1,721,016 research outputs found
Enhanced application of square wave voltammetry with glassy carbon electrode coupled to multivariate calibration tools for the determination of B6 and B12 vitamins in pharmaceutical preparations
Get PDFVitamins B6 (VB6) and B12 (VB12) were simultaneously determined in pharmaceutical preparations by using square wave voltametry (SWV) together with artificial neural networks (ANNs). Supporting electrolyte solution, pH and voltametric technique were optimised. The calibration set was built with several artificial samples containing both active ingredients and excipients. Deviations from linearity were observed for both analytes. It is probably due to interactions among the electro active components and competition by the electrode surface, fact that supports the use of ANNs. Recoveries when analysing a nine sample validation set, of 100.2 and 96.4 were calculated for VB6 and VB12, respectively. Commercial samples were analysed with reasonably good results considering the complexity of the mixture studied.Fil: Hernández, Silvia Raquel. Universidad Nacional del Litoral; ArgentinaFil: Ribero, Gustavo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Goicoechea, Hector Casimiro. Universidad Nacional del Litoral; Argentin
Cheese freezing by immersion in concentrated aqueous solutions
No full textFil: Ribero, Gustavo Gabriel. Universidad Nacional del Litoral. Facultad de Ingeniería Química; ArgentinaThe freezing of cheeses has been used to extend its shelf-life and to expand its commercialization to distant places. The soft cheeses represent the sector with the highest dynamism and technological innovation. In the case of Mozzarella cheese, its freezing by immersion in NaCl solutions may be an innovative procedure for the dairy industry to reduce the effect of freezing on the final cheese quality, and to reduce the processing time because it combines conveniently salting and freezing processes. The main objective of this thesis was to evaluate the influence of this type of freezing method and of the frozen storage of samples on the main physicochemical, biochemical, rheological and structural properties of Mozzarella cheese.
In the main experimental design, cheese slabs (dimensions: 2x10x10 cm3) were immersed in 23% NaCl solutions (control samples: 4ºC, 90 min; frozen and frozen-stored samples: -15ºC, 180 min). The frozen-stored samples were stored at -20ºC for 2 months and then thawed at 4ºC. The samples were stored at 4ºC and assayed at 1, 7, 14, 20, 27, 34, and 41 days to evaluate physicochemical, biochemical, rheological and structural properties.
Although the immersion freezing of Mozzarella cheese affects some of the studied parameters, the differences observed were small. Therefore, it was considered that the immersion freezing could be useful for the manufacture and preservation of Mozzarella cheese.La congelación de quesos ha sido usada para prolongar su vida útil y extender su comercialización a lugares distantes. Los quesos blandos representan el segmento de mayor dinamismo e innovación tecnológica. En el caso de queso Mozzarella, su congelación por inmersión en soluciones de NaCl podría ser una alternativa interesante para disminuir el efecto de la congelación sobre la calidad final del queso y para disminuir el tiempo de procesamiento ya que los procesos de salado y congelación ocurren simultáneamente. El objetivo principal de esta Tesis fue evaluar el efecto de la congelación por inmersión y del almacenamiento de las muestras congeladas sobre las principales propiedades fisicoquímicas, bioquímicas, reológicas y estructurales de queso Mozzarella.
En el diseño experimental principal, se usaron placas de queso (dimensiones: 2x10x10 cm3), las que fueron sumergidas en soluciones de NaCl 23% p/p (muestras control: 4°C, 90 min; muestras congeladas y muestras almacenadas congeladas: –15°C, 180 min). Las muestras almacenadas congeladas fueron mantenidas a –20°C durante 2 meses y luego se descongelaron a 4°C. Todas las muestras fueron envasadas al vacío y almacenadas a 4°C para su maduración. Se evaluaron propiedades fisicoquímicas, bioquímicas, reológicas y estructurales de muestras de cada tratamiento a los 1, 7, 14, 20, 27, 34 y 41 días de maduración.
Si bien la congelación por inmersión afectó estadísticamente algunos de los parámetros estudiados, las diferencias observadas son pequeñas, por lo que se considera que el proceso de congelación por inmersión podría ser muy útil para la elaboración y conservación del queso Mozzarella.Agencia Nacional de Promoción Científica y TecnológicaUniversidad Nacional del LitoralFundación AntorchasConsejo Nacional de Investigaciones Científicas y Técnica
Cheese freezing by immersion in concentrated aqueous solutions
No full textFil: Ribero, Gustavo Gabriel. Universidad Nacional del Litoral. Facultad de Ingeniería Química; ArgentinaThe freezing of cheeses has been used to extend its shelf-life and to expand its commercialization to distant places. The soft cheeses represent the sector with the highest dynamism and technological innovation. In the case of Mozzarella cheese, its freezing by immersion in NaCl solutions may be an innovative procedure for the dairy industry to reduce the effect of freezing on the final cheese quality, and to reduce the processing time because it combines conveniently salting and freezing processes. The main objective of this thesis was to evaluate the influence of this type of freezing method and of the frozen storage of samples on the main physicochemical, biochemical, rheological and structural properties of Mozzarella cheese.
In the main experimental design, cheese slabs (dimensions: 2x10x10 cm3) were immersed in 23% NaCl solutions (control samples: 4ºC, 90 min; frozen and frozen-stored samples: -15ºC, 180 min). The frozen-stored samples were stored at -20ºC for 2 months and then thawed at 4ºC. The samples were stored at 4ºC and assayed at 1, 7, 14, 20, 27, 34, and 41 days to evaluate physicochemical, biochemical, rheological and structural properties.
Although the immersion freezing of Mozzarella cheese affects some of the studied parameters, the differences observed were small. Therefore, it was considered that the immersion freezing could be useful for the manufacture and preservation of Mozzarella cheese.La congelación de quesos ha sido usada para prolongar su vida útil y extender su comercialización a lugares distantes. Los quesos blandos representan el segmento de mayor dinamismo e innovación tecnológica. En el caso de queso Mozzarella, su congelación por inmersión en soluciones de NaCl podría ser una alternativa interesante para disminuir el efecto de la congelación sobre la calidad final del queso y para disminuir el tiempo de procesamiento ya que los procesos de salado y congelación ocurren simultáneamente. El objetivo principal de esta Tesis fue evaluar el efecto de la congelación por inmersión y del almacenamiento de las muestras congeladas sobre las principales propiedades fisicoquímicas, bioquímicas, reológicas y estructurales de queso Mozzarella.
En el diseño experimental principal, se usaron placas de queso (dimensiones: 2x10x10 cm3), las que fueron sumergidas en soluciones de NaCl 23% p/p (muestras control: 4°C, 90 min; muestras congeladas y muestras almacenadas congeladas: –15°C, 180 min). Las muestras almacenadas congeladas fueron mantenidas a –20°C durante 2 meses y luego se descongelaron a 4°C. Todas las muestras fueron envasadas al vacío y almacenadas a 4°C para su maduración. Se evaluaron propiedades fisicoquímicas, bioquímicas, reológicas y estructurales de muestras de cada tratamiento a los 1, 7, 14, 20, 27, 34 y 41 días de maduración.
Si bien la congelación por inmersión afectó estadísticamente algunos de los parámetros estudiados, las diferencias observadas son pequeñas, por lo que se considera que el proceso de congelación por inmersión podría ser muy útil para la elaboración y conservación del queso Mozzarella.Agencia Nacional de Promoción Científica y TecnológicaUniversidad Nacional del LitoralFundación AntorchasConsejo Nacional de Investigaciones Científicas y Técnica
Initial freezing point of Mozzarella cheese
Get PDFThe initial freezing point in unsalted fresh Mozzarella cheese was measured. The influence of the water-soluble solids on the freezing point depression of unsalted Mozzarella cheese was analyzed. Central temperature profiles and the initial freezing point of unsalted cylindrical cheese samples (1 cm radius; 3 cm height) were determined. A lyophilized aqueous extract of the soluble solids at pH 4.6 was obtained from the unsalted cheese. Initial freezing points of the solutions, prepared with a concentration of soluble solids similar to the one occluded in unsalted cheese matrix and different NaCl concentrations, were determined. Initial freezing points of the unsalted cheese were in the range of -1.2 to -2.4 ºC, while a value of -1.7 ± 0.1 0C was observed in the solution of soluble solids without NaCl. Moreover, the initial freezing points of the solutions of soluble solids and NaCl showed an additional depression of approximately -1.7 0C compared to the initial freezing point of NaCl solutions. Therefore, it was clearly shown that not only NaCl but also the other soluble solids present in the aqueous phase significantly contribute to the freezing point depression of Mozzarella cheese.Fil: Ribero, Gustavo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Rubiolo, Amelia Catalina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Zorrilla, Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentin
Microstructure of Mozzarella cheese as affected by the immersion freezing in NaCl solutions and by the frozen storage
Get PDFThe freezing of Mozzarella cheese by immersion in NaCl solutions may be an innovative procedure for the dairy industry because it combines conveniently salting and freezing processes. The influence of this type of freezing method and of the frozen storage of samples on the microstructure of Mozzarella cheese was studied. Slabs (2 10 10 cm3) were immersed in 23% w/w NaCl solutions (control samples: 4 C, 90 min; frozen samples: 15 C, 180 min). Half of the frozen samples were immediately thawed at 4 C. The other half was stored at 20 C for 2 months and then was thawed at 4 C (frozen-stored samples). Samples were stored at 4 C and assayed at 1, 14 and 41 days. Although the immersion freezing of Mozzarella cheese affects its microstructure, only small differences were observed in the frozen-stored samples compared to control and frozen samples. Those differences consisted on less defined honey-comb appearance and the presence of small cracks at 41 days of ripening in the frozen-stored samples. Therefore, it was considered that the immersion freezing might be useful for the manufacture and commercialization of Mozzarella cheese.Fil: Ribero, Gustavo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Rubiolo, Amelia Catalina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Zorrilla, Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentin
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Influence of Immersion Freezing in NaCl Solutions and of Frozen Storage on the Viscoelastic Behavior of Mozzarella Cheese
Get PDFThe freezing of Mozzarella cheese by immersion in NaCl solutions may be an innovative procedure for the dairy industry because combines conveniently salting and freezing processes. In this work, the influence of this type of freezing method and of the frozen storage of samples on the viscoelastic behavior of Mozzarella cheese was studied. Slabs (2x10x10 cm3) were immersed in 23% w/w NaCl solutions (control samples: 4ºC, 90 min; frozen samples: -15ºC, 180 min). Half of the frozen samples were immediately thawed at 4ºC. The other half was stored at -20ºC for 2 months and then was thawed at 4ºC (frozen-stored samples). Samples were stored at 4ºC and assayed at 1, 7, 14, 20, 27, 34, and 41 days. Rheological tests were carried out in oscillatory mode (parallel-plate geometry, diameter: 20 mm, gap: 1 mm, frequency: 1 Hz). Strain sweeps were run (0.001£g0£0.1) at 20, 40, and 60ºC, and temperature sweeps were run from 20 to 65ºC (1.33ºC min-1, g0=0.005). Similar crossover temperatures were observed after 20 days of ripening. The influence of temperature on complex viscosity was studied by an Arrhenius-type equation. Activation energy values of 15.9±0.4, 14.1±0.5 and 13.8±0.6 Kcal mol-1 were obtained at 41 days for control, frozen and frozen-stored samples, respectively. Although the immersion freezing of Mozzarella cheese affects some of the studied parameters, the differences observed between frozen and frozen-stored samples with control samples were small. Therefore, it was considered that the immersion freezing might be useful for the manufacture and commercialization of Mozzarella cheese.Fil: Ribero, Gustavo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Rubiolo, Amelia Catalina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Zorrilla, Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentin
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