Psychophysical estimation of acid intensity and determination of sweet-acid interaction in a fish paste containing glycerol

In a fish paste made with cooked Brazilian flathead (Percophis brasiliensis), glycerol (17%), sodium chloride (1.5%) and potassium sorbate (0.1%) the following acid percentages: 0.2; 0.4; 0.6; 0.8, 1 and 1.5% w/w were incorporated to determine the relationship between added acetic acid and the sensorially perceived intensity, and the effects of the combination of sweet-acid tastes. Tests for paired comparison, ranking and structured verbal scales for sweet and acid attributes and psychophysical test were carried out. There was a perceptible difference among samples for differences of 0.4 units of acid concentration. Samples indicated as sweeter by 89.47% of the judges were those containing a lesser acid concentration. A reduction in glycerol sweetness when increasing acid levels was observed. Acetic acid reduced the sweetness of glycerol and inversely glycerol reduced the acidity of acetic acid. The data obtained with the magnitude estimation test agree with Steven’s law.Foram incorporados glicerol (17%), cloreto de sódio (1,5%) e sorbato de potássio (0.1%) nas seguintes porcentagens de ácido: 0,2; 0,4; 0,6; 0,8; 1 e 1,5% p/p, em um patê elaborado a partir de congro-real (Percophis brasiliensis) cozido, com o intuito de determinar a relação entre o ácido acético adicionado e a intensidade sensorialmente percebida, assim como o efeito da combinação dos gostos doce e ácido. Foram realizados testes de comparação pareada, de classificação e também estruturada uma escala verbal para os atributos ácido e doce, e testes psicofísicos. Foi percebida diferença entre as amostras com diferença de 0,4 unidades de concentração de ácido. As amostras indicadas como as mais doces por 89,47% dos julgadores foram as que continham menor concentração de ácido. Foi observada a redução da doçura do glicerol quando aumentaram os níveis de ácido. O ácido acético reduziu a doçura do glicerol e, inversamente, o glicerol reduziu a acidez do ácido acético. Os dados obtidos com o teste de estimação de magnitude concordaram com a lei de Steven

Mass Transfer During Osmotic Dehydration of Chub Mackerel Cylinders in Ternary Solution

In the analysis, design and optimization of an osmotic dehydration process is important to know the kinetic of water loss and solutes gain. In this study, the mass transfer during osmotic dehydration of chub mackerel (Scomber japonicus) cylinders in ternary solution glycerol/salt/water was analyzed. The models of Zugarramurdi & Lupín and Azuara were used to describe mass transfer and to estimate equilibrium values. The radial effective diffusion coefficient was estimated using the analytical solution of Fick's second law. Diffusion coefficients were determined for a finite cylinder, for an infinite cylinder considering only the first term of the series and considering higher order terms of the series. The profiles of water and solutes during the osmotic dehydration were calculated by using the estimated water and solutes diffusivities. According to the results obtained, using three terms in the analytical solution of the Fick's second law is appropriate to determine the diffusion coefficients. The diffusion coefficient for infinite cylinder were 2.63×10-6, 4.11×10-6 and 4.25×10-6 cm2/s for water loss, salt and glycerol gain respectively. For a finite cylinder these values were 2.30×10-6, 3.67×10-6 and 3.78×10-6 cm2/s respectively. All the models proposed were in agreement with experimental data for solutes gain ((0.967<R2adj<0.986); (0.0016<RMSE<0.039) and (4.17<P<10.0)). The model based on the solution of Fick’s Law for an infinite cylinder with higher order terms was the best fit for water loss and solutes gain. The equilibrium values estimated with Azuara model agree with the experimental (0<relative error<9.8). Water and solute distributions as a function of time and location in the radial direction were plottedCentro de Investigación y Desarrollo en Criotecnología de AlimentosConsejo Nacional de Investigaciones Científicas y Técnica

Mass Transfer During Osmotic Dehydration of Chub Mackerel Cylinders in Ternary Solution

In the analysis, design and optimization of an osmotic dehydration process is important to know the kinetic of water loss and solutes gain. In this study, the mass transfer during osmotic dehydration of chub mackerel (Scomber japonicus) cylinders in ternary solution glycerol/salt/water was analyzed. The models of Zugarramurdi & Lupín and Azuara were used to describe mass transfer and to estimate equilibrium values. The radial effective diffusion coefficient was estimated using the analytical solution of Fick's second law. Diffusion coefficients were determined for a finite cylinder, for an infinite cylinder considering only the first term of the series and considering higher order terms of the series. The profiles of water and solutes during the osmotic dehydration were calculated by using the estimated water and solutes diffusivities. According to the results obtained, using three terms in the analytical solution of the Fick's second law is appropriate to determine the diffusion coefficients. The diffusion coefficient for infinite cylinder were 2.63×10-6, 4.11×10-6 and 4.25×10-6 cm2/s for water loss, salt and glycerol gain respectively. For a finite cylinder these values were 2.30×10-6, 3.67×10-6 and 3.78×10-6 cm2/s respectively. All the models proposed were in agreement with experimental data for solutes gain ((0.967<R2adj<0.986); (0.0016<RMSE<0.039) and (4.17<P<10.0)). The model based on the solution of Fick’s Law for an infinite cylinder with higher order terms was the best fit for water loss and solutes gain. The equilibrium values estimated with Azuara model agree with the experimental (0<relative error<9.8). Water and solute distributions as a function of time and location in the radial direction were plottedCentro de Investigación y Desarrollo en Criotecnología de AlimentosConsejo Nacional de Investigaciones Científicas y Técnica

Lomitos de caballa preservados mediante tecnología de obstáculos

El objetivo de este trabajo fue diseñar una preserva de caballa de humedad intermedia mediante combinación de barreras de estrés microbiano. Las barreras utilizadas fueron: disminución de la carga bacteriana e inactivación enzimática por cocción al vapor disminución de la actividad de agua, envasado al vacío en películas impermeables al O2, tratamiento térmico moderado y almacenamiento en refrigeración. Los troncos de caballa se cocinaron al vapor durante 20 minutos, se dejaron orear en refrigeración y se eliminó la piel, espinas y músculo rojo. Los lomitos se deshidrataron osmóticamente en una solución de glicerol y sal (aw=0,64) durante 19 hs en refrigeración, se envasaron al vacío en bolsas termosellables de polietileno de baja densidad y poliamida y se pasteurizaron a 60 °C durante 50 minutos (con Staphylococcus aureus como microorganismo de control). Luego de la pasteurización se enfriaron y se almacenaron en refrigeración (5 °C). La preserva tuvo una aw de 0,89, un pH de 5,5 y un contenido de agua de 49,70 %. Los lomitos se analizaron el día de su preparación, semanalmente durante el primer mes y mensualmente durante 11 meses. Se realizaron análisis fisicoquímicos (aw y contenido de agua), análisis microbiológicos (recuento total de microorganismos psicrótrofos, mesófilos, clostridios sulfito reductores y Staphylococcus spp) y análisis sensoriales (color y aroma rancio). No se detectó crecimiento microbiano y los parámetros sensoriales y fisicoquímicos se mantuvieron sin variación durante todo el tiempo de almacenamiento. Se diseño satisfactoriamente una preserva de caballa mediante el uso de la tecnología de obstáculos.Facultad de Ciencias ExactasCentro de Investigación y Desarrollo en Criotecnología de Alimento

Espacio, comunicación y cultura III. Movilidades / inmovilidades de cuerpos y de signos en el espacio social público de una ciudad en transformación. 16H238

Este proyecto es una continuidad de investigaciones previas centradas en el análisis comunicacional y sociocultural de actuales procesos de reurbanización de la ciudad de Posadas. Para ello, se prioriza una perspectiva relacional/sociocultural y política y se recurre a aportes teórico-metodológicos de varias disciplinas, en particular de la Comunicación Social, la Semiótica, el Análisis del Discurso, la Sociología y la Antropología Social. Se busca en esta instancia abordar la dimensión simbólica de una dinámica urbana - en este caso de una ciudad como Posadas-, en correlación con un orden urbano emergente y hegemónico que viene generando modificaciones profundas en su configuración (tanto en su trazado como en su trama social). Partimos para ello de los efectos de sentido de divisiones del espacio urbano posibilitadas por la reurbanización que habilitan nuevas oposiciones entre sus habitantes; promueven ciertos flujos y prácticas de espacio, pero también exclusiones y “refuerzos de fronteras” (territoriales, sociales, simbólicas); acorde con “un discurso de lo urbano” y con políticas de espacio que buscan instituir un “modelo de ciudad” y por ende un modo de concebir /habitar/convivir en la ciudad profundamente signado por el mercado. De allí que se busque focalizar el análisis en producciones discursivas y prácticas sociales vinculadas por un lado con espacios de alta densidad de la ciudad (“la costa” y “el centro”); y por otro con disputas –pasadas y presentes- por el suelo urbano y el espacio público; como un modo posible más de aproximación a la conflictividad de las sociedades contemporáneas

Obtenção dos tempos de equilíbrio e coeficientes de difusão de ácido e de sal para desenhar o processo de marinado de filés de Engraulis anchoita

Foi estudada a difusão simultânea de cloreto de sódio e ácido acético em filés de anchoíta. Os resultados mostram que foram alcançadas condições de equilíbrio entre os filés e a solução de marinado, de acordo com os valores K obtidos para fechar a unidade. A solução de marinado precisou de agitação para evitar a formação de uma camada superficial diluída nos filés de pescado. Os tempos de equilíbrio para ácido e sal foram maiores para as amostras agitadas durante o marinado. O gasto de cloreto de sódio e ácido acético durante o marinado dos filés de anchoíta pode ser explicado pela lei de Fick. Os valores do coeficiente de difusão para ácido acético a 20 °C foram 3,39 × 10-6 e 3,49 × 10-6 cm²/segundos para marinado com e sem agitação, respectivamente. O valor do coeficiente de difusão de cloreto de sódio para marinado sem agitação foi de 2,39 × 10-7 cm²/segundos, contudo, para marinado com agitação, não pôde ser fixado

Analysis of applicability of Peleg model to the cooking-infusion of mackerel (Scomber japonicus) slices

Mass transfer kinetics in osmotic dehydration is usually modeled by Fick's law, empirical models and probabilistic models. The aim of this study was to determine the applicability of Peleg model to investigate the mass transfer during osmotic dehydration of mackerel (Scomber japonicus) slices at different temperatures. Osmotic dehydration was performed on mackerel slices by cooking-infusion in solutions with glycerol and salt (a w = 0.64) at different temperatures: 50, 70, and 90 ºC. Peleg rate constant (K1) (h(g/gdm)-1) varied with temperature variation from 0.761 to 0.396 for water loss, from 5.260 to 2.947 for salt gain, and from 0.854 to 0.566 for glycerol intake. In all cases, it followed the Arrhenius relationship (R²&gt;0.86). The Ea (kJ / mol) values obtained were 16.14; 14.21, and 10.12 for water, salt, and glycerol, respectively. The statistical parameters that qualify the goodness of fit (R²&gt;0.91 and RMSE<0.086) indicate promising applicability of Peleg model