decreased significantly the MW of chitosan through the scission of glycosidic bonds without affecting its functional groups, while the DD (72–75 %) did not vary (p > 0.05). The AC of the chitosan solutions increased with the reduction of MW of chitosan by gamma irradiation

Transcriptome responses to Ralstonia solanacearum infection in the roots of the wild potato Solanum commersonii

Background: Solanum commersonii is a wild potato species that exhibits high tolerance to both biotic and abiotic stresses and has been used as a source of genes for introgression into cultivated potato. Among the interesting features of S. commersonii is resistance to the bacterial wilt caused by Ralstonia solanacearum, one of the most devastating bacterial diseases of crops. Results: In this study, we used deep sequencing of S. commersonii RNA (RNA-seq) to analyze the below-ground plant transcriptional responses to R. solanacearum. While a majority of S. commersonii RNA-seq reads could be aligned to the Solanum tuberosum Group Phureja DM reference genome sequence, we identified 2,978 S. commersonii novel transcripts through assembly of unaligned S. commersonii RNA-seq reads. We also used RNA-seq to study gene expression in pathogen-challenged roots of S. commersonii accessions resistant (F118) and susceptible (F97) to the pathogen. Expression profiles obtained from read mapping to the S. tuberosum reference genome and the S. commersonii novel transcripts revealed a differential response to the pathogen in the two accessions, with 221 (F118) and 644 (F97) differentially expressed genes including S. commersonii novel transcripts in the resistant and susceptible genotypes. Interestingly, 22.6% of the F118 and 12.8% of the F97 differentially expressed genes had been previously identified as responsive to biotic stresses and half of those up-regulated in both accessions had been involved in plant pathogen responses. Finally, we compared two different methods to eliminate ribosomal RNA from the plant RNA samples in order to allow dual mapping of RNAseq reads to the host and pathogen genomes and provide insights on the advantages and limitations of each technique. Conclusions: Our work catalogues the S. commersonii transcriptome and strengthens the notion that this species encodes specific genes that are differentially expressed to respond to bacterial wilt. In addition, a high proportion of S. commersonii-specific transcripts were altered by R. solanacearum only in F118 accession, while phythormone-related genes were highly induced in F97, suggesting a markedly different response to the pathogen in the two plant accessions studied

Compendio de las alternativas para el desarrollo de materiales que brindan las estructuras celulósicas aisladas de residuos de la agroindustria de musáceas

Desde finales del siglo XX tanto a nivel científico como tecnológico se vienen analizando múltiples tipos de estructuras derivadas de plantas que puedan ser empleadas como reforzantes o aditivos para mejorar el desempeño mecánico, eléctrico, térmico, magnético, o químico de múltiples tipos productosque pueden ser empleados en campos tan diversos como la industria textil, el desarrollo o mejoramiento de alimentos o incluso para el desarrollo de baterías o sistemas de almacenamiento de energía. Las fibras naturales, también conocidos como haces fibrosos y en especial las derivadas de plantas, cada vez másrepresentan una importante alternativa en esta línea debido a las ventajas que ofrecen tanto desde el punto de vista técnico como ambiental y económico. Dentro de las fuentes alternativas para obtener fibras naturales y la gama de subestructuras de celulosa que pueden ser aisladas a partir de ellas, los residuos agroindustriales se consolidan como una importante fuente de materias primas, en especial cuando se desea promover procesos de economía circular, o el cierre de ciclos productivos bajo consideraciones de sostenibilidad. En el presente texto se abordan diferentes alternativas de uso de las fibras naturales y sus respectivas subestructuras celulósicas que pueden ser obtenidas a partir de los residuos generados por dos de los cultivos de Musáceas más importantes de Colombia, y que corresponden al bananero y el platanero. Las alternativas presentadas en este texto, además de actuar como un compendio, también puede mostrar ejemplos que puedan orientar la investigación y el desarrollo de productos empleando los desechos de cosecha y pos cosecha de otro tipo de cultivos.Fil: Zuluaga, Robin. Universidad Pontificia Bolivariana; ColombiaFil: Osorio, Marlon. Universidad Pontificia Bolivariana; ColombiaFil: Velásquez Cock, Jorge. Universidad Pontificia Bolivariana; ColombiaFil: Molina, Carlos. Universidad Pontificia Bolivariana; ColombiaFil: Correa, Carlos. Universidad Pontificia Bolivariana; ColombiaFil: Vélez Acosta, Lina. Universidad Pontificia Bolivariana; ColombiaFil: Castro, Cristina. Universidad Pontificia Bolivariana; ColombiaFil: Ruiz-Ramírez, Luis. Universidad Pontificia Bolivariana; ColombiaFil: Serpa, Angélica. Universidad Pontificia Bolivariana; ColombiaFil: Restrepo, Adriana. Universidad Pontificia Bolivariana; ColombiaFil: Álvarez, Catalina. Universidad Pontificia Bolivariana; ColombiaFil: Betancourt, Santiago. Universidad Pontificia Bolivariana; ColombiaFil: Montoya Rojo, Ursula Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; ArgentinaFil: Gañán, Piedad. Universidad Pontificia Bolivariana; Colombi