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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.
1

Otimização de metodologia para determinação de hidrocarbonetos policíclicos aromáticos pela técnica de extração por líquido pressurizado e sua aplicação a diferentes solos brasileiros / Methodology optimization for polycyclic aromatic hydrocarbons determination by pressurized liquid extraction technique and its applications to different soils

Plinio de Freitas Martinho 28 February 2013 (has links)
Os hidrocarbonetos policíclicos aromáticos (HPA) representam hoje grande preocupação à comunidade científica devido a sua comprovada ação cancerígena e mutagênica, assim tornam-se necessárias metodologias mais eficientes para suas determinações. O presente trabalho desenvolveu a técnica de extração por líquido pressurizado com a etapa de clean-up simultânea a extração, com sílica e alumina como adsorventes dentro da cela do equipamento ASE-350. A metodologia desenvolvida foi comparada com a tradicional extração por Sohxlet através de material de referência certificado. A extração por Soxhlet, apesar de eficiente, mostrou-se dispendiosa pelo gasto enorme de tempo, solvente e adsorventes quando comparada a extração por líquido pressurizado. De maneira geral a extração por líquido pressurizado apresentou-se mais vantajosa que a tradicional extração por Soxhlet. A eficiência da metodologia desenvolvida também foi testada através de quatro diferentes tipos de solos brasileiros fortificados com solução padrão de HPA. Os solos utilizados foram dos seguintes locais: Nova Lima MG, Lavras MG, Casimiro de Abreu RJ e Luiz Eduardo Magalhães BA. Todos possuíam características granulométricas e químicas diferentes entre si. Dois solos foram classificados em latossolos vermelhos, um em vermelho-amarelo e um em planossolo. Houve diferença significativa na eficiência de recuperação de alguns HPA quando comparados os quatro tipos de solos, já para outros HPA não evidenciou-se influência da tipologia do solo / Polycyclic aromatic hydrocarbons (PAH) are now a great concern to the scientific community due to its proven carcinogenic and mutagenic action. Therefore more efficient methodologies become necessary for its determinations. This research developed the technique of extraction by pressurized liquid with the clean-up step simultaneous to the extraction, i.e., the soil sample is extracted as the clean-up occurs. For this silica and alumina adsorbents was used in the ASE-350 equipment cell. For the study four different types of Brazilian soils with their well-defined characterizations were used. The soils used were from the following locations: Nova Lima - MG, Lavras - MG, Casimiro de Abreu - RJ and Luiz Eduardo Magalhães - BA. All of them had different soil gradation and chemical characteristics. The soils were classified as red oxisols, red-yellowish oxisols and planosols. There was significant difference between the recovery efficiency of some PAH in the four soil types, as for other HPA showed up no influence of soil type. The developed methodology was compared to traditional Sohxlet extraction by certified reference material (CRM). The Soxhlet extraction, although effective, has proved costly for large expenditure of time, adsorbents and solvent when compared to pressurized liquid extraction. In general the pressurized liquid extraction was more advantageous than traditional Soxhlet extraction. The developed methodology efficiency was also tested through four different Brazilian soil types spiked with standard PAH solution. The soils used were from the following locations: Nova Lima - MG, Lavras - MG, Casimiro de Abreu - RJ and Luiz Eduardo Magalhães - BA. All of them had different soil gradation and chemical characteristics among themselves. Two soils were classified as red oxisols, one as red-yellowish oxisol and one as planosol. There was significant difference among the recovery efficiency of some PAHs when the four soil types were compared; as for other HPA showed up no evidence of soil type influence
2

Otimização de metodologia para determinação de hidrocarbonetos policíclicos aromáticos pela técnica de extração por líquido pressurizado e sua aplicação a diferentes solos brasileiros / Methodology optimization for polycyclic aromatic hydrocarbons determination by pressurized liquid extraction technique and its applications to different soils

Plinio de Freitas Martinho 28 February 2013 (has links)
Os hidrocarbonetos policíclicos aromáticos (HPA) representam hoje grande preocupação à comunidade científica devido a sua comprovada ação cancerígena e mutagênica, assim tornam-se necessárias metodologias mais eficientes para suas determinações. O presente trabalho desenvolveu a técnica de extração por líquido pressurizado com a etapa de clean-up simultânea a extração, com sílica e alumina como adsorventes dentro da cela do equipamento ASE-350. A metodologia desenvolvida foi comparada com a tradicional extração por Sohxlet através de material de referência certificado. A extração por Soxhlet, apesar de eficiente, mostrou-se dispendiosa pelo gasto enorme de tempo, solvente e adsorventes quando comparada a extração por líquido pressurizado. De maneira geral a extração por líquido pressurizado apresentou-se mais vantajosa que a tradicional extração por Soxhlet. A eficiência da metodologia desenvolvida também foi testada através de quatro diferentes tipos de solos brasileiros fortificados com solução padrão de HPA. Os solos utilizados foram dos seguintes locais: Nova Lima MG, Lavras MG, Casimiro de Abreu RJ e Luiz Eduardo Magalhães BA. Todos possuíam características granulométricas e químicas diferentes entre si. Dois solos foram classificados em latossolos vermelhos, um em vermelho-amarelo e um em planossolo. Houve diferença significativa na eficiência de recuperação de alguns HPA quando comparados os quatro tipos de solos, já para outros HPA não evidenciou-se influência da tipologia do solo / Polycyclic aromatic hydrocarbons (PAH) are now a great concern to the scientific community due to its proven carcinogenic and mutagenic action. Therefore more efficient methodologies become necessary for its determinations. This research developed the technique of extraction by pressurized liquid with the clean-up step simultaneous to the extraction, i.e., the soil sample is extracted as the clean-up occurs. For this silica and alumina adsorbents was used in the ASE-350 equipment cell. For the study four different types of Brazilian soils with their well-defined characterizations were used. The soils used were from the following locations: Nova Lima - MG, Lavras - MG, Casimiro de Abreu - RJ and Luiz Eduardo Magalhães - BA. All of them had different soil gradation and chemical characteristics. The soils were classified as red oxisols, red-yellowish oxisols and planosols. There was significant difference between the recovery efficiency of some PAH in the four soil types, as for other HPA showed up no influence of soil type. The developed methodology was compared to traditional Sohxlet extraction by certified reference material (CRM). The Soxhlet extraction, although effective, has proved costly for large expenditure of time, adsorbents and solvent when compared to pressurized liquid extraction. In general the pressurized liquid extraction was more advantageous than traditional Soxhlet extraction. The developed methodology efficiency was also tested through four different Brazilian soil types spiked with standard PAH solution. The soils used were from the following locations: Nova Lima - MG, Lavras - MG, Casimiro de Abreu - RJ and Luiz Eduardo Magalhães - BA. All of them had different soil gradation and chemical characteristics among themselves. Two soils were classified as red oxisols, one as red-yellowish oxisol and one as planosol. There was significant difference among the recovery efficiency of some PAHs when the four soil types were compared; as for other HPA showed up no evidence of soil type influence
3

Extração de compostos bioativos do bagaço da amora-preta (Rubus spp.) utilizando líquidos pressurizados / Extração de compostos bioativos do bagaço da amora-preta (Rubus spp.) utilizando líquidos pressurizados

Machado, Ana Paula da Fonseca, 1988- 24 August 2018 (has links)
Orientador: Julian Martinez / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-24T23:53:07Z (GMT). No. of bitstreams: 1 Machado_AnaPauladaFonseca_M.pdf: 16373539 bytes, checksum: f53317f4e6ab35edd8a0c99170b4a457 (MD5) Previous issue date: 2014 / Resumo: A amora-preta é um fruto rico em compostos fenólicos, com destaque para os pigmentos antociânicos. Além do consumo in natura, a amora-preta é utilizada industrialmente na fabricação de sucos e derivados. Entretanto, este processamento gera cerca de 10 % de resíduos sólidos que contêm ainda uma grande porcentagem de fitoquímicos do fruto. Visando ao aproveitamento desse subproduto, o objetivo desse trabalho foi obter extratos ricos em seus principais compostos bioativos, os polifenóis, empregando a técnica limpa de extração com líquido pressurizado (PLE). Para isso, primeiramente, o bagaço da polpa da amora-preta foi caracterizado quanto ao teor de fenólicos totais (FT), antocianinas monoméricas (AM), atividade antioxidante (AA), pH, sólidos solúveis totais (SS) e composição centesimal. Em seguida, foram realizadas PLE¿s usando 3 temperaturas (60, 80 e 100 ºC) e 4 diferentes solventes (água, água acidificada a pH 2,5, etanol e mistura de etanol e água 50 %), resultando em 12 diferentes ensaios. Nos processos de extração por PLE foram fixados a pressão (75 bar), a razão S/F (18,0), o tempo de corrida (30 min) e a massa de matéria-prima (5,0 g). Posteriormente, foram identificadas as antocianinas majoritárias e minoritárias nos extratos subcríticos por cromatografia líquida de ultra performance (UPLC-QToF-MS). Além da técnica PLE, realizou-se a técnica clássica de extração Soxhlet juntamente com a maceração, com o intuito de comparar os resultados obtidos por estas com os obtidos na melhor condição de PLE. Ainda na melhor condição de extração por PLE foi realizada a cinética de extração em três diferentes vazões de solvente (1,67; 3,35 e 6,70 mL/min). Os extratos obtidos pelas diferentes técnicas foram avaliados em termos do rendimento global (X0), FT, AM e AA. A caracterização da matéria-prima mostrou que a mesma é altamente rica em proteínas, carboidratos, fibras e compostos bioativos (polifenóis), constituindo-se em uma boa fonte calórica e alimentícia, o que possibilita sua potencial aplicação na indústria alimentícia. Em geral, observou-se que o aumento da temperatura de 60 para 100 ºC resultou em melhores valores das variáveis respostas, com exceção da AM, em que se observou uma leve diminuição. A análise por UPLC-QToF-MS mostrou que as antocianinas presentes em maior quantidade no resíduo são a cianidina-3-glicosídeo e a cianidina-3-rutinosídeo e as minoritárias são a cianidina-3-malonil-glicosídeo e a cianidina-3-dioxalil-glicosídeo. A condição que se considerou como a melhor foi a que utilizou a mistura hidroetanólica como solvente de extração, na temperatura de 100 ºC. As variáveis respostas nesta condição obtiveram os seguintes valores: FT = 7,36 EAG/g resíduo fresco (RF), AM = 1,02 EC3G/g RF, DPPH = 76,03 ET/g RF, ABTS = 68,28 ET/g RF e X0 = 6,33 %. Comparando estes valores com os obtidos pelas técnicas convencionais (Soxhlet e maceração), em geral estes foram maiores. Os estudos dos parâmetros cinéticos indicam que vazões baixas são mais interessantes de se trabalhar quando se emprega mistura hidroetanólica em altas temperaturas (100 ºC) via procedimento PLE. Diante de tudo isso, pode-se concluir que a técnica PLE pode ser uma alternativa promissora na extração de compostos antioxidantes / Abstract: Blackberry is a fruit rich in phenolic compounds, especially in anthocyanins. Besides its consumption as fresh fruit, blackberry is used industrially in the manufacture of juices and derivatives. However, this process generates about 10 % of solid residue, which still contains a large amount of phytochemicals. In order to add value to these wastes, the aim of this study was to obtain extracts rich in blackberry¿s major bioactive compounds, such as polyphenols, by employing the clean technique of pressurized liquid extraction (PLE). First, bagasse pulp of blackberry was characterized with respect to total phenolic content (PC), monomeric anthocyanins (MA), antioxidant activity (AA), pH, total soluble solids (SS) and chemical composition. Then, PLEs were carried out using three temperatures (60, 80 and 100 °C) and 4 different solvents (water, acidified water with pH 2.5, ethanol and a mixture of ethanol and water 50%), resulting in 12 different assays. In the extraction processes by PLE some parameters were fixed: pressure (75 bar), ratio S/F (18.0 g solvent/g fresh residue), running time (30 min) and mass of raw material (5.0 g). Subsequently, the major and minor anthocyanins were identified in subcritical extracts by Ultra performance liquid chromatography (UPLC-QTOF-MS). Besides PLE, classical Soxhlet extraction technique and maceration were performed in order to compare the results with those obtained in the best condition of PLE. Also, at the best conditions of PLE, extraction kinetics were determined at three different flow rates (1.67, 3.35 and 6.70 mL/min). The extracts obtained by the different techniques were evaluated in terms of global yield (X0), PC, MA and AA. The characterization of the raw material showed that it is highly rich in protein, carbohydrates, fiber and bioactive compounds (polyphenols). Thus, blackberry is a good and caloric food source, which enables its potential application in the food industry. In general, it was observed that the increase of temperature from 60 to 100 °C resulted in better values for the response variables, except for the MA, in which a slight decrease was observed. The analysis by UPLC-QToF-MS showed that cyanidin-3-glucoside and cyanidin-3-rutinoside are the major anthocyanins present in blackberry residues. Cyanidin-3-glucoside and cyanidin-malonyl-3-dioxalil-glucoside are the anthocyanins present in lower levels. The condition that was considered the best of all tested in the present work was the one that used hydroethanolic mixture as the extraction solvent, at a temperature of 100 ºC. The values of the response variables in this condition were: PC = 7.36 EAG/g fresh residue (FR), MA = 1.02 EC3G/g (RF), DPPH = 76.03 TE/g FR, ABTS = 68.28 TE/g FR and X0 = 6.33 %. Comparing these values with those obtained by conventional techniques (Soxhlet and maceration), they were generally higher. Studies of the kinetic parameters indicated that is more interesting to work with low flow rates when employing hydroethanolic mixture at high temperatures (100 °C) via PLE procedure. Therefore, the PLE technique may be a promising alternative for the extraction of antioxidants from food matrices / Mestrado / Engenharia de Alimentos / Mestra em Engenharia de Alimentos
4

Extração de antocianinas de resíduo de jabuticaba (Myrciaria cauliflora) utilizando líquido pressurizado e fluido supercrítico : caracterização química, avaliação econômica e modelagem matemática / Obtaining of extract from amazon oil matrix via supercritical technology : chemical characterization, economic evaluation and mathematical modeling.

Cavalcanti, Rodrigo Nunes 04 August 2013 (has links)
Orientador: Maria Angela de Almeida Meireles / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-22T03:30:32Z (GMT). No. of bitstreams: 1 Cavalcanti_RodrigoNunes_D.pdf: 5256950 bytes, checksum: 08795bef1266bd8fc10cd8e88b7a19ca (MD5) Previous issue date: 2013 / Resumo: Atualmente, o conhecimento científico sobre a utilização de produtos naturais com propriedades funcionais, a exigência do consumidor quanto à qualidade dos alimentos, bem como ações legislativas para redução do uso de corantes sintetizados quimicamente têm propiciado o aumento da utilização de corantes naturais. Dentre estes, as antocianinas constituem pigmentos aquosolúveis responsáveis pelas principais cores encontradas na natureza, podendo variar desde o laranja, vermelho, violeta até o azul. Antocianinas são moléculas polares derivadas do cátion flavilion (C6-C3-C6) constituindo um importante subgrupo dos flavonóides. As principais propriedades biológicas atribuídas às antocianinas são atividade: antiinflamatória, anticarcinogênica e antioxidante. Diversos métodos de extração têm sido utilizados na obtenção de antocianinas. A extração supercrítica apresenta vantagens consideráveis sobre os métodos convencionais: o solvente é facilmente removido do soluto; utiliza pouco ou nenhum solvente orgânico; possibilita uma rápida extração; e, por fim, opera a baixas temperaturas favorecendo a extração de produtos voláteis e termolábeis. Este trabalho visou estudar o processo de extração supercrítica de antocianinas otimizando as diversas etapas do processo através de ensaios experimentais, simulação e comparação com outro(s) método(s) de extração. Inicialmente fez-se a caracterização da matéria-prima a qual apresentou altos teores de proteínas, carboidratos e fibras. As extrações via extração com fluido supercrítico (SFE ¿ supercritical fluid extraction) e extração com líquido pressurizado (PLE ¿ pressurized liquid extraction) utilizaram etanol, isopropanol e água como co-solvente e solvente, respectivamente. A composição dos extratos foi avaliada por espectrofotometria apresentando altos teores de fenólicos, flavonóides, antocianinas e atividade antioxidante em relação aos dados da literatura. Os melhores rendimentos de compostos fenólicos, flavonóides e atividade antioxidante foram obtidos por SFE utilizando co-solventes alcoóis. Já com relação ao teor de antocianinas houve pouca diferença entre os métodos PLE e SFE os quais atingiram melhores resultados utilizando água e alcoóis como solvente e co-solventes, respectivamente. De acordo com os resultados de tempo de retorno e custo de manufatura ambos os métodos de extração foram economicamente viáveis para a produção de extrato bruto de subproduto de jabuticaba. Os menores custos foram obtidos nas condições que apresentaram maior rendimento de extração e nas células extratoras de maior capacidade volumétrica. O estudo dos parâmetros cinéticos indicam que os melhores resultados foram obtidos utilizando alta vazão de solvente para ambos os processos SFE e PLE / Abstract: Currently, scientific knowledge about the use of natural products with functional properties, the consumer demand for quality food, as well as legislative action to reduce the use of chemically synthesized colorants have prompted an increasing use of natural colorants. Among these, anthocyanin are water-soluble pigments responsible for main colors found in nature ranging from orange, through red and violet to blue. Anthocyanins are polar molecules derived from the flavilium cation (C6-C3-C6) constituting an important subgroup of flavonoids. The main biological properties of anthocyanins are activity: anti-inflammatory, anticarcinogenic and antioxidant. Several extraction methods have been used to obtain anthocyanins. Supercritical fluid extraction has considerable advantages over conventional methods: the solvent is easily removed from the solute; uses little or no organic solvent, enables a rapid extraction and, finally, operates at low temperatures favoring the extraction of volatile and thermolabile compounds. This work aims to study the process of supercritical extraction of anthocyanins optimizing the various steps of the process through experimental testing, simulation and comparison with other(s) extraction method(s). Initially it was made the characterization of raw material which showed high levels of protein, carbohydrates and fiber. The extractions were carried out via SFE and PLE using ethanol, isopropanol and water as co-solvent and solvent, respectively. The extracts composition was evaluated by spectrophotometry showing high levels of phenolics, flavonoids, anthocyanins and antioxidant activity (%AA) with respect to the literature data. The highest phenolics and flavonoids content and %AA were obtained by SFE using alcohols as co-solvent. On the other hand, anthocyanins content achieve the best results using water and alcohols as a solvent and co-solvents, respectively. According to payback time and cost of manufacturing results both extraction methods were economic feasible to the production of crude extract from jabuticaba byproduct. The higher the extraction yield and extraction vessel capacity the lower the cost of manufacturing. The study of the kinetic parameters shows the best results were achieved at higher solvent mass flow for both extraction methods / Doutorado / Doutor em Engenharia de Alimentos
5

Extrakce, separace a identifikace anthokyanů ve slupkách bobulí červených odrůd Vitis vinifera / Extraction, separation and identification of anthocyans in skin of red cultivars of Vitis vinifera

Watzková, Jarmila January 2008 (has links)
This diploma thesis deals with application of pressurized liquid extraction (PFE) on grape skins of Vitis vinifera cultivars Alibernet and Svatovavřinecké to gain extraction of anthocyanin pigments in the form of 3-monoglucosides. This thesis deals with comparison efficiency pressurized liquid extraction (PFE) for the range temperatures 40–120 °C and the Soxhlet extraction with four extraction solvents. The identification of the anthocyanin pigments by high-performance liquid chromatography with diode array detection (HPLC/DAD) based on Synergi C12 column separation (Phenomenex) was performed. The anthocyanin pigments were identified at wavelength 520 nm. The complete amount of anthocyanin pigments grape skins was depended on the extraction solvent and temperature in range 0,38–244,06 mg/g for cultivar Alibernet and 0,28–105,01 mg/g for cultivar Svatovavřinecké. The contents of anthocyanin pigments was determined in the samples of wine both cultivars in the range 3,83–2836,84 mg/l too. PFE followed by HPLC/DAD employing Synergi C12 column provides relatively fast, quantitative and reproducible determination of anthocyanins in grape skins and wines.
6

Análise da concentração de compostos bioativos e avaliação da toxicidade aguda in vivo dos diterpenos cafestol e caveol presentes no óleo de grãos de café verdes obtidos por extração supercrítica e por extração com fluido pressurizado / Concentration of bioactive compounds analysis and evaluation of acute toxicity in vivo of the diterpenes cafestol and kahweol from green beans coffee oil obtained by supercritical and pressurized fluid extractions

Oliveira, Naila Albertina de 22 July 2015 (has links)
Este estudo visou à utilização da tecnologia que emprega CO2 em estado supercrítico (SFE) para estudar a bioatividade dos diterpenos presentes no óleo de café verde, cafestol (C) e caveol (K), contudo propondo também a otimização de extração com líquido pressurizado (PLE) em batelada, utilizando para isto um Delineamento Composto Central Rotacional (DCCR2). O referido tema tem caráter inovador e inédito, já que a tecnologia de extração com líquido pressurizado, até então empregada para extração de analitos, passa a ser estudada em processos de extração de óleos vegetais tais como, óleo de pequi, óleo de café verde, extrato de sementes de pitanga no LTAPPN. Esta técnica utiliza solventes orgânicos e emprega elevada temperatura de extração, o que aumenta a capacidade de solubilização do solvente, e o emprego de altas pressões que acelera a difusão nos poros da matriz já que a viscosidade do solvente é diminuída. Este comportamento ocasiona maior penetração do solvente na matriz, aumentando sua capacidade de extração. A extração supercrítica (SFE) é uma tecnologia limpa, pois não emprega solventes orgânicos sendo promissora na obtenção de extratos enriquecidos com compostos bioativos que possam desempenhar alguma atividade. O estudo da atividade aguda dos diterpenos presentes no óleo de grãos de café verdes obtidos via SFE e PLE demonstrou que o óleo extraído com CO2 supercrítico, na dose de 2.000 mg/Kg no estudo de toxicidade aguda e nas doses de 25, 50 e 75 mg/Kg no estudo de toxicidade de doses repetidas, não apresentou letalidade aos animais, porém parâmetros bioquímicos, hematológicos e histológicos, apresentaram alterações. Todavia para aplicações do óleo de café verde em produtos desenvolvidos pelas indústrias farmacêuticas, alimentícias e/ou cosméticas, mais estudos de avaliação dos efeitos do óleo de café verde in vivo são necessários. Igualmente, o estudo de inovação tecnológica para obtenção de óleo de café verde visa obter extratos enriquecidos em diterpenos, evitando a degradação e tornando-os mais estáveis. Os resultados obtidos indicam que o óleo dos grãos de café verde extraídos via SFE e PLE (em batelada) possuem altas concentrações dos compostos ativos cafestol e caveol, sendo a condição de melhor rendimento a condição 4 (70º C e 8 min. ) a de maior rendimento de óleo 9,78%. / This study aimed to evaluate the bioactivity of the diterpenes in green coffee oil, cafestol (C), and kahweol (K) using supercritical fluid extraction (SFE- CO2), and to optimize the extraction with pressurized liquid extraction (PLE) in batch by using a rotatable central composite design (RCCD2). This issue has innovative and novel character, since the pressurized liquid extraction technology available until now for analyte extraction has been studied in vegetable oil extraction processes such as Pequi oil, green coffee oil, and Pitanga seeds extracts, at LTAPPN. This technique uses organic solvents and high extraction temperature, which increases the solvent solubilization capacity. The use of high pressure accelerates the diffusion rates into the pores of the matrix, due to the lower solvent viscosity. This behavior provides greater penetration of the solvent into the matrix, increasing solvent extraction capacity. The supercritical fluid extraction (SFE) is a clean technology as it does not employ organic solvents, besides being a promising alternative to obtain extracts enriched with bioactive compounds. The results of the acute activity of diterpenes in green coffee oil extracted by SFE and PLE showed that although no lethality was observed in the animals using the oil extracted by SFE at a dose of 2,000 mg / kg in an acute toxicity study, and 25, 50, and 75 mg / kg in a repeated dose toxicity study, changes were observed in biochemical, hematological, and histological parameters. However, more in vivo studies about the effects of green coffee oil are required for pharmaceutical, food, and cosmetic applications. Similarly, the technological innovation to obtain the green coffee oil aims at obtaining extracts enriched in diterpenes, preventing degradation and increasing stability. The results indicate that green coffee oil extracted by SFE and PLE (in batch) have high concentrations of the active compounds cafestol and kahweol, and the best extraction condition was the trial 4 (70 º C, and 8 min), and the highest oil yield was 9.78%.
7

PLE with integrated clean up followed by alternative detection steps for cost-effective analysis of dixons and dioxin-like compounds

Spinnel, Erik January 2008 (has links)
Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are two structurally related groups of chemicals, generally referred to as `dioxins´. These are of great concern due to their high toxicity and global spread. Other groups of compounds with similar chemical structure and toxicity mechanisms are the brominated analogues polybrominated dibenzo-p-dioxins (PBDDs) and polybrominated dibenzofurans (PBDFs), and the dioxin-like polychlorinated biphenyls (PCBs). Numerous studies have been undertaken to investigate sources and transport routes of dioxins. However, much remains to be done, including analytical, inventories of dioxin-like compounds, such as PBDD/Fs, and the development of more convenient analytical methods. The currently standard procedure for analyzing dioxins (and dioxin-like compounds) is to use Soxhlet extraction followed by multi-step clean-up and gas chromatography - high resolution mass spectrometry (GC- HRMS) for detection. Unfortunately, this method is very solvent, labor and time-consuming, making it very expensive. The main aim of the studies this thesis was to develop pressurized liquid extraction (PLE) with integrated clean up techniques for fast, convenient preparation of dioxin samples. PLE with integrated clean-up has previously been used for extracting dioxins from biological samples, but in these studies the possibility of extending its use to abiotic samples was explored. The results show that PLE with an integrated carbon trap is suitable for analyzing dioxins in various types of soil samples, sediment and flue gas samples. The results also showed that it has potential for analyzing dioxins in fly ash. The thesis focuses on developments of the methodology for dioxin analysis, but also includes results obtained from PBDDs and dioxin-like PCB analyses. In addition, the possibility of using various other kinds of detection techniques rather than GC-HRMS, such as enzyme-linked immunosorbent assays (ELISAs) or two-dimensional gas chromatography with micro electron capture detection (GCxGC-µECD) was explored. The results indicate that ELISA and GCxGC-µECD could serve as complementary detection systems in some cases. However, it is not yet possible to fully replace GC-HRMS. A further refinement of the PLE with in-cell clean-up technique is the modular approach developed in these studies. With this technique it is possible to include various steps for both clean-up and fractionation. For example, sulphuric acid impregnated silica could be combined with active carbon for the simultaneous removal of lipids (along with other interferences) and fractionation of PCBs and PCDD/Fs. It was shown that the method could provide data that agreed reasonably well with both reference values and values obtained using traditional methods. In general PLE proved to have high extraction efficiency and to yield very similar congener profiles to the reference method. In addition, it was shown that it allowed one-step extraction and clean-up of a salmon sample. Such single-step procedures are the ultimate goals for any extraction technique, and it would be highly desirable to develop one-step methods that could be extended to other types of samples. For the rest of the matrices tested (soil, sediment, mussel and crab tissue and flue gas) the method was successful, however a final polishing step is currently required, involving either dilution or clean-up using miniaturized multilayer silica columns, to obtain extracts that are pure enough for GC-HRMS analysis. Using the developed modular-PLE system substantial costs could be saved. It was estimated that the method could reduce the cost of preparing samples by up to 90%, which would greatly facilitate large-scale inventories.
8

Dissipation and phytotoxicity of oil sands naphthenic acids in wetland plants

Armstrong, Sarah Anne 09 July 2008
Naphthenic acids (NAs) are toxic organic acid compounds released during the caustic hot-water extraction of crude oil from oil sands in north-eastern Alberta, Canada. NAs subsequently accumulate in the large volume of oil sands process water (OSPW) produced daily by oil sands operations. The complexity of dealing with a mixture of over 200 individual NA compounds, combined with their acute aquatic toxicity and large volume of production has made them an emerging pollutant of concern for western Canada. The following thesis outlines a variety of experiments designed to determine the potential to use wetland plants to enhance the dissipation of NAs from OSPW (phytoremediation). <p>Investigations were carried out with three native emergent macrophyte species cattail (<i>Typha latifolia</i>), common reed (<i>Phragmites australis </i>subsp. <i>americanus</i>), and hard-stem bulrush (<i>Scirpus acutus</i>) to see if they enhanced the dissipation of NAs from a hydroponic system. Dissipation of NAs (at 30 mg L-1 and 60 mg L-1) was investigated with both a commercially available NA mixture as well as with a NA mixture extracted from the OSPW. Dissipation of NAs was also investigated under the different ionized forms of NAs (ionized, pH = 7.8; and non-ionized, pH = 5.0) to better elucidate the mechanisms of NA uptake and toxicity in plants. Phytotoxicity of NAs was investigated in hydroponic experiments through fresh weight gain and evapotranspiration was monitored throughout the experiment by water uptake. Commercially available NA mixture was more phytotoxic than oil sands NAs mixture. As well, NAs were found to be more phytotoxic in their non-ionized form therefore indicating that they may be taken up through an ion-trap‟ mechanism. However despite this, no significant dissipation of total NAs was observed from planted hydroponic systems. Nevertheless there was a significant change in the distribution (percent abundance) of individual NA families of certain size. These changes were related to the one- and two-ring NA compounds (Z = -2 and Z = -4). Despite not detecting any dissipation of total NAs from the systems, plants were able to reduce the toxicity of a NA system over 30 days by 45% as determined by Daphnia magna acute toxicity bioassays; a 11% greater reduction than unplanted systems.<p> Studies were also conducted investigating the microbial community inhabiting cattail roots exposed to NAs. It was observed that the rhizosphere community changed with NA exposure, with a general increase in potentially pathogenic bacteria and a decrease in bacteria previously found to be beneficial to plant growth. The observed microbial community change could be an indirect effect of the Phytotoxicity experienced by aquatic macrophytes exposed to NAs. Synchrotron-sourced, fourier transform microspectroscopy analysis of root cross sections revealed that there were significant physiological changes to those roots exposed to NAs. These changes were identified as being cell death in the plant root epidermis as well as a change in the chemistry of parenchyma cells in the root pith. It is not known if these changes are a direct effect of NAs to the plant or due to changes of the associated rhizosphere community in the roots or some combination of both these factors.
9

Dissipation and phytotoxicity of oil sands naphthenic acids in wetland plants

Armstrong, Sarah Anne 09 July 2008 (has links)
Naphthenic acids (NAs) are toxic organic acid compounds released during the caustic hot-water extraction of crude oil from oil sands in north-eastern Alberta, Canada. NAs subsequently accumulate in the large volume of oil sands process water (OSPW) produced daily by oil sands operations. The complexity of dealing with a mixture of over 200 individual NA compounds, combined with their acute aquatic toxicity and large volume of production has made them an emerging pollutant of concern for western Canada. The following thesis outlines a variety of experiments designed to determine the potential to use wetland plants to enhance the dissipation of NAs from OSPW (phytoremediation). <p>Investigations were carried out with three native emergent macrophyte species cattail (<i>Typha latifolia</i>), common reed (<i>Phragmites australis </i>subsp. <i>americanus</i>), and hard-stem bulrush (<i>Scirpus acutus</i>) to see if they enhanced the dissipation of NAs from a hydroponic system. Dissipation of NAs (at 30 mg L-1 and 60 mg L-1) was investigated with both a commercially available NA mixture as well as with a NA mixture extracted from the OSPW. Dissipation of NAs was also investigated under the different ionized forms of NAs (ionized, pH = 7.8; and non-ionized, pH = 5.0) to better elucidate the mechanisms of NA uptake and toxicity in plants. Phytotoxicity of NAs was investigated in hydroponic experiments through fresh weight gain and evapotranspiration was monitored throughout the experiment by water uptake. Commercially available NA mixture was more phytotoxic than oil sands NAs mixture. As well, NAs were found to be more phytotoxic in their non-ionized form therefore indicating that they may be taken up through an ion-trap‟ mechanism. However despite this, no significant dissipation of total NAs was observed from planted hydroponic systems. Nevertheless there was a significant change in the distribution (percent abundance) of individual NA families of certain size. These changes were related to the one- and two-ring NA compounds (Z = -2 and Z = -4). Despite not detecting any dissipation of total NAs from the systems, plants were able to reduce the toxicity of a NA system over 30 days by 45% as determined by Daphnia magna acute toxicity bioassays; a 11% greater reduction than unplanted systems.<p> Studies were also conducted investigating the microbial community inhabiting cattail roots exposed to NAs. It was observed that the rhizosphere community changed with NA exposure, with a general increase in potentially pathogenic bacteria and a decrease in bacteria previously found to be beneficial to plant growth. The observed microbial community change could be an indirect effect of the Phytotoxicity experienced by aquatic macrophytes exposed to NAs. Synchrotron-sourced, fourier transform microspectroscopy analysis of root cross sections revealed that there were significant physiological changes to those roots exposed to NAs. These changes were identified as being cell death in the plant root epidermis as well as a change in the chemistry of parenchyma cells in the root pith. It is not known if these changes are a direct effect of NAs to the plant or due to changes of the associated rhizosphere community in the roots or some combination of both these factors.
10

Obtenção de extratos enriquecidos em carotenoides e produtos hidrolisados através do fracionamento da fibra de palma prensada com solventes limpos e fluidos pressurizados / Obtaining of carotenoid-rich extracts and hydrolysate products by fractionation of pressed palm fiber using clean solvents and pressurized fluids

Cardenas Toro, Fiorella Patricia, 1980- 27 August 2018 (has links)
Orientadores: Maria Angela de Almeida Meireles Petenate, Tânia Forster Carneiro / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-27T17:37:35Z (GMT). No. of bitstreams: 1 CardenasToro_FiorellaPatricia_D.pdf: 20104541 bytes, checksum: 3c5867a10520478debcff56ff3a375e4 (MD5) Previous issue date: 2015 / Resumo: A fibra de palma prensada (Elaes guineensis) é um resíduo procedente da indústria de extração de óleo de palma que possui na sua composição compostos bioativos tais como alfa- e beta-caroteno, assim como os polissacarídeos (celulose e hemicelulose). Estes compostos podem ser recuperados mediante processos de extração e hidrólise com a finalidade de produzir de forma sustentável, extratos enriquecidos com carotenoides e produtos hidrolisados com aplicação na indústria química, de alimentos e farmacêutica. Entre as tecnologias que utilizam solventes limpos a altas e baixas pressões, temos a extração por Soxhlet (LPSE-SOX), extração por percolação (LPSE-PE), extração por líquido pressurizado (PLE), extração com fluído supercrítico (SFE) e hidrólise subcrítica com água (SubWH). Neste trabalho, um processo integrado utilizando SFE e SubWH foi proposto como modelo de aproveitamento integral da fibra de palma prensada. O estudo incluiu a avaliação dos efeitos dos parâmetros operacionais de extração: temperatura e pressão empregando uma razão mássica de solvente por massa de matéria-prima (S/F) de 30 na obtenção de um extrato rico em carotenoides; e dos parâmetros operacionais de hidrólise: temperatura, pressão, S/F e tempo de residência na produção de monossacarídeos e oligossacarídeos nos produtos hidrolisados. Após esse primeiro estudo, um segundo estudo dos processos de extração LPSE-SOX, LPSE-PE e PLE utilizando etanol como solvente limpo foi realizado com o objetivo de explorar as condições de operação: temperatura, pressão e vazão na razão S/F de 20, que favorecessem a produção de um extrato rico em carotenoides (alfa e beta-caroteno) incluindo a avaliação econômica de cada processo. Os resultados do primeiro estudo para o SFE utilizando dióxido de carbono como solvente indicaram que o maior rendimento de carotenoides totais no extrato foi 800 ± 200 ug beta-caroteno/g extrato na condição de 318 K (45°C) e 15 MPa. Posteriormente, os experimentos de hidrólise subcrítica da fibra de palma desengordurada obtiveram uma mistura de produtos hidrolisados e produtos de degradação de açúcares, sendo a condição de 523 K (250°C), 15 MPa, tempo de residência de 2,5 min e S/F de 120 aquela com maiores rendimentos de açúcares redutores totais (22,9 g glicose/100 g carboidrato). Este estudo mostrou a viabilidade de integração de processos para o melhor aproveitamento da fibra de palma prensada. Na segunda parte do estudo, os processos de extração com etanol à baixa e alta pressão com melhores rendimentos de carotenoides foram: 305 ± 18 ug alfa-caroteno/g extrato e 713 ± 46 ug beta-caroteno/g extrato para o processo PLE na condição de 308 K (35°C), 4 MPa, 2,4 g/min e 37 min; 142 ± 13 ug alfa-caroteno/g extrato e 317 ± 46 ug beta-caroteno/g extrato para o processo LPSE-SOX num tempo de 6 h; 79 ± 9 ug alfa-caroteno/g extrato e 195 ± 20 ug beta-caroteno/g extrato para o processo LPSE-PE na condição de 308 K (35°C), 2,4 g/min e 37 min. Os custos de manufatura (COM) na escala industrial de 0,5 m3 utilizando 2 extratores em modo contínuo foram de US$98,1/g carotenoide para o processo LPSE-SOX; US$48,9/g carotenoide para o processo LPSE-PE e US$28,7/g carotenoide para o processo PLE. Diante dos resultados obtidos no primeiro e segundo estudo, um estudo cinético dos processos de extração a altas pressões PLE e SFE foi realizado nas condições operacionais que obtiveram altos rendimentos de carotenoides no extrato. O rendimento de extração na razão S/F de 7 e 10 resultou em 90% do total do extrato obtido no final da extração para o processo PLE e SFE, respectivamente. Para o processo PLE e SFE os menores valores de COM foram encontrados para as capacidades de extratores industriais de 0,05 m3 e 0,5 m3. Para o processo PLE, na razão S/F de 8 obtiveram-se os menores valores de COM e COM* específico: US$30,4/kg extrato e US$0,02/g carotenoide para 0,5 m3. Uma tendência similar foi observada para o processo SFE com valores de COM de US$30,8/kg extrato e US$0.08/g carotenoide para 0,5 m3. Baseados nestes resultados, o processo PLE apresenta uma melhor vantagem econômica que o processo SFE e pode ser considerado como a primeira etapa do processo integrado de obtenção de extrato rico em carotenoides seguido do processo SubWH para a obtenção de produtos hidrolisados / Abstract: Pressed palm fiber (Elaes guineensis) is a residue obtained from the palm oil extraction industry that is a source of bioactive compounds such as alpha- and beta-carotene present in the residual oil and polysaccharides (cellulose and hemicellulose), which can be recovered by extraction and hydrolysis processes in order to produce in a sustainable manner extracts enriched with carotenoid for direct application in food industry as additives and/or formation of hydrolysate products with high yields of monosaccharides and oligosaccharides with application in the chemical food and pharmaceutical industry. Technologies that use clean solvents at high and low pressures include Soxhlet extraction (LPSE-SOX), extraction by percolation (LPSE-PE), pressurized liquid extraction (PLE), supercritical fluid extraction (SFE) and subcritical hydrolysis (SubWH). In this work, an integrated process using SFE and SubWH was proposed as the model of completely utilization of pressed palm fiber. The study included the evaluation of the effects of operating parameters of extraction: temperature and pressure at the ratio of solvent mass to feed mass (S/F) of 30 in the obtaining of extracts rich in carotenoids and the study of operational parameters of hydrolysis: temperature, pressure, S/F and residence time on the production of monosaccharides and oligosaccharides in the hydrolyzed products. After this first study, a second study of the extraction processes LPSE-SOX, LPSE-PE and PLE using ethanol as a clean solvent was conducted in order to explore the operational conditions: temperature, pressure and flow rate at S/F ratio of 20, which promotes the production of an extract rich in carotenoids (alpha- and beta-carotene) including the economic evaluation of each process. Results of the first study for SFE using carbon dioxide as a solvent indicated that the highest yield of total carotenoids in the extract was 800 ± 200 ug alpha-carotene/g extract at the condition of 318 K (45°C) and 15 MPa. Thereafter, the experiments of subcritical hydrolysis of defatted pressed palm fiber resulted in a mixture of hydrolysate products and sugar degradation products, where the condition of 523 K (250°C), 15 MPa, residence time of 2.5 min and S/F 120 presented the highest yield of total reducing sugars (glucose 22.9 g/100 g carbohydrate). In the second part of this study, the extraction processes with ethanol at low and high pressure with highest yields of carotenoids in extracts were: 305 ± 18 ug alpha-carotene/g extract and 713 ± 46 ug beta-carotene/g extract for the PLE process at the condition of 308 K (35°C), 4 MPa, 2.4 g/min and 37 min; 142 ± 13 ug alpha-carotene/g extract and 317 ± 46 ug beta-carotene/g extract for LPSE-SOX process at 6 h; and 79 ± 9 ug alpha-carotene/g extract and 195 ± 20 ug beta-carotene/g extract for LPSE-PE process at condition of 308 K (35°C), 2.4 g/min and 37 min. The cost of manufacturing (COM) for the industrial scale of 2 extractors in continuous mode with capacity of 0.5 m3 were US$98.1/g carotenoid for the LPSE-SOX process, US$48.9/g carotenoid for the LPSE-PE process and US$28.7/g carotenoid for the PLE process. From the results obtained in the first and second study, a kinetic study of the PLE and SFE processes at the operating conditions which obtained the highest carotenoid yields from pressed palm fiber was carried out in order to find the adequate processing time and manufacturing cost. The results showed that the extraction at the S/F ratio of 7 and 10 resulted in extract yields higher than 90% for the PLE and SFE process. On the other hand, the carotenoid yield of carotenoids in the extract increased with the S/F ratio. For PLE and SFE processes, the lowest COM values were found for the industrial scale of extractors of 0.05 and 0.5 m3. For PLE process, the S/F ratio of 8 resulted in the lowest COM and specific COM* value: US$30.4/kg extract and US$0.02/g carotenoid for 0.5 m3. A similar trend was observed for the SFE process with values of US$30.8/kg extract and US$0.08/g carotenoid for capacity of 0.5 m3. Based on these results, the PLE process is economically more advantageous than the SFE process and PLE can be considered as the first step of the integrated process for obtaining of extract rich in carotenoids followed by SubWH for obtaining of hydrolysate products / Doutorado / Engenharia de Alimentos / Doutora em Engenharia de Alimentos

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