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Los biopolímeros tienen un gran potencial en el campo del cuidado y la cicatrización de heridas. El almidón, como biopolímero abundante en la naturaleza, puede ser utilizado para reparar tejidos y mejorar su función natural, siempre y cuando cumpla con ciertas características específicas que se logran mediante la modificación de las propiedades fisicoquímicas del biomaterial. Por lo anterior, en este artículo se realiza una revisión sistemática del uso de biomateriales a base de almidón en el desarrollo de apósitos. Siguiendo las directrices de la metodología Prisma, se buscaron y analizaron artículos originales de los últimos siete años, donde se estudió la elaboración de biomateriales a base de almidón y su uso en la cicatrización de heridas. La selección de estos artículos incluyó criterios de inclusión y exclusión que permitieron elegir 57 estudios para cumplir con el objetivo de la revisión. Así, se describe detalladamente el tipo de apósito creado, las técnicas utilizadas para su obtención, los principales polímeros y aditivos empleados, así como los métodos de evaluación del biomaterial. Las técnicas de fabricación influyeron directamente en el tipo de apósito obtenido y las ventajas funcionales que adquirieron, donde sus modificaciones fisicoquímicas resultaron relevantes para que el biomaterial tuviera la capacidad de funcionar adecuadamente como apósito; además, los apósitos compuestos por diversos materiales y aditivos tienen mejor comportamiento mecánico que los elaborados a partir de un solo material. Se debe tener en cuenta que los métodos de caracterización permiten una evaluación precisa de los biomateriales, asegurando que estos proporcionen los beneficios esperados en la curación y el cuidado de heridas.

O desenvolvimento e a melhoria de materiais são fatores fundamentais para o aprimoramento social, ambiental e econômico em diversos países. Nesse contexto, os aditivos bioquímicos para materiais à base de cimento têm sido bastante explorados pelo caráter sustentável. Os biopolímeros têm sido estudados como aditivos/substitutos parciais ou totais de componentes das pastas de cimento, com o intuito de melhorar as propriedades do material. O objetivo desta revisão é identificar os principais materiais e propriedades que têm sido explorados em estudos utilizando biopolímeros em pastas cimentícias. O método utilizado foi a revisão sistemática da literatura em artigos publicados entre 2010 e 2020 nas bases de dados Web of Science, Scopus, Periódicos CAPES e Science Direct. Os artigos foram categorizados por meio das ferramentas StArt e Excel. Os resultados mostraram tendência do crescimento desse tema a partir do ano de 2015, sendo a viscosidade a principal propriedade estudada. Houve convergência na redução da viscosidade das misturas, a partir das características plastificantes dos biopolímeros, e melhoria em outras propriedades, como resistência à compressão, trabalhabilidade e outros. A utilização de biopolímeros consolidados no mercado mundial e amplamente comercializados, como bactérias, quitosana e lignina, se destaca nos estudos revisados.

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The cape gooseberry (Physalis peruviana L.) is recognized in national and international markets as an exotic fruit with high nutritional value. However, its short shelf life and post-harvest losses affect its marketing. The objective of this research was to develop the formulation of an edible coating to extend the useful life of the fruits, based on a Box-Benhken response surface design, using different concentrations of chitosan (1, 1.5 and 2 %) (w/w), beeswax, and glycerol (1, 2 and 3 %) (w/w). Weight loss, firmness, color index, and respiration rate were the response variables. The generated quadratic polynomial models were suitable to explain the effects of chitosan, beeswax, and glycerol concentrations. Experimental validation confirmed the suitability of the cape gooseberry coating formulation using response surface methodology with 1.33 % chitosan, 2.14 % beeswax, and 1.29 % glycerol. The coating maintained the physiological and physical properties of cape gooseberry for up to 15 days at room temperature. [ABSTRACT FROM AUTHOR]

This research carried out a bibliometric analysis and literature review on the production of gelatin-based films for application as food packaging, addressing the main advances and limitations. The search for articles was performed in the Scopus database, and bibliometric data were obtained using the Bibliometrix tool (RStudio software). It was observed that a wide variety of compounds can be incorporated into gelatin films to overcome the limitations related to their high solubility and low mechanical properties, as well as to obtain active or smart functions. Among the most reported compounds were essential oils, pigments extracted from vegetables, and other antimicrobial agents. The most reported foods as an application matrix were meat (fish, chicken, and shrimp), milk, cheese, and minimally processed fruits. Even with promising trends, the biggest challenge for large-scale applications is to obtain easily degradable biopolymers with structural and functional stability similar to synthetic polymers. Thus, a greater focus on this theme in research may favor significant advances in the use of these packages and positively impact several of the Sustainable Development Goals, as recommended by the United Nations. [ABSTRACT FROM AUTHOR]

The toxic effects caused by agrochemicals have led to the generation of innocuous alternatives for the control of phytopathogens, such as chitosan, a harmless biopolymer with fungicidal effect. Therefore, it was proposed to extract chitosan from shrimp shell to control Pythium aphanidermatum and Sclerotium rolfsii. It was possible to obtain chitosan with 100% deacetylation and 457,000 g.mol-1 molecular weight, with which we prepared a culture medium supplemented at different concentrations (50, 100, 150 and 200 ppm). Its antagonistic effect against the mentioned phytopathogens was evaluated in vitro. The statistical analysis of the inhibition data showed that the different concentrations of chitosan had an inhibitory effect. The 200 ppm concentration was the one that presented the highest percentage of inhibition (63.82 and 91.67%) against P. aphanidermatum and S. rolfsii, respectively. Therefore, chitosan could be considered as an organic alternative in the management of these phytopathogens. [ABSTRACT FROM AUTHOR]

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An evaluation of incorporated polylactic acid (PLA) active biodegradable films of essential oils to inhibit microbial adhesion was performed using a 25-1V fractional exploratory design, combining the factors, amount of PEG 400 plasticizer (10 and 20%), amount of cinnamon essential oil (0.5% and 1%), amount of oregano essential oil (0.5% and 1%), Salmonella spp. concentration (10³ CFU mL-1 and 104 CFU mL-1) and Staphylococcus aureus concentration (10³ CFU mL-1 and 104 CFU mL-1). The results of microbial adhesion inhibition test showed that the maximum inhibition percentage reached 73.82 ± 0.35% corresponding to experiment 7 (bce), which contains 10% of PEG 400, 1% of cinnamon essential oil, 1% of oregano essential oil, 10³ CFU mL-1 of Salmonella spp. concentration, 104 CFU mL-1 of Staphylococcus aureus concentration. Statistical analysis determined that there is strong significant evidence (p-value = 0.0283) that Staphylococcus aureus concentration influences the inhibition percentage to microbial adhesion; as well as that the cinnamon essential oil-Salmonella spp. interaction has little significant evidence (p-value = 0.0711) that influences the inhibition percentage. Inhibition results greater than 60% have the highest concentration of Staphylococcus aureus as a common factor. PLA active biodegradable films with a higher inhibition percentage can potentially be used in the food industry as a barrier mechanism to avoid bacterial contamination. [ABSTRACT FROM AUTHOR]

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La evaluación de películas biodegradables activas de ácido poliláctico (PLA) incorporado de aceites esenciales para inhibir la adhesión microbiana se realizó mediante un diseño exploratorio fraccionario , combinando los factores, cantidad de plastificante PEG 400 (10 y 20%), cantidad de aceite esencial de canela (0,5 y 1%), cantidad de aceite esencial de orégano (0,5 y 1%), concentración en unidades formadoras de colonias (UFC) de Salmonella spp. (103 y 104 UFC mL-1) y concentración de Staphylococcus aureus (103 y 104 UFC mL-1). Los resultados del ensayo de inhibición a la adhesión microbiana mostraron que el porcentaje máximo de inhibición alcanzó el 73,82 ± 0,35 %, correspondiente al experimento 7 (bce), el cual contiene 10% PEG400, 1% aceite esencial de canela, 1% aceite esencial de orégano, 103 UFC mL-1 de concentración de Salmonella spp. y 104 UFC mL-1 de concentración de Staphylococcus aureus. El análisis estadístico determinó que existe evidencia significativa (valor p = 0,0283) que indica que la concentración de Staphylococcus aureus influye en el porcentaje de inhibición a la adhesión microbiana; así como también, que la interacción del aceite esencial de canela-Salmonella spp. tiene poca evidencia significativa (valor p = 0,0711) que influye en el porcentaje de inhibición. Los resultados de inhibición están en función del tipo de bacteria, siendo mayor para las Gram positivas. Los resultados de inhibición superiores al 60% tienen como factor común la concentración más alta de Staphylococcus aureus. Por lo tanto, las películas biodegradables activas de PLA con mayor porcentaje de inhibición pueden usarse potencialmente en la industria alimentaria como mecanismo de barrera para evitar contaminación bacteriana.

Se realizó una caracterización físico-química de los efluentes procedentes de industrias del sector educación, metalmecánico, lácteos y confitería de la ciudad de Manizales, Caldas; posteriormente se obtuvieron aislamientos, en medios diferenciales suplementados, de bacterias con potencial para la producción de biopolímeros a los cuales se les aplicó pruebas para la caracterización morfológica, bioquímica y molecular. Los parámetros físico químicos obtenidos de los efluentes industriales demuestran diferencias entre ellos, ya que cada industria genera diferentes residuos aportando una determinada contaminación al efluente, se obtuvieron 73 aislamientos productores de exopolisacáridos (EPS) y 101 productores de polihidroxialcanoatos (PHA), con características morfológicas y bioquímicas variables. El estudio muestra que los efluentes industriales son una gran fuente de bacterias de interés para la producción de diversos polímeros microbianos; principalmente aquellos que producen polímeros tipo biopoliésteres intracelulares como PHA, debido a su variabilidad físico-química y nutricional permitiendo que los microorganismos se adapten a diversas características medioambientales y de composición.

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El alto índice de contaminación plástica en la actualidad ha llevado a la búsqueda de soluciones que sean amigables con el ambiente. Se presenta un estudio de la fabricación de polímero biodegradable a base de almidón de tubérculos panameños seleccionados (yuca, ñame, otoe y ñampí) y su evaluación mediante un análisis de tensión y biodegradación. Se generó un procedimiento para la extracción de almidón de los tubérculos, así como de la fabricación de biopolímero. El ensayo de tensión se hizo de manera artesanal con una probeta ASTM D638-14 tipo IV incrementando progresivamente el peso y registrando fotográficamente hasta su fractura. El ensayo de biodegradación se monitoreaba la presencia de hongos, se hizo un ensayo con una solución con enzimas digestivas que contenía amilasa, registrando su desintegración en 24 horas y por último, se sembraron los segmentos directamente al suelo y se registró su descomposición después de 7 y 15 días. Se pudo extraer el almidón y fabricar biopolímeros de todos los tubérculos mediante la metodología presentada. La acuosidad del almidón decantado variaba según el tubérculo. El biopolímero generado por ambos fue muy similar y dos de los óptimos para fabricar y cortar. En los ensayos de tensión el biopolímero de otoe mostro mayor resistencia al esfuerzo y deformación previa a la fractura comparado con los demás tubérculos y biopolímero de almidón de maíz utilizando la misma metodología de fabricación. Todos los biopolímeros mostraron avances en su proceso de biodegradación.

El presente trabajo se realizó para generar una alternativa sostenible en la producción de bioplásticos para usos agroindustriales, aprovechando cultivos de El Salvador tales como papa (Solanum tuberosum) y yuca (Manihot esculenta Crantz) ricos en almidón, modificando la estructura molecular por procesos térmicos y químicos para obtener un almidón termoplástico capaz de ser moldeable como película biodegradable y ser mezclado como biocompuesto. Esto con el objetivo de mitigar la contaminación por plásticos petroquímicos con altas emisiones de gases de efecto invernadero y daños directos a la biodiversidad, puesto que la dinámica de crecimiento poblacional ha conllevado el arraigo por factores socio-económicos y culturales al uso desmedido de plásticos, demanda que incrementará paralelamente con la producción de alimentos.

Introducción. El uso de biopolímeros en el tratamiento de efluentes permite controlar el impacto ambiental asociado a la descarga de aguas residuales agroindustriales. Objetivo. Evaluar la efectividad del quitosano como coagulante natural en el tratamiento de efluentes de producción de aceite de palma. Materiales y métodos. Se determinaron los parámetros: demanda química de oxígeno (DQO), los sólidos suspendidos totales (SST) y volátiles (SSV), turbidez y grasas y aceites (GYA) sobre en el agua residual asociada a la producción de aceite de palma proveniente del municipio de Agustín Codazzi en el departamento del Cesar (Colombia), por el ensayo de pruebas de jarras. Se aplicó quitosano en dosis de: 100, 200, 300, 400 y 0 mg L-1 a tres niveles de pH 4, 5 y 6 del agua. Se implementó un diseño experimental completamente aleatorizado, de dos vías, con efectos fijos. Para el análisis de datos se utilizó un análisis multivariado de los parámetros fisicoquímicos del efluente industrial. El estudio se realizó en el año 2012. Resultados. El quitosano permitió reducir más del 87 % de turbidez, DQO, SST, SSV y grasas y aceites en todas las dosis del coagulante, mientras que el control (0 mg L-1) fue diferente estadísticamente (p

Plastic is used excessively due to its excellent properties and its low cost. This has led to the ubiquitous accumulation of waste as it takes a very long time to biodegrade. Until now, several research projects have developed different biodegradable plastics, and the tests to validate them are still being undertaken. In this research, a biodegradability test was performed on a bioplastic synthesized from tamarind xyloglucan and ethyl acrylate (b-XgT), designed to be a substitute for polystyrene. A sample of the b-XgT was composted in laboratory conditions and CO2 release measurements were made. The results showed a biodegradation time of 18 days with a loss of mass of 40.3% and a final pH of 7.1. The b-XgT was found to be biodegradable of the compostable type through the anaerobic route, which promotes the digestion of compounds such as xylose that contribute to the degradation of the whole polymer. [ABSTRACT FROM AUTHOR]

Introduction: Eggshell membrane (ESM) is a tissue found between the eggshell and the albumen of eggs that has attractive properties for use in drug delivery systems. Aim: To incorporate in ESM and used it as a model drug in release studies. The color change and FTIR analysis of the biopolymer proved the incorporation of nimesulide in ESM. Results: The drug uptake was 176.83 and 122.69 mg g-1 by natural and cross-linked ESM. Release studies were carried out using a spectrophotometric flow system in simulated intestinal fluid pH 7.4. The release profiles showed that after 60 minutes 54.55 and 42.58 % of the drug were released from natural and crosslinked ESM, respectively. Kinetics parameters indicated that drug release was better described by the Higuchi model and through a non-Fickian release. Conclusion: Considering these results is proved that ESM has the potential to become a polymeric matrix for drug release systems. [ABSTRACT FROM AUTHOR]

The adverse impacts in the Santa Cruz do Apodi Watershed Basin (BHASCA) prevent Biofilms are biodegradable and/or edible films made from biopolymers. The application of biofilms as packaging is directly related to its characteristics, and to their interactions with the product and the environment. Proteins are promising materials, due to the wide range of functional properties. Gelatine is an attractive biomaterial, due to its large production and low cost. However, gelatine has limitations in its physicochemical properties when compared to synthetic polymers. The improvement of these properties was proposed in this study from the incorporation of bentonite clay in the gelatin films. In order to increase the interaction between clay and gelatin, clay was modified in the presence of a surfactant (sodium dodecyl sulfate), aiming at the basal spacing between the silicate layers. The films of gelatin with modified bentonite clay were characterized as bionanocomposite through analysis of Optical Microscopy (MO), Angle of Contact (AC), water vapor permeability (PVA), solubility, mechanical properties and humidity. The incorporation of bentonite clay into gelatin films reduced 40.8% of the water vapor permeability, and increased the rupture stress by 55%. The clay significantly improved the physicochemical properties of the biopolymer film. [ABSTRACT FROM AUTHOR]

Copyright of Revista de la Sociedad Química del Perú is the property of Sociedad Quimica del Peru and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

La actividad antifúngica del quitosano, aceites esenciales (canela y eucalipto) y su combinación fueron evaluadas contra dos patógenos Colletotrichum acutatum y Colletotrichum gloeosporioides aislados de aguacate (Persea americana Mill). Se utilizó quitosano a diferentes concentraciones (0.1, 0.5 y 1.0%). Las concentraciones de aceites esenciales evaluadas fueron 0.1, 0.5 y 2.0% (eucalipto y canela). El efecto de la combinación del quitosano con los aceites esenciales se evaluó utilizando las concentraciones más eficaces del quitosano (0.1 y 0.5%) y el aceite esencial de eucalipto y canela con el mayor efecto inhibitorio (2%). Los tratamientos de quitosano y aceites esenciales cada uno por separado fueron parcialmente efectivos para evitar el desarrollo de las cepas evaluadas, inhibiendo el crecimiento micelial en un rango de 17 a 21% y 18 a 50% respectivamente. Por lo contrario, el crecimiento micelial de ambas cepas fue totalmente reducido mediante la aplicación combinada del quitosano (0.1%) con aceite esencial de canela (2%), sin embargo; la combinación del quitosano con aceite esencial de eucalipto no fue efectiva. Hasta donde sabemos, esta investigación es la primera que informa sobre cepas de Colletotrichum resistentes al quitosano aisladas de frutos de aguacate.

Una de las primeras etapas en la potabilización del agua superficial es la coagulación floculación de sólidos suspendidos. La presencia de sólidos altera las propiedades físico-químicas del agua, pudiendo afectar su color y sabor, generando, en algunos casos, contaminación microbiológica. El coagulante-floculante más utilizado es el sulfato de aluminio; sin embargo, la presencia de aluminio residual en el agua se ha asociado con trastornos en la salud de los consumidores, ya que el aluminio, como sal soluble, llega a ser biodisponible en el metabolismo humano. Por tanto, se plantea la posibilidad de reemplazar el sulfato de aluminio con biopolímeros no tóxicos como el quitosano. Así, se analizó, mediante pruebas de jarras, el agua que llega de diferentes vertientes a los tanques de almacenamiento de la planta de tratamiento de Bellavista en la ciudad de Quito. Se encontró que el quitosano en concentraciones de 8 ppm ocasiona un 19,7% de disminución en la turbidez del agua cruda; a esta misma concentración, el sulfato de aluminio genera el efecto contrario, produce un incremento de turbidez del 19,3%. Debido a este comportamiento, el quitosano puede convertirse en una alternativa viable para clarificar agua para consumo humano, además de su cualidad como polímero natural.

México es el principal exportador de jitomate a nivel mundial. El uso de invernaderos favorece la protección y producción de hortalizas, sin embargo, las plántulas de jitomate son sensibles al ataque de hongos necrotróficos como Alternaria sp. y el uso de fungicidas para el control de enfermedades aunque efectivo, daña al medio ambiente y favorece la aparición de cepas resistentes, situación que impulsa a buscar alternativas seguras para el uso de fungicidas sintéticos. El quitosano posee actividad antifúngica además de la capacidad de activar mecanismos de defensa en las plantas. En este estudio, a las plantas de jitomate se les aplicó quitosano a diferentes concentraciones. Se determinó el porcentaje de daño foliar, germinación de esporas, inducción de peróxido de hidrógeno y actividad enzimática (peroxidasa y polifenoloxidasa). Se obtuvo una reducción estadísticamente significativa en el daño foliar y la germinación de esporas en plantas tratadas con 0.01% de quitosano (hasta un 80%) en comparación con el control. La producción de H2O2 y la actividad enzimática fue inducida en plantas tratadas. Por lo tanto, la aplicación de quitosano puede ser una alternativa viable para el control de la pudrición causada por Alternaria sp. en jitomate.

As preocupações ambientais vêm aumentando nos últimos anos, principalmente devido ao uso de vários produtos derivados de petróleo, os quais levam anos para se degradar na natureza. Para minimizar esse problema, vários estudos focam na utilização de materiais naturais biodegradáveis. Nesse contexto, verificou-se que a fécula de mandioca pode ser aproveitada como matéria prima para produção de um biopolímero que pode ser utilizado como isolante térmico. O biopolímero foi produzido por um processo de expansão térmica controlada com frações volumétricas de 30% de água e 70% de fécula de mandioca. Foram analisadas as propriedades físicas e térmicas do material com intuito de obter dados sobre a viabilidade de seu uso como isolante térmico. O material apresentou uma condutividade térmica de 0,152 W/mK, podendo ser aplicado como isolante em sistemas quente de até 270 °C e um limite de resistência a temperatura de 270°C observado pela análise termogravimétrica. O biopolímero de fécula de mandioca mostrou-se eficiente quanto à isolação térmica, devido possuir propriedades semelhantes às de isolantes térmicos disponíveis comercialmente. Além disso, foram realizadas análises de inflamabilidade, a qual o material se apresentou como não inflamável. Além disso, analisou-se dureza caracterizando-o como um material duro. Diante disso, o material mostrou-se promissor a ser aplicado como isolante térmico. Essas análises foram fundamentadas em normas ABNT, ASTM e UL-94 e os resultados obtidos experimentalmente comprovam que o biopolímero de fécula de mandioca pode ser utilizado para fins de isolamento térmico.

The antifungal effectiveness of aqueous extracts of coconut mesocarp (Cocos nucifera L.) (AEC) and commercial chitosan (CQ) applied individually and in combination was evaluated against Rhizopus stolonifer in terms of mycelial growth, sporulation, spore germination, as well the primary growth models at two storage temperatures (15-25 oC) was obtained. The use of AEC applied individually, significantly reduced the mycelial growth of R. stolonifer (> 45 %); on the other hand, CQ (1.5 %) showed up to 87 % of control, however, the combination of AEC (10 %) with CQ (1.5 %) was more effective in reducing mycelial growth (> 93 %). All treatments were effective in inhibiting spore production (> 94 %) compared to control (agar). CQ combined with AEC was more effective by inhibiting the germ tube elongation (> 98 %) compared to the individual treatments (< 48 %). The modified Gompertz model showed an adequate fit for both temperature ranges (> 98-99 %), observing significant differences (p ≤ 0.05) between the variables maximum speed (Vmax) and latency period (ƛ), however all treatments showed a fungistatic effect on the mycelial development of R. stolonifer. The combination of AEC and CQ can be an eco-friendly alternative against soft rot in soursop fruits. [ABSTRACT FROM AUTHOR]

Plásticos biodegradáveis à base de amido têm adquirido bastante importância tendo em vista a sua possibilidade de substituir os plásticos convencionais derivados de fontes fósseis. O objetivo desta pesquisa foi avaliar o efeito da adição de queratina (0, 10 e 20%, em relação à quantidade de amido), oriunda de penas de frangos, nas propriedades de biofilmes de amido de milho-glicerol. Os filmes foram obtidos por casting e os ensaios para obtenção e caracterização dos mesmos foram conduzidos nos laboratórios de Físico-química e de Processos Químicos do Instituto Federal de Educação, Ciência e Tecnologia do Rio Grande do Norte, Campus Nova Cruz. Avaliou-se os parâmetros espessura, gramatura, densidade, transparência, umidade, solubilidade em água, permeabilidade ao vapor de água e transparência dos biofilmes. Os valores da transparência, espessura, gramatura e densidade não foram afetados com os tratamentos, enquanto que, os da solubilidade em água e da taxa de permeação ao vapor de água dos filmes reduziram com o aumento da quantidade de queratina.

Se sintetizaron hidrogeles semi-interpenetrados (semi-IPN) obtenidos a partir de acrilamida (AAm) y el biopolímero poli(hidroxibutirato-co-hidroxivalerato) (P(HB-co-HV)) de diferente masa molar (Mv). El análisis de la estructura química de los materiales se realizó mediante espectroscopia FT-IR. Los resultados sugirieron la incorporación del P(HB-co-HV) dentro de la red entrecruzada de la poliacrilamida (PAAm), lo que indicó que el hidrogel semi-IPN fue sintetizado. Adicionalmente, se analizaron muestras del gel seco semi-IPN a través de calorimetría diferencial de barrido. Se siguió gravimétricamente el comportamiento de hinchamiento de los hidrogeles en agua y se analizó el efecto de la composición porcentual y del porcentaje de reactivo entrecruzante (N,N’-metilenbisacrilamida, MBAAm) sobre los mecanismos de transporte de agua. Los resultados obtenidos indicaron que los hidrogeles semi-IPN se hinchan menos que el hidrogel de PAAm pura, lo que se atribuyó al carácter hidrófobo del biopolímero incorporado dentro de la red entrecruzada del material. Se calculó el exponente de difusión de los hidrogeles (n) y en todos los casos se obtuvo que n < 0,50. Por tanto, el proceso de difusión es menos Fickiano, lo que significa que la rapidez de penetración del agua es mucho menor que la velocidad de relajación de las cadenas de polímero.

La producción de plásticos a nivel mundial presenta cifras abrumadoras debido a que tienen aplicaciones en diferentes campos, desde la medicina hasta la industria de empaques. Uno de los problemas radica en que la materia prima para preparar esos plásticos proviene de fuentes fósiles, los principales responsables de las emisiones de dióxido de carbono a la atmósfera y después de usar esos materiales se desechan y tardan varios años en descomponerse. Otro problema está enfocado hacia la agricultura e incluye los procesos que generan desechos orgánicos como la industria azucarera y del café, que pueden contaminar el medio ambiente sin tratamiento adecuado. Cada vez cobra más importancia reemplazar los plásticos convencionales por biomateriales cuyos sustratos de partida provengan de fuentes renovables, que sean biodegradables y que puedan tener aplicaciones similares a los materiales convencionales. Por ello, en este artículo se destacan los últimos avances en el área de los materiales a partir de recursos renovables, en especial de los polímeros biobasados, de su biodegradabilidad y sus aplicaciones, para generar curiosidad y propiciar la búsqueda de alternativas de aprovechamiento de las fuentes renovables en la obtención de nuevos biopolímeros.

One of the challenges of aquaculture is to develop efficient technology packages for different species with zootechnical potential. Several researchers have been studying the stability of macrodietes in water, since leaching processes happen quickly, causing nutrients to be released into the water, leading to pellet disaggregation and, consequently, decreasing the availability of capture of farmed animals. The objective of this work was to show the effect of the sodium alginate crosslinking process, as well as to evaluate the influence of this step on the resistance of commercial feed to leaching processes. The coating was performed by immersing the commercial feed pellets in a sodium alginate solution, followed by the crosslinking process in calcium chloride solution. The methodology employed in pellet coating proved to be very efficient and easy to apply. Determinations of nitrogen and phosphorus concentrations in water samples decreased for treatments using coated commercial diets, this factor may lead to the maintenance of physical chemical parameters of water quality. The proposed methodology may be an alternative in the production of feed aiming at a greater stability of the pellets and water of the farming system. [ABSTRACT FROM AUTHOR]

Ultrasonic nebulization was used as a novel method of chitosan (CH) and acidic electrolyzed water (AEW) application on table eggs; effects on preservation, quality and antimicrobial properties were investigated. The effect of the application of CH and AEW alone or in combination on eggs quality was evaluated in terms of weight loss, shell thickness, yolk colour, Haugh units and shell strength. Additionally, the application of CH and AEW as antimicrobial agent was investigated in order to evaluate their efficacy against Salmonella enteritidis and Escherichia coli (ATCC 25922). A negative effect was observed by the sole application of AEW on eggshell thickness and strength. Conversely, the combination of AEW and CH improve eggshell strength, as well as avoid water losses. The use of CH alone stable Yolk colour values and Haugh units compared to control eggs during the storage time. The combination of AEW and CH reduced the antimicrobial activity. However, the sole application of CH or EAW was effective depending the type of inoculation and the strain evaluated. [ABSTRACT FROM AUTHOR]

Copyright of Revista de la Sociedad Química del Perú is the property of Sociedad Quimica del Peru and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Biodegradable plastics based on starch have acquired considerable importance in view of their possibility of replacing the conventional plastics derived from fossil sources. The aims of this research was to evaluate the effect of the addition of keratin (0, 10 and 20%, relative to the amount of starch) from chicken feathers on the properties of corn-glycerol starch biofilms. Films is obtained by casting and the tests to obtain and characterize them were conducted in the physicochemical and chemical processes laboratories from Federal Institute of Education, Science and Technology of Rio Grande do Norte, Campus Nova Cruz. The parameters thickness, weight, density, transparency, humidity, water solubility and biofilms water vapor permeability were evaluate. The values of transparency, thickness, weight and density of the films no affected with treatments applied. The water solubility and the water vapor permeation rate of the films reduced with increasing amount of keratin. [ABSTRACT FROM AUTHOR]

Copyright of Ingeniería Agrícola y Biosistemas is the property of Universidad Autonoma Chapingo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Em busca de um correto direcionamento a rejeitos, vê-se na produção de materiais cerâmicos a possibilidade potencial de reaproveitamento a partir da junção de resíduos e compostos biopoliméricos, que venham a conferir melhores características básicas aos produtos cerâmicos. Os resíduos de lapidários e o biopolímero quitosana, têm em sua composição uma diversidade de minerais que ampliam a possibilidade de aplicação na indústria cerâmica. No presente trabalho, foram confeccionados corpos de prova com diferentes proporções de pó de lapidário e argila, sendo a água para o preparo da massa, substituída por solução de quitosana 2% (em massa). Após os processos de queima nas temperaturas de 850, 950 e 1100°C, os corpos de prova foram submetidos a análise de Difusividade segundo a lei de Fick. Donde foi possível concluir que a adição de pó de lapidário diminuiu a taxa de difusão e o ganho de massa nas amostras, mostrando um incremento nas características desejáveis para os produtos. In search of an adequate destination of residues, the reuse is seen in the production of ceramic materials from the junction of residues and biopolymer compounds, which will confer better characteristics to the ceramic products. The residues of lapidary and the biopolymer chitosan have in their composition minerals that extend the possibility of application in the ceramic industry. In the present work, specimens were prepared with different proportions of lapidary powder and clay, the water for the preparation of the mass being replaced by chitosan solution 2% (w/w). After the processes of burns at 850, 950 and 1100°C, the specimens were submitted to analysis of Diffusivity according to Fick’s law. It was concluded that the addition of lapidary powder decreased the diffusion rate and the mass gain in the samples, showing an increase in desirable characteristics for the products.

To determine the effect of the application of Chitosan on cucumber (Cucumis sativus L.), an experiment was carried out in glasshouse conditions. The treatments consisted of the application of three doses of Chitosan 100, 200 and 300 mg ha-1 and a control, on the varieties INIVIT and RACER, for a total of 8 treatments that were distributed in a completely randomized design with three repetitions. At the time of harvest, plant samples were taken to determine stem height, root length, nitrogen, phosphorus and potassium content in the leaf tissue, as well as the number of fruits per plant, biomass, length and width of the fruits The results indicated that the variables of the growth and accumulation of nutrients were positively infiuenced with the application of Chitosan, especially with the maximum dose of 300 mg ha-1, although also the number of fruits as well as the length and its diameter were increased from 200 mg ha-1. There was a positive and highly significant linear relationship between the variables of nutrient growth and absorption and the amount of fruits per plants and their characteristics. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Wood Science / Revista Ciência da Madeira is the property of Brazilian Journal of Wood Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Cellulose is an important biopolymer, used as a raw material for different industrial applications. This represents the most abundant natural polymer on the planet, because it is present as the constituent of most of the biomass of the plants, located in the plant cell wall. With the technological advance, different alternatives different alternatives to develop this material in a sustainable and productive way are searched, one of them is the production of cellulose from microbial metabolism. Kombucha consists of a broth fermented from a symbiotic association between bacteria and yeasts capable of producing bacterial cellulose (CB). The obtained cellulose was treated with water and with NaOH, and through Scanning Electron Microscopy (SEM), we observed greater preservation in the integrity of the fiber in the treatment with water. This was confirmed in the filtration test where the CB (H2O) presented a reduction of 82.8% in the microbial population of the water coming from a stream, followed by 47.9% in the CB (NaOH). Infrared spectrometry (FT-IR) revealed a subtle difference between the two treatments, while the tensile test showed that the alkaline treatment reduces the resistance limit of the fiber by more than 2 times. Based on the results obtained we can assess that the cellulose obtained from kombucha has interesting characteristics for commercial use in several segments as use in human grafts to coat the skin and as a filter for retention of biological particles Indoors as airplanes and even hospital use to contain the dissemination of pathogens. [ABSTRACT FROM AUTHOR]

Chitin is the second largest lineal biopolymer in the world. Recent advances suggest chitin can be obtained from fish scales. In this article, three different treatments were used to obtain chitin from red tilapia (Orechromis sp.) fish scales. All samples were insoluble in solvents and acid used. They also presented different percentages of carbon (3.27-55.80 %); oxygen (22.09-42.51 %); nitrogen (11.61-11.81 %); P (1.08-22.2 %); Ca (1.26-26.11 %); Na (0.53-1.02 %); and Mg (0.26-0.91 %). The 3,340-3,380 cm-1 bands shown in infrared spectra correspond to hydroxyl group of polymeric glucosamine bases and 1,415 -1,456 cm-1 peaks correspond to characteristic N-H bond of amide functional group. Images (SE) showed different dimensions of particles (0.1 -30 μm) and mean molecular masses, Mw, for Ch1, Ch2 and Ch3 were 1064.28, 1064.56 and 823.428, respectively, with a 1.0074 polydispersity. [ABSTRACT FROM AUTHOR]

The antifungal activity of chitosan, essential oils (cinnamon and eucalyptus) and their combination were evaluated against two pathogens Colletotrichum acutatum and Colletotrichum gloeosporioides isolated from avocado (Persea americana Mill). Chitosan was used at different concentrations (0.1, 0.5 and 1.0%). The concentrations of essential oils evaluated were 0.1, 0.5 and 2.0% (eucalyptus and cinnamon). The effect of the combination of chitosan with the essential oils was evaluated using the most effective concentrations of chitosan (0.1 and 0.5%) and the essential oil with the highest inhibitory effect (2%).The treatments of chitosan and essential oils were partially effective against fungal development by inhibiting mycelial growth in a range of 17 to 21% and 18 to 50%, respectively. The mycelia growth of both strains was totally reduced by the application of chitosan (0.1%) with cinnamon essential oil (2%), however; the combination of chitosan with eucalyptus essential oil was not effective. To our knowledge this research is the first that reports chitosan resistant strains of Colletotrichum isolated from avocado fruits. [ABSTRACT FROM AUTHOR]

Mexico is the main exporter of tomato worldwide. The use of greenhouses favors the protection and production of vegetables, however; tomato seedlings are sensitive to necrotrophic fungi such as Alternaria sp. The use of fungicides for disease control has been effective, however; the damage to the environment and the appearance of resistant strains leads the investigation of safe alternatives to the use of synthetic fungicides. Chitosan possesses antifungal activity in addition to the ability to activate defense mechanisms in plants. In this study, tomato seedlings were treated with chitosan at different concentrations. The percentage of foliar damage, spore's germination, induction of hydrogen peroxide and enzymatic activity (peroxidase and polyphenoloxidase) was determined. A statistically significant reduction in leaf damage and germination of spores was obtained in plants treated with 0.01% chitosan (up to 80%) compared to the control. The production of H2O2 and the enzymatic activity was induced in treated plants. Thus, the application of chitosan can be a viable alternative for rot control caused by Alternaria sp. in tomato. [ABSTRACT FROM AUTHOR]

Peripheral nerve regeneration is a serious clinical problem. The goal of this work was to evaluate comparatively a biopolymer tube of sugarcane with an expanded polyethylene tube as a tube guide in peripheral nerve regeneration. Fourteen male albino Wistar rats were used, separated into three different groups: control (CG), lesion + polyethylene tube (PG) and lesion + sugarcane biopolymer (SBG). At 60 days old, animals from the PG and SBG underwent surgery for tubulization of the sciatic nerve, and 60 days after the injury they were sacrificed for collection of the nerve. In the analysis of the number of nerve fibers, a smaller number was seen in the PG and SBG groups compared to the CG, no difference was seen between the PG and SBG groups (p<0.05). With regard to the number of blood vessels, the SBG group had a larger number than the CG and PG groups (p<0.05). The SBG also presented increase on axonal diameter and G -ratio compared to PG (p<0.05). Taken together these data revealed that biopolymer tube favors a suitable environment for peripheral nerve regeneration. [ABSTRACT FROM AUTHOR]

The normal process of obtaining chitin from the shrimp exoskeleton consists in associated compounds extraction through successive steps of demineralization, deproteinization and depigmentation, using strong acids and alkalis. It constitutes a risk for personal and environmental integrity. A solution to this problem is the alternative methods use, such as enzymatic extraction, which in addition to maintain the structure of chitin intact, do not produce wastes that may affect their biomedical applications. The exoskeleton, once clean, dry and ground to 300 μm, is demineralized, up to 95,67% using glacial acetic acid at 15% at room temperature and stirring for 3 hours. A treatment with α-chymotrypsin in an enzyme-substrate ratio E / S 0,7: 100 (QB2) shows a higher percentage of protein hydrolysis, 73,48% than the E / S ratio 0,5: 100 (QB1) . However, it was found that there is not statistically significant difference between the different treatments, only a difference between the QB1 and QB2 treatments was observed, which seems to indicate which seems to indicate that a greater deproteinization of the substrate occurs at a higher concentration of chymotrypsin.On the other hand, papain treatments reached similar percentages of deproteinization, 65,43% and 67,13% for E/S ratios of 0,5: 100 and 0,7: 100 respectively, which indicates that both treatments are statistically acceptable. Regarding the degree of deacetylation, all the treatments showed a value of approximately 20% and a molecular mass of the order of 106, thus demonstrating the effectiveness of the combination of treatments with weak acids and proteolytic enzymes. [ABSTRACT FROM AUTHOR]

Copyright of Revista Eletrônica em Gestão, Educação e Tecnologia Ambiental is the property of Revista Eletronica em Gestao, Educacao e Tecnologia Ambiental and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Environmental concerns have been rising in recent years, mainly due to the use of various petroleum products, which take years to degrade in nature. To minimize this problem, several studies focus on the use of natural biodegradable materials. In this context, it has been found that cassava starch can be used as raw material for the production of a biopolymer that can be used as a thermal insulation. The biopolymer was produced by a controlled thermal expansion process with volumetric fractions of 30% water and 70% cassava starch. The physical and thermal properties of the material were analyzed in order to obtain data on the feasibility of its use as thermal insulation. The material had a thermal conductivity of 0.152 W / mK, and can be applied as an insulator in hot systems up to 270 ° C and a temperature resistance limit of 270 ° C observed by thermogravimetric analysis. Cassava starch biopolymer proved to be efficient in thermal insulation, due to its properties similar to those of commercially available thermal insulators. In addition, flammability analyzes were performed, to which the material presented as non-flammable. In addition, hardness was analyzed by characterizing it as a hard material. In view of this, the material proved promising to be applied as a thermal insulation. These analyzes were based on ABNT, ASTM and UL-94 standards and the results obtained experimentally prove that the biopolymer of cassava starch can be used for thermal insulation purposes. [ABSTRACT FROM AUTHOR]

Biopolymers are biodegradable commonly, fragile, hydrophilic and have low thermal resistance, which has limited its commercial application. In contrast, synthetic polymers or derived from non-renewable resources generally lower cost and limited or minimal biodegradability, have good mechanical and thermal characteristics. The blend of biopolymers and synthetic polymers provides materials with properties and reasonable costs for certain applications. This article is a literature review on the main applications recently reported for the most important blends of biopolymers and biodegradable synthetic polymers. The literature search was performed with the "Tree of Science" tool and narratively. The results showed that mixtures of aliphatic and polysaccharide polymers are the most used in engineering applications biological tissues, control drug delivery and packaging industry.

ABSTRACT INTRODUCTION: Promising treatments for tympanic membrane perforation closure have been studied. Therapies derived from tissue engineering probably eliminate the need for conventional surgery. Bacterial cellulose is presented as an alternative that is safe, biocompatible, and has low toxicity. OBJECTIVES: To investigate the effect on healing of direct application of a bacterial cellulose graft on the tympanic membrane compared to the conventional approach with autologous fascia. METHODS: Randomized controlled trial. Forty patients with tympanic membrane perforations secondary to chronic otitis media were included, and were randomly assigned to an experimental group (20), treated with a bacterial cellulose graft (BC) and control group (20), treated with autologous temporal fascia (fascia). We evaluated the surgical time, hospital stay, time of epithelialization and the rate of tympanic perforation closure. Hospital costs were compared. The statistical significance level accepted was established at p < 0.05. RESULTS: The closure of perforations was similar in both groups. The average operation time in the fascia group was 76.50 min versus 14.06 min bacterial cellulose in the group (p = 0.0001). The hospital cost by the Brazilian public health system was R$ 600.00 for the bacterial cellulose group, and R$ 7778.00 for the fascia group (p = 0.0001). CONCLUSION: Bacterial cellulose grafts promoted the closure of the tympanic membrane perforations, and were demonstrated to be innovative, effective, safe, minimally invasive, efficacious and to have a very low cost.

Introdução: A cirurgia de Sling é considerada padrão ouro para o tratamento da Incontinência Urinária de Esforço. Essa técnica cirúrgica utiliza um material sintético no espaço suburetral para prover um arcabouço de fibrose e corrigir a perda urinária. A partir do melaço da cana-de-açúcar, por síntese da bactéria Zoogloea sp, obtivemos o biopolímero da cana-de-acúcar que pode ser processada em forma de membrana. Nosso objetivo é mostrar a ação do biopolímero da cana-de-açúcar comparando-o com o polipropileno, no tocante à reação inflamatória e indução da formação de fibras colágenas. Material e Métodos: Trata-se de um estudo experimental, prospectivo, controlado, tipo ensaio clínico. Utilizámos 30 ratos Wistar, divididos em dois grupos de 15 animais, que tiveram uma tela de polipropileno e outra membrana do biopolímero da cana-de-açúcar implantadas no subcutâneo da parede abdominal. Sendo esses animais sacrificados após sete e 120 dias do procedimento. Analisámos e comparámos a reação inflamatória e a deposição de fibras colágenas induzidas pelos materiais utilizados. Todas as conclusões foram tomadas ao nível de significância de 5%. Resultados: As reações inflamatória aguda e linfoplasmocitária foram maiores, nos primeiros sete dias, induzidas pelo biopolímero. Sendo essas respostas semelhantes entre os materiais após 120 dias. A deposição de fibras colágenas foi significativamente maior quando induzida pelo biopolímero, tanto após sete dias, quanto após 120 dias. Não foi demonstrada rejeição, infecção, necrose em nenhum dos animais do estudo. Discussão: A reação inflamatórias aguda e linfoplasmocitária mais intensa no biopolímero causou uma maior produção de células gigantes de corpo estranho. Consequentemente a isso, tivemos uma maior deposição de fibras colágenas induzidas pelo biopolímero sem que esse material induzisse a rejeição. Conclusão: O biopolímero no subcutâneo dos ratos, em nosso experimento, estimulou uma resposta inflamatória e um acúmulo de fibras colágenas que mimetiza o processo cicatricial ocorrido abaixo da uretra de mulheres submetidas a cura da Incontinência Urinária.