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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
181

Characterisation of groundwater in mainly old and closed landfill sites

Gajree, Meenu January 1999 (has links)
A study is made of the use of chemical analysis of groundwater samples to assess groundwater quality. Samples from forty-seven boreholes within and around ten landfill sites in the London Borough of Hounslow were analysed. Most of the landfill sites studied were filled prior to the implementation of the Control of Pollution Act 1974 and were not designed with environmental protection in mind. Boreholes were tested for methane, carbon dioxide and groundwater samples were analysed for electrical conductivity (EC), ammonium nitrogen (NI14-N), COD, TOC, Cl-, NO3, SO42-, Na+, K+, Ca2+, Ni2+, Cu2+, Pb2+, oxidation - reduction - potential (ORP) and pH. The first ten of these analytical parameters were considered for groundwater quality assessment and the most important selected for more detailed study namely CH4, C02, EC, NH4-N, COD and TOC. Pollution ratings are allocated on the basis of single pollutant analytical data and averaged for each of the bore hole samples. Goodness of fit values between the single analyte values and the average data were calculated and no set of single analyte data was found to provide good groundwater quality assessment. A series of formulae combining the six analyte parameters was considered and the data evaluated by goodness of fit calculations to provide an effective means of assessing groundwater quality. The ratings obtained from the best formula are compared with historical broad band classification of landfill sites and show how sites must be assessed on the basis of samples taken from within the site and not around the perimeter. The production of acetic acid in the acetogenic phase of landfill reactions will increase the leachability and mobility of many metal pollutants and particularly of lead. Studies on the leachability of lead in acetic acid media show how lead solubility is increased in acetic acid media by the formation of triacetatolead(II) species, Pb(CH3CO2)3-.
182

Performance of clinical prediction rules for diagnosis of pleural tuberculosis in a high-incidence setting

Solari, Lely, Soto, Alonso, Van der Stuyft, Patrick 10 1900 (has links)
El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / Objectives: Diagnosis of pleural tuberculosis (PT) is still a challenge, particularly in resource-constrained settings. Alternative diagnostic tools are needed. We aimed at evaluating the utility of Clinical Prediction Rules (CPRs) for diagnosis of pleural tuberculosis in Peru. Methods: We identified CPRs for diagnosis of PT through a structured literature search. CPRs using high-complexity tests, as defined by the FDA, were excluded. We applied the identified CPRs to patients with pleural exudates attending two third-level hospitals in Lima, Peru, a setting with high incidence of tuberculosis. Besides pleural fluid analysis, patients underwent closed pleural biopsy for reaching a final diagnosis through combining microbiological and histopathological criteria. We evaluated the performance of the CPRs against this composite reference standard using classic indicators of diagnostic test validity. Results: We found 15 eligible CPRs, of which 12 could be validated. Most included ADA, age, lymphocyte proportion and protein in pleural fluid as predictive findings. A total of 259 patients were included for their validation, of which 176 (67%) had PT and 50 (19%) malignant pleural effusion. The overall accuracy of the CPRs varied from 41% to 86%. Two had a positive likelihood ratio (LR) above 10, but none a negative LR below 0.1. ADA alone at a cut-off of ≥40 IU attained 87% diagnostic accuracy and had a positive LR of 6.6 and a negative LR of 0.2. Conclusion: Many CPRs for PT are available. In addition to ADA alone, none of them contributes significantly to diagnosis of PT.
183

Measurement, nature and removal of stickies in deinked pulp

Sarja, T. (Tiina) 21 May 2007 (has links)
Abstract Stickies refer to tacky contaminants in recovered paper, excluding wood extractives. Stickies originate from adhesives, ink binders and coating binders. Stickies able to pass a sieve of 100 or 150 μm (depending on standard) are called micro stickies, whereas the particles retained on the screen are called macro stickies. Dissolved and colloidal stickies are called secondary stickies. There are standard methods for macro stickies, but a standard method measuring the total amount of stickies is lacking. Furthermore, the size distribution, and nature of stickies in the sense if they are free particles or agglomerated with some other substances, has not been previously known. The information on the removal of stickies in different unit operations was also not known very well except for macro stickies. The aim of this thesis was thus to develop an analysis method for the total amount of stickies, determine the size distribution and nature of stickies, and find ways to better remove stickies in the deinking process. Extraction with tetrahydrofuran (THF) and High Pressure Liquid Chromatography (HPLC) with Size Exclusion Column (SEC) was used here to separate hydrophobic polymers (stickies) from the pulp suspension. An Evaporating solvent Light Scattering (ELS) detector was utilized to quantify the polymers after SEC. This analysis procedure was used in this thesis to measure stickies. Fractionation of pulp before the analysis was carried out if information of different-sized stickies was desired. The majority of stickies are micro stickies. A significant, although lower, portion of stickies are macrostickies, especially in the beginning of the deinking process. The dissolved and colloidal phase was found to contain wood extractives, and only trace amounts of stickies. Flotation is very effective in stickies removal. Ink and micro stickies were removed nearly equally in flotation, because they both are hydrophobic and are both in an optimal size range for removal in flotation. Ink measurements may be used for estimating the trends of stickies removal in flotation. The stickies removal in flotation may be enhanced by optimizing the pulper chemistry.
184

The Evaulation of test protocols for dispersive soil identification in Southern Africa

Maharaj, Amrita January 2013 (has links)
Dispersive soils are prevalent in many areas of South Africa and the presence of these soils has not only posed a problem in earth dam construction but has led to problems with a number of road projects. The use of dispersive soils in roadway embankments and structures can lead to serious engineering problems if the soils are not accurately identified before use and appropriate mitigation measures taken. Although the causes and consequences of soil dispersion are well understood, the consistent and positive identification of dispersive soils still remains a problem. Many identification methods have been proposed but none has been completely successful. The current tests used for identification include the pinhole, double hydrometer, crumb and chemical tests, which are generally used in combination to obtain the most reliable outcome. These laboratory tests, however, have not always been entirely consistent, either when used in combination or individually, and it is possible that the reason lies in the actual testing procedures. Recent investigations have shown that in many cases the identification and classification problems appear to be related to inconsistencies in the test methods and testing protocols. This has been highlighted recently at various conferences and presentations in South Africa, with a recommendation that the problem be investigated fully. The main objective of this project was thus to carry out a detailed investigation into the current methods used for the testing and identification of dispersive soils. The test methods were thoroughly analysed and shortcomings identified. The differences in results and interpretation resulting from different test techniques are examined and solutions to overcome the problems proposed. A further objective of this study is the assessment of the interpretation of results obtained from dispersive soil chemical analysis. A pilot study was first carried out, which recognized deficiencies in the identification process resulting from problems with the test methods. The pilot study allowed for the identification of these shortcomings in the test methods and their modification. The modified methods were used in the full study to obtain more consistent and reliable results. The study found the pinhole test as well as the Gerber and Harmse (1987) ESP versus CEC chart to be highly unreliable. The double hydrometer and crumb tests are good indicators of dispersivity if carried out accurately and repeatably using a standard test method. The chemical analysis of the soils should be carried out using the standard methods employed by the Soil Science Society of South Africa. Final rating systems were also found to be unreliable since they put a great deal of weight on the poorly reproducible pinhole test. Emphasis is thus put on the test methods being as simple and unambiguous as possible to promote repeatability and reproducibility of the results. Recommendations are finally made proposing a suite of tests as well as a decision process which should be followed when faced with a potentially dispersive soil. This investigation was aimed solely at the evaluation of test protocols and not the suitability or specification of limits for any rating systems. This should now be assessed using the standard test methods proposed in this thesis. / Dissertation (MSc)--University of Pretoria, 2013. / gm2014 / Geology / unrestricted
185

The petrogenesis of the volcanic rocks of the Witwatersrand triad in the Klerksdorp area, Transvaal

Bowen, Michael Peter January 1985 (has links)
Several hundred chemical analyses of early Proterozoic lavas of the Witwatersrand triad (incorporating the Dominion Group, Witwatersrand Supergroup and Ventersdorp Supergroup) in the Klerksdorp area, have revealed the presence of various distinct magma types. These essentially correspond to formally defined lithostratigraphic units, but several inconsistencies have necessitated the use of informal nomenclature. The lavas have been regionally metamorphosed to low-grade, greenschist facies assemblages. Original igneous textures are preserved, despite a metamorphic overprint. Metamorphism has resulted in a certain degree of random chemical remobilization. Ba, Sr, Rb, K₂0, Na₂0 and CaO have been highly mobile, and their usefulness in petrogenetic modelling is extremely limited. In contrast, Zr, Nb, Y, LREE's, Cr, Ni, Ti0₂ P₂0₅ and Al₂0₃ have remained immobile. Ti/Zr and Ti/P ratios together constitute efficient discriminating variables for characterizing the different magma types. Lava compositions range from primitive Mg-rich tholeiites to rhyolites, the bulk being tholeiitic andesites. Al₂0₃ contents do not exceed 15%, a feature which reflects the tholeiitic, as opposed to calcalkaline, character of these lavas. Two magma-types are present within the Dominion Group, which is a typical example of bimodal volcanism. The Dominion basic lavas are overlain by the Dominion acid porphyries, with a limited amount of interfingering. The basic lava suite is highly fractionated, with compositions ranging from Mg-, Cr- and Ni-rich tholeiites (close to primary mantle melts) to evolved tholeiitic andesites. The most primitive liquids evolved by 45% fractional crystallization of hornblende, followed by a further 70% crystallization of an orthopyroxene-plagioclase assemblage containing up to 3% sulphides. The Dominion porphyries are rhyolitic, display very limited compositional variation, and probably represent a crustal melt related to the same magmatic event which produced the basic lavas. The only lavas from the Witwatersrand Supergroup present in the Klerksdorp area are those of the Crown Formation (Jeppestown amygdaloid). These are tholeiitic dacites which display extremely limited compositional variation, and are unrelated to any of the other magmas of the Witwatersrand triad. The Ventersdorp Supergroup comprises 4 magma-types: The Kliprivierberg Group lavas at the base are subdivisible into 3 sub-types on the basis of Zr contents. (Zr>11Oppm) are the most evolved. They are tholeiitic andesites which display fairly limited compositional variation. It is likely that more evolved compositions are present in other areas where the porphyritic lavas which characterize this unit are better developed. The overlying Orkney lavas are characterized by 110ppm>Zr>90ppm. They are tholeiitic andesites of similar composition to the Alberton lavas, but have lower incompatible element levels, higher siderophile element levels, and are of extremely uniform composition. The uppermost Loraine/Edenville lavas range from magnesian tholeiites to tholeiitic andesites. They are distinguished by Zr< 90ppm, and contain the most primitive magmas af the Witwatersrand triad, with up to 17,5% MgO, 2600ppm Cr, 600ppm Ni and M-values up to 77. The most primitive liquids evolved by 38% fractional crystallization of orthopyroxene ∓ chromite, followed by 35% fractional crystallization of an extract containing clinopyroxene and plagioclase. The absence of olivine precipitation is a result of the inherently high Si0₂ content of the magma. The Loraine/Edenville, Orkney and Alberton lavas do not lie on a common liquid line of descent, but are probably consanguinous. The Platberg Group overlies the Kliprivierberg Group, and has a coarse-clastic sedimentary unit, the Kameeldoorns Formation, at the base. Three petrographically distinct porphyritic lava sequences overlie the Kameeldoorns Formation, namely the informal "Goedgenoeg formation", the Makwassie quartz-feldspar porphyries and the Rietgat Formation. Despite petrographic differences, the Goedgenoeg and Rietgat lavas are chemically indistinguishable and thus form a single magma-type. The Makwassie porphyries are dacitic in composition with a high proportion of feldspar and quartz phenocrysts. Rational variation trends are attributed to a nett loss of Si0₂ during secondary alteration. The porphyries are probably of crustal origin. The Goedgenoeg/Rietgat lavas display unusual chemistry and a broad, irrational compositional spectrum. They contain very high incompatible element levels, high nonnative quartz, as well as high MgO, M-values, Cr and Ni relative to the other tholeiitic andesites of the Witwatersrand triad. It is tentatively suggested that they are hybrid magmas containing both crust and mantle components, the former possibly represented by the Makwassie porphyries. Field evidence suggests that Platberg volcanism commenced directly after Klipriviersberg volcanism ceased, and was accompanied by a period of enhanced tectonic activity. The Platberg lavas thus probably reflect a crustal melting cycle associated with the Klipriviersberg magmatic event. The Allanridge lavas are the youngest rocks of the Witwatersrand triad. They are separated from the Platberg Group by a unit of flat-lying sediments, the Bothaville Formation, which was deposited after an extended period of peneplanation. The Allanridge lavas form a separate magma-type. They are tholeiitic andesites of similar composition to the Alberton lavas, but have higher incompatible element levels and are not consanguinous. The compositional similarities amongst the basic magma-types of the Witwatersrand triad suggests that all were generated in an hydrous mantle. Interelement ratio differences between the various magma-types nevertheless support the concept that the mantle was chemically heterogeneous during the early Proterozoic.
186

Caracterização química e atividade biológica de senna alata l. Roxb e senna siamea

SILVA, Grace Kelly Cordeiro Da 23 August 2013 (has links)
Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2017-07-14T19:14:08Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) DISSERTAÇÃO - GRACE KELLY C. DA SILVA Final.pdf: 3244075 bytes, checksum: 27d5c4bb143cedbc4228d134925e8b5a (MD5) / Made available in DSpace on 2017-07-14T19:14:08Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) DISSERTAÇÃO - GRACE KELLY C. DA SILVA Final.pdf: 3244075 bytes, checksum: 27d5c4bb143cedbc4228d134925e8b5a (MD5) Previous issue date: 2013-08-23 / O uso de produtos naturais na medicina popular como agente terapêutico é conhecido por praticamente todas as civilizações antigas. O gênero Senna Mill, é uma importante fonte de substâncias com grande diversidade estrutural, sendo atualmente utilizada como laxantes e purgativas. Diante disso, este trabalho teve como objetivo caracterização química e atividades biológicas do extrato bruto metanólico das folhas de Senna alata L. Roxb e Senna siamea (Lam.). O perfil fitoquímico foi realizado em cromatografia de camada delgada, com diferentes fases móveis e reveladores. A extração do óleo essencial foi utilizada por hidrodestilação e analizado em cromatografia gasosa acoplada ao espectro de massa (CG/MS). A atividade larvicida do óleo essencial foi avaliada segundo o método recomendado pela Organização Mundial de Saúde, adaptado. A atividade antimicrobiana foi realizada pelo método de difusão em Agar, e identificação da concetração inibitória mínima. Os métodos de Mosman (1983) e Costa-Lotufo et al. (2002) foram utilizados para analisar a atividade hemolítica e citotóxica, respectivamente. O potencial de toxicidade aguda foi avaliado segundo a OECD 423. A metodologia de Rao et al., 1997, modificada, foi utilizado para análise da atividade laxante. A caracterização fitoquímica evidenciou os seguintes metabólitos: açucares redutores; flavonóides; antraquinonas, triterpenos, cumarinas, monoterpenos e sesquiterpenos, proantocianidinas e leucoantocianidina. Após análise em CG/MS, 03 (três) compostos foram identificados: ácido n-hexadecanóico, fitol e 9,12,15- ácido octadecatrienóico (Z,Z,Z). O óleo essencial da S. siamea não apresentou atividade larvicida. Não foi evidenciada atividade antimicrobiana do extrato bruto metanólico das folhas (EBMF) de S. siamea. Entretanto o EBMF de S. alata apresentou atividade moderada contra B. subitilis (AM04), e baixa atividade contra S. aureus (AM103) e S. aureus (AM1210). Ambos os extratos se mostraram inativos frente à atividade hemolítica e citotóxica. Na toxicidade aguda não houve óbito dos animais após administração da dose 2000mg/kg, com isso, ambos os extratos são considerados atóxicos ou baixa toxicidade. O Extrato metanólico bruto das folhas (EMBF) de S. siamea e S. alata, nas doses de 62,5mg/kg, 125mg/kg e 250mg/kg, não apresentaram atividade laxante. Estudos mais aprofundados dos extratos são necessários para garantir a segurança e eficácia terapêutica dos mesmos. / The use of natural products in folk medicine as a therapeutic agent is known by virtually all ancient civilizations. The genus Senna Mill, is an important source of substances with great structural diversity, being currently used as laxatives and purgatives. The objective of this work was to characterize the chemical and biological activities of the crude methanolic extract of the leaves of Senna alata L. Roxb and Senna siamea (Lam.). The phytochemical profile was performed in thin layer chromatography, with different mobile phases and developers. The extraction of the essential oil was used by hydrodistillation and analyzed by gas chromatography coupled to the mass spectrum (CG / MS). The larvicidal activity of the essential oil was evaluated according to the method recommended by the World Health Organization, adapted. The antimicrobial activity was performed by the agar diffusion method, and identification of minimal inhibitory concentration. The methods of Mosman (1983) and Costa-Lotufo et al. (2002) were used to analyze the hemolytic and cytotoxic activity, respectively. The acute toxicity potential was evaluated according to OECD 423. The methodology of Rao et al., 1997, modified, was used to analyze the laxative activity. The phytochemical characterization showed the following metabolites: reducing sugars; Flavonoids; Anthraquinones, triterpenes, coumarins, monoterpenes and sesquiterpenes, proanthocyanidins and leucoanthocyanidin. After analysis in CG / MS, 03 (three) compounds were identified: n-hexadecanoic acid, phytol and 9,12,15-octadecatrienoic acid (Z, Z, Z). The essential oil of S. siamea showed no larvicidal activity. There was no evidence of antimicrobial activity of the crude methanolic leaf extract (EBMF) of S. siamea. However, S. alata EBMF showed moderate activity against B. subitilis (AM04), and low activity against S. aureus (AM103) and S. aureus (AM1210). Both extracts were inactive against hemolytic and cytotoxic activity. In acute toxicity, the animals did not die after administration of the 2000mg / kg dose, with both extracts being considered nontoxic or low toxicity. The crude methanolic extract of the leaves (EMBF) of S. siamea and S. alata, at doses of 62.5mg / kg, 125mg / kg and 250mg / kg, presented no laxative activity. Further studies of extracts are necessary to ensure the therapeutic safety and efficacy of the extracts.
187

Identificação de genes com variação de expressão durante o amadurecimento da banana pela aplicação de técnicas de análise diferencial / Identification of genes with variation of expression during ripening of the banana by the application of differential analysis techniques

Adriana de Godoy 26 July 2006 (has links)
No amadurecimento ocorrem alterações bioquímicas que têm impacto nas características organolépticas dos frutos, tais como cor, sabor, odor, maciez, etc e também na composição química com reflexos no valor nutricional. Nesse processo altamente coordenado, em que enzimas são sintetizadas de novo, a expressão gênica desempenha um papel importante em seu controle. Porém no que tange a frutos tropicais, em especial a banana (fruto de estudo), as informações relativas ao controle de expressão gênica, se restringem a algumas enzimas-chave. Assim sendo, uma abordagem ampla, e não restrita somente a alguns genes, pode contribuir para o entendimento da regulação de algumas etapas metabólicas do amadurecimento. Deste modo, o objetivo desse trabalho foi identificar genes com variação de expressão durante o amadurecimento da banana. O trabalho experimental foi feito com dois tipos de amostras, uma referente ao período pré-climatérico e a outra ao climatérico. Para tanto, foram utilizadas duas técnicas com princípios diferentes: \"differential display\" RT-PCR e a biblioteca de subtração de cDNA, de modo a otimizar e ampliar a possibilidade de se obterem genes diferentes, e que, por ventura, fossem obtidos por uma técnica, mas não por outra. Ambas metodologias tiveram como ponto de partida a extração de RNA de amostras de banana referentes aos dois períodos em estudo. Ao utilizar a técnica \"differential display\" RT-PCR foram obtidos nove genes com variação de expressão, quatro com aumento de expressão em bananas pré-climatéricas, similares à imunofilina, translocador de adenina nucleotídeo, proteína de cloroplasto e proteína bacteriana e cinco com aumento de expressão no período climatérico, similares à aquaporina, legumina, desoxiguanosina quinase, NADH dehidrogenase e proteína bacteriana. Com a biblioteca de subtração de cDNA foram obtidos cinco genes com aumento de expressão em bananas climatéricas, os quais foram similares à expansina, omega-3-desaturase, taumatina, NADH mitocôndrial e metalotioneína. / During ripening many biochemistry modifications have impact in organoleptical characteristics of fruits, like colour, flavor, softness, etc and also in chemical composition (nutritional value). In this process highly coordinated, which enzymes are de novo synthesize, genic expression has an important role in this control. However, in tropical fruits, especially banana (fruit choosen), some information relative to gene expression control, are restrict to some key enzymes. An approach, not only restrict to some genes, can contribute to understand some ripening metabolic steps. So, the objective ot this work was obtain and identify genes with altered expression in banana ripening, defining two analysis fases, about respiratory period and ethylene pick. The experimental work used two kinds of sample, one of them before climateric period and the other after climateric period. They were applied two tecniques with different principle: differential display RT-PCR and cDNA subtraction library, to optimize and increase the possibility to obtain different genes, and which can be obtain by one technique but not in other. Both metodologies had the same first step, the RNA extraction. Following, genes with altered expression were obtained, identified and confirmed. In differential display RT-PCR were obtained nine genes, four of them had an increase of expression before climateric bananas and they were similar to immunophilin, adenine nucleotide translocator, chloroplast protein and bacterial protein and five with an increase of expression after climateric which were similar to aquaporin, legumin, desoxiguanosine quinase, NADH dehydrogenase and bacterial protein. Using cDNA subtraction Iibrary were obtained five genes with an increase of expression in post-climateric bananas and these sequences were similar to expansin, omega-3-desaturase, thaumatin, NADH mithocondrial and methalotionein.
188

Composição físico-química e nutricional do mel adicionado com própolis / Physico-chemical composition and nutritional of the honey added with propolis

Alexandre Bera 04 May 2004 (has links)
O presente estudo teve, como objetivo principal, a determinação da composição físico-química e nutricional de onze amostras de méis com própolis comercializados no Estado de São Paulo, de acordo com as metodologias analíticas da legislação brasileira vigente (Instrução Normativa nº11 de 20 de outubro de 2000), que segue os métodos preconizados pelos Codex Alimentarius Commission (CAC), 1990 e Association of Official Analytical Chemists (AOAC), 1990). Amostras de mel puro e de própolis foram usadas como referência. Os resultados mostraram que os mesmos métodos usados para o controle de qualidade do mel puro (umidade, HMF, açúcares redutores, sacarose aparente, cinzas, acidez livre, sólidos insolúveis em água) foram adequados para o controle de qualidade do mel com própolis, exceto pela analise de atividade diastásica, que precisou de uma adaptação metodológica. A análise de minerais demonstrou que essas amostras não são fontes de ferro, magnésio, zinco e cálcio. A própolis adicionada ao mel aumentou o seu valor energético comparado com o mel puro. Cinco das onze amostras analisadas não apresentaram, na sua rotulagem, os valores nutricionais como recomenda a legislação. É indicada a necessidade de uma fiscalização mais rigorosa, assim como uma legislação específica para o controle de qualidade destes produtos. / The present work has, as its main objective, to determine the physico-chemical and nutritional composition of commercial samples of propolis added to honey from São Paulo State. Eleven honey-propolis samples were analyzed, according to the methods established by the Brazilian Law (Instrução Normativa n.11 de 20 de outubro de 2000) which recommends the same methods established by Codex Alimentarius Commission (CAC) and the Association of Official Analytical Chemists (AOAC, 1990). The results showed that the same methods used for pure honey quality control (moisture, HMF, reducing sugars, apparent sucrose, ash, free acidity, insoluble solids in water) except for the diastase activity which had to be adapted, can also be used for the honey-propolis quality control. The mineral analyses results showed that the samples were not a good source for iron, magnesium, zinc and calcium. Honey has its energy value enhanced by the addition of propolis if compared with pure honey. As five of the eleven samples analyzed did not have the nutritional values information on the labels as it is mandatory by the Brazilian Legislation, a more rigorous inspection and even a specific law should be established for the quality control of those products.
189

Cerveja envelhecida em barril de madeira, aspectos químicos e microbiológicos / Aged beer in wooden barrels, chemical and microbiological aspects

Luís Henrique Poleto Angeloni 18 November 2015 (has links)
Nas últimas décadas, houve um aumento do consumo de cerveja no Brasil e no resto do mundo. Existem diversos conceitos e metodologias que diferenciam os estilos de cerveja, sejam nas modificações dos processos de produção, uso de diferentes ingredientes, fermentações em fermentadores de diferentes tipos, metodologias de envase, utilização de madeira na maturação da bebida, entre outros. Paralelamente à evolução dos conhecimentos científicos em Microbiologia, tais como, o crescente entendimento da fisiologia celular, as técnicas de imobilização da levedura cervejeira e o isolamento de novas estirpes que fornecem características aromáticas diferenciadas às cervejas. O armazenamento de bebidas em barris de madeira é amplamente utilizado desde a antiguidade na produção de bebidas, seja na forma de armazenamento e no aumento da complexidade do produto. O objetivo desta pesquisa foi avaliar a formação de alguns compostos aromáticos durante o envelhecimento de cerveja tipo Flanders Red Ale em barris de madeira, levando em consideração aspectos químicos e microbiológicos tais como: congêneres de maturação analisando os conteúdos de compostos fenólicos de baixo peso molecular determinados por cromatografia líquida de alto desempenho, congêneres voláteis (aldeídos, ésteres e álcoois superiores) determinadas por cromatografia em fase gasosa e as propriedades microbiológicas da cerveja como viabilidade celular, meios de cultivo diferenciados para isolamento de levedura totais, bactérias ácidos acéticas, bactérias láticas e meio modificado para isolamento de Brettanomyces. O estudo foi realizado nas dependências da microcervejaria do Departamento de Agroindústria, Alimentos e Nutrição da Escola Superior de Agricultura Luiz de Queiroz, Piracicaba (SP). A fermentação primária do mosto cervejeiro foi conduzida à 23°C em fermentador cilíndrico cônico de inox, após refrigeração a 0°C por duas semanas a cerveja foi armazenada em barris (50 litros) de carvalho americano à 25°C por três e cinco meses. Após a maturação, uma cerveja nova (Young Ale) foi produzida e misturada (Blend) com a cerveja envelhecida em diferentes proporções: cerveja Young Ale; blends com 33% e 66% de cerveja envelhecida; 100% cerveja envelhecida, após os Blends, as cervejas foram engarrafadas e armazenadas por um período de três meses para início das análises químicas, microbiológicas e sensoriais. Ocorreram alterações químicas e microbiológicas que favoreceram o aumento da complexidade da cerveja após passar por um período de armazenamento em barril de carvalho, sendo que, essa alteração foi maior proporcionalmente ao aumento do tempo de armazenamento da cerveja. / In recent decades, there has been an increase in beer consumption in Brazil and around the world. There are many methodologies and concepts that differentiate styles of beer, are the modifications of the production processes, use of various ingredients fermentations in fermenters of different types of packaging methodologies, wood use in beverage maturation, among others. Parallel to the development of scientific knowledge in microbiology, such as the growing understanding of cellular physiology, the immobilization techniques of brewing yeast and isolation of new strains that provide aromatic characteristics differentiated the beers. The storage of drinks in wooden barrels is widely used since antiquity in the production of drinks. The objective of this research was to evaluate the formation of some aromatic compounds at Ale type beer aging in wooden barrels, taking into account chemical and microbiological aspects such as: maturation of similar analyzing the content of phenolic compounds of low molecular weight determined by chromatography high performance liquid volatile counterparts (aldehydes, esters and higher alcohols) determined by gas chromatography using a flame ionization detector and microbiological properties of beer analyzing cell viability, different culture media for total yeast, bacteria acetic acid, Lactic acid bacteria and growth medium modified to Brettanomyces. The study was conducted in the microbrewery premises of the agribusiness department, food and nutrition Luiz de Queiroz College of Agriculture, Piracicaba (SP). The primary fermentation was conducted at 23° C in tapered cylindrical stainless steel fermenter after cooling to 0° beer was stored in barrels (50 liters) American oak at 25° C for three and five months. After maturation, a new beer (Young Ale) was produced and blended (blend) with the aged beer bottled and stored for analysis. After maturation, a new beer (Young Ale) was produced and mixed ( Blend ) with the beer aged in different proportions : Young beer Ale ; blends of 33 % and 66 % of aged beer; 100 % aged beer, the beers were bottled and stored for a period of three months to the beginning of the chemical, microbiological and sensory analysis. Microbial and chemical chenges accurred that favored increased complexity of the beer after passing through a storage period in oak barrel, and that changes was greater in proportion to the increase beer storage time.
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Caracterização e determinação de minerais em amostras de açúcares brasileiros / Characterization and determination of minerals in Brazilian sugar samples

Anna Flavia de Souza Silva 13 March 2017 (has links)
O Brasil é o maior produtor de cana-de-açúcar e de açúcar, um dos principais derivados. O termo açúcar refere-se à sacarose, carboidrato classificado como dissacarídeo, sendo o tipo de açúcar mais consumido no mundo. A produção brasileira de açúcar é derivada exclusivamente da cana-de-açúcar e cerca de um terço do que é produzido permanece no mercado interno. Ao contrário do que acontece com o açúcar do tipo exportação, existem poucas informações sobre as questões mercadológicas, assim como para o padrão de qualidade com o qual o açúcar está chegando à mesa dos consumidores brasileiros. Neste sentido, para avaliar o perfil mineral dos açúcares de mesa consumidos pela população brasileira utilizou-se a espectrometria de emissão óptica com plasma indutivamente acoplado (ICP OES) para a determinação de enxofre, potássio, fósforo, cálcio, cobre, manganês, magnésio, silício, ferro e zinco. As amostras de açúcar foram ainda caracterizadas quanto a atributos básicos de qualidade definidos pela Copersucar: pH, umidade e resíduos insolúveis. A maior parte do açúcar consumido no Brasil é proveniente do Estado de São Paulo, embora seja possível observar a tendência de expansão para novas fronteiras agrícolas. Para a ampliação na participação de mercado e maiores receitas, as indústrias (usinas de açúcar) estão investindo na certificação, principalmente as mais novas e as localizadas na região de Expansão. A caracterização quanto aos atributos de qualidade do açúcar revelou que o pH está dentro dos padrões, a umidade apresenta problemas pontuais em algumas amostras (em função de problemas no armazenamento) e o teor de resíduos insolúveis está muito superior ao recomendado. A alteração do padrão da matéria-prima pode explicar esta observação, assim como explica as concentrações muito superiores para cálcio, potássio, enxofre, silício e ferro observado ao se comparar com as tabelas de composição nutricional dos alimentos. Além da determinação quantitativa realizada por ICP OES foi possível observar a viabilidade de métodos de análise direta de sólidos, LIBS (espectrometria de emissão óptica com plasma induzido por laser) e EDXRF (espectrometria de fluorescência de raios-X dispersiva em energia), em caráter qualitativo e, também, como promissoras ferramentas analíticas quantitativas para a rotina de análises de açúcar em usinas. / Brazil is the major producer of sugarcane and sugar, which is one of its main products. The term sugar refers to sucrose, a carbohydrate classified as a disaccharide, which is the most consumed in the world. Brazilian sugar production derives exclusively from sugarcane and about a third of what is produced remains for domestic retail. As opposed to what happens to the exportation type sugar, there is scarce information about this sugar type concerning to marketing issues in general, as well as the quality standard, which the sugar is available to the consumers. For evaluating the mineral profile of table sugar consumed by the Brazilian population (identification of the mineral elements: sulphur, potassium, phosphorous, calcium, copper, manganese, magnesium, silicon, iron and zinc), it was applied multi-element analytical instrumental method: Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES). The samples of sugar were still characterized as the basic quality attributes defined by Copersucar: pH, moisture and insoluble residues. Most of the sugar consumed in Brazil, in the domestic market, comes from the state of Sao Paulo, although it is possible to observe the trend of expansion to new agricultural frontiers. The industries (sugar mills), especially the new ones and located in the Expansion area, are investing in certification for the expansion in market share and higher revenues. The characterization of the sugar quality attributes showed that the pH is within the standards, the humidity presents specific problems in some samples (because of problems during storage) and the insoluble residues content is much higher than recommended. The new pattern in the raw material may explain this observation, as well as explains the much higher concentration of calcium, potassium, sulfur, silicon and iron observed when compared with nutritional food composition tables. In the quantitative determination carried out by ICP OES, it was possible to observe the viability of applying methods of direct analysis of solids, LIBS (Laser Induced Breakdown Spectroscopy) and EDXRF (Energy Dispersive X-ray Fluorescence), in qualitative and as promising quantitative analytical tools for routine analysis in sugar mills.

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