29 research outputs found

    Application of non-destructive techniques for the determination of quality parameters and classification of iberian pig carcasses

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    Tesis por compendio de publicaciones[ES]El cerdo ibérico es una raza autóctona ligada al ecosistema de la dehesa, localizada en el sureste de la Península Ibérica y reconocida por la destacable calidad organoléptica de los productos derivados. La alta demanda de productos ibéricos, junto con una limitada producción de animales cebados en regímenes extensivos alimentados a base de bellota y pasto (montanera), ha dado lugar a la cría de animales en regímenes intensivos y al empleo de cruces con razas mejorantes. La calidad final de la carne de estos animales, y de sus productos derivados, está fuertemente relacionada con diferentes factores como la producción animal, la raza, la alimentación, la edad o el peso en el momento del sacrificio. Son diversos los métodos analíticos que han sido estudiados y aplicados de cara a poder garantizar la autenticidad de la raza y la alimentación suministrada al animal, sin embargo, en el momento actual no existe ningún método analítico oficial. La espectroscopia de infrarrojo cercano (NIR) es una herramienta multiparamétrica que ha sido ampliamente empleada para evaluar características de la carne y calidad de los productos cárnicos. En el sector ibérico, la tecnología NIR ha sido aplicada para la cuantificación de los contenidos en proteína, grasa y humedad, para la predicción del perfil en ácidos grasos y de la dieta del cerdo durante el proceso de engorde. Esta metodología analítica permite obtener los resultados de forma inmediata, individualizada, no destructiva y respetuosa con el medio ambiente. Sin embargo, la interpretación de los espectros obtenidos mediante su aplicación requiere ser complementada con complejos métodos quimiométricos. En esta tesis se propone el uso de la tecnología NIRS con el fin de predecir parámetros determinantes de la calidad de la grasa en cerdo ibérico como el perfil lipídico y la relación isotópica de Carbono (δ13 C). Se aborda así mismo la aplicación de la tecnología NIRS y la espectrometría de movilidad iónica acoplada a la cromatografía de gases (GC-IMS) con fines de clasificación/autentificación. Finalmente, la tesis analiza la viabilidad del uso de equipos portátiles, que facilitan el trabajo en campo, y que han experimentado un claro auge en los últimos años. En el primer artículo incluido en la presente tesis, se estudió la posibilidad de predecir la composición del perfil de ácidos grasos y el valor de δ13 C (‰) en grasa subcutánea intacta usando un equipo NIRS portátil. Los resultados se compararon con los obtenidos aplicando el equipo NIRS de sobremesa tanto en grasa fundida como intacta. En el segundo de los artículos se evalúan los cambios en el perfil lipídico de la grasa y en la relación isotópica de carbono, antes y después de la fase de cebo en montanera, analizándose así mismo la influencia de diferentes tiempos de permanencia en montanera. La existencia de correlaciones entre el isótopo δ13 C (‰) y el perfil lipídico también ha sido estudiada con el fin de poder clasificar el producto en función de la alimentación animal. El tercer artículo evalúa el potencial de clasificación de la tecnología NIRS frente a GC-IMS, en grasa subcutánea, en el momento del sacrificio. El objetivo que se persigue es la clasificación en función de la raza de los animales y los días que han permanecido alimentándose en régimen de montanera. Las conclusiones que derivan de los estudios realizados señalan que la utilización de la espectroscopia NIR, tanto con equipos de sobremesa como portátiles, resulta adecuada para predecir parámetros de calidad en la grasa de cerdo ibérico. Esta tecnología podría reemplazar a los análisis químicos en el laboratorio, más costosos y menos respetuosos con el medio ambiente. La combinación de herramientas quimiométricas con las técnicas de CG-IMS y NIRS ha permitido clasificar la grasa en función del periodo de alimentación en montanera y de la raza. Todo ello apunta al enorme potencial la metodología NIRS para garantizar la autenticidad de las canales en el sector del cerdo ibérico, ofreciendo la posibilidad de conocer los resultados de forma inmediata y de operar de forma rutinaria en las líneas de faenado. [EN]The Iberian pig is an indigenous breed associated with the dehesa ecosystem, which is located in the southwest of the Iberian Peninsula. It is well known for the remarkable organoleptic quality of its derivatives. The high demand for Iberian products, together with the limited production of Iberian pigs reared extensively and fed on acorns and grass (the montanera system), has led to intensive rearing of this breed and also to its crossbreeding with improved breeds. The final quality of the meat from these animals and their products is strongly correlated with different factors such as animal production, the breed, the feeding regime, and the age or slaughter weight. Several analytical techniques have been studied and applied to guarantee the authenticity of the breed and the feeding regime. However, there is currently no official analytical method for the purpose. Near Infrared Spectroscopy (NIR) is a multi-parametric tool which has been widely used to assess meat characteristics and meat product quality. In the sector of the Iberian breed, NIR technology has been applied to quantify protein, fat, and moisture, to predict the fatty acid profile, and to determine the feeding regime during the fattening period. This analytical methodology allows immediate individualised results to be obtained without sample destruction and in an environmentally friendly manner. However, the spectra obtained need to be interpreted by complex chemometric methods. This PhD thesis proposes the use of NIRS technology for predicting parameters which determine the quality of Iberian pig fat, such as the lipid profile and the carbon isotopic ratio δ13 C (‰). The application of NIRS technology and gas chromatography together with ion mobility spectrometry (GC-IMS) for classification/authentication purposes is also addressed. Finally, this study analyses the viability of using portable equipment, which facilitates work in situ and has experienced a boom in recent years. The first article included in the PhD thesis evaluated the feasibility of predicting the lipid profile composition and the δ13 C (‰) of intact subcutaneous fat by using a portable NIRS device. The results were compared with those obtained by using benchtop NIRS equipment on both extracted and intact fat.In the second article, the changes in the lipid profile and the carbon isotope ratio observed before and after the fattening period on the montanera were evaluated. The influence of different montanera times on these parameters was also analysed. Significant correlations between the δ13 C isotope (‰) and the different fatty acids were studied in order to classify the samples according to animal feeding. The third article compares the classification ability of NIRS and GC-IMS technologies when applied at slaughter to subcutaneous fat. The aim was to achieve a correct classification according to the breed and the number of days spent feeding under the montanera system. The conclusions deriving from the present studies indicate that the application of NIR spectroscopy, using both benchtop and portable equipment, is suitable for predicting the quality parameters of Iberian fat. This technology could replace costlier and less environmentally-friendly laboratory chemical analyses. The combination of chemometric tools with NIRS and GC-IMS technologies has made it possible to classify Iberian fat correctly according to the fattening time and the breed. All these results point to the enormous potential of NIRS technology to guarantee the authenticity of Iberian pig carcasses. In fact, it offers the possibility of ascertaining the results immediately which allows for routine operations on the slaughter lines

    Proceedings of 14th international symposium Modern trends in livestock production

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    Polímeros inteligentes para aplicaciones en seguridad y control alimentario

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    Este trabajo describe el diseño de materiales poliméricos con diferentes aplicaciones en el campo de la alimentación. En primer lugar, de polímeros inteligentes como sensores colorimétricos para el análisis de diversas sustancias de interés en alimentación (aminas biógenas, polifenoles totales y nitritos). En segundo lugar, de materiales con potencial antimicrobiano, capaces de incrementar hasta en un 50% la vida útil de alimentos cárnicos envasados. Por último, de polímeros capaces de retener almidón y fenoles en su estructura, utilizados como parte del análisis de actividad diastásica en el caso del almidón y actividad glucosa oxidasa y catalasa en el caso de los fenoles. Todos los materiales desarrollados se han probado en matrices alimentarias, demostrando así su correcto funcionamiento y, por consiguiente, su potencial utilidad en la industria alimentaria.This work describes the design of polymeric materials, which are widely used in the food industry. Firstly, the use of smart polymers as colorimetric sensors for substances of interest such as biogenic amines, total polyphenols and nitrites is described. Secondly the antimicrobial capacity of a material is studied. This can increase the shelf-life of packaged meat foods by up to 50%. Finally, polymers able to keep starch and phenols in their structure are analyzed as part of the study of diastasic activity in the case of starch and glucose oxidase and catalase activity in the case of phenols. Every material developed, has been tested in food matrices in order to prove its effectiveness and therefore its potential use in the food industr

    Meet your meat: Psychological factors impacting on attitudes towards animals, their consumption, and plant based alternatives

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    A way to address health and sustainability concerns with the current food systems is to shift away from current levels of consumption of animal-sourced products, especially meat, toward an increased intake of plant-based foods. The general aim of this work was to explore how to trigger such transitions through a set of four articles, focused on the ways people perceive: (1) animals as living beings, examining the impact of characteristics of the perceiver (e.g., gender, pet attachment) and of the target (e.g., biological category of the animals) on perceptions (e.g., edibility, moral concern); (2) animals as food products and how resemblance to the animal source impacts on appetite for meat, independently from the impact of product familiarity; (3) alternatives to meat consumption (e.g., legumes, tofu) and the impact of framing (i.e., meal vs. ingredient) as a strategy to promote more positive attitudes toward meat alternatives. Finally, the ending section of this work provides a reflection about the existent gaps in this literature, integrates the main findings of the present body of work, and outlines how they might inform audiences interested in promoting transitions toward reduced meat consumption and more sustainable, healthier, plant-based diets.Uma das formas de responder aos desafios de saúde e sustentabilidade com os sistemas alimentares atuais passa por reduzir o consumo de produtos de origem animal, particularmente de carne, para um aumento no consumo de alimentos de origem vegetal. O objetivo geral deste trabalho passou por explorar como desencadear estas transições através de um conjunto de quatro artigos, com foco na forma como as pessoas percecionam (1) os animais como seres vivos, examinando o impacto das características individuais (e.g., género, ter animais de estimação) e do alvo (e.g., categoria biológica) nestas perceções (e.g., comestibilidade, preocupação moral); (2) os animais enquanto produtos alimentares e como a semelhança desses produtos com os animais influencia o apetite por carne, independentemente do impacto da sua familiaridade; e (3) alternativas ao consumo de carne (e.g., legumes, tofu) e o impacto do enquadramento da refeição como estratégia para promover atitudes mais positivas em relação às alternativas à carne. Por fim, a seção final deste trabalho apresenta uma reflexão sobre as lacunas existentes nesta literatura, integra os resultados mais relevantes do presente corpo de trabalho e descreve como estes podem informar audiências interessadas na promoção de transições rumo à redução do consumo de carne e à adoção de dietas mais sustentáveis, saudáveis e mais baseadas em alimentos de origem vegetal

    Automatic marbling prediction of sliced dry-cured ham using image segmentation, texture analysis and regression

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    Dry-cured ham is a traditional Mediterranean meat product consumed throughout the world. This product is very variable in terms of composition and quality. Consumer’s acceptability of this product is influenced by different factors, in particular, visual intramuscular fat and its distribution across the slice, also known as marbling. On-line marbling assessment is of great interest for the industry for classification purposes. However, until now this assessment has been traditionally carried out by panels of experts and this methodology cannot be implement in industry. We propose a complete automatic system to predict marbling degree of dry-cured ham slices, which combines: (1) the color texture features of regions of interest (ROIs) extracted automatically for each muscle; and (2) machine learning models to predict the marbling. For the ROIs extraction algorithm more than the 90% of pixels of the ROI fall into the true muscle. The proposed system achieves a correlation of 0.92 using the support vector regression and a set of color texture features including statistics of each channel of RGB color image and Haralick’s coefficients of its gray-level version. The mean absolute error was 0.46, which is lower than the standard desviation (0.5) of the marbling scores evaluated by experts. This high accuracy in the marbling prediction for sliced dry-cured ham would allow to deploy its application in the dry-cured ham industryThis work has received financial support from the Xunta de Galicia (Centro singular de investigación de Galicia, accreditation 2020– 2023) and the European Union (European Regional Development Fund–ERDF), Project ED431G-2019/04. IRTA’s contribution was also funded by the CCLabel project (RTI-2018- 096883-R-C41) and the CERCA programme from Generalitat de CatalunyaS

    Reducing sodium in salted meats : effects of partial replacement of sodium chloride by other chloride salts

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    Orientador: Marise Aparecida Rodrigues PollonioTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de AlimentosResumo: Os produtos cárneos salgados são amplamente consumidos em todo o mundo e caracterizam-se pelo alto valor nutricional, estabilidade microbiológica e propriedades sensoriais típicas. No entanto, ao longo de seu processo de fabricação, adiciona-se uma elevada concentração de cloreto de sódio (NaCl) para garantir um processo de salga com a esperada redução da atividade de água. Dessa forma, essa categoria de produtos cárneos poderá contribuir com o aumento do consumo de sódio na dieta, particularmente, se as operações de dessalga não forem padronizadas adequadamente. Segundo a Organização Mundial de Saúde (OMS), o consumo de sódio acima do recomendado (2000 mg por dia), aumenta o risco de ocorrência de diversas doenças crônicas tais como hipertensão, doenças renais, doenças cardiovasculares e alguns tipos de câncer. Em carnes salgadas, a substitutição de NaCl é um grande desafio para a indústria de processamento devido às complexas reações que podem ser influenciadas pela utilização de outros sais clorados, particularmente, as propriedades físico-químicas, microbiológicas e sensoriais. Com base nessas considerações, este estudo teve como objetivo avaliar os efeitos da substituição parcial de 50% NaCl, com base na força iônica, por cloreto de potássio (KCl) e cloreto de cálcio (CaCl2) na forma de blends em produto cárneo salgado, sobre as características de processo, propriedades físico-químicas, sensoriais, estabilidade microbiológica, reações lipolíticas e proteolíticas de carne salgada. Na primeira etapa do trabalho (capítulo 2), foram estudadas as características físico-químicas, microbiológicas e sensoriais de jerked beef elaborados com redução de 50% de NaCl através de sua substituição por diferentes sais clorados. A partir dos resultados obtidos no capítulo 2, investigaram-se os efeitos da incorporação de lisina e extrato de levedura com finalidade de melhorar os atributos sensoriais dos tratamentos de carne salgada contendo blends de CaCl2 e KCl, dando origem ao capítulo 3. A fim de avaliar o comportamento da água em carne salgada durante vida de prateleira de 180 dias, no capítulo 4, foram realizadas análises físico-químicas, de microestrutura e ressonância magnética de baixo campo. No capítulo 5, as reações de lipólise foram investigadas analisando-se os ácidos graxos, compostos voláteis e oxidação lipídica em tratamentos de carne salgada contendo redução de 50% de NaCl e substituição por blends de KCl e CaCl2. No capítulo 6, as reações de proteólise foram estudadas através de análise de força de cisalhamento e perfil eletroforético durante 180 dias. Finalmente, no capítulo 7, os parâmetros físicos-químicos de tratamentos de carne salgada ao longo das etapas de salga úmida, salga seca e maturação foram analisados. A substituição parcial do NaCl por KCl e CaCl2 nas etapas de salga úmida e seca reduziu expressivamente o teor de sódio no produto final e não impactou a estabilidade microbiológica. Lisina e extrato de levedura demonstraram ser uma boa opção para os efeitos sensoriais negativos ocasionados pela redução de NaCl e adição de KCl e CaCl2 em produto cárneo salgado com redução de sódio. O uso de CaCl2 no blend de sais afetou negativamente os atributos sensoriais e físico-químicos, aumentando o sabor amargo, dureza e aroma de ranço. Os resultados também evidenciaram que o CaCl2 promove o aumento das reações lipolíticas e proteoliticas resultando em mudança da morfologia da carne salgada, além de prejudicar o processo de desidratação. Em geral, o blend contendo NaCl + KCl resultou em efeitos tecnológicos e sensoriais similares ao tratamento controle com 100% de NaCl, mostrando ser uma boa estratégia para reduzir o teor de sódio na categoria de produtos cárneos salgados. O presente estudo contribuiu efetivamente para recomendar soluções tecnológicas consistentes no âmbito industrial para redução de sódio em carnes salgadas, resultando em produto mais saudável, seguro e com aceitação sensorialAbstract: Salted meat products are widely consumed all over the world, and characterized by high nutritional value, microbiological stability and typical sensory properties. However, due to its manufacturing process, a high concentration of sodium chloride (NaCl) is added to ensure a salting process with the expected reduction in water activity. Thus, this category of meat products may contribute to the increased sodium intake in the diet, particularly if the desalting operations are not standardized properly. According to the World Health Organization (WHO), high levels sodium, above the recommended 2000 mg per day, increase the risk of several chronic diseases such as hypertension, kidney and cardiovascular diseases and some type of cancers In salted meat, the replacement of NaCl is one of the most great challenge for processing industry due to the complex reactions that can be influenced when other chlorides salts are used, particularly the regarding to physicochemical, microbiological and sensory properties. Based on these considerations, this study aimed to evaluate the effects of partial substitution of 50% NaCl based on ionic strength by potassium chloride (KCl) and calcium chloride (CaCl2) in the form of blends in salted meat product on process characteristics, physicochemical properties, sensory properties, microbiological stability, lipolytic and proteolytic reactions of salted meat. In the first step of the work (chapter 2), were studied the physicochemical, microbiological and sensory characteristics of jerked beef performed with 50% reduction of NaCl through its replacement by different chloride salts. From the results obtained in chapter 2, The effects of incorporating lysine and yeast extract were investigated in order to improve the sensory attributes of salted meat treatments containing CaCl2 and KCl blends, giving rise to chapter 3. In order to evaluate the behavior of water in salt meat during shelf life of 180 days, in chapter 4, were performed physicochemical, microstructure and low field magnetic resonance analysis. In chapter 5, lipolysis reactions were investigated by analyzing fatty acids, volatile compounds and lipid oxidation in salt meat treatments containing 50% NaCl reduction and substitution by KCl and CaCl2 blends. In chapter 6, the proteolysis reactions were studied by shear force and electrophoretic profile analysis during 180 days. Finally, in the last chapter, the physicochemical parameters of salted meat treatments along the wet salting, dry salting and ripening steps were analyzed. Partial substitution of NaCl by KCl and CaCl2 in the wet and dry salting steps significantly reduced the sodium content in the final product and did not impact microbiological stability. Lysine and yeast extract have been shown to be a good option to minimize negative sensory effects caused by NaCl reduction and addition of KCl and CaCl2 in salted meat product with reduced sodium content. The use of CaCl2 in the salt blend negatively affected sensory and physicochemical attributes, increasing bitter taste, hardness and rancid aroma. The results also showed that CaCl2 promotes the increase of lipolytic and proteolytic reactions resulting in a change in the morphology of salted meat, besides impairing the dehydration process. In general, the blend containing NaCl + KCl resulted in technological and sensory effects similar to 100% NaCl control treatment, proving to be a good strategy to reduce sodium content in the salted meat product category. The present study effectively contributed to recommend to industry a consistent technological solutions for sodium reduction in salted meat, resulting in a healthier and safe final product with sensorial acceptanceDoutoradoTecnologia de AlimentosDoutor em Tecnologia de Alimentos140533/2015-0CNP

    Optimization of the image acquisition procedure in low-field MRI for non-destructive analysis of loin using predictive models

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    The use of low-field magnetic resonance imaging (LF-MRI) scanners has increased in recent years. The low economic cost in comparison to high-field (HF-MRI) scanners and the ease of maintenance make this type of scanner the best choice for nonmedical purposes. However, LF-MRI scanners produce low-quality images, which encourages the identification of optimization procedures to generate the best possible images. In this paper, optimization of the image acquisition procedure for an LF-MRI scanner is presented, and predictive models are developed. The MRI acquisition procedure was optimized to determine the physicochemical characteristics of pork loin in a nondestructive way using MRI, feature extraction algorithms and data processing methods. The most critical parameters (relaxation times, repetition time, and echo time) of the LF-MRI scanner were optimized, presenting a procedure that could be easily reproduced in other environments or for other purposes. In addition, two feature extraction algorithms (gray level co-occurrence matrix (GLCM) and one point fractal texture algorithm (OPFTA)) were evaluated. The optimization procedure was validated by using several evaluation metrics, achieving reliable and accurate results (r > 0.85; weighted absolute percentage error (WAPE) lower than 0.1%; root mean square error of prediction (RMSEP) lower than 0.1%; true standard deviation (TSTD) lower than 2; and mean absolute error (MAE) lower than 2). These results support the high degree of feasibility and accuracy of the optimized procedure of LF-MRI acquisition. No other papers present a procedure to optimize the image acquisition process in LF-MRI. Eventually, the optimization procedure could be applied to other LF-MRI systems

    Development and evaluation of tools to improve the texture and quality of dry-cured ham

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    El jamón curado es considerado un producto típico de la región mediterránea elaborado con las patas traseras del cerdo, las cuales se salan y curan durante un período largo. Sin embargo, existen otros productos curados como el jamón curado de cordero, el Fenalår, típico de Noruega, que se sala, se ahúma y se cura durante un período más corto de tiempo. La textura de los productos curados es un criterio de calidad importante para los consumidores. Sin embargo, el desarrollo de la textura, así como también de los defectos de textura de los productos curados tanto de cerdo como de cordero son un tema complejo puesto que hay muchos factores involucrados. Por este motivo, hay un interés creciente de la industria alimentaria en encontrar soluciones para reducir la incidencia de productos con texturas blandas y/o defectuosas.El principal objetivo de esta Tesis es desarrollar y evaluar herramientas para mejorar el proceso de elaboración y la calidad de dos productos curados: el jamón curado y el Fenalår. Para ello, se han llevado a cabo diferentes estudios los cuales se presentan en esta Tesis en diferentes artículos científicos. El artículo I aborda los principales factores que afectan al desarrollo de la textura y a la modelización de la textura. El segundo artículo muestra los resultados de la microbiología predictiva utilizada para estudiar la seguridad alimentaria en relación con el proceso de elaboración y la reducción del contenido de sal, así como también la omisión de nitrificantes (artículo II). En el artículo III se investigó un método para evaluar de manera no destructiva el punto final del proceso en función de las medidas obtenidas en la superficie del jamón. En el artículo IV,se presentan los resultados obtenidos de un primer intento para el desarrollo de un método para evaluar la pastosidad con el reómetro y evitar así los tediosos análisis sensoriales. Finalmente, el uso de un tratamiento de altas presiones como acción correctora para productos con texturas defectuosas se presenta en el artículo V.Con la finalidad de estudiar de forma más detallada el desarrollo de la textura, se desarrolló un modelo matemático (artículo 1), que relaciona las condiciones de procesado y las características de la materia prima con la textura del producto. Este modelo no sólo permite evaluar el efecto de estos factores, sino que también podría permitir una optimización del proceso de elaboración a nivel industrial. Los resultados mostraron que el contenido de sal, el pH, las características de la materia prima y las condiciones de procesado (temperatura de secado y merma final) son factores importantes que afectan al desarrollo de la textura, tal y como se presenta en el artículo I, y a la vez comprometen la seguridad del producto. En el artículo II, la reducción del contenido de sal no sólo dio como resultado texturas más blandas, sino que también produjo un incremento de los riesgos microbiológicos, especialmente cuando se omitieron los nitrificantes, tal y como muestran los resultados obtenidos mediante los modelos de microbiología predictiva. Además, los defectos de textura en ambosproductos curados representan un importante desafío para la industria.A pesar de los esfuerzos realizados para mejorar el proceso de elaboración, es posible que algunos productos sigan siendo defectuosos, evidenciando así la necesidad de nuevas herramientas y/o tecnologías con potencial para su aplicación a nivel industrial. En esta Tesis, se estudió una metodología para evaluar si el producto tenía o no la textura adecuada para su comercialización (artículo III), así como también un análisis para evaluar instrumentalmente el defecto de pastosidad en jamón curado loncheado (papel IV). Los resultados presentados en el artículo III muestran que el método ITAS permitió evaluar de manera no destructiva el punto final del proceso; esta metodología consiste ensimular la valoración táctil en la superficie del jamón realizada actualmente por los expertos. La máxima precisión de clasificación fue del 82,1%, obtenida al combinar las mediciones junto con el espesor de la grasa subcutánea. La implantación de esta tecnología a nivel industrial no sólo mejoraría la calidad del producto, sino que también supondría un ahorro económico, energético y de espacio, ya que permitiría un mejor ajuste del tiempo de secado necesario para cada jamón.En el artículo IV se presentan los resultados obtenidos en un primer estudio para el desarrollo de un método para evaluar la pastosidad utilizando un reómetro. Los resultados obtenidos mostraron un aumento de la viscosidad de los extractos a medida que aumentaba la intensidad del defecto de pastosidad, mostrando así la posibilidad de detectar instrumentalmente este defecto utilizando el reómetro. Sin embargo, hay otros factores a parte de la viscosidad que pueden afectar/alterar los resultados y el reómetro sólo permite discriminar las muestras con una pastosidad intensa de aquellas que tienen un defecto medio o que no son pastosas.También se han llevado a cabo acciones correctoras en lonchas de jamón curado utilizando tratamientos mediante altas presiones a diferentes temperaturas (artículo V).Los resultados obtenidos muestran que, si bien las temperaturas de 7 ºC y 20 ºC son útiles para corregir el defecto en las lonchas con pastosidad media, se necesita una temperatura superior (35 ºC) para las de pastosidad intensa. Por lo tanto, conocer las características iniciales de textura del producto es clave para definir las condiciones óptimas para su procesado mediante altas presiones cuando se busca mejorar la textura sin deteriorar el color ni el aroma.Las metodologías desarrolladas y evaluadas en esta Tesis pueden utilizarse para mejorar el proceso de elaboración y la calidad del jamón curado. Además, representan un primer paso en el desarrollo de nuevas herramientas para uso industrial.Dry-cured ham is considered a typical product of the Mediterranean area made of pig¿s hind leg which is dry-salted and has a long maturation period. However, there are other typical dry-cured products such as the dry-cured lamb ham, Fenalår, from Norway, which is dry-salted and smoked followed by a short maturation period. The texture of dry-cured products is an important quality criterion for the consumers. However, texture development and also texture defects of dry cured products from both pork and lamb are a complex issue since many factors are involved. For this reason, there is an increasing interest of the industry in finding solutions to reduce the incidence of products with soft and/or defective textures. The main objective of this PhD Thesis dissertation was to develop and evaluate tools to improve the manufacturing process and the quality of two examples of dry-cured products; dry-cured ham and Fenalår. For this reason, different studies were conducted and herein presented as different papers. First one addresses the main factors affecting texture development and texture prediction modelling (presented in paper I). The second paper presents the results of predictive microbiology used to study food safety in relation to manufacturing process with reduced salt and nitrites addition (in paper II). Next study investigated a method to non-destructively evaluate the end of process based on the measurements taken at the surface of the ham (in paper III). The results of an attempt to develop a method to evaluate pastiness with a rheometer to avoid the tedious sensory analysis are presented in paper IV. Finally, the use of high pressure treatments as a corrective action for products with defective textures is presented in paper V. In order to study texture development in more detail, mathematical models were developed (paper I), that relate processing conditions and raw material characteristics to the texture of the product. These models not only allow the effect of these factors to be evaluated but could also enable further optimisation of the process in the industry. The results showed that salt content, pH, raw material characteristics and processing conditions (drying temperature and final weight loss) are important factors affecting texture development, as shown in paper I, while affecting product safety. In paper II, reduced salt content not only resulted in softer textures but also in an increase of microbiological hazards especially when no nitrite was used as evaluated by predictive microbiology models. Furthermore, texture defects in both dry-cured products represent an important challenge for the industry. Despite the efforts to improve the manufacturing process, some products may still be defective and the need for new tools and/or technologies with potential for industrial application is emerging. In this Thesis, a methodology to evaluate whether the product had the appropriate texture to be sent to the market or not (paper III) and an analysis to instrumentally evaluate pastiness defect in sliced dry-cured ham (paper IV) were studied. Results presented in paper III show that ITAS method allowed to non-destructively assess processing end point; this methodology consist of simulating the tactile assessment of ham surface as currently made by the experts. The maximum classification accuracy was 82.1% obtained when combining measurements with subcutaneous fat thickness. The implementation of this technology in industry would not only improve the quality of the product but also economic, energy and space savings, as it would enable better adjustment of required drying time for each ham. Results of the study in paper IV represent a first attempt for the development of a method to evaluate pastiness using a rheometer to avoid the tedious sensory analysis. An increase in viscosity of water extracts with an increase in pastiness intensity, show the ability to instrumentally detect this defect using the rheometer. However, there are factors other than viscosity that can affect/alter the results and this method allows discriminating only samples with high pastiness intensity from those with medium or non-pastiness defect. Corrective actions for dry-cured ham slices using HPP treatments at different temperatures were also analysed (paper V). The obtained results show that while temperatures of 7 ºC and 20 ºC are useful to correct ham slices with medium pastiness, higher temperature (35 ºC) is needed in the case of high pastiness. Therefore, knowing textural properties of the product is key information to define optimal HP processing conditions when aiming to improve texture without deteriorating colour and aroma. The methodologies developed and evaluated in the present work can be used to improve the manufacturing process and quality of dry-cured ham. They represent a first step in development of new tools for industrial use. <br /

    Use of ultrasound for the characterization and correction of textural defects in dry-cured ham

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    Tesis por compendio[EN] Dry-cured ham is a product highly appreciated by consumers, nevertheless, there are a large number of manufacturing process-related parameters, as well as ham intrinsic factors, that compromise its final quality. One of the main problems in the quality of dry-cured ham is the appearance of textural defects, in particular, the development of pastiness. This defect is characterized by an excessive softness and loss of elastic behavior of the ham and when tasted, it provokes a feeling similar to the mouth-coating sensation produced by a flour-water paste during the mastication process. Pastiness also makes slicing difficult and promotes the adhesiveness between slices. Currently, the methods available to measure ham pastiness are time-consuming and destructive. For this reason, the seek of faster and non-destructive technologies capable of detecting pastiness is of great importance. In this sense, different technologies such as near infrared spectroscopy, X-rays or ultrasound, that have been previously tested for the nondestructive characterization of different meat products, could be of interest for the detection of ham pastiness. Different approaches, such as the use of high hydrostatic pressure (HHP) or the application of low-temperature long-time thermal treatments (LTLT) at the end of the ham manufacturing, have been previously addressed for the correction of pastiness in dry-cured ham. Notwithstanding, the high cost and the long time required for the HHP and LTLT treatments, respectively, highlights the need for moderate cost and faster alternatives. In this context, the main goals of this thesis were to determine the feasibility of using low intensity ultrasound to non-destructively detect the appearance of pastiness during ham manufacturing and to characterize the level of pastiness in the final product, as well as to explore the feasibility of mild ultrasonic assisted thermal treatments to correct this textural defect. To meet the goal of ham pastiness characterization and correction, a customized drycured ham manufacturing was designed and carried out in order to obtain hams with different levels of pastiness with no remarkable differences on the salt content. During ham manufacturing, the feasibility of using contact ultrasound to monitor the appearance of pastiness was addressed. The ultrasonic velocity was measured in the raw ham, at the end of the salting and post-salting stages, 3 times during the drying-maturation and once the manufacturing was finished. At the end of the manufacturing, the pastiness level (high, medium and no pasty) was also sensory evaluated by an expert panel. As the manufacturing progressed, a progressive increase in the ultrasonic velocity, from 1536 m/s in the raw ham to 1713 m/s in the final dry-cured ham, was found. Notwithstanding, the increase in the ultrasonic velocity was not related with the pastiness defect, probably because the ham texture changes linked to pastiness were masked by the great influence of the compositional changes (salt gain and moisture loss) on the ultrasonic velocity. Therefore, the ultrasonic velocity was not an effective parameter to detect the appearance of pastiness in hams during manufacturing, neither to classify them according to its pastiness level at the end of the manufacturing. Contact ultrasound was also used to monitor the compositional and textural changes taking place along the ham post-salting stage. For this purpose, another batch of hams was salted and post-salting times from 7 to 56 days were tested. During post-salting, the hams were weighted and the ultrasonic velocity was measured every 2 days. Each 7 post-salting days, the composition and the textural properties of a different ham were destructively analyzed. The ham weight loss during the post-salting stage was satisfactorily (r=0.95) described by the increase in the ultrasonic velocity. Moreover, the salt distribution and the moisture loss in the internal parts of the ham were satisfactorily related (r=0.93 and r=0.86, respectively) with the increase in the ultrasonic velocity. The variation in the ham hardness during post-salting was negligible and hence, the velocity increase was mainly attributed to the compositional changes, being barely affected by the changes in texture. The hams obtained after the customized manufacturing were sliced and the ultrasonic velocity and attenuation were measured on the Biceps femoris muscle with the aim of nondestructively finding out its pastiness level. Furthermore, in order to better analyze this textural defect, the composition, protein degradation, instrumental texture and microstructure of the hams were analyzed. Pasty samples presented the highest proteolysis index (38.7% compared to 33.1% for non-pasty hams), exhibited the more relevant structural degradation (merged myofibril structures and appearance of large gaps) and consequently, were the softest (5.4 N of hardness compared to 16.7 N for non-pasty hams) and presented the most intense viscous behavior (0.434 compared to 0.372 for non-pasty hams), although a high degree of experimental variability was found. The non-destructive assessment performed with ultrasound revealed that ultrasonic attenuation could be successfully applied for the grading of dry-cured ham slices according to its pastiness level. Thus, the greater the pastiness, the higher the ultrasonic attenuation, being the average attenuation coefficient for high, medium and no-pasty samples 48.2, 45.4 and 43.1 Np/m, respectively. Notwithstanding, the ultrasonic velocity was similar in all the ham samples, regardless its pastiness level. As observed in whole hams, the ultrasonic velocity was not a satisfactory parameter to detect pastiness in sliced ham, since the large influence of the composition on the ultrasonic velocity added to a similar salt and moisture content of the samples, regardless its pastiness level, led to a similar velocity for the different pastiness levels. Air-coupled ultrasonic techniques in both through-transmission and pulse-echo modes were developed for the characterization of dry-cured ham texture. The non-invasive nature of aircoupled ultrasound allows a contactless measurement, which makes easier its industrial implementation compared to conventional ultrasound techniques for high speed applications without material surface alteration and cross-contamination between food items. As for corrective actions of the texture defects in dry-cured ham, mild thermal treatments in two different heating media (water and air) were evaluated. Furthermore, the feasibility of intensifying these mild thermal treatments with the assistance of power ultrasound was considered. For that purpose, commercial vacuum-packed dry-cured ham slices were heated in a liquid medium, with and without ultrasonic assistance, at different temperatures (40, 45 and 50 ºC), measuring the temperature in the Biceps femoris and in the Semimembranosus muscles. Regarding the treatments in air, commercial vacuum-packed dry-cured ham cylinders were used. In the first set of experiments, ham was heated at a constant air velocity (2 m/s) until different temperatures (40, 45 and 50 ºC) were reached. While in the second set of experiments, ham was treated at constant air temperature (50 ºC) at different air velocities (1, 2, 3, 4 and 6 m/s). In both sets, the treatments were performed with and without power ultrasound application, measuring the temperature in the center of the cylinder. Thermal treatments were extended until a target temperature of 5 ºC lower than the medium (water-air) heating temperature was reached, thus, holding temperature stage did not exist and the treatments only considered the heating one. The heating kinetics of the ham treated in both water and air heating media were mathematically described by means of a heat conduction model. Once the heating finalized, the textural changes of ham (hardness and elastic behavior) were evaluated. The experiments showed that power ultrasound application sped up the heat transfer, significantly (p<0.05) shortening the heating time and increasing the apparent thermal diffusivity up to 51 and 37% for water and air heat treatments, respectively. For the thermal treatments using water, the increase in temperature during the heating brought about a lower ultrasonic intensification (the apparent thermal diffusivity was increased by 51% at 40 ºC compared to the 21% at 50 ºC). On the contrary, in experiments with air, the higher the temperature, the greater the ultrasonic enhancement (the apparent thermal diffusivity was increased by 5% at 40 ºC compared to the 38% at 50 ºC). The effect of the ultrasound application decreased as the air velocity increased, being minimal when the air velocity was the highest (the apparent thermal diffusivity was increased by 21% at 1 m/s compared to the 5% at 6 m/s). As regards the changes in the textural properties of ham after the mild thermal treatments at short times, an increase in hardness and elastic behavior was observed. Finally, the texture correction in dry-cured ham with different levels of pastiness was tackled. For this purpose, vacuum-packed dry-cured ham slices with high, medium and no pastiness were heated in a liquid medium at 40 and 50 ºC for a longer time (5 h, including heating and holding stages) than heating experiments, with and without the assistance of power ultrasound during the heating phase. The texture (hardness, elastic behavior and adhesiveness) and the microstructure of the ham was evaluated in both treated and control samples. After the mild thermal treatments, the texture of ham was improved since the hardness was increased (102%) and the viscous behavior diminished (11%). On average, the increase of hardness at 50 ºC was 159% higher than at 40 ºC, while the decrease of the viscous behavior was 13.5% larger at 50 ºC compared to 40 ºC. The ham adhesiveness was also enhanced independently of the treatment temperature, with a 55% reduction being observed. The application of power ultrasound during the heating phase did not involve any additional textural change. Likewise, after the thermal treatments, the microstructure of hams with pastiness notably changed, experiencing a severe shrinkage of the myofibrils, which contributed to explain the reported textural changes. In conclusion, pastiness is a relevant and highly complex textural defect in dry-cured ham. The use of contact ultrasound and the measurement of the ultrasonic attenuation could be considered a potential technology to non-destructively detect and characterize pastiness in sliced dry-cured ham. Future work should focus on extending this approach to identify pasty whole hams, considering for this purpose the use of air-coupled ultrasound. Moreover, the use of mild thermal treatments in liquid or gas media could be a feasible method to correct the defective texture of dry-cured hams and the application of power ultrasound during the heating phase could be a relevant means of speeding up the thermal treatments.[ES] El jamón curado es un producto muy apreciado por los consumidores, sin embargo, existen numerosos parámetros relacionados con el procesado, así como factores intrínsecos del jamón, que comprometen su calidad final. Uno de los principales problemas de calidad del jamón curado es la aparición de defectos de textura, concretamente, el desarrollo de pastosidad. Este defecto se caracteriza por una textura excesivamente blanda y un comportamiento menos elástico del jamón. A nivel sensorial, provoca una sensación de recubrimiento en boca similar a la masticación de una pasta de harina y agua. La pastosidad también dificulta el loncheado y promueve la adhesividad entre lonchas. Actualmente, los métodos disponibles para caracterizar la pastosidad requieren mucho tiempo y son destructivos. Por esta razón, la búsqueda de tecnologías más rápidas y no destructivas capaces de detectar la pastosidad es de gran importancia. En este sentido, distintas tecnologías como espectroscopía de infrarrojo cercano, rayos-X o ultrasonidos, que han sido ensayadas previamente para la caracterización no destructiva de diferentes productos cárnicos, podrían ser de interés para la detección de pastosidad en jamón. Diferentes alternativas, como el uso de altas presiones hidrostáticas (HHP) o la aplicación de tratamientos térmicos de larga duración a baja temperatura (LTLT) al final del proceso de elaboración del jamón, han sido abordadas previamente para la corrección de pastosidad en jamón curado. Sin embargo, el elevado coste y el largo tiempo requerido para los tratamientos HHP y LTLT, respectivamente, pone de manifiesto la necesidad de encontrar alternativas con un coste moderado y más rápidas. En este contexto, los principales objetivos de esta tesis fueron determinar la viabilidad de la utilización de ultrasonidos de baja intensidad para detectar de manera no destructiva la aparición de pastosidad durante el proceso de elaboración de jamón curado y caracterizar el nivel de pastosidad en el producto final, así como explorar la viabilidad de tratamientos térmicos moderados asistidos por ultrasonidos de alta intensidad para corregir dicho defecto de textura. Para cumplir el objetivo de caracterizar y corregir el defecto de pastosidad en jamón, se diseñó y se llevó a cabo un proceso de elaboración para obtener jamones con distintos niveles de pastosidad sin diferencias considerables del contenido en sal. Durante el procesado, se abordó la viabilidad de utilizar ultrasonidos por contacto para monitorizar la aparición de la pastosidad. Así, la velocidad ultrasónica se midió en el jamón fresco, al final de las etapas de salado y postsalado, 3 veces durante el secado-maduración y una vez terminado el proceso de elaboración. Al final del procesado, también se evaluó el nivel de pastosidad (alto, medio y sin pastosidad) en el jamón loncheado por un panel experto. A medida que avanzó el proceso de elaboración, se observó un aumento progresivo de la velocidad ultrasónica, de 1536 m/s en jamón fresco hasta 1713 m/s en jamón curado. Sin embargo, el aumento en la velocidad ultrasónica no se relacionó con el defecto de pastosidad, probablemente porque los cambios de textura del jamón vinculados con la pastosidad fueron enmascarados por la gran influencia de los cambios composicionales (ganancia de sal y pérdida de humedad) en la velocidad ultrasónica. Así, la velocidad ultrasónica no fue un parámetro útil para detectar la aparición de pastosidad en jamón durante su procesado ni para clasificar los jamones según su nivel de pastosidad al final del procesado. Los ultrasonidos por contacto también se utilizaron para monitorizar los cambios composicionales y texturales que tienen lugar a lo largo de la etapa de postsalado del jamón. Para ello, se saló otro lote de jamones y se evaluaron distintos tiempos de postsalado, desde 7 hasta 56 días. Durante el postsalado, los jamones se pesaron y se midió su velocidad ultrasónica cada 2 días. Cada 7 días de postsalado, se analizó destructivamente la composición y las propiedades texturales de un jamón. La pérdida de peso de los jamones durante la etapa de postsalado fue descrita satisfactoriamente (r=0.95) por el aumento de la velocidad ultrasónica. Además, la distribución de sal y la pérdida de humedad en el interior del jamón se relacionaron de forma satisfactoria (r=0.93 y r=0.86, respectivamente) con el aumento de la velocidad ultrasónica. La variación en la dureza del jamón durante el postsalado fue no significativa y, por ello, el aumento de la velocidad ultrasónica se atribuyó principalmente a los cambios de composición, siendo apenas afectada por los cambios de textura. Los jamones obtenidos con distintos niveles de pastosidad después del proceso de elaboración, se cortaron y se midió la velocidad y la atenuación ultrasónica del músculo Biceps femoris con el objetivo de averiguar de forma no destructiva su nivel de pastosidad. Además, con el fin de analizar mejor este defecto de textura, se analizaron el índice de proteólisis, la microestructura, la textura instrumental y la composición de los jamones. Las muestras pastosas presentaron el índice de proteólisis más alto (38.7% comparado con el 33.1% de los jamones no pastosos), mostraron la degradación estructural más relevante (estructuras miofibrilares fusionadas y aparición de grandes huecos) y, en consecuencia, fueron las más blandas (5.4 N de dureza en comparación con los 16.7 N de los jamones no pastosos) y presentaron el comportamiento viscoso más intenso (0.434 comparado con el 0.372 de los jamones no pastosos), aunque se encontró una gran variabilidad experimental. La evaluación no destructiva llevada a cabo mediante ultrasonidos reveló que la atenuación ultrasónica se podría aplicar con éxito para la clasificación de las lonchas de jamón curado según su nivel de pastosidad. Así, cuanto mayor fue la pastosidad, mayor fue la atenuación ultrasónica, siendo el coeficiente de atenuación promedio de las muestras con alta, media y sin pastosidad de 48.2, 45.4 y 43.1 Np/m, respectivamente. Sin embargo, la velocidad ultrasónica fue muy similar en todas las muestras de jamón, independientemente de su nivel de pastosidad. Como se observó en los jamones enteros, la velocidad ultrasónica no fue un parámetro útil para cuantificar el defecto de pastosidad en jamón loncheado, ya que la gran influencia de la composición en la velocidad ultrasónica sumada al contenido similar de sal y humedad de las muestras, independientemente de su nivel de pastosidad, dio lugar a una velocidad similar en todos los niveles de pastosidad. Se desarrollaron dos técnicas de ultrasonidos acoplados por aire, tanto en modo transmisión-recepción como en pulso-eco, para caracterizar la textura de jamón curado. El carácter no invasivo de los ultrasonidos acoplados por aire permite llevar a cabo medidas sin contacto, facilitando su aplicación a nivel industrial en comparación con las técnicas ultrasónicas convencionales, ya que pueden realizarse medidas a mayor velocidad, sin alterar la superficie del material y evitando la contaminación cruzada entre alimentos. En cuanto a las medidas de corrección de defectos texturales en jamón curado, se evaluaron tratamientos térmicos moderados en dos medios de calentamiento diferentes (agua y aire). Además, se consideró la viabilidad de intensificar dichos tratamientos mediante la aplicación de ultrasonidos de alta intensidad (o de potencia). Para ello, se calentaron lonchas de jamón curado comercial envasadas al vacío en medio líquido, con y sin la aplicación de ultrasonidos, a diferentes temperaturas (40, 45 y 50 ºC), midiendo la temperatura en los músculos Biceps femoris y Semimembranosus. Respecto a los tratamientos en aire, se utilizaron cilindros de jamón curado comercial envasado al vacío. En el primer set de experimentos, el jamón se calentó a velocidad de aire constante (2 m/s) a diferentes temperaturas (40, 45 y 50 ºC); mientras que, en el segundo experimento, el jamón se calentó a temperatura de aire constante (50 ºC) a distintas velocidades (1, 2, 3, 4 y 6 m/s). En los dos sets, los tratamientos se llevaron a cabo con y sin la aplicación de ultrasonidos de potencia, midiendo la temperatura en el centro del cilindro. Los tratamientos térmicos se prolongaron hasta alcanzar la temperatura objetivo, definida como 5 ºC por debajo de la temperatura del medio de calentamiento (agua o aire). Así, no se llevó a cabo una fase de mantenimiento de la temperatura y sólo se consideró la fase de calentamiento de los tratamientos térmicos. Las cinéticas de calentamiento del jamón tratado tanto en agua como en aire se describieron matemáticamente considerando que la transferencia de calor estuvo únicamente controlada por conducción. Una vez finalizado el calentamiento, se evaluaron los cambios texturales del jamón (dureza y comportamiento elástico). Los experimentos mostraron que la aplicación de ultrasonidos de potencia aceleró la transferencia de calor, reduciendo significativamente (p<0.05) el tiempo de calentamiento y aumentando la difusividad térmica aparente hasta un 51 y 37% en los tratamientos térmicos en agua y aire, respectivamente. En el caso de los tratamientos térmicos en agua, el aumento de la temperatura durante el calentamiento provocó una intensificación ultrasónica menor (la difusividad térmica aparente aumentó un 51% a 40 ºC comparado con el 21% a 50 ºC). Por el contrario, en las experiencias en aire, cuanto mayor fue la temperatura, más efectiva fue la aplicación de los ultrasonidos (la difusividad térmica aparente incrementó un 5% a 40 ºC comparado con el 38% a 50 ºC). El efecto de la aplicación de los ultrasonidos disminuyó con el aumento de la velocidad del aire, siendo mínimo con la velocidad de aire más alta ensayada (la difusividad térmica aparente aumentó un 21% a 1 m/s comparado con el 5% a 6 m/s). En cuanto a los cambios de las propiedades texturales del jamón después de los tratamientos térmicos moderados limitados a la fase de calentamiento, se observó un aumento en su dureza y en su comportamiento elástico. Por último, se abordó la corrección de textura en jamón curado con distintos niveles de pastosidad. Para ello, se calentaron lonchas de jamón con alta, media y sin pastosidad envasadas al vacío en medio líquido a 40 y 50 ºC durante tiempos más largos (5 h, incluyendo las fases de calentamiento y mantenimiento) que en las experiencias sólo de calentamiento, con y sin la aplicación de ultrasonidos de potencia únicamente durante la

    Intelligence, Creativity and Fantasy

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    UID/HIS/04666/2019 This is the 2nd volume of PHI series, published by CRC Press, the 4th published by CRC Press and the 5th volume of PHI proceedings.The texts presented in Proportion Harmonies and Identities (PHI) - INTELLIGENCE, CREATIVITY AND FANTASY were compiled with the intent to establish a multidisciplinary platform for the presentation, interaction and dissemination of research. The aim is also to foster the awareness and discussion on the topics of Harmony and Proportion with a focus on different visions relevant to Architecture, Arts and Humanities, Design, Engineering, Social and Natural Sciences, and their importance and benefits for the sense of both individual and community identity. The idea of modernity has been a significant motor for development since the Western Early Modern Age. Its theoretical and practical foundations have become the working tools of scientists, philosophers, and artists, who seek strategies and policies to accelerate the development process in different contexts.authorsversionpublishe
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