9,553 research outputs found

    Effect of various processing parameters on the quality of papaya fruit tea

    Get PDF
    Exotic fruits from which drinks are ma de in most tropical countries are so abundant and such in a great variety, that it would probably be impossible for people to sample all of them, but they worth a try. Some of the great varieties of fruits used in drinks are bananas, guavas, papayas, oranges, pineapples, grapes, mangoes, watermelon, coconuts, longans, rambutans, strawberries, lime and tamarind

    Control vector parameterization with sensitivity based refinement applied to baking optimization

    Get PDF
    In bakery production, product quality attributes as crispness, brownness, crumb and water content are developed by the transformations that occur during baking and which are initiated by heating. A quality driven procedure requires process optimization to improve bakery production and to find operational procedures for new products. Control vector parameterization (CVP) is an effective method for the optimization procedure. However, for accurate optimization with a large number of parameters CVP optimization takes a long computation time. In this work, an improved method for direct dynamic optimization using CVP is presented. The method uses a sensitivity based step size refinement for the selection of control input parameters. The optimization starts with a coarse discretization level for the control input in time. In successive iterations the step size was refined for the parameters for which the performance index has a sensitivity value above a threshold value.With this selection, optimization is continued for a selected group of input parameters while the other nonsensitive parameters (below threshold) are kept constant. Increasing the threshold value lowers the computation time, however the obtained performance index becomes less. A threshold value in the range of 10–20% of the mean sensitivity satisfies well. The method gives a better solution for a lower computation effort than single run optimization with a large number of parameters or refinement procedures without selection

    SusOrganic - Development of quality standards and optimised processing methods for organic produce - Final report

    Get PDF
    The SusOrganic project aimed to develop improved drying and cooling/freezing processes for organic products in terms of sustainability and objective product quality criteria. Initially, the consortium focused on a predefined set products to investigate (fish, meat, fruits and vegetables). Contacting participants in the fruit and vegetable sector showed that there is only little perceived need for making changes for the improvement of the processes. At the same time, it became clear that hops and herb producers (drying) face several challenges in terms of product quality and cost of drying processes. Therefore, the range of products was extended to these products. The results of a consumer survey conducted as part the project showed clearly that consumers trust in the organic label, but also tend to mix up the term organic with regional or fair ­trade. Further, the primary production on farm and not the processing is explicitly included in the consumers’ evaluation of sustainability. Appearance of organic products was found to be one of the least important quality criteria or attributes regarding buying decisions. However, there are indications that an imperfect appearance could be a quality attribute for consumers, as the product then is perceived to be processed without artificial additives. Regarding drying operations, small scale producers in the organic sector often work with old and/or modified techniques and technologies, which often leads to an inefficient drying processes due to high energy consumptions and decreased product quality. Inappropriate air volume flow and distribution often cause inefficient removal of the moisture from the product and heterogeneous drying throughout the bulk. Guidelines for improvement of the physical setup of existing driers as well as designs for new drying operations, including novel drying strategies were developed. Besides chilling and freezing, the innovative idea of superchilling was included into the project.The superchilled cold chain is only a few degrees colder than the refrigeration chain but has a significant impact on the preservation characteristic due to shock frosting of the outer layer of the product and the further distribution of very small ice crystals throughout the product during storage. Super­chilling of organically grown salmon eliminated the demand of ice for transport, resulting in both, a reduction of energy costs and a better value chain performance in terms of carbon foot printing. This is mainly due to the significantly reduced transport volume and weight without the presence of ice. The product quality is not different but the shelf life is extended compared to chilled fish. This means that the high quality of organic salmon can be maintained over a longer time period, which can be helpful,e.g. to reach far distant markets. The same trend was found for superchilled organic meat products such as pork and chicken. The consortium also developed innovative noninvasive measurement and control systems and improved drying strategies and systems for fruits, vegetables, herbs, hops and meat. Those systems are based on changes occurring inside the product and therefore require observation strategies of the product during the drying process. Through auditing campaigns as well as pilot scale drying tests it has been possible to develop optimisation strategies for both herb and hops commodities, which can help reduce microbial spoilage and retain higher levels of volatile product components whilst reducing the energy demands. These results can be applied with modifications to the other commodities under investigation. The environmental and cost performance of superchilling of salmon and drying of meat, fruit and vegetables were also investigated and the findings indicated that both superchilling and drying could improve sustainability of organic food value chains especially in case of far distant markets. An additional outcome of the project, beyond the original scope was the development of a noninvasive, visual sensor based detection system for authenticity checks of meat products in terms of fresh and prefrozen meats

    Preparation, Proximate Composition and Culinary Properties of Yellow Alkaline Noodles from Wheat and Raw/Pregelatinized Gadung (Dioscorea Hispida Dennst) Composite Flours

    Get PDF
    The steady increase of wheat flour price and noodle consumptions has driven researchers to find substitutes for wheat flour in the noodle making process. In this work, yellow alkaline noodles were prepared from composite flours comprising wheat and raw/pregelatinized gadung (Dioscorea hispida Dennst) flours. The purpose of this work was to investigate the effect of composite flour compositions on the cooking properties (cooking yield, cooking loss and swelling index) of yellow alkaline noodle. In addition, the sensory test and nutrition content of the yellow alkaline noodle were also evaluated for further recommendation. The experimental results showed that a good quality yellow alkaline noodle can be prepared from composite flour containing 20% w/w raw gadung flour. The cooking yield, cooking loss and swelling index of this noodle were 10.32 g, 1.20 and 2.30, respectively. Another good quality yellow alkaline noodle can be made from composite flour containing 40% w/w pregelatinized gadung flour. This noodle had cooking yield 8.93 g, cooking loss 1.20, and swelling index of 1.88. The sensory evaluation suggested that although the color, aroma and firmness of the noodles were significantly different (p ≤ 0.05) from wheat flour noodle, but their flavor remained closely similar. The nutrition content of the noodles also satisfied the Indonesian National Standard for noodle. Therefore, it can be concluded that wheat and raw/pregelatinized gadung composite flours can be used to manufacture yellow alkaline noodle with good quality and suitable for functional food

    Optimization of ultrasound, vanillin and pomegranate extract treatment for shelf-stable unpasteurized strawberry juice

    Get PDF
    Optimum combination of ultrasound, vanillin and pomegranate extract to improve quality of strawberry juice was determined using response surface methodology. Samples were stored at 5 °C for 14 days. The optimal conditions to simultaneously minimize native microflora, maximize nutritional parameters and minimize the impact on sensory quality resulted in: 7.5 min of ultrasound treatment, pomegranate extract concentration of 360 μg/mL and vanillin concentration of 0.925 mg/mL. A new batch of strawberry juice was treated at these optimal conditions and stored for validation of the optimization and to evaluate the performance of the optimum treatment on quality parameters throughout storage. Furthermore, a second batch of juice was inoculated with Escherichia coli O157:H7 and processed at optimal conditions to evaluate the effectiveness of the treatment on the pathogen survival. The native microflora of the juice, as well as inoculated pathogen, decreased significantly using the proposed hurdle technologies, with no impact on sensory parameters. Ascorbic acid retention was slightly decreased by the optimum treatment; however, DPPH and polyphenolic compounds were significantly higher than those in untreated sample. Overall, a combination of ultrasound, vanillin and pomegranate extract showed interesting potential to enhance quality and safety of strawberry juice, extending the shelf-life of the product.Fil: Tomadoni, Bárbara María. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Cs.agrarias. Area Ciencia de Alimentos; ArgentinaFil: Cassani, Lucía Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Ciencia. Tecnología e Innovación Productiva. Agencia Nacional de Promoción Cientifíca y Tecnológica; ArgentinaFil: Ponce, Alejandra Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Cs.agrarias. Area Ciencia de Alimentos; ArgentinaFil: Moreira, Maria del Rosario. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Cs.agrarias. Area Ciencia de Alimentos; ArgentinaFil: Agüero, M. V.. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    Effect of curing conditions and harvesting stage of maturity on Ethiopian onion bulb drying properties

    Get PDF
    The study was conducted to investigate the impact of curing conditions and harvesting stageson the drying quality of onion bulbs. The onion bulbs (Bombay Red cultivar) were harvested at three harvesting stages (early, optimum, and late maturity) and cured at three different temperatures (30, 40 and 50 oC) and relative humidity (30, 50 and 70%). The results revealed that curing temperature, RH, and maturity stage had significant effects on all measuredattributesexcept total soluble solids

    Modeling of yeast thermal resistance and optimization of the pasteurization treatment applied to soft drinks

    Get PDF
    open8noYeast are usually responsible for spoilage of soft drinks and fruit beverages, because of the particular characteristics of these products (low pH, high C/N ratio). The microbial stability is guaranteed by thermal treatments. However, excessive heat treatments can affect food sensorial quality. In this work the thermal resistance of different yeasts strains (seven belonging to the species Saccharomyces cerevisiae and six belonging to the species Kluyveromyces marxianus, Zygosaccharomyces bisporus, Z. mellis, Z. rouxii, Schizosaccharomyces pombe and Saccharomycodes ludwigii) was assessed in a model system. The results showed non-linear death curves and a high variability also within the same species. The most resistant strain, belonging to the species S. cerevisiae, was chosen for further experiments in orange juice based industrial beverages: first, death curves were performed; then, the probability of beverage spoilage in relation to process parameters (initial inoculum, temperature, treatment time) was evaluated using a logistic regression model. Finally, a cross-validation was performed to investigate the predictive capability of the fitted model. Pasteurization in the soft drink industry is commonly applied according to parameters defined several decades ago, which does not consider the successive findings concerning microbial physiology and stress response, the process improvement and the more recent tools provided by predictive microbiology. In this perspective, this study can fill a gap in the literature on this subject, going to be a basis for optimizing thermal processes. In fact, the data obtained indicated an interesting possibility for food industry to better modulated (and even reduce) thermal treatments, with the aim to guarantee microbial stability while reducing thermal damage and energy costs.embargoed_20200731Montanari, Chiara; Tabanelli, Giulia; Zamagna, Ilaria; Barbieri, Federica; Gardini, Aldo; Ponzetto, Mauro; Redaelli, Erika; Gardini, FaustoMontanari, Chiara; Tabanelli, Giulia; Zamagna, Ilaria; Barbieri, Federica; Gardini, Aldo; Ponzetto, Mauro; Redaelli, Erika; Gardini, Faust

    A study of the water-energy nexus in power plants

    Get PDF
    Tesis por compendio de publicaciones[ES] La tesis se llevó a cabo a través de compendio de artículos científicos, de modo que se lleva a cabo un resumen de cada artículo, así como la información de cada uno. Artículo 1 Título: Optimal gas treatment and coal blending for reduced emissions in power plants: A case study in Northwest Spain. Autores: Lidia S Guerras y Mariano Martín. Revista: Energy DOI: 10.1016/j.energy.2018.12.089 Resumen: En este trabajo se ha desarrollado un marco de toma de decisiones para el diseño de la sección de tratamiento de gases de combustión de una central eléctrica, que incluye operaciones de remoción de partículas, NOx y SO2. Se ha aplicado a una central térmica de carbón en España para seleccionar las tecnologías óptimas y su secuencia. Se han desarrollado modelos sustitutos para los tratamientos. El problema corresponde a una programación no lineal entera mixta que incluye la eliminación de NOx catalítica y no catalítica, lo que permite varias asignaciones para la tecnología catalítica, precipitación electrostática y eliminación de SO2 húmedo o seco. Se reformula como un problema no lineal para evaluar las oportunidades de bypass. La optimización sugiere el uso de precipitación electrostática, seguida de la eliminación catalítica de NOx y la eliminación de SO2 seco. A continuación, también se ha resuelto un problema de mezcla de carbón para dos funciones objetivo. Cuando solo se consideran los costos de tratamiento, se recomienda el uso de carbón importado, pero un aumento del 4% en su precio puede cambiar la decisión por el uso de carbón nacional. Si la energía del carbón se agrega a la función objetivo, el carbón de alquitrán crudo se incluye en la mezcla y el carbón importado se usa para mantener las emisiones dentro de los límites. La oxidación forzada de piedra caliza es la tecnología seleccionada. Artículo 2 Título: Optimal Flue Gas Treatment for Oxy-Combustion-Based Pulverized Coal Power Plants Autores: Lidia S Guerras y Mariano Martín. Revista: Industrial & Engineering Chemistry Research DOI: 10.1021/acs.iecr.9b04453 Resumen: La oxicombustión es reconocida como la tecnología más limpia que utiliza carbón como fuente de energía. La limpieza de los gases de combustión es esencial para un funcionamiento sostenible. En este trabajo se determina la selección óptima de las tecnologías de tratamiento de gases de combustión en centrales de oxicombustión. Se utiliza un procedimiento de dos etapas que combina heurística y programación matemática para evaluar las tecnologías involucradas, incluida la caldera, la desnitrificación, la precipitación electrostática, la eliminación de dióxido de azufre y la captura de carbono. Para el funcionamiento de la planta, se debe seleccionar la alimentación de carbón. Se resuelve un problema de mezcla extendido para evaluar el tipo de carbón que se comprará en función de su costo y composición. El procesamiento óptimo de los gases de combustión consiste en la precipitación electrostática, seguida de la eliminación de SO2 seco y la purificación de CO2 con zeolitas. No se requiere ningún método de desnitrificación específico debido a los bajos niveles de concentración de NOx generados en la oxicombustión. Esta hoja de flujo se utiliza para seleccionar uno entre una mezcla de tres tipos diferentes de carbón: alquitrán de hulla nacional, importado y crudo. Sin embargo, no se recomienda ninguna mezcla ya que se seleccionó alquitrán de hulla crudo. Aunque los costos de procesamiento son más altos, se ve compensado por el menor coste de la materia prima. Artículo 3 Título: On the water footprint in power production: Sustainable design of wet cooling towersAutores: Lidia S Guerras y Mariano Martín. Revista: Applied Energy DOI: 10.1016/j.apenergy.2020.114620 Resumen: Las plantas de energía renovable deben instalarse donde esté disponible el recurso principal. El clima afecta el diseño y la huella hídrica de estas plantas. Se estudian dos tipos de ciclos de potencia, un ciclo Rankine regenerativo, representativo de biomasa y plantas termosolares, y el ciclo combinado, correspondiente a procesos basados en biogás o gasificación. Las instalaciones se modelan en detalle unidad por unidad para calcular el rendimiento del ciclo, el trabajo del condensador, el consumo de agua y la geometría de la torre de enfriamiento húmedo de tiro natural para su diseño sostenible. Las regiones cálidas, apropiadas para instalaciones solares, y las regiones húmedas requieren torres más grandes y caras. Las áreas con alta disponibilidad solar también muestran un mayor consumo de agua, lo que representa un intercambio para un futuro sistema de energía basado en energías renovables. Además, también se han desarrollado pautas de diseño y modelos sustitutos para estimar el consumo de agua, el tamaño de la torre de enfriamiento y su costo en función del clima. Los sustitutos son útiles para el análisis de la huella hídrica de un sistema de energía de base renovable que sustituye al de base fósil. Artículo 4 Título: Multilayer Approach for Product Portfolio Optimization: Waste to Added-Value Products Autores: Lidia S. Guerras, Debalina Sengupta, Mariano Martín, and Mahmoud M. El-Halwagi Revista: ACS Sustainable Chemistry & Engineering. DOI: 10.1021/acssuschemeng.1c01284 Resumen: Se ha desarrollado un procedimiento sistemático multicapa de varias etapas para la selección de la cartera de productos óptima a partir de biomasa residual como materia prima para sistemas que implican el nexo “wáter-energy-food”. Consiste en una metodología híbrida heurística, basada en métricas y optimización que evalúa el desempeño económico y ambiental de productos de valor agregado a partir de una materia prima en particular. La primera etapa preselecciona los productos prometedores. A continuación, se formula un problema de optimización de la superestructura para valorizar o transformar los residuos en el conjunto óptimo de productos. La metodología se ha aplicado dentro de la iniciativa “Waste to Power and Chemicals” para evaluar el mejor uso de los residuos de biomasa de la industria del aceite de oliva en alimentos, productos químicos y energía. La etapa heurística se basa en la revisión de la literatura para analizar los productos y técnicas factibles. A continuación, se han desarrollado y utilizado métricas simples para preseleccionar productos que son prometedores. Finalmente, se utiliza un enfoque de optimización de la superestructura para diseñar la instalación que procesa hojas, astillas de madera y aceitunas en productos finales. La mejor técnica para recuperar fenoles del “alperujo”, un residuo sólido húmedo/subproducto del proceso, consiste en el uso de membranas, mientras que la técnica de adsorción se utiliza para la recuperación de fenoles de hojas y ramas de olivo. La inversión necesaria para procesar los residuos asciende a 110,2 millones de euros por 100 kt/año para la instalación de producción de aceitunas, mientras que el beneficio depende del nivel de integración. Si la instalación está adscrita a la producción de aceite de oliva, el beneficio generado oscila entre los 14,5 MM €/año (cuando los residuos se compran a precios de 249 € por tonelada de alperujo y 6 € por tonelada de hojas y ramas de olivo) y 34,3 MM €/año cuando el material de desecho se obtiene de forma gratuita
    corecore