Characterization of thermal, mechanical and hydration properties of novel films based on Saccharomyces cerevisiae biomass

Characterization of films made of Saccharomyces cerevisiae biomass was performed so as to better understand their properties. The treated yeast biomass, named HTH, was prepared by subsequent steps including a first homogenization, heat treatment and final homogenization. Glycerol was added as plasticizer and films were evaluated using different techniques to measure mechanical behaviour, thermal properties and water sorption. Temperature of maximum decomposition rate was found near 300 °C, while the gradually disappearance of amide II band (1543 cm−1) occurred from 225 °C, identified by FTIR spectra of residues of thermally treated films by TGA. A glass transition at 64.5 ± 3.0 °C and two low energy endotherms at 61.2 ± 2.3 and 106.1 ± 0.7 °C were determined in completely dehydrated films without glycerol. When glycerol content was increased the glass transition temperature was shifted to lower values, a maximum elongation of 12% was reached, Young's modulus decreased from 88 to 9 MPa and the water uptake of films raised from 0.49 to 0.79 g H2O/g of dry matter. The characterization of yeast biodegradable films provided evidence of their properties for a potential future use in packaging industry. Industrial relevance: The development of biodegradable films based on yeast biomass carries many advantages to the food industry, such as, the possibility of using commercial pressed baker's yeast or an industrial residue from brewing industry, the use of a low-cost sources and the application of environmentally friendly procedures. The methodologies applied for the development of the film forming dispersion, high pressure homogenization and thermal treatment, are able to be scaled-up to an industrial level.Fil: Delgado, Juan Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; ArgentinaFil: Peltzer, Mercedes Ana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; ArgentinaFil: Salvay, Andrés Gerardo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; ArgentinaFil: de la Osa, Orlando. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; ArgentinaFil: Wagner, Jorge Ricardo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Biobased materials from microbial biomass and its derivatives

There is a strong public concern about plastic waste, which promotes the development of new biobased materials. The benefit of using microbial biomass for new developments is that it is a completely renewable source of polymers, which is not limited to climate conditions or may cause deforestation, as biopolymers come from vegetal biomass. The present review is focused on the use of microbial biomass and its derivatives as sources of biopolymers to form new materials. Yeast and fungal biomass are low-cost and abundant sources of biopolymers with high promising properties for the development of biodegradable materials, while milk and water kefir grains, composed by kefiran and dextran, respectively, produce films with very good optical and mechanical properties. The reasons for considering microbial cellulose as an attractive biobased material are the conformational structure and enhanced properties compared to plant cellulose. Kombucha tea, a probiotic fermented sparkling beverage, produces a floating membrane that has been identified as bacterial cellulose as a side stream during this fermentation. The results shown in this review demonstrated the good performance of microbial biomass to form new materials, with enhanced functional properties for different applications.Fil: Cottet, Agustina Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Ramírez Tapias, Yuly Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: Delgado, Juan Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: de la Osa, Orlando. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: Salvay, Andrés Gerardo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: Peltzer, Mercedes Ana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentin

Caracterización de algunos estados emocionales en pacientes con retinosis pigmentaria típica en dos de sus estadios

The present investigation was conducted to characterize the emotional states in patients with typical retinitis pigmentary in its first two stages that were treated at the "Arnaldo Milian Castro" Surgical Hospital, the City of Santa Clara, Villa Clara province, between September 2011 and April 2012. It was left for both the methologic  design research and for analysis of the results of joint paradigm; quantitative and qualitative data were linked in psychological research. Transversal descriptive study was conducted using a sample of 10 patients in each one of the first two stages of the disease from a simple random sampling probabilistic; Inclusion and exclusion criteria were established to form the samples. Information for the study was obtained from the application of different psychological tools of exploration. It was concluded that depression, followed by anxiety, predominates over the other emotional states studied in both groups, both had their impact mainly in the personal area of these subjects and an uncertain expectation of the future to find and significant degree of psychological involvement. The more strongly personally experienced emotional states were found in stage II of the disease closely related with its progression; also appeared more affected in their social relationships.La presente investigación se realizó con el objetivo de caracterizar los estados emocionales en pacientes con retinosis pigmentaria típica en sus dos primeros estadios que fueron atendidos en el Hospital Clínico Quirúrgico “Arnaldo Milián Castro”, de la Ciudad de Santa Clara, Provincia de Villa Clara, entre septiembre de 2011 y abril de 2012. Se partió tanto para el diseño metodológico como para el análisis de los resultados del paradigma mixto de investigación; se vincularon datos cuantitativos y cualitativos en la investigación psicológica. Se realizó un estudio de tipo descriptivo transversal en una muestra de 10 pacientes de cada uno de los dos primeros estadios de la enfermedad a partir de un muestreo de tipo probabilístico aleatorio simple; se establecieron criterios de inclusión y exclusión para conformar las muestras. La información para el estudio se obtuvo de la aplicación de distintos instrumentos psicológicos de exploración. Se concluyó que la depresión, seguida de la ansiedad, predomina por encima de los demás estados emocionales estudiados en ambos grupos, que ambas tuvieron su repercusión, principalmente, en el área personal de estos sujetos y que se encontraron una expectativa incierta del futuro y un grado importante de afectación psicológica. Los estados emocionales más fuertemente vivenciados se encontraron en el estadio II de la enfermedad estrechamente relacionados con su progresión; apareció también mayor afectación en sus relaciones sociales

Red de torres meteorológicas de referencia para el programa eólico cubano. Resultados preliminares del estudio del viento con fines energéticos

Ponencia presentada en: XXX Jornadas Científicas de la AME y el IX Encuentro Hispano Luso de Meteorología celebrado en Zaragoza, del 5 al 7 de mayo de 2008

Measurement of W+W− production in association with one jet in proton–proton collisions at sqrt(s) = 8TeV with the ATLAS detector

The production of W boson pairs in association with one jet in pp collisions at View the MathML sources=8 TeV is studied using data corresponding to an integrated luminosity of 20.3 fb−1 collected by the ATLAS detector during 2012 at the CERN Large Hadron Collider. The cross section is measured in a fiducial phase-space region defined by the presence of exactly one electron and one muon, missing transverse momentum and exactly one jet with a transverse momentum above 25 GeV and a pseudorapidity of |η|<4.5|η|<4.5. The leptons are required to have opposite electric charge and to pass transverse momentum and pseudorapidity requirements. The fiducial cross section is found to be View the MathML sourceσWWfid,1-jet=136±6(stat)±14(syst)±3(lumi) fb. In combination with a previous measurement restricted to leptonic final states with no associated jets, the fiducial cross section of WW production with zero or one jet is measured to be View the MathML sourceσWWfid,≤1-jet=511±9(stat)±26(syst)±10(lumi) fb. The ratio of fiducial cross sections in final states with one and zero jets is determined to be 0.36±0.050.36±0.05. Finally, a total cross section extrapolated from the fiducial measurement of WW production with zero or one associated jet is reported. The measurements are compared to theoretical predictions and found in good agreement

Effect of Hygrothermal History on Water and Mechanical Properties of Glass/Vinylester Composites

The effects of hygrothermal aging on the mechanical and viscoelastic properties of vinylester (VE)/unidirectional glass-fiber composites are reported. The studies are done by means of a dynamometer (INSTRON) and a dynamic mechanical thermal analyzer (Perkin Elmer). The studies are carried out at three different temperatures: 20, 40, and 60 C. The adhesion between the fibers and matrix is studied by scanning electron microscopy (SEM) microphotographs. Flexural strength, flexural modulus, storage modulus in the glass state (Tg - 50 K), in rubber state (Tg + 50 K), and the glass transition temperatures are also investigated. These parameters are determined in the case of the matrix and composites materials, for the initial and final states. The diffusion coefficients are calculated by using the simplest Fick's equation.Fil: de la Osa, Orlando. Universidad Nacional de Quilmes; ArgentinaFil: Alvarez, Vera Alejandra. 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: Vázquez, Analía. 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; Argentin

Use of Residual Yeast Cell Wall for New Biobased Materials Production: Effect of Plasticization on Film Properties

The use of renewable resources to develop food contact materials, such as proteins or polysaccharides, and the use of industrial residues for alternative applications are trending topics for researchers and the industry. Yeast cell wall (YCW) is a very rich waste from the yeast extract industry. Due to this, the aim of this work is to develop new biodegradable films based on residual YCW and the study of the effect of plasticization on films properties. Residual YCW was used as base matrix and different concentrations of glycerol (0, 15, 25 and 35 wt%) were tested to obtain casted films. Homogeneous and yellow-brownish films, which allow seeing through them, were obtained from the YCW. Total soluble matter demonstrated that glycerol enhanced solubility of films but glycerol was retained in the polymer matrix. TGA studies indicated that YCW films exhibited substantial degradation at temperatures above 180 °C. FTIR spectra of the casted films were representative of yeast cell wall material and SEM photographs showed that cell wall maintained their shape after film formation. As expected, Young’s modulus and tensile strength values were decreased with the increasing amount of glycerol. However, elongation at break was not increased further with higher concentration of plasticizer and the addition of 15 wt% of glycerol seemed to be enough to improve mechanical properties. The linear increment of water vapour permeability with glycerol concentration was produced by the increase in water solubility in the film. Therefore, based on solubility in water, mechanical, and barrier properties, it is possible to propose yeast cells residues as film-forming material for biodegradable film developments.Fil: Peltzer, Mercedes Ana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: Salvay, A.G.. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: Delgado, Juan Francisco. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: de la Osa, Orlando. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: Wagner, Jorge Ricardo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Impact of the film-forming dispersion pH on the properties of yeast biomass films

BackgroundYeast biomass, mainly composed by proteins and polysaccharides (mannans and β‐glucans), has been proposed to develop films. pH can affect the solubility of polysaccharides, the structure of the cell‐wall and the interactions between proteins. Considering the potential impact of these effects, the pH of yeast film‐forming dispersions was studied from 4 to 11.ResultsIn tensile tests, samples increased their elongation by increasing pH, from 7 ± 2% (pH 4) to 29 ± 5% (pH 11), but Young´s modulus was not significantly modified. Regarding thermal degradation, the maximum degradation rate temperature was shifted 46 °C from pH 4 to 11. Differences in water vapour permeability, colour, opacity and roughness of films were also found. According to the results of differential protein solubility assay, at pH 4 hydrophobic interactions and hydrogen bonding were promoted but, at pH 11 disulphide bonds were benefited, in addition to partial β‐glucan dissolution and break‐up of the alkali‐sensitive linkage in molecules from the cell wall.ConclusionResults let to conclude that film‐functional characteristics were greatly benefited at pH 11 in comparison to the regular pH of dispersion (pH 6). These results could help to understand and select the pH conditions to enhance the desired properties of yeast biomass films.Fil: Delgado, Juan Francisco. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; Argentina. 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: Salvay, Andrés Gerardo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; ArgentinaFil: de la Osa, Orlando. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; ArgentinaFil: Wagner, Jorge Ricardo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; ArgentinaFil: Peltzer, Mercedes Ana. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Ingeniería en Alimentos; Argentin

Development of innovative biodegradable films based on biomass of Saccharomyces cerevisiae

Biodegradable alternatives to petroleum-based polymers are being developed for food packaging. Saccharomyces cerevisiae has been widely used for the production of fermented beverages and leavened foods. In this work, the application of high pressure homogenisation and a thermal treatment to the yeast biomass was studied to develop biodegradable films. The highest dispersibility indexes of protein (84.5 ± 3.3%), carbohydrates (24.3 ± 1.1%), RNA (40.6 ± 0.9%) and soluble solids released were found at high homogenisation pressure (125 MPa). Combinations of one or two homogenisations and a thermal treatment at 90 °C during 20 minutes were applied and dispersions were fully characterised, focusing on their film-forming capacity. The best combination was homogenisation, heat treatment and a further homogenisation, since it produced films that presented good attributes, great continuity and homogeneity without small cracks. However, hydration of films was increased from 0.31 to 0.48 gH2O/g.d.m with the number of homogenisation processes applied. Results revealed that yeast biomass is a viable source to be used in biodegradable films. Industrial relevance Saccharomyces cerevisiae yeasts have many applications in food industry. The development of biodegradable films based on yeast biomass carries many advantages such as, the possibility of using commercial pressed baker's yeast or an industrial residue from brewing industry, the use of a low-cost sources and the application of environmentally friendly procedures. The methodologies applied for the development of the film forming dispersion, high pressure homogenisation and thermal treatment, are able to be scaled-up to an industrial level.Fil: Delgado, Juan Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: Sceni, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: Peltzer, Mercedes Ana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: Salvay, Andrés Gerardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: de la Osa, Orlando. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: Wagner, Jorge Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentin

Obtención de nanocelulosas secas redispersables enagua

En la última década las celulosas nanofibriladas de origen vegetal (NFC) y bacteriano (BNC) han merecido notable interés en base a su origen renovable, extraordinarias propiedades mecánicas, baja densidad, alta área superficial, biodegradabilidad y biocompatibilidad, entre otros. Sin embargo, el almacenamiento, transporte y comercialización de nanocelulosas en el formato de suspensiones acuosas con bajo contenido de sólidos en que se las obtiene involucra elevados costos económicos y técnicos. El desafío es lograr deshidratar las suspensiones acuosas de nanocelulosa sin que se produzcan cambios en sus dimensiones nanométricas a causa de la agregación irreversible por puentes de hidrógeno entre nanofibras (fenómeno conocido como hornificación), que altera las propiedades originales asociadas a sus secciones en la nanoescala (1). En este contexto, la inclusión de aditivos disruptores de puentes de hidrógeno se presenta como una alternativa atractiva para producir polvos de nanocelulosa que sean luego redispersables en agua (2). En este trabajo se secaron suspensiones acuosas de BNC y NFC por diferentes métodos, con o sin agregado de manitol como aditivo disruptor; y se evaluó el alcance del fenómeno de hornificación.Fil: Montoya, Úrsula. 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; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Tupa Valencia, Maribel Victoria. 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: Leidi, Leandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: de la Osa, Orlando. Universidad Nacional de Quilmes; ArgentinaFil: Delgado, Juan Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes; ArgentinaFil: Ramírez Rigo, María Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; ArgentinaFil: Bucala, Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; ArgentinaFil: Foresti, María Laura. 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; ArgentinaIV Workshop de Polímeros Biodegradables y Biocompuestos BIOPOLI 2020Mar del PlataArgentinaUniversidad Nacional de Mar del PlataInstituto de Investigación en Ciencia y Tecnología de Materiale