El presente trabajo se ha centrado en el desarrollo de emulsiones alimentarias aceite-en-agua estabilizadas con proteínas de atún. Específicamente, se ha analizado la influencia del método de conservación de las proteínas aisladas (liofilización, congelación) y de las condiciones de procesado seleccionadas sobre el comportamiento reológico y la microestructura de dichas emulsiones. Se han preparado emulsiones aceite en agua (con un contenido del 70% en peso de aceite) estabilizadas con proteínas de atún. La concentración de emulsionante usada ha sido 0,50% en peso. El comportamiento reológico de estas emulsiones no depende significativamente del método de conservación de la proteína empleado. Por otra parte, un aumento de la velocidad de agitación durante el proceso de manufactura de la emulsión da lugar a una disminución continua del tamaño medio de gota y a un aumento de las funciones viscoelásticas dinámicas, menos significativo a medida que aumenta dicha velocidad de agitación. | This work is focused on the development of o/w salad dressing-type emulsions stabilized by tuna proteins. The influence of protein conservation methods after the extraction process (freezing or liofilization) on the rheological properties and microstructure of these emulsions was analyzed. Processing variables during emulsification were also evaluated. Stable emulsions with adequate rheological and microstructural characteristics were prepared using 70% oil and 0.50% tuna proteins. From the experimental results obtained, we may conclude that emulsion rheological properties are not significantly affected by the protein conservation method selected. On the contrary, an increase in homogenization speed favours an increase in the values of the linear viscoelastic functions. Less significant is the fact that as agitation speed increases further, mean droplet size steadily decreases.

This work is focused on the development of o/w salad dressing-type emulsions stabilized by tuna proteins. The influence of protein conservation methods after the extraction process (freezing or liofilization) on the rheological properties and microstructure of these emulsions was analyzed. Processing variables during emulsification were also evaluated. Stable emulsions with adequate rheological and microstructural characteristics were prepared using 70% oil and 0.50% tuna proteins. From the experimental results obtained, we may conclude that emulsion rheological properties are not significantly affected by the protein conservation method selected. On the contrary, an increase in homogenization speed favours an increase in the values of the linear viscoelastic functions. Less significant is the fact that as agitation speed increases further, mean droplet size steadily decreases. | El presente trabajo se ha centrado en el desarrollo de emulsiones alimentarias aceite-en-agua estabilizadas con proteínas de atún. Específicamente, se ha analizado la influencia del método de conservación de las proteínas aisladas (liofilización, congelación) y de las condiciones de procesado seleccionadas sobre el comportamiento reológico y la microestructura de dichas emulsiones. Se han preparado emulsiones aceite en agua (con un contenido del 70% en peso de aceite) estabilizadas con proteínas de atún. La concentración de emulsionante usada ha sido 0,50% en peso. El comportamiento reológico de estas emulsiones no depende significativamente del método de conservación de la proteína empleado. Por otra parte, un aumento de la velocidad de agitación durante el proceso de manufactura de la emulsión da lugar a una disminución continua del tamaño medio de gota y a un aumento de las funciones viscoelásticas dinámicas, menos significativo a medida que aumenta dicha velocidad de agitación.

Dissertação de Mestrado em Segurança Alimentar | RESUMO - Com o intuito de tornar possível o consumo de água de coco fora das regiões produtoras, torna-se fundamental a sua industrialização. O processamento térmico é usado como forma efetiva na conservação dos alimentos. Entretanto, em alguns casos o uso do calor pode afetar o produto final de forma negativa, levando a alterações sensoriais e físico químicas do produto. Alguns processos não térmicos vêm sendo aplicados para a conservação de alimentos sem causar os efeitos adversos do uso do calor. Um desses processos é o tratamento de alimentos com luz ultravioleta, que tem sido bastante estudada pela eficiência na inativação microbiológica em água, sucos e em superfícies de diversos materiais. Este trabalho tem por objetivo a avaliação microbiológica de amostras de água de coco processada industrialmente com aplicação de raios ultravioletas de forma experimental combinada com diferentes tratamentos térmicos, como congelação e refrigeração, visando a conservação e segurança do produto final para o consumidor. As análises realizadas consistiram na Pesquisa de Salmonella spp, (ISO 6887-5:2010) e Escherichia coli (ISO 4831:2012), quantificação de coliformes totais e termotolerantes (ISO 4831:2012), mesófilos totais (ISO 6611:2004) e bolores e leveduras (ISO 4833-1:2013). Verificou-se a diminuição da carga microbiológica das amostras tratadas com ultravioleta quando comparadas com amostras submetidas a outro tratamento térmico, resultados compatíveis com os obtidos em estudos semelhantes em sumos. Para validação dos protocolos é fundamental que este estudo seja desenvolvido com um número maior de amostras, diferentes lotes e pesquisa de outros grupos de microrganismos. | ABSTRACT - In order to make it possible to consume and commercialize coconut water in distant regions from the production sites, industrialization of coconut water production is needed. During the bottling procedure for coconut water, the fruit goes through an external cleaning before opening. Thermal processing is an effective way to preserve food. However, in some cases the use of heat can negatively affect the final product, leading to sensorial and physical-chemical changes. Some non-thermal processes have been studied and applied to preserve food without causing the adverse effects of using heat. One of these processes is the treatment of food with ultraviolet light, which has been studied extensively for its efficiency in microbiological inactivation of water, juices and on surfaces of different materials. This work aimed to perform a microbiological evaluation of industrially prepared coconut water samples with the application of ultraviolet light combined with different thermal treatments, such as freezing and refrigeration, aiming at the conservation and safety of the final product for the consumer. The analyzes performed consisted of the identification of Salmonella spp, (ISO 6887-5: 2010) and Escherichia coli (ISO 4831: 2012), quantification of total and thermotolerant coliforms (ISO 4831: 2012), mesophiles (ISO 6611: 2004) and molds and yeasts (ISO 4833-1: 2013).Results revealed a decrease in the microbiological load of samples treated with ultraviolet when compared to samples submitted exclusively to thermal treatment. In future studies, for protocol validation purposes it will be essential to include a higher number of samples, belonging to different batches and also to investigate other groups of microorganisms. | N/A

Abstract Semen cryopreservation is associated with low productivity results. This study aimed to test the Coconut Water Powder (ACP®-103) as a ressuspension diluent after thawing semen, also evaluate sperm quality during the cooling curve until thawing of the semen. For this, the semen was collected from 15 boars once a week, incubated at 30 ºC for 15 minutes, and afterwards, the samples were diluted in the diluent Beltsville Thawing Solution - BTS (Control) or ACP-103®, and subjected to a slow cooling curve, where the force and the motility were analyzed in each step. The thawed semen was ressuspended in its respective solvents and analyzed in the characteristics of vigor, motility, vitality, acrosome integrity and functionality of the membrane. During the analysis of vigor and motility that make up the cooling curve, and thawing, for analysis of vitality and intact acrosomal membrane, it was observed that there was no significant difference between treatments. Besides, after thawing, the BTS showed better results of sperm vigor, sperm motility and membrane functionality. However, the cooling curve and coconut water powder can be used in the protocol for cryopreservation of boar semen, as both ensured quality of sperm viability that may be used in artificial insemination. | Resumo A criopreservação seminal apresenta baixos resultados produtivos. Objetivou-se testar a Água de Coco em Pó (ACP-103®) como diluente de ressuspensão após a descongelação seminal e avaliar a qualidade espermática durante a curva de resfriamento até a descongelação do sêmen. Para isso, o sêmen de 15 reprodutores foi coletado uma vez por semana, incubado a 30 ºC por 15 minutos, e em seguida diluído em Beltsville Thawing Solution - BTS (controle) ou em ACP-103®, e submetidos a uma curva de resfriamento lenta, onde foram feitas análises de vigor e motilidade em cada passo. O sêmen descongelado foi ressuspenso em seus respectivos diluentes e analisado quanto às características: vigor, motilidade, vitalidade, integridade acrossomal e funcionalidade da membrana. Durante as análises de vigor e motilidade que compõem a curva de resfriamento, e na descongelação, para as análises de vitalidade e membrana acrossomal intacta, observou-se que não houve diferença significativa entre os tratamentos. Já após a descongelação, o BTS apresentou melhores resultados de vigor, motilidade espermática e funcionalidade da membrana. No entanto, a curva de resfriamento e o ACP-103® podem ser utilizadas no protocolo de criopreservação do sêmen suíno, visto que ambas asseguraram qualidade da viabilidade espermática.

The effects of four different blanching methods - boiling water, steam, stepwise, and a mixed method microwave followed by boiling water on the texture and ascorbic acid content of frozen white asparagus were compared. The results showed that microwaving followed by boiling water yielded a more acceptable and uniform product texture, shortening blanching time and reducing ascorbic acid losses. Slow rates are the best method to thaw precoocked frozen asparagus.

"La cadena del frio es parte importante en la inocuidad de los alimentos, donde son substanciales los procesos de conservación por congelación, sin embargo, la etapa efectiva de congelación solo se ha considerado como una parte insignificante de todo el proceso; la mayoría de los estudios se han enfocado a los efectos provocados por la misma o durante el almacenamiento y/o transporte, pero las explicaciones relacionadas con una negativa a la recongelación, centran su enfoque a cambios principalmente microbiológicos y no en sí a lo que sucede en el proceso de cambio de fase del agua. Así mismo, se sabe que el efecto de la formación de escarcha superficial en alimentos y específicamente en carne, debe ser considerada como parte de la aplicación de la cadena del frio en productos congelados, ya que modifica las propiedades termofísicas importantes que perturban la transferencia de calor durante la congelación. En la revisión bibliográfica se presentan los tópicos relacionados con la carne, desde una perspectiva económica, de composición y de los daños propiciados por una inadecuada conservación; por otro lado se presentan fundamentos de la congelación o cristalización del agua en la carne, así como los procesos térmicos y termodinámicos involucrados, entre otros puntos. En la metodología se describen las acciones experimentales que permitieron llevar a cabo la investigación. En este trabajo, se evaluó el cambio de los parámetros termodinámicos en condiciones no isotérmicas y cuasi isotérmicas para establecer las transiciones más importantes en la carne fresca, congelada, recongelada y sus derivados liofilizados hidratados; se adaptaron una serie de criterios no convencionales en el área de alimentos, como es el Cp complejo y el ángulo de fase, que nos hacen confirmar la presencia de cambios en la proteína de la carne por efecto de la congelación y recongelación. Se comparó el efecto de dos velocidades de congelación, lenta en cámara de congelación por convección forzada y rápida por contacto indirecto con nitrógeno líquido, sobre cambios en proteínas (proteína total, enzimas y mioglobina) con técnicas rápidas de análisis y se confirmó el efecto de los tratamientos térmicos a bajas temperaturas por comparación en el infrarrojo cercano. En la última parte se consideró importante determinar el deterioro de la carne desde un punto de vista microscópico, como un daño estructural en las fibras de carne por efecto de la congelación; macroscópicamente, como el color, el brillo y la reflectancia, asemejando lo que puede ser perceptible por el ojo humano. Estas variables fueron influenciadas por la escarcha que se formaba en la superficie por lo que, durante la congelación con fluctuación de temperatura, fue medido el espesor y determinadas las propiedades termofísicas que afectan directamente a los cambios microestructurales. Así mismo se adaptó una secuencia de análisis de textura estadística, basada en imagen, para determinar el efecto de las estructuras superficiales formadas en la escarcha. Todas estas actividades fueron encaminadas a demostrar el efecto de las malas prácticas durante la congelación, dando respuesta científica y tecnológica; además para explicar y fundamentar los aspectos termodinámicos y termofísicos relacionados con la aplicación del método de conservación." | Traditionally has been referred to the cold chain is an important part in food safety; however, the effective freezing stage is only considered as an insignificance part of the whole process. Many studies have focused on the frozen effects caused during storage or transport. The associated explanations relating to a refusal to the re-freezing practice focus its approach to microbiological changes not whether to what happens in the water phase change process. Likewise, it is known that the effect of surface frost formation in food and specifically in meat, must be considered as part of the cold chain implementation, that modifies important thermo physical properties, which disrupt the heat transfer during freezing. The literature review presents the topics related to meat, from an economic perspective, composition and damages propitiated by inadequate preservation. On the other hand, presents the meat water freezing and crystallization fundamentals, as well as the involved thermal and thermodynamics processes, among other things. The methodology describes the experimental procedures that allowed carrying out the research. In this work, the changes in thermodynamic parameters, in non-isothermal and quasi isothermal conditions, was assessed to establish the most important transitions in the fresh, frozen, re-freezing meat and their freeze-dried hydrated; a series of not conventional criteria in the food area, as it is the complex Cp and the phase angle, were adapted, confirming the presence of changes in the meat protein caused by the freezing and refreezing process. The effects of two freezing rate on the changes in proteins (total protein, enzymes and Myoglobin) were compared: the slow rate by a freeze chamber with forced convection, and quick rate by indirect liquid nitrogen contact. The analyses were made with quick techniques and to confirm the low-temperature treatments effects, were used the near-infrared spectroscopy. In the latter part, it was considered important to determine the meat deterioration from a microscopic point of view, such as structural damage to meat fibres by the freezing effect; macroscopically, such as color, brightness and the reflectance, similar to what may be perceived by the human eye. These variables were influenced by the frost formed on the surface, and during the freezing with temperature fluctuation, the thickness was measured and determined the thermo physical properties that directly affect the microstructural changes. Likewise, an analysis sequence for statistical texture, based on image, were adapted to determine the effect of surface structures formed in the frost. All these activities were aimed at demonstrating the effect of bad freezing practices, providing a scientific and technological response; in addition to explain and substantiate the thermodynamic and thermo physical aspects relating to the implementation of the preservation method.

Water availability and management issues related to the supply of drinking water in northern communities are problematic in Canada. While rivers and lakes are abundant, they are vulnerable to contamination and may become dry in winter due to freezing. Groundwater can often provide a more secure and sustainable water source, however its availability is limited in northern Canada due to the presence of permafrost. Moreover, the exploitation of northern aquifers poses a dual challenge of identifying not only permafrost-free areas, but also permeable areas which will allow groundwater recharge and exploitation. Suitable aquifers are not as common in northern Canada since the shallow subsurface is mostly composed of low-permeability crystalline rocks or unconsolidated sediments of glacial origin that are highly heterogeneous. In order to investigate groundwater occurrence and associated geological contexts in Nunavik (northern Quebec, Canada), along with exploring how these resources will evolve in response to climate change, field and compilation work were conducted in the surroundings of the four villages of Salluit, Kuujjuaq, Umiujaq and Whapmagoostui-Kuujjuarapik. These villages are located in different permafrost zones, ranging from continuous to discontinuous, as well as in different geological environments. It was found that despite the ubiquitous presence of permafrost, unfrozen aquifers could be identified, which suggests that groundwater may be available as a source of drinking water for small communities. Expected climate change, with predicted permafrost thawing and increases in temperature and precipitation, should enhance groundwater availability and may contribute to a more secure source of drinking water for northern communities.