Mestrado em Controlo de Qualidade / MSc in Quality Control

Mestrado em Controlo de Qualidade / MSc in Quality Control

Mestrado em Controlo de Qualidade / MSc in Quality Control

Mestrado em Controlo de Qualidade / MSc in Quality Control

Mestrado em Controlo de Qualidade / MSc in Quality Control / O principal objectivo do trabalho apresentado na presente dissertação foi a implementação de um sistema “lab-on-valve” (LOV) associado ao conceito de “bead injection” aplicado à extracção em fase sólida de compostos fenólicos presentes em amostras alimentares, seguida pela quantificação através do método de Folin-Ciocalteu. Foi desenvolvido um ciclo analítico automático contendo as principais etapas do processo de extracção em fase sólida, incluindo neste caso também a formação da coluna de adsorvente OASISTM HLB num dos canais do dispositivo LOV. Foi efectuada a avaliação da retenção dos compostos na coluna utilizando o ácido gálhico como composto modelo. Neste caso foi avaliada a influência da composição da matriz da amostra e da solução transportadora usada na remoção da matriz. Também foi avaliada a eficiência da eluição recorrendo a distintos eluentes. A utilização de padrões acidificados com HCl 10 mM, o uso de água com transportador e a utilização da solução eluente composta por metanol 50% (v/v) + hidróxido de sódio 10 mM foram as condições escolhidas para posterior aplicação à amostras. O procedimento automático desenvolvido foi aplicado a outros compostos fenólicos (ácido cafeico, galhato de octilo, quercetina e ácido tânico), a um composto não-fenólico (ácido ascórbico), reactivo e quantificável pelo método de Folin-Ciocalteu, e a amostras de vinho tinto e sumo de laranja. Os resultados obtidos para os compostos testados evidenciaram a retenção selectiva dos compostos fenólicos e a não-retenção do ácido ascórbico, tendo sido possível estimar a contribuição dos compostos fenólicos na capacidade redutora das amostras através do método de Folin-Ciocalteu. / The main objective of the work presented in this dissertation was the development of a lab-on valve (LOV) system associating the bead injection concept for application to solid phase extraction of phenolic compounds in food samples, followed by their quantification using the Folin-Ciocalteu method. An analytical cycle comprising the main steps present on solid phase extraction protocols was implemented, including also the on-line formation of OASISTM HLB sorbent column inside one of the channels of LOV device. The retention of phenolic compounds on this sorbent was evaluated using gallic acid as model analyte under different sample matrix and carrier solution compositions. Elution efficiency was also assessed for different eluents. Application to samples was attained using standard solutions prepared in HCl 10 mM, water as carrier and methanol 50% (v/v) + sodium hydroxide 10 mM as eluent. The automatic protocol was applied to several phenolic compounds (caffeic acid, octylgallate, quercetin and tannic acid), to a non-phenolic compound (ascorbic acid), which reacts with and can be quantified by Folin-Ciocalteu method, and also to red wine and orange juice samples. Results obtained showed that phenolic compounds were retained selectively and ascorbic acid was not retained, which allowed the estimation of phenolics contribution to the Folin-Ciocalteu reducing index for antioxidant assessment.

Mestrado em Controlo de Qualidade / MSc in Quality Control

Water is a critical resource that is essential for human well-being and economic development. Many regions around the world face ongoing water scarcity and competition over water resources. Climate change, other drastic social changes, and population and economic growth can significantly impact the supply and consumption of water. There has been an increasing body of research focusing on the Food-Energy-Water (FEW) nexus. There is a mismatch between the spatial resolution of data availability and the resolution that water resources follow. Lack of quality sub-county water data also makes the research of micro-level food-water dynamics difficult if not impossible. These challenges pose obstacles to the further understanding of water scarcity in the context of the FEW nexus and leaves critical gaps in the research of the nexus. In this dissertation I asked and answered the question: how do socio-economic forces shape localized groundwater depletion and surface water scarcity within the United States at the field and basin scale? Specifically, I tested whether irrigated farm size leads to reduction in groundwater application per unit area and whether an increase in the annual depletion in the underlying aquifer storage increases the probability of an irrigated land transfer, with a Kansas field level dataset and an econometrics approach. I estimated the FEW production and the water footprint of FEW production in every US watershed and compare the water footprint of production against their water scarcity. Then the groundwater reserves and dam storage in watersheds were examined as the buffers for the watersheds' FEW production against water shortages. I mapped the transfers of FEW goods and services and both the virtual and physical water flows from watersheds to US cities. The transportation infrastructure and other infrastructure that supports the FEW transfers are analyzed in terms of their contributions to the movement of FEW goods. This dissertation improves our understanding of how broad structural changes within the agricultural industry are interconnected with the overexploitation of groundwater resources. It is the first study of water footprint accounting with the most recent input data for the whole US food-energy-water system at the watershed level and includes an analysis of cities' infrastructure reliance for food-energy-water transfers and infrastructure as buffers. The transfers of virtual water and physical water were compared. The resulting data and findings from the novel data synthesis will provide insights for consumers, food companies, and other decision-makers at various levels on their connection to water resources in non-local areas. The outcomes of this dissertation will also improve our ability to analyze drivers and solutions to local small-scale watershed water scarcity challenges and allow a quantifiable basis for policy support in the water resources management domain and beyond. / Doctor of Philosophy / Water is an important resource for humans and the economy, but many regions around the world face ongoing water shortages and competition over the limited water resources. The Food-Energy-Water (FEW) nexus has gained increasing attention as a framework for understanding the complex relationships between water, food, and energy systems. However, research in this area has faced challenges in data availability and data resolution. This dissertation addresses these challenges while exploring how socio-economic forces shape localized groundwater depletion and surface water scarcity within the United States at the field, basin, and city scales. The author tests hypotheses related to irrigated farm size, irrigation water use, groundwater depletion, and the irrigated land transfers. The author estimates the FEW production and water footprint of production in every US watershed. The author also tracks and analyzes the transfers of FEW goods and services and embedded water footprint. Infrastructure's role in delivering FEW goods and buffering against water shortages were also examined. Overall, this dissertation provides insights into the connections between water resources and broad structural changes within the food system, and offers a novel data synthesis that can facilitate the understanding of connections between production and consumption of FEW at various spatial scales and water resources in local and non-local areas. The findings will also help analyze the drivers and solutions to local small-scale watershed's water scarcity challenges, and provide a quantifiable basis for policy support in the water resources management domain and beyond.

Demand for both food and water are projected to increase substantially in the next four decades. Water scarcity is also projected to increase in scale and complexity. Climate change is projected to increase temperatures, spatio-temporal variability in rainfall, frequency and severity of droughts and soil water stresses to crops. Due to the crucial role of water in crop growth and yield formation, prolonged or severe soil water deficits in crop producing areas can result in substantial yield penalties. The potential of food trade to help address food insecurity as a result of insufficient water availability for crop production has been rationalized in the virtual water concept. The aim of this thesis was to improve the evidence base for understanding and evaluating the relationships between future water availability for crop production and food trade (or virtual water flows), and the utility of the virtual water concept to inform policy and management decisions on water-food security. The UK and barley were used as a model country and crop, respectively. Three crop growth simulation models (AquaCrop, CropWat and WaSim) were evaluated for their abilities to estimate the water use of 10 barley genotypes. Subsequently, the effect of projected climate change on UK barley yields in the 2030s, 2040s and 2050s was simulated using the high, medium and low emission scenarios data from the UK Climate Projections 2009 (UKCP09). Projections of total UK feed barley supply and demand were performed to quantify potential virtual water flows and to analyse the implications for food security and policy. The results show that the predicted water use of barley differed between the models but not among the genotypes. Predicted seasonal water use of the barley genotypes ranged from 241.4 to 319.2 mm. Based on the root mean square error (RMSE) and the index of agreement (D-Stat) values, CropWat performed poorly while AquaCrop and WaSim performed excellently. Barley yields under projected climate change increased substantially over baseline yields in all UK regions. Projected mean barley yields for the UK ranged from 6.04 tons ha-1 (2030s) to 7.77 tons ha-1 (2050s). In spite of the projected increase in yields, the UK faces the risk of large deficits in feed barley and meat supply from the 2030s to the 2050s due to a combination of population growth, increased per capita meat demand and reductions in land area allocated to barley production. Finally, current water scarcity concepts were found to be incompatible with water availability and consumption in crop producing areas, a situation that diminishes the usefulness of the virtual water concept for policy. To address this deficiency, a framework for making water scarcity compatible with crop production was proposed. In conclusion, the poor performance of CropWat has implications for its wider use in quantifying global virtual water flows associated with crop trade. Even though UK barley yields are projected to increase under projected climate change, the projected deficits in feed barley and meat supply threatens to destabilize future UK food security. The UK can rely on import to offset the large deficits in feed barley and meat supply but can use the proposed framework to reduce the effect of its imports on water scarcity in the exporting countries. The proposed framework improves understanding and evaluation of the role and usefulness of the virtual water concept in water-food security policy and management decisions.

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<p>The Food-Energy-Water (FEW) nexus conceptualizes the interactions and tension between production and consumption of food, energy, and water. With increasing uncertainties due to climate change, there is a need to address these tensions within the nexus and better comprehend the existing interdependencies and tradeoffs. Water integrity – considering both water availability and quality – is of critical concern within the FEW nexus. Thus, it is important to develop robust decision-making strategies using a FEW nexus lens. This study focuses on addressing water integrity concerns through FEW nexus assessment using an agricultural watershed in northeastern Indiana, with predominantly corn-soybean rotations, as a pilot site. Historical and futuristic climate and hydrological data were used for hydrological modeling using SWAT to quantify water quantity, quality, and crop production. Scientific literature values for farm machinery fuel requirements and their carbon emissions were implemented to obtain values based on the implemented agronomic practices. Results of this study provide methodologies and information that can be implemented to evaluate water resources management, as well as inform policymaking for more sustainable agricultural management practices.</p>