Dissertations / Theses: 'Alginates'

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Wilcox, Matthew David. "Bioactive alginates." Thesis, University of Newcastle Upon Tyne, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.578262.

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Alginates are polysaccharides extracted from the cell walls of brown seaweed or from certain bacteria such as Azotobacter vinelandii. Alginates have been shown to reduce the activity of pepsin and initial data suggest that it may affect the activity of pancreatic lipase. Pancreatic lipase plays an important role in the breakdown of triacylglycerol, if the activity of pancreatic lipase can be reduced then the breakdown of triacylglycerol would be reduce which in turn would lower the amount absorbed by the body. A pharmaceutical treatment for obesity called orlistat inhibits lipase and accounts for 66% of all prescriptions for treatments for obesity in 2008 in the UK. However the side effects of orlistat (uncontrolled diarrhoea and steatorrhea) can reduce the compliance with the treatment. If orlistat is taken with a high fibre product it has been shown that this can greatly reduce or eliminate the side effects. Since alginate is a dietary fibre it is believed that this could be an effect treatment for obesity. Colourimetric and turbidimetric assays were used to determine the effect of a wide range of alginates and other dietary fibres on pancreatic lipase. Alginates have the ability to inhibit pancreatic lipase, with a maximum inhibition of 72.2% (±9.9). Pectin could also inhibit lipase by a maximum of 71.8% (±22.3), however, specific enzymactically modified alginates could activate the enzyme by up to 22.0% (±10.1). Carrageenan and Hydroxypropyl methylcellulose could also activate the enzyme by a maximum of 37.3% (±24.5). The structure of the alginate is key to the inhibition or activation of the enzyme. Consecutive guluronate residues are important for inhibition whereas alternating mannuronate and guluronate blocks are detrimental to inhibition. The alginate that activated the enzyme was almost entirely consisting of poly-alternating uronate residues. The level of esterification was important for pectins inhibition of lipase with higher levels causing little inhibition. Alginate causes sustained inhibition at low concentrations of biopolymer compared to pectin. Therefore alginate could play a potential role in the management of obesity. ii

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Nogueira, Marcela Tiemi. "Extração e caracterização de alginato de sódio da macroalga Sargassum cymosum C. Agardh /." Assis, 2017. http://hdl.handle.net/11449/150488.

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Orientadora: Ivanise Guilherme Branco
Banca: Cassia Roberta Malacrida Mayer
Banca: Izabel Cristina Freitas Moraes
Resumo: As algas marinhas pardas são as principais fontes de alginato de sódio utilizados na indústria alimentícia. O Brasil não possui o processamento de alginato, sendo assim dependente de produtos importados para suprir a demanda. A macroalga Sargassum sp. é comumente encontrada nas regiões costeiras do litoral de São Paulo, a extração de alginato dessa alga possibilitaria autonomia brasileira na produção de alginato de sódio. O meio ambiente e as condições climáticas em que as algas marinhas vivem influencia no rendimento de alginato, na massa molecular e na capacidade antioxidante. No primeiro capítulo foi realizado a otimização da extração de alginato de sódio por delineamento Box-Behnken e também o estudo da influência dos parâmetros de pH, temperatura e tempo de extração sobre o rendimento, viscosidade intrínseca e massa molecular. O pH influencia no rendimento, viscosidade intrínseca e massa molecular, enquanto que o tempo apresentou baixo efeito sobre o rendimento e a temperatura não influenciou nas respostas avaliadas. Os resultados da otimização mostraram que máximo rendimento (46,04%), viscosidade intrínseca (4,89 dL/g) e massa molecular (231,78 kDa) podem ser obtidos utilizando na extração a temperatura de 80°C, pH 10 por 90,08 minutos. No segundo capítulo foram estudados alginatos extraídos de Sargassum cymosum C. Agardh coletadas em duas localidades diferentes do litoral de São Paulo (Ubatuba-ASU e São Sebastião-ASS) com relação ao rendimento, massa molecular, compor... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Brown seaweeds are the main sources of sodium alginate used in the food industry. Brazil doesn't have alginate processing, so it is dependent on imported products to supply the demand. The macroalgae Sargassum sp. is commonly found in the coastal regions of São Paulo, the extraction of alginate from this alga would allow Brazilian autonomy in the production of sodium alginate. The environment and climatic conditions in which marine algae live influence alginate yield, molecular weight and antioxidant capacity. In the first chapter, the optimization of the sodium alginate extraction by the Box-Behnken design was carried out, as well as the influence of pH, temperature and extraction time parameters on yield, intrinsic viscosity and viscosimetric molecular mass. pH influenced yield, intrinsic viscosity and molecular mass, while time had low effect and temperature did not influence the responses evaluated. The optimization results showed that maximum yield (46.04%), intrinsic viscosity (4.89 dL / g) and viscosimetric molecular weight (231.78 kDa) can be obtained using the extraction at temperature of 80 ° C, pH 10 and 90 minutes. In the second chapter, alginates extracted from Sargassum cymosum C. Agardh were studied in two different locations along the coast of São Paulo (Ubatuba-ASU and São Sebastião-SSA) and were studied the difference between them in the yield, molecular mass, rheological behavior and antioxidant activity. The yield presented higher values for the alginates ... (Complete abstract click electronic access below)
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Aarstad, Olav Andreas. "Alginate sequencing : Block distribution in alginates and its impact on macroscopic properties." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for bioteknologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-20246.

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Turbiani, Franciele Rezende Barbosa. "Desenvolvimento e caracterização de filmes ativos de alginato de sodio reticulados com benzoato de calcio." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266253.

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Orientador: Theo Guenter Kieckbusch
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: Filmes biodegradáveis são produzidos a partir de polímeros naturais, principalmente polissacarídeos e proteínas, e tem potencial aplicação na área médica, farmacêutica e alimentícia. A incorporação de agentes ativos pode ampliar suas funções como embalagens antimicrobianas, por exemplo. Filmes foram confeccionados à base de alginato de sódio usando cloreto de cálcio como agente reticulante e glicerol como plastificante. O uso de benzoato de cálcio foi investigado como agente ativo (íons benzoato) e como auxiliar na reticulação (íons cálcio). Devido ao alto poder gelificante do Ca++, confeccionou-se, inicialmente, um filme de baixa reticulação a partir de soluções filmogênicas contendo até 0,54% de Ca++ (1º estágio). Esse filme sofreu uma reticulação complementar com excesso de Ca++ (2º estágio). Dentre os vários procedimentos avaliados (contato do filme com tecido e/ou esponja umidecidas, pincel ou rolo de pintura e imersão do filme em solução reticuladora), a simples imersão em solução contendo de 3 a 7% de CaCl2 no 2º estágio produziu filmes com alto grau de reticulação. O aumento da concentração de glicerol nessa solução melhora a manuseabilidade e plasticidade dos filmes, porém aumenta a solubilidade em água e o conteúdo de umidade dos mesmos e um adequado compromisso foi obtido usando 5% desse plastificante. Ensaios nos quais o CaCl2 foi substituído, total ou parcialmente, por benzoato de cálcio indicou que o mesmo não pode ser usado na solução do 2º estágio por favorecer a precipitação de cristais sobre o filme. Filmes ativos de 0,06 mm de espessura, pré-reticulados apenas com benzoato de cálcio e 0,7% de glicerol na solução do 1º estágio e imersos por 30 minutos em banho contendo 3% de CaCl2 e 5% de glicerol no 2º estágio, apresentaram baixa solubilidade em água (até 20% da matéria seca). Estes filmes têm baixo grau de intumescimento (< 50% da massa inicial), boa resistência mecânica à tração, mas baixa elasticidade. A permeabilidade ao vapor de água é moderada e os valores encontrados são típicos de biofilmes hidrofílicos. Ensaios de liberação de benzoato utilizando água como sorvedouro, apresentaram bom ajuste as soluções da 2ª Lei de Fick, com valores de difusividade efetiva do benzoato variando de 3 a 5.10-7 cm2/s. Os valores de difusividade diminuiram com o aumento da reticulação e aumentaram com o aumento da concentração de benzoato no filme
Abstract: Biodegradable films are produced from natural polymers, structurized mainly by polysaccharides or proteins, and have potential applications in the medical, pharmaceutical or food area. The incorporation of active agents can extend their application as antimicotic packaging, for instance. Films were manufactured with sodium alginate, using calcium chloride as cross-linking agent and glycerol as plasticizer. The use of calcium benzoate as active agent (benzoate ions) and as crosslinking agent (calcium ions) was investigated. Due to the strong gelling power of Ca++ ions, impeding smooth casting procedures, films with low reticulation are initially manufactured, using less than 0.54% Ca++ in the filmogenic solutions (1st stage). These films are further crosslinked with an excess of Ca++ by immersion in a solution of 3% to 7% of CaCl2 (2nd stage). Increasing the glycerol concentration in this solution improves the handling and plasticity of the films but increase water solubility and moisture content and an adequate compromise was obtained using 5% plasticizer. Tests conducted with partial or total substitution of CaCl2 by calcium benzoate indicated that the later could not be used in the 2nd stage solution since it promoted crystals precipitation on film surface. Active films, 0.06mm thick, pre-reticulated with calcium benzoate only and with 0.7% glycerol in the solution of the 1st stage, immersed for 30 minutes in a 3% CaCl2 and 5% glycerol solution (2nd stage) had around 17% moisture content and low water solubility (up to 20% of total dry mass). These films show low swelling degree (<50% of initial mass), good tension strength but low elongation ability. The water vapor permeability is moderate, typical of highly hydrophilic films. Benzoate liberation tests, using pure water as sink, presented good fit to solutions of Fick¿s 2nd law and effective diffusivities found varied from 4.2 to 6.3 × 10-7 cm2/s. The diffusivity values decreased with the degree of reticulation and increase with benzoate concentration in the film
Mestrado
Engenharia de Processos
Mestre em Engenharia Química

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Pires, Ana Luiza Resende 1984. "Desenvolvimento de curativos flexíveis e neutralizados de quitosana e alginato contendo Alphasan 'Marca Registra' RC2000." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266655.

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Orientador: Ângela Maria Moraes
Dissertação (mestrado-) - Universidade Estadual de Campinas, Faculdade de Engenharia Química
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Resumo: Polímeros biodegradáveis estão sendo amplamente aplicados na constituição de curativos para o tratamento de lesões de pele de diferentes origens, estando a quitosana e o alginato dentre os mais estudados. A associação de alginato e quitosana em curativos pode atuar de maneira positiva na absorção de fluidos das lesões, além de propiciar a incorporação de fármacos. Entretanto, a flexibilidade do dispositivo é baixa e o processo de obtenção é lento em função de etapas como a correção do pH para a neutralidade, secagem e reticulação. Neste trabalho teve-se por objetivo melhorar as propriedades mecânicas de membranas de quitosana e alginato pela incorporação de um gel de silicone comercial (Silpuran® 2130 A/B), avaliar os efeitos da correção do pH em etapa única, da temperatura de secagem e também da eliminação das etapas de reticulação nas características de membranas de quitosana e alginato na presença e ausência de AlphaSan®RC2000, um agente microbicida à base de prata. As membranas foram caracterizadas quanto à espessura, à absorção de fluidos, à perda de massa quando expostas a diferentes fluidos fisiológicos e à resistência mecânica. Análises complementares de FTIR e EDS também foram realizadas. Os resultados obtidos mostraram que as membranas secas a 60 °C apresentaram superfície mais lisa que as secas a 37 °C. A espessura diminuiu com a correção do pH para 7,0 e aumentou na presença de AlphaSan®RC2000. Para as formulações livres do antimicrobiano, a elevação do pH aumentou a absorção de soro fetal bovino e solução salina e aumentou também a perda de massa nesta última solução. Já as amostras obtidas na presença de AlphaSan® RC2000 apresentaram aumento na absorção de água. A elevação da temperatura reduziu somente a perda de massa após o contato com a água. A reticulação, após a secagem, com CaCl2 a 2% mostrou-se indispensável para a estabilização das membranas, resultando em materiais com aspecto mais rugoso e maior espessura. A absorção de fluidos, a estabilidade em diferentes fluidos e a resistência mecânica diminuíram tanto na presença quanto na ausência de prata. Análises por EDS e FTIR mostraram que tanto o AlphaSan® RC2000 quanto o Silpuran® 2130 A/B, não são removidos após a etapa de lavagem das membranas. As formulações contendo o composto siliconado apresentaram-se mais homogêneas, flexíveis e com maior caráter adesivo, assim como menor espessura. A absorção de soluções por estas formulações foi menor e a estabilidade em solução foi maior. A resistência mecânica aumentou significativamente com a incorporação de silicone, atingindo-se uma tensão de ruptura máxima de 63 MPa. Dessa forma, é viável a diminuição do tempo de processamento das membranas pelo ajuste do pH em etapa única, pelo uso de temperaturas mais elevadas de secagem e pela eliminação da etapa de reticulação primária. A incorporação de Silpuran® 2130 A/B mostrou-se uma boa alternativa para a melhora das propriedades mecânicas dos curativos de quitosana e alginato
Abstract: Biodegradable polymers are widely applied in the constitution of dressings for treating various types of skin lesions, being chitosan and alginate two of the most studied raw materials. The association between alginate and chitosan in wound dressings can act positively in the absorption of fluids from lesions, allowing also the incorporation of drugs. However, the device flexibility is frequently low and its production is time-consuming due to steps such as adjusting the pH to neutrality, sample drying and crosslinking. This study aimed to improve the mechanical properties of chitosan-alginate wound dressings by incorporating a commercial silicone gel (Silpuran® 2130 A/B) and to evaluate the effects of pH correction in one step, of the drying temperature and also of the elimination of the crosslinking steps in the characteristics of chitosan-alginate membranes obtained in the presence and absence of AlphaSan® RC2000, an antimicrobial agent containing silver in its composition. The membranes were characterized regarding thickness, absorption of fluids, mass loss in different fluids and mechanical resistance. Complementary analyzes of FTIR and EDS were also performed. The results showed that membranes dried at 60 °C presented smoother surfaces than when dried at 37 °C. Membrane thickness decreased with the correction of the pH to 7,0 and increased in the presence of AlphaSan® RC2000. For formulations free of the antimicrobial agent, the pH adjustment increased bovine fetal serum and saline solution absorption, increasing also sample mass loss in the latter solution. Devices containing AlphaSan® RC2000, on the other hand, had increased water absorption. The increase of drying temperature, however, reduced mass loss due to prolonged contact with water. The crosslinking with CaCl2 2% after a drying step was shown to be essential for membrane stabilization, conducting to materials with less smooth surfaces and with greater thickness. The absorption of fluids decreased for samples prepared both in the presence and absence of silver, as did membrane stability and mechanical properties. EDS and FTIR analyzes showed that both AlphaSan® RC2000 and Silpuran® 2130 A/B were not removed from the membranes after the washing step. The formulations incorporating the silicone compound showed more homogeneous surfaces, greater flexibility and adhesivity, as well as lower thickness. The solution absorption was lower and membrane stability was higher for those devices. The mechanical strength increased with the incorporation of silicone, reaching a maximum of 63 MPa. Thus, it is viable to decrease the processing time of the membranes by pH adjustment in a single step, through the use of higher temperatures during drying and by the eliminating of the primary crosslinking step. The incorporation of Silpuran® 2130 A/B proved to be a good alternative for the improvement of the mechanical properties of chitosan and alginate dressings
Mestrado
Desenvolvimento de Processos Biotecnologicos
Mestra em Engenharia Química

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Caswell, R. C. "Bacterial degradation of alginates." Thesis, Bucks New University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234705.

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Yamashita, Camila. "Efeito da aplicação de ozônio na qualidade de alginato extraído de algas pardas : (Sargassum spp.) /." Assis, 2019. http://hdl.handle.net/11449/181871.

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Orientadora: Ivanise Guilherme Branco
Banca: Cassia Roberta Malacrida Mayer
Banca: Izabel Cristina Freitas Moraes
Resumo: O alginato, presente na parede celular das algas marinhas pardas, apresenta coloração marrom, sendo necessário seu branqueamento para melhor aceitabilidade do mercado consumidor. O gás ozônio (O3) tem mostrado grande potencial de aplicabilidade como agente clareador mais sustentável. O presente estudo visa a otimização, utilizando a análise de superfície de resposta, dos parâmetros de clareamento (tempo, fluxo de oxigênio e temperatura), utilizando ozônio como agente branqueador, sobre os parâmetros colorimétricos (porcentagem de transmitância e índice de luminosidade), composição química (razão entre os ácidos manurônico (M) e gulurônico (G) M/G) e propriedades reológicas (viscosidade dinâmica, viscosidade intrínseca e massa molar) do alginato de sódio extraído de algas pardas (Sargassum spp.). Nas condições otimizadas de clareamento também foi verificada a influência da ozonização sobre a atividade antioxidante do alginato. O tempo é a variável independente que apresentou maior influência nas respostas, seguido da temperatura e fluxo de oxigênio. A condição otimizada encontrada foi um tratamento com fluxo de oxigênio de 2 L/min por 35 minutos à 25oC. A amostra clareada na condição otimizada apresentou capacidade antioxidante maior que a amostra comercial, indicando que o processo de clareamento por ozonização pode ser menos prejudicial aos compostos bioativos. Além disso, os antioxidantes naturais presentes no alginato de sódio aqui estudado podem agregar valor aos produtos que utilizam esse composto em preparações alimentícias
Abstract: Alginate is a polysaccharide which can be found in the cell wall of brown algae. Its original color is brown that is why a bleaching process is needed to improve this visual impairment. The ozone gas (O3) has shown a great potential as a more sustainable bleaching agent. The present study aims the optimization of bleaching parameters (time, oxygen flow rate and temperature) of sodium alginate from brown seaweeds (Sargassum spp.) using ozone gas as the bleaching agent on the colorimetrics parameters (percent transmittance and index of luminosity), chemical compositon (mannuronic (M) and guluronic (G) acid ratio M/G) and rheological properties (intrinsic viscosity, dynamic viscosity and molar mass). Once it was found the optimal conditions of bleaching, it was also verified the influence of ozonation on antioxidant activity of sodium alginate. The findings point out that ozonation time is the independent variable that most affects the responses, followed by the temperature and oxygen flow rate. The optimized bleaching conditions were determinated with an oxygen flow rate at 2 L/min, during 35 min at 25oC. The bleached sample on the optimized conditions presented a higher antioxidant capacity than the commercial sodium alginate sample, highlighting that the discoloration by ozone might be less harmful to bioactive compounds. Besides, natural antioxidants of sodium alginate can add value to products that use this compound in food preparations
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Chater, Peter. "Bioactive alginates and macronutrient digestion." Thesis, University of Newcastle upon Tyne, 2014. http://hdl.handle.net/10443/2460.

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Macronutrient digestion is a major factor in health and metabolic diseases such as obesity and diabetes and presents a huge global challenge. Modulating macronutrient digestion with food additives and pharmaceuticals has been shown to be a fruitful approach to the treatment of obesity (Orlistat) and diabetes (Acarbose). Previous work has shown that bioactive agents have novel modulatory effects on the major enzymes of digestion, and work in this lab has shown that specific alginates can inhibit pancreatic lipase up to 70%. Alginates are now being investigated as a potential anti-obesity agent. The purpose of this thesis was to develop in vitro methodologies and an analytical approach for investigating the effects of exogenous compounds on the major digestive enzymes; -amylase, pepsin, trypsin, and lipase. A 3-step process was developed consisting of; higher-throughput single enzyme analysis, selected enzyme kinetics and model gut analysis. Alginates were shown to inhibit the action of pepsin, but have no effect on trypsin activity in vitro. The structure of alginate is key to the inhibition of pepsin, and rheological and viscometric data suggested that this effect was due to a pH dependent interaction between alginate and protein substrate as well as direct enzyme-inhibitor interactions. A similar effect was observed with Fucoidan and sulphated carrageenans. In the model gut analysis, these effects manifested as inhibition of proteolysis in the simulated gastric phase, but not in the small-intestinal phase. Alginates were shown to increase the activity of α-amylase during in vitro single enzyme analysis, but have no significant affect on carbohydrate digestion in a model gut simulation. Fat digestion in the model gut simulation was inhibited by specific alginates, adding further weight to the potential use of alginates as a therapeutic treatment of obesity.

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Cruz, Maria Clara Pinto. "Influencia do poli(etileno glicol) (PEG) no processo de microencapsulação da oxitetraciclina no sistema alginato/quitosana : modelamento "in vitro' da liberação oral." [s.n.], 2004. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267677.

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Orientadores: Lucia Helena Innocentini Mei, Sergio Persio Ravagnani
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Quimica
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Resumo: Neste trabalho as análises de difusão de oxitetracilina (OTC) como espécie ativa, foram realizadas a 37 +/- 0,5 °C; em soluções tampão pH=7,4 e 1,2, condições estas similar ao trato gastro-intestinal, com microesferas de alginato de cálcio; microcápsulas de alginato de cálcio coacervado com quitosana (baixa, média e alta viscosidade); microcápsulas de alginato de cálcio coacervada com a quitosana baixa viscosidade, e revestidas com o polietileno glicol - PEG (2000, 4600 e 10000); microcápsulas de alginato de cálcio revestidas com o PEG e, finalmente, microcápsulas de alginato de cálcio revestidas com EUDRAGIT®. Na primeira parte do trabalho, priorizou-se o estudo da estrutura, sequência e composição das unidades repetitivas dos biopolímeros alginato e quitosana, as quais certamente exercem profunda influência na liberação controlada do fármaco. Na segunda parte, o coeficiente de difusão (D) de OTC foi calculado através de equações estabelecidas por Crank, para difusão em esferas, que seguem a segunda lei de Fick. Considerou-se a difusão do interior para o exterior das micropartículas, utilizando o método dos mínimos quadrados e método iterativo de Newton Raphson para ajuste dos dados. Foi verificado que o modelo matemático para a difusão de OTC tem uma representatividade muito boa em meio básico, mesmo com o efeito de disparo de OTC em forma de cristais alojados na superfície das micropartículas, conforme observado por Microscopia Eletrônica de Varredura (MEV). No entanto, em meio ácido, o ajuste não foi o esperado, pois fatores como a alta solubilidade do fármaco no meio; além da presença de fissuras nas microesferas, devido aos cristais na superfície, contribuíram para que o perfil desviasse do obtido em outros meios, resultando em um comportamento não-Fickiano. Finalmente, observou-se a possibilidade de modulação da velocidade de liberação nos diversos tipos de microesferas
Abstract: Diffusion studies of oxytetracycline (OTC) entrapped in microbeads of calcium alginate, calcium alginate coacerved with chitosan (high, medium and low viscosity) and calcium alginate coacerved with chitosan low viscosity, covered with Poly (ethylene glycol) - PEG (2 000, 4 600 and 10 000) and alginate covered with EUORAGITI®, were carried out at 37 +/- 0.5 °C, in buffer solutions at pH 7.4 and pH 1.2, similar to the conditions of the gastric-intestinal system. The diffusion coefficient, or diffusivity (D), of OTC was calculated by equations provided by Crank for diffusion, which follows Fick's second law, considering the diffusion from the inner parts to the surface of the microbeads. The least square and the Newton Raphson methods were used to obtain the diffusion coefficients. The microbeads swelling in pH 7.4 and OTC diffusion is classically Fickian, suggesting that the OTC transport, in this case, is controlled by the exchange rates of free water and relaxation of calcium-alginate chains. In case of acid media, it was observed that the phenomenon did not follow Fick's law, due probably to the high solubility of the OTC in this environment and the presence of cracks formed during the drying process of the microbeads. It was possible to model the release rate of OTC in several types of microbeads
Doutorado
Ciencia e Tecnologia de Materiais
Doutor em Engenharia Química

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Sacchetin, Priscila Soares Costa. "Incorporação de Flavobacterium columnare inativado em microparticulas de alginato e quitosana para a imunização de tilapia do Nilo (Oreochromis Niloticus) por via oral." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267175.

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Orientador: Angela Maria Moraes
Dissertação (mestrado) - Universadade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: A imunização oral destaca-se por sua praticidade, custo moderado e ao baixo estresse que provoca nos animais. Esta técnica possui como principal entrave a dificuldade de proteger o agente de imunização dos processos digestivos e da decomposição por enzimas às quais este é submetido durante a passagem pelo trato gastrointestinal. Neste contexto, este trabalho teve como objetivo propiciar ao agente antigênico um sistema de proteção frente à ação de degradação no trato gastrointestinal. Para isso, propôs-se a incorporação de um antígeno-modelo (células inativadas de Flavobacterium columnare) em partículas de alginato e de quito sana recobertas com alginato preparadas por métodos passíveis de escalonamento baseados na formação de emulsões. Aspectos como a temperatura, o uso de diferentes impelidores, a alteração na concentração dos biopolímeros no diâmetro e na forma das micropartículas produzidas foram avaliadas. O comportamento in vitro destes sistemas microestruturados, sua estabilidade e o perfil de liberação do agente antigênico foram também analisados. Micropartículas com diâmetros médios inferiores a 50 µm foram obtidas. As micropartículas de alginato foram capazes de encapsular praticamente 100% das células inativadas, enquanto que as de quito sana incorporaram até 84% do agente antigênico. As partículas produzidas resistiram às condições gastrointestinais simuladas de tilápia do Nilo, liberando um máximo de 4% do antígeno em pH estomacal e de 9% em pH intestinal. As partículas produzidas poderiam, desta forma, ser eficientemente empregadas, hipoteticamente, no controle de columnariose em tilápias do Nilo
Abstract: Oral immunization is a practical and low cost fish vaccination method with the advantage of causing low stress to the animals. The main concern regarding oral vaccination is related to protecting the immunizing agent from exposure to the digestive processes and enzymatic decomposition when crossing the gastrointestinal tract. In this context, the goal of this work was to provide a protection system to the antigenic agent when facing degradation action in gastrointestinal conditions. Thus, the incorporation of a model antigen (inactivated Flavobacterium columnare cells) in alginate micropartic1es and also in chitosan micropartic1es coated with alginate was evaluated, using methods suited to up-scaling based on emulsion formation. Aspects such as temperature, the use of distinct impellers and the variation on the biopolymers concentration in the diameter and shape of the produced micropartic1es were analyzed. The microstructured system behavior in vitro, its stability and the antigenic agent release profile were also evaluated. Microparticles with less than 50 µm in average diameter were produced. The alginate microparticles were capable of encapsulating almost 100% of the inactivated cells, while the chitosan micropartic1es incorporated up to 84% of the antigenic agent. The produced partic1es were resistant to Nile tilapia simulated gastrointestinal conditions, releasing at most 4% of the cells in stomach pH and less than 9% in intestinal pH. The produced partic1es, in this way, could be successfully employed, hypothetically, to control Nile tilapia columnariosis
Mestrado
Desenvolvimento de Processos Biotecnologicos
Mestre em Engenharia Química

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Reehorst, Camilla M. "The Mucin-Alginate Interplay : Investigating the Rheological Impact of Alginates and Their Influence on Particle Mobility." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for bioteknologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-24921.

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Mucus is a hydrogel that covers epithelial cells and acts as an intermediary between the exterior and interior surfaces of the human body. It is complex and diverse, comprised of various compounds and serves as a selective barrier to pathogens, nutrients and administered substances. It is therefore important to circumvent or penetrate this barrier to increase drug bioavailability. The most important constituent of mucus is mucin glycoprotein that enables gel formation. Due to the molecular nature of mucin, it interacts with most substances including polyanionic biopolymers like alginates. Alginate molecules have been extensively used in pharmaceutical and medical industries as mediators because they possess suitable characteristics for a variety of biomedical applications. They have also been shown to influence mucus rheology, and could hold potential to alter other properties of mucus as well, such as particle mobility. In this thesis, the effect of different molecular weight alginates were investigated on the rheology of porcine gastric (PG) mucin, porcine small intestinal mucus (PSIM), porcine tracheobronchial mucus (PTBM) and bio-similar mucus. In addition, the effect of alginate on particle mobility in PG mucin samples were investigated using multiple particle tracking (MPT). The rheological effect of alginate G-block DPn 12, DPn 24, DPn 33 and alginate LFR 5/60 on PG mucin was inconclusive as the sample suffered from pH and mechanical instabilities. Particle mobility was greatest for G-block DPn 12 and G-block DPn 33 treated PG mucin at long time scales. In addition, their mean-square displacement (MSD) trajectories were more narrowly distributed than the other samples, which correlates to a higher degree of uniform pore sizes. The rheological behaviour of bio-similar mucus and PSIM after treatment of G-block DPn 12, G-block DPn 33 and LFR 5/60 did not coincide, despite bio-similar mucus being a model system for porcine intestinal mucus (PIM). This was ascribed interactions between alginate and polyacrylate in the bio-similar mucus causing phase separation. Alginate G-block DPn 12 weakened the PSIM and PTBM gel, while G-block DPn 33 and LFR 5/60 had minor strengthening effects on PSIM.

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Ayarza-León, Jorge Luis. "Alginates: 20000 applications of submarine algae." Revista de Química, 2014. http://repositorio.pucp.edu.pe/index/handle/123456789/100618.

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Desde la antigüedad, el ser humano ha encontrado recursos de gran utilidad en el mar. Las algas pardas marinas de la clase Phaeophyceae son la fuente de un biopolímero con propiedades muy interesantes, denominado alginato. En la actualidad, el alginato es extraído y comercializado en muchos lugares del mundo, es un componente importante en muchos productos de uso diario, e incluso se le emplea a nivel de investigación académica.
Since antiquity, mankind has depended on the sea to obtain valuable resources. Marine brown algae from the class Phaeophyceae are the source of a biopolymer with very interesting properties called alginate. Nowadays, alginate is extracted and commercialized around the world, it is an essential component in many everyday products, and it is even used in academic research.

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Bouffar-Roupe, Christine. "Structure et propriétés gélifiantes des alginates." Grenoble 1, 1989. http://www.theses.fr/1989GRE10030.

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Mise en evidence de zones riches en mannuronates et/ou guluronates par hydrolyse partielle; la structure des zones de defaut est constituee d'une distribution aleatoire de ces deux unites. Determination du pourcentage en acide guluronique par hydrolyse chimique totale. Influence de la composition sur les principales grandeurs physicochimiques. Gelification par diffusion des ions calcium dans une solution d'alginate de sodium a haute temperature

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Munin, Aude. "Microparticules de composés naturels réticulés par transacylation : mise au point et étude." Thesis, Reims, 2011. http://www.theses.fr/2011REIMP201.

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Les travaux concernent la mise au point et l'étude de microcapsules de composés naturels réticulés pour des applications en cosmétologie
The study deals with the development of microcapsules from reticulated natural products, for cosmetological applications

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Tacin, Mariana Vendrasco [UNESP]. "Imobilização da enzima álcool desidrogenase em suportes alginato-quitosana e glioxil-agarose." Universidade Estadual Paulista (UNESP), 2015. http://hdl.handle.net/11449/123821.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
As enzimas são importantes catalisadores de reações biológicas, sendo que as de origem microbiológicas tem recebido atenção especial devido à facilidade de obtenção ou até mesmo na síntese de enzimas geneticamente modificadas. O uso desses catalisadores biológicos na indústria vem aumentando com o avanço de estudos e pesquisas de suas propriedades e melhoramento dos processos em que são empregados. A álcool desidrogenase (ADH) é uma enzima de uso industrial e biotecnológico importante para quantificação de etanol em biocombustíveis e em bebidas, onde, em comparação com outros métodos, têm mostrado ser o mais eficaz. A melhora da estabilidade da enzima é feita pelo processo de imobilização. Alguns métodos de imobilização são mais comumente aplicados devido à facilidade de preparo e/ou imobilização da enzima no suporte, como por exemplo, o suporte alginato-quitosana. Os suportes alginato-quitosana e glixil-agarose foram utilizados neste trabalho para se tentar melhorar a estabilidade da ADH. O objetivo principal deste estudo foi o de encontrar um método mais eficaz para imobilizar a ADH e avaliar sua estabilidade frente a pH, temperatura, variação de concentração de substrato, adição de sais metálicos ao ensaio, entre outros. Os resultados mostraram que houve interferência do pH na estabilidade das esferas de alginato-quitosana impossibilitando seu uso neste ensaio e quando imobilizada em suporte glioxil-agarose apresentou estabilidade maior em maiores temperaturas e pH, mas não demonstrou boa estabilidade quando estocada.
Enzymes are important catalysts of biological reactions, and the microbiological origin has received special attention due to the ease of obtaining or even in the synthesis of genetically modified enzymes. The use of these biological catalysts in the industry is increasing with the advancement of studies and research of its properties and improving processes in which they are employed. The alcohol dehydrogenase (ADH) is an enzyme of industrial use and biotechnological important for quantitation of ethanol in biofuels and beverages, which in comparison with other methods, have shown to be most effective. The improvement of the enzyme stability is made by the immobilization process. Some methods of immobilization are most commonly applied because of the ease of preparation and/or immobilization of the enzyme on the support, for example, alginate-chitosan support. The supports alginate-chitosan and glyoxyl-agarose were used in this study to try to improve the stability of ADH. The aim of this study was to find a more effective method to immobilize the ADH and evaluate its stability against pH, temperature, variation of substrate concentration, addition of metal salts in the assay, among others. The results showed that there was interference of pH on the stability of alginate-chitosan beads precluding their use in this assay and when immobilized on glyoxyl agarose support was more stable at higher temperatures and pH, but showed good stability when stored.

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Zactiti, Erica Marostica. "Desenvolvimento e caracterização de filmes biodegradaveis de alginato de calcio sem e com sorbato de potassio." [s.n.], 2004. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267668.

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Orientador: Theo Guenter Kieckbusch
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: Questões relacionadas à preservação ambiental têm sido intensamente discutidas, não somente devido à escassez de recursos naturais, mas também, em função da legislação que está cada vez mais rigorosa. Visando o desenvolvimento sustentável, a procura por novos materiais e tecnologias capazes de minimizar os danos ao meio ambiente tem aumentado consideravelmente. Filmes biodegradáveis estão inseridos nesse contexto. Eles são produzidos a partir de polímeros naturais, principalmente polissacarídeos e proteínas, com potencial aplicação nas indústrias farmacêutica e alimentícia. Filmes confeccionados a partir de biopolímeros podem ser utilizados como embalagens antimicrobianas para produtos alimentícios se os agentes ativos são incorporados. Alginato de sódio foi utilizado como substância formadora de filme, cloreto de cálcio como agente reticulante e glicerol como plastificante. Um processo de confecção de filmes reticulados realizado em dois estágios foi desenvolvido, sendo possível obter filmes com baixa solubilidade em água. Filmes com diferentes graus de reticulação foram caracterizados em relação a suas propriedades, tais como: solubilidade em água, permeabilidade ao vapor de água, resistência mecânica, grau de intumescimento e temperatura de transição vítrea. Para o desenvolvimento de embalagens ativas, sorbato de potássio foi incorporado ao filme. Medidas de permeabilidade utilizando uma célula de diafragma indicaram que o processo de migração do sorbato foi afetado pela concentração de sorbato na solução e que o aumento do grau de crosslinking da matriz polimérica diminui a taxa de transferência de massa. Experimentos de liberação de sorbato realizados com água (22 °C) como sorvedouro mostraram rápida liberação do material ativo por difusão (95 % da massa total liberada em aproximadamente 4 minutos). Dados de massa de sorbato liberada apresentaram bom ajuste ao modelo difusional derivado da segunda lei de Fick, com os valores de difusividade variando entre 2,32 x10-7 a 3,32 x10-7cm2/s. Estes valores são inferiores aos dados de difusão de sorbato em filmes de proteína, indicando um uso potencial como sistemas de liberação de substâncias antimicóticas
Abstract: The concern and consciousness relative to the environmental preservation is raising global issues, not only due to the shortage of natural resources, but also because of the legislation that is becoming more and more stringent. Seeking the sustainable development, the number of researches on new materials and technologies that are able to minimize the environmental damages have grown considerably. Biodegradable films are inserted in this context. They are produced from natural polymers, mainly polysaccharides and proteins, with potential applications in the pharmaceutical and food industries. Films manufactured with biopolymers can be used as antimicotic packaging for food products if active agents are incorporated. Sodium alginate was used as film matrix, calcium chloride as reticulating (crosslinking) agent and glycerol as plasticizer. A two-stage reticulation film manufacture process was developed and rendered films with low solubility in water. Films with different degree of reticulation were characterized according to properties such as water solubility, water vapor permeability, mechanical resistance, degree of swelling and glass transition temperature. For the development of active packaging, potassium sorbate was incorporated into the film. Permeability measurements using a diaphragm 0011 indicated that the sorbate migration process was affected by the sorbate concentration and that higher crosslinking degree of the polymeric matrix decreases the mass transfer rates. Sorbate release experiments conducted with water at 22°C as a sink showed rapid exhaustion of the active material by diffusion (95 % of total mass delivered in about 4 minutes). The mass of sorbate release data were well fitted to Fick's second law diffusional model, with O values ranging from 2,32 x10-7 to 3,32 x10-7 cm2/s. These values are lower than published data of sorbate diffusion in protein film, foreseeing a potential use of calcium alginate as an antimicotic packaging
Doutorado
Engenharia de Processos
Doutor em Engenharia Química

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Tacin, Mariana Vendrasco. "Imobilização da enzima álcool desidrogenase em suportes alginato-quitosana e glioxil-agarose /." Araraquara, 2015. http://hdl.handle.net/11449/123821.

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Orientador: Edwil Aparecida de Lucca Gattás
Banca: Saulo Santesso Garrido
Banca: Maristela de Freitas Sanches Peres
Resumo: As enzimas são importantes catalisadores de reações biológicas, sendo que as de origem microbiológicas tem recebido atenção especial devido à facilidade de obtenção ou até mesmo na síntese de enzimas geneticamente modificadas. O uso desses catalisadores biológicos na indústria vem aumentando com o avanço de estudos e pesquisas de suas propriedades e melhoramento dos processos em que são empregados. A álcool desidrogenase (ADH) é uma enzima de uso industrial e biotecnológico importante para quantificação de etanol em biocombustíveis e em bebidas, onde, em comparação com outros métodos, têm mostrado ser o mais eficaz. A melhora da estabilidade da enzima é feita pelo processo de imobilização. Alguns métodos de imobilização são mais comumente aplicados devido à facilidade de preparo e/ou imobilização da enzima no suporte, como por exemplo, o suporte alginato-quitosana. Os suportes alginato-quitosana e glixil-agarose foram utilizados neste trabalho para se tentar melhorar a estabilidade da ADH. O objetivo principal deste estudo foi o de encontrar um método mais eficaz para imobilizar a ADH e avaliar sua estabilidade frente a pH, temperatura, variação de concentração de substrato, adição de sais metálicos ao ensaio, entre outros. Os resultados mostraram que houve interferência do pH na estabilidade das esferas de alginato-quitosana impossibilitando seu uso neste ensaio e quando imobilizada em suporte glioxil-agarose apresentou estabilidade maior em maiores temperaturas e pH, mas não demonstrou boa estabilidade quando estocada.
Abstract: Enzymes are important catalysts of biological reactions, and the microbiological origin has received special attention due to the ease of obtaining or even in the synthesis of genetically modified enzymes. The use of these biological catalysts in the industry is increasing with the advancement of studies and research of its properties and improving processes in which they are employed. The alcohol dehydrogenase (ADH) is an enzyme of industrial use and biotechnological important for quantitation of ethanol in biofuels and beverages, which in comparison with other methods, have shown to be most effective. The improvement of the enzyme stability is made by the immobilization process. Some methods of immobilization are most commonly applied because of the ease of preparation and/or immobilization of the enzyme on the support, for example, alginate-chitosan support. The supports alginate-chitosan and glyoxyl-agarose were used in this study to try to improve the stability of ADH. The aim of this study was to find a more effective method to immobilize the ADH and evaluate its stability against pH, temperature, variation of substrate concentration, addition of metal salts in the assay, among others. The results showed that there was interference of pH on the stability of alginate-chitosan beads precluding their use in this assay and when immobilized on glyoxyl agarose support was more stable at higher temperatures and pH, but showed good stability when stored.
Mestre

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18

Houghton, David. "Modulation of fat digestion using bioactive alginates." Thesis, University of Newcastle upon Tyne, 2014. http://hdl.handle.net/10443/2520.

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Obesity is a fast growing medical issue worldwide and is one of the leading causes of mortality. There is evidence to suggest that various forms of dietary fibre may be used in weight management and for their general health benefits. There is evidence to suggest that the addition of alginate to a food or beverage has the potential to alter the digestion process and potentially reduce the activity of digestive enzymes. Data from this laboratory have demonstrated that alginate possesses the ability to inhibit pancreatic lipase in-vitro. Pancreatic lipase is secreted in the small intestine and hydrolyses fat so that it can be absorbed in the digestive system. If the activity of pancreatic lipase can be reduced then the amount of fat absorbed will be reduced. A modified Periodic Acid Schiffs (PAS) assay is an effective, repeatable and simple method for quantifying alginate in solution. Furthermore with any potential weight loss treatment the release rate must be determined. The model gut system developed in this laboratory is able to digest the alginate enriched bread and the modified PAS assay system is able to quantify the release rate of the alginate, with between 12-20% released in the gastric phase and 80-88% released in the small intestinal phase. The data here also confirms that the bread is protecting the alginate during the cooking process, and that the alginate retains its inhibition properties despite the cooking and digestion process. The model gut is an effective model for digesting fat substrates and foods high in fat such as butter and olive oil. Alginate enriched bread has the ability to inhibit fat substrates glyceryl trioleate, trioctanoate, tributyrate, and foods butter and olive oil 62, 39 and 32, 95 and 78% respectively after 180 minutes in the model gut. Alginate enriched bread is able to modulate fat digestion in ileostomy subjects following ingestion. This was evident by a significant increase in fat content of the effluent fluid. There was an increase in fat content of 81g and 112g when subjects consumed alginate bread when compared with control bread at 240-270-300 minutes and when total fat was combined for all time points respectively. There was also an increase of 292g in wet effluent weight for alginate bread when compared with the control bread. In addition a significant relationship between the wet effluent weight and fat content of the effluent was reported. The alginate enriched bread had no problems with palatability or adverse side effects associated with fat digestion and suggest that alginate enriched bread may be a suitable method for the delivery of alginate into a normal diet. The data in this thesis suggests that alginate enriched products are able to attenuate the digestion of fat and therefore may be used in weight management and in the treatment of obesity, however further longitudinal clinical research is required in a healthy population before any health claims can be made.

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Pawar, Siddhesh Nitin. "Chemical Modification of Alginates in Organic Media." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/52635.

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Alginates are (1and4) linked linear copolysaccharides composed of B-D-mannuronic acid (M) and its C-5 epimer, a-L-guluronic acid (G). Several strategies to synthesize organically modified alginate derivatives have been reported, but almost all chemistries are performed in either aqueous or aqueous-organic media. The ability to react alginates homogeneously in organic solvents would open up access to a wide range of new chemistries and derivatives. However, past attempts have been restricted by the absence of methods for alginate dissolution in organic media. We therefore report a strategy to solubilize tetrabutylammonium (TBA) salts of alginic acid in polar aprotic solvents containing tetrabutylammonium fluoride (TBAF). Acylation of TBA-alginate was performed in DMSO/TBAF to get products with DSacetyl up to ~ 1.0. We further report that by using appropriate solvent conditions, placement of acyl groups can be controlled to achieve either random or M-selective substitution. Alginate acetates synthesized in an M-selective fashion were used to study the ability of these derivatives to form Ca-crosslinked hydrogels. Detailed structure-property analyses were performed to identify acetylation reaction conditions and product properties that may be ideal for hydrogel formation. Furthermore, alginate esters were synthesized via modification of carboxylate groups on the backbone. These derivatives dissolved in polar aprotic solvents without the need to add TBAF. A proof of concept study showed their utility in the solubility enhancement of the poorly water soluble flavonoid naringenin.
Ph. D.

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Aguiar-Oliveira, Elizama. "Imobilização da enzima frutosiltransferase extracelular de Rhodotorula sp. e aplicação na produção de frutooligossacarideos." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256544.

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Orientador: Francisco Maugeri Filho
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: obtenção de frutooliogossacarídeos (FOS) por enzimas imobilizadas abrange dois conceitos em grande expansão nos últimos anos: aplicação industrial de enzimas imobilizadas e alimentos funcionais. A opção de imobilização é principalmente induzida pela facilidade de controle da reação e possibilidade de reutilização do sistema, além de permitir escalonamento industrial. Dentre os alimentos funcionais estão os FOS que agem como prebióticos ao induzirem o crescimento de uma microflora desejável e benéfica ao organismo. As leveduras do gênero Rhodotorula apresentam bom potencial de transfrutosilação e sua enzima extracelular recuperada do meio de cultivo por precipitação com álcool anidro foi imobilizada em diferentes suportes para seleção de uma metodologia adequada de imobilização. Os melhores resultados foram obtidos ao se imobilizar a enzima por adsorção em suporte sólido ácido inorgânico composto por nióbio e grafite, comercializado pela Companhia Brasileira de Metalurgia e Mineração. A eficiência de imobilização foi de 97,76% para uma razão de 164 Ui/g suporte. O perfil de pH da enzima imobilizada foi deslocado e estendido para valores mais básicos do que o apresentado pela enzima livre, indicando efeito causado pela carga negativa do suporte. A adição de sais a 10 mM no meio de incubação demonstrou aumentar a estabilidade térmica do imobilizado, especialmente para o sal CuSO4. Em pH 4,5 e 6,0 foi observada alta atividade enzimática e estabilidade em diferentes temperaturas, e ambos os pHs foram selecionados para caracterização do sistema. A meia-vida da enzima imobilizada a 50oC em pH 4,5 e 6,0 foi respectivamente de 24 e 48 dias e a temperatura ótima para cada pH foi de 61oC e 63oC. A cinética enzimática apresentou inibição pelo substrato sacarose, efeito não observado com a enzima livre. Sínteses de FOS tendo sacarose a 50% como substrato inicial, foram realizadas em micro-reatores do tipo batelada nos pHs selecionados, a conversão de FOS obtida apresentou valores em torno de 60%, não muito diferentes da enzima livre. Com base nos resultados obtidos, é possível afirmar que a metodologia selecionada é viável para aplicação da enzima imobilizada em biorreatores para produção de FOS
Abstract: Fructooligosaccharides (FOS) production by immobilized enzymes encloses two concepts that have faced great expansion in the last few years: industrial application of enzymes and functional foods. The option for enzyme immobilization is mainly induced by the easiness of controlling the reaction and the possibility of reusing the biocatalyst, besides the fact of allowing industrial scale-up. Amongst functional foods, there are the FOS for acting as a prebiotic inducing the growth of a desirable and beneficial microflora to our organism. Yeasts from the genre Rhodotorula has demonstrated a great transfructosilation potential and its extracellular enzyme recovered from fermented medium by alcohol precipitation were immobilized on different supports and by different methodologies in order to select the most adequate of them. The best results were achieved immobilizing the enzyme by adsorption on a solid acid support consisted of niobium ore and graphite, commercialized for Companhia Brasileira de Metalurgia e Mineração. The immobilization efficiency reached 97,76% at a rate of 164 Ui/g of support. Considering the immobilized enzyme, the pH profile changed to more basics values comparing to free enzyme, indicating an effect caused by negative charge of the support. Salt addition at 10 mM to incubation medium demonstrated to increase thermal stability, especially for CuSO4 salt. At pH 4,5 and 6,0 high activity and good stability were observed in different temperatures, and both were selected for system characterization. The half-life obtained at 50oC and pH 4,5 and 6,0 were respectively 24 and 48 days and the maximum activities for each pH were at temperature of 61oC and 63oC. Enzymatic kinetic for the immobilized enzyme presented inhibition by substrate concentration, effect not observed with free enzyme. FOS synthesis with sucrose at 50% as starting substrate were conducted in micro-reactors in both pH and the FOS conversion obtained were around 60%, similar to free enzyme. Based in these results it is possible to say that this methodology for enzyme immobilization is viable for application in large scale bioreactors for FOS production
Mestrado
Mestre em Engenharia de Alimentos

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Tamayo, Rojas Sebastián Alfredo 1986. "Estudo do uso de hidrocolóides como estabilizante de espuma em cervejas." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256410.

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Orientador: Flávio Luís Schdmit
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: O Brasil vem se destacando como grande mercado produtor e consumidor de cerveja no cenário mundial, o que mostra a importância de se desenvolver novas tecnologias cervejeiras, buscando melhoria da qualidade do produto. Esta pesquisa teve como objetivo estudar a estabilidade da espuma da cerveja "mainstream" mediante a adição de hidrocolóides não convencionais após o processo de filtragem. Doze hidrocolóides dentre os grupos pectina, xantana, gelana, carragena, carboximetil celulosa e locusta foram comparados com o alginato de propilenglicol (APG), atualmente utilizado na indústria brasileira. Foi utilizada uma cerveja lager tipo Pilsen elaborada sem aditivos espumantes previamente desgaseificada a 8ºC com injeção de hélio a 50 KPa adaptado de um equipamento Shimadzu® DGU-2A. Primeiramente descartaram-se os hidrocolóides que não se dissolveram corretamente na cerveja nas concentrações de 0,01g/L a 1g/L. Posteriormente, realizou-se uma análise de viscosidade das misturas dos hidrocolóides selecionados, em água e com cerveja, para avaliar diferenças significativas entre os mesmos nas concentrações testadas (0,01 a 0,1 g/L). Em seguida se avaliou a capacidade espumante, mediante um teste de agitação das cervejas com os hidrocolóides nas concentrações de 0,01 a 1g/L, baseado no procedimento descrito por Knapp e Bamforth (2002), as quais foram comparadas com o APG. Finalmente, as cervejas foram misturadas com os diferentes hidrocolóides em concentrações de 0,5 g/L, e submetidas novamente a um teste de estabilidade de espuma na presença de lipídeos (ácido palmítico, ácido oléico e ácido linoléico) em concentrações de 1mg/L. Foram pré-selecionados os hidrocolóides KIMILOID BF (APG), Genu GUM RL 200-Z; Genu Pectin 106-HV e Genu Pectin 121 Slow Set. Em relação à viscosidade, nenhum hidrocolóide diferiu significativamente (p<0,05) do outro na sua capacidade espessante em soluções aquosas ou em cerveja, nas concentrações testadas. Em relação à manutenção da qualidade da espuma, os melhores hidrocolóides foram a APG e a Genu® Pectin tipo 106-HV, os quais foram estatisticamente iguais em todas as concentrações testadas e apresentaram os melhores desempenhos na estabilização da espuma. De forma geral, os hidrocolóides diminuíram o prejuízo causado pelos ácidos graxos, sendo que o melhor efeito foi sobre o acido linoléico, seguido do acido oléico. Nestes ácidos graxos a Genu® Pectin tipo 121 Slow Set foi a que apresentou melhor desempenho, seguida do KIMILOID® BF (APG). Somente a APG conseguiu diminuir o prejuízo na espuma causado pelo ácido graxo palmítico
Abstract: Beer production and consumption has gained increasing importance in Brazil. New brewer technologies are needed for improvement of product quality. This research aimed to study the stability of mainstream beer foam by the addition of non-conventional hydrocolloids after the filtering process. Twelve hydrocolloids among pectin, xanthan, gellan, carrageenan, carboxymethyl cellulose (CMC) and locust groups were compared with propylene glycol alginate (PGA), currently used in Brazilian industry. It was used Pilsen lager beer produced without foaming additives previously degassed at 8°C with injection of helium at 50 kPa adapted from a Shimadzu DGU-2A® equipment. Hydrocolloids which did not dissolve properly in beer at concentrations of 0.01 g/L to 1g/L were discarded. Subsequently, viscosity analyses (Brookfield LVDVI-Prime® spindle and cup ULA. In order to keep CUP at 20°C it was used a Brookfield TC-550 water bath) of the selected hydrocolloids in water and beer solutions were performed to assess significant differences among them in the tested concentrations (0.01 to 0.1 g/L). Then foaming capacity was evaluated by a stirring beer test with hydrocolloids at concentrations of 0.01 to 1 g/L, based on the procedure described by Knapp and Bamforth (2002), which were compared with the APG. Finally, the beers were mixed up with the various hydrocolloids at concentrations of 0.5 g/L, and again subjected to a test of foam stability in the presence of palmitic, oleic and linoleic acids at 1 mg/L. The preselected hydrocolloids were KIMILOID BF® (APG), Genu GUM RL 200-Z®; Genu Pectin® 106-HV e Genu Pectin® 121 Slow Set (Figure 1). No hydrocolloid was significantly different (p<0.05) in relation to the capacity of thickening aqueous or beer solutions. Concerning the quality of the foam maintenance, the best hydrocolloids were APG and Genu Pectin 106-HV type, which were statistically similar in all tested concentrations. Generally, hydrocolloids reduced the damage caused by the fatty acids and the best effect was on linoleic followed by oleic acid. In these conditions, Genu Pectin type 121 Slow Set showed the best performance, followed by KIMILOID BF (APG). The damage in the foam caused by the palmitic fatty acid was only minimized by APG
Mestrado
Tecnologia de Alimentos
Mestre em Tecnologia de Alimentos

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22

Mørch, Yrr A. "Novel Alginate Microcapsules for Cell Therapy – A study of the structure-function relationships in native and structurally engineered alginates." Doctoral thesis, Norwegian University of Science and Technology, Norwegian University of Science and Technology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-2003.

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Alginate microcapsules have the potential as immune barriers for cell transplantation where the alginate gel protects the transplant from the host immune system. Microencapsulation can thus provide a way to overcome the need for immunosuppressive drugs. The successful use of alginates as immobilization material has, however, been hampered by their mechanical instability and high porosity. To overcome this problem, a polycation layer has traditionally been added to the alginate gels. However, polycations are toxic to cells and provoke inflammatory reactions. Hence, the main goal of the present work was to improve the functionality of alginate gels in order to omit the use of polycations. Alginate gel properties were found to depend strongly on many factors such as the choice of alginate material, choice of gelling ion and method of preparation, all which can be manipulated to form alginate gel beads with enhanced functionality.

In particular, specific enzymes (C-5 epimerases) that modify the alginate chain were used to form novel alginate materials, some with extreme composition not found in nature. Gels of enzymatically engineered alginate were found to be more elastic and compact, less permeable, and extremely stable under physiological conditions, offering significant advantages over native alginates. Hence, by controlling alginate nanostructure in a highly specific way, we were able to manipulate the macroscopic properties.

One of the most striking features of epimerization was the effect seen upon increasing the amount of alternating sequences in the alginate chains using the specific epimerase AlgE4. On the basis of a detailed study on the resulting products of AlgE4 epimerized alginate we hypothesized the direct involvement of the alternating sequences in junction formation. The choice of gelling ions for alginate gel formation was also found to have significant effects on the final gel properties. Interestingly, the effect was highly dependent on the alginate material used. Application of alginates with extreme composition revealed that different block structures in the alginate bound the ions to different extent. Alginate beads with enhanced functionality could hence be formed using a proper combination of ions and alginate material. Finally, confocal laser scanning microscopy (CLSM) was established as a versatile and easy method to visualize the macroscopic character of alginate microcapsules such as the polymer distribution in capsules. Further, effect of different encapsulation procedures on the final capsule characteristics was revealed.

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23

陳曉芳 and Xiao-fang Chen. "The effect of propylene glycol alginates on oil uptake texture of steamed-and-fried instant noodles." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1997. http://hub.hku.hk/bib/B3121504X.

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24

Chen, Xiao-fang. "The effect of propylene glycol alginates on oil uptake texture of steamed-and-fried instant noodles /." Hong Kong : University of Hong Kong, 1997. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19003456.

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25

Nichols, Paul Vincent. "An Investigation of the Dimensional Stability of Dental Alginates." Thesis, The University of Sydney, 2006. http://hdl.handle.net/2123/1270.

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Dimensional stability was defined by Nicholls (1977) as “the ability (of a material) to maintain accuracy over time”, and the result of loss of accuracy, “distortion”, as “the relative movement of a single point, or group of points, away from some originally specified reference position such that permanent deformation is apparent”. Maintaining dimensional stability of dental impression materials is vital if the impression cannot be cast (in stone) soon after removal from the mouth. Dental irreversible hydrocolloid (alginate) is a major dental impression material used worldwide in many clinical procedures. However, alginate is dimensionally unstable and changes its dimensions (suffers “distortion”) after removal from the mouth. With storage times of more than ten minutes, alginate begins to distort, and after one to three hours (depending on the product and storage conditions) cannot be used for many clinical purposes, especially fixed prosthodontics such as crowns and bridges (Hampson 1955, Skinner & Hoblit 1956, Wilson & Smith 1963, Rudd et al. 1969, Miller 1975, Inohara 1977, Schoen et al. 1978, Coleman et al. 1979, Linke et al. 1985, Habu et al. 1986, Peutfeldt & Asmussen 1989, Mathilde & Peters 1992, Khan & Aziz Sahu 1995, Eriksson et al. 1998, Schleier et al. 2001, and Donovan & Chee 2004). This loss of accuracy, due to dimensional instability, manifests as a time-dependent distortion of the poured stone cast, and thus any prosthesis fabricated will not fit in the mouth. With the introduction of the more stable elastomers in the 1950s (Stackhouse 1970, Glenner 1997, Brown 2003) that could be stored for days if necessary, without loss of accuracy, the alginates fell out of favour for fixed prosthodontics. Recently, there has been a resurgence of interest in alginate for use in dental procedures where dimensional stability is critical (Peutzfeldt and Asmussen 1989, Eriksson et al. 1998). This in part is due to the favourable properties of alginate not found in the elastomers. Of greatest significance is that alginate hydrocolloid is hydrophilic, whereas elastomers are hydrophobic (Phillips & Ito 1958, Glenner 2004). Thus, alginate materials are able to reproduce wet oral areas with greater precision and to produce a superior "fit" of, say, a gold casting produced by the Lost Wax technique (Skinner and Phillips 1982). A number of reports have been published which investigate newer alginate materials that are claimed to be more dimensionally stable than older formulations. Puetzfeldt and Asmussen (1989) found that a newer alginate , if stored at 100% relative humidity, retained accuracy over 24 hours that was equivalent to that of the elastomers. More recently, the manufacturer of another alginate has claimed equivalent dimensional stability to the elastomers for up to 100 hours, and, whilst this claim has not been reported on in the literature, the present thesis will show that, under favourable conditions of storage, the material maintained clinically useful accuracy for up to 100 hours. Another approach to improving the accuracy of alginate impressions has been to combine reversible hydrocolloid with alginate (the “Bilaminar” technique). Frederick and Caputo (1997) confirmed that the new agar reversible hydrocolloids are just as accurate (at the time of removal from the mouth) as the new elastomers. Mathilde et al. (1992) and Eriksson et al. (1998) have shown that several of the “bilaminar” impression techniques for fixed prosthodontics, where alginate is used as a tray material supporting a reversible hydrocolloid (agar) wash, are as accurate and dimensionally stable as elastomers for up to three hours. However, these studies are difficult to interpret due to lack of uniformity in the testing methods, and the fact that there is no regulatory standard available to measure dimensional stability for dental alginates. The International Standard (IS) for alginate impression materials (ISO 1563:1990E) contains no specification for dimensional stability, and thus places no requirement for manufacturers to state dimensional stability properties on their labels. In contrast, ISO 4823:1992(E) specifies the IS for elastomeric dental impression materials, and it does specify a requirement for dimensional stability (less than 1.5% distortion after 24 hours). Further, the IS sets a method for determination of dimensional stability. Briefly, this method (the Optical Method) uses a travelling optical microscope to measure the accuracy of the distance between score lines on an impression of a test grid, at various time periods. The American Dental Association Specification No. 19 for dental elastomeric impression materials is identical to the IS. There is currently no specific Australian Standard (AS) for the dimensional stability of any dental impression material. Overview of Experimental Methods A. The Optical Method The aim of Part A of this investigation was to: 1. Adapt the Optical Method of the IS for elastomers to be reproducible for dental alginates. This was achieved by using a perforated test tray (to simulate clinical conditions), and measuring the grid pattern on a dental stone button after casting the test impression, rather than direct measurement of the impression, as for the IS. 2. To measure and rank the dimensional stability of a number of locally available dental alginates. Measurements of the test stone buttons proved reproducible, and the results were different for each sample, allowing them to be ranked according to dimensional stability after 50 and 100 hours of storage. The results show that the traditional optical method for measuring dimensional stability, as specified in the IS for dental elastomers, can be adapted to measure the dimensional stability of dental alginates However, the Optical Method of measuring dimensional stability of dental alginates is cumbersome and time-consuming. It was hypothesised that dimensional stability of dental alginates could be measured more conveniently by finding a thermal property that is directly proportional to dimensional stability. This method could be useful for the rapid determination of relative performance, and allow comparison with a determined benchmark. B. The Thermal Method Recently, modern methods of Thermal Analysis, Thermal Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) have been used to rapidly age various polymers, including food alginates (Chinachoti 1996), in order to measure thermal stability. This thesis shows that thermal stability is an indicator of dimensional stability. The aim of Part B of this investigation was therefore to adapt thermal analysis techniques to dental alginates, and develop a method to measure their thermal stability. These results were then compared with those for dimensional stability measured by the Optical Method to determine the relationship between thermal and dimensional stability for dental alginates. The results show that current thermal analysis methods of TGA and DSC can be adapted to measure relative dental alginate dimensional stability, and are both rapid and convenient. This study also provides evidence that commercial products differ as regards the property of dimensional stability, and can be ranked accordingly. C. Practical Application of the Methods The aim of part C of this thesis was to validate the methods (both optical and thermal) developed in this study by using them to investigate the effect of varying the water/powder ratio on the dimensional stability of dental alginates. It was shown that dimensional stability is affected by changes to the recommended water/powder ratio, that both the methods detected and measured the changes, and that the results were proportional, in that any percentage change detected by the optical method, was mirrored by the thermal method, confirming that the more convenient thermal methods can be used to measure dimensional stability.

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26

Nichols, Paul Vincent. "An Investigation of the Dimensional Stability of Dental Alginates." University of Sydney, 2006. http://hdl.handle.net/2123/1270.

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Master of Science (Dentistry)
Dimensional stability was defined by Nicholls (1977) as “the ability (of a material) to maintain accuracy over time”, and the result of loss of accuracy, “distortion”, as “the relative movement of a single point, or group of points, away from some originally specified reference position such that permanent deformation is apparent”. Maintaining dimensional stability of dental impression materials is vital if the impression cannot be cast (in stone) soon after removal from the mouth. Dental irreversible hydrocolloid (alginate) is a major dental impression material used worldwide in many clinical procedures. However, alginate is dimensionally unstable and changes its dimensions (suffers “distortion”) after removal from the mouth. With storage times of more than ten minutes, alginate begins to distort, and after one to three hours (depending on the product and storage conditions) cannot be used for many clinical purposes, especially fixed prosthodontics such as crowns and bridges (Hampson 1955, Skinner & Hoblit 1956, Wilson & Smith 1963, Rudd et al. 1969, Miller 1975, Inohara 1977, Schoen et al. 1978, Coleman et al. 1979, Linke et al. 1985, Habu et al. 1986, Peutfeldt & Asmussen 1989, Mathilde & Peters 1992, Khan & Aziz Sahu 1995, Eriksson et al. 1998, Schleier et al. 2001, and Donovan & Chee 2004). This loss of accuracy, due to dimensional instability, manifests as a time-dependent distortion of the poured stone cast, and thus any prosthesis fabricated will not fit in the mouth. With the introduction of the more stable elastomers in the 1950s (Stackhouse 1970, Glenner 1997, Brown 2003) that could be stored for days if necessary, without loss of accuracy, the alginates fell out of favour for fixed prosthodontics. Recently, there has been a resurgence of interest in alginate for use in dental procedures where dimensional stability is critical (Peutzfeldt and Asmussen 1989, Eriksson et al. 1998). This in part is due to the favourable properties of alginate not found in the elastomers. Of greatest significance is that alginate hydrocolloid is hydrophilic, whereas elastomers are hydrophobic (Phillips & Ito 1958, Glenner 2004). Thus, alginate materials are able to reproduce wet oral areas with greater precision and to produce a superior "fit" of, say, a gold casting produced by the Lost Wax technique (Skinner and Phillips 1982). A number of reports have been published which investigate newer alginate materials that are claimed to be more dimensionally stable than older formulations. Puetzfeldt and Asmussen (1989) found that a newer alginate , if stored at 100% relative humidity, retained accuracy over 24 hours that was equivalent to that of the elastomers. More recently, the manufacturer of another alginate has claimed equivalent dimensional stability to the elastomers for up to 100 hours, and, whilst this claim has not been reported on in the literature, the present thesis will show that, under favourable conditions of storage, the material maintained clinically useful accuracy for up to 100 hours. Another approach to improving the accuracy of alginate impressions has been to combine reversible hydrocolloid with alginate (the “Bilaminar” technique). Frederick and Caputo (1997) confirmed that the new agar reversible hydrocolloids are just as accurate (at the time of removal from the mouth) as the new elastomers. Mathilde et al. (1992) and Eriksson et al. (1998) have shown that several of the “bilaminar” impression techniques for fixed prosthodontics, where alginate is used as a tray material supporting a reversible hydrocolloid (agar) wash, are as accurate and dimensionally stable as elastomers for up to three hours. However, these studies are difficult to interpret due to lack of uniformity in the testing methods, and the fact that there is no regulatory standard available to measure dimensional stability for dental alginates. The International Standard (IS) for alginate impression materials (ISO 1563:1990E) contains no specification for dimensional stability, and thus places no requirement for manufacturers to state dimensional stability properties on their labels. In contrast, ISO 4823:1992(E) specifies the IS for elastomeric dental impression materials, and it does specify a requirement for dimensional stability (less than 1.5% distortion after 24 hours). Further, the IS sets a method for determination of dimensional stability. Briefly, this method (the Optical Method) uses a travelling optical microscope to measure the accuracy of the distance between score lines on an impression of a test grid, at various time periods. The American Dental Association Specification No. 19 for dental elastomeric impression materials is identical to the IS. There is currently no specific Australian Standard (AS) for the dimensional stability of any dental impression material. Overview of Experimental Methods A. The Optical Method The aim of Part A of this investigation was to: 1. Adapt the Optical Method of the IS for elastomers to be reproducible for dental alginates. This was achieved by using a perforated test tray (to simulate clinical conditions), and measuring the grid pattern on a dental stone button after casting the test impression, rather than direct measurement of the impression, as for the IS. 2. To measure and rank the dimensional stability of a number of locally available dental alginates. Measurements of the test stone buttons proved reproducible, and the results were different for each sample, allowing them to be ranked according to dimensional stability after 50 and 100 hours of storage. The results show that the traditional optical method for measuring dimensional stability, as specified in the IS for dental elastomers, can be adapted to measure the dimensional stability of dental alginates However, the Optical Method of measuring dimensional stability of dental alginates is cumbersome and time-consuming. It was hypothesised that dimensional stability of dental alginates could be measured more conveniently by finding a thermal property that is directly proportional to dimensional stability. This method could be useful for the rapid determination of relative performance, and allow comparison with a determined benchmark. B. The Thermal Method Recently, modern methods of Thermal Analysis, Thermal Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) have been used to rapidly age various polymers, including food alginates (Chinachoti 1996), in order to measure thermal stability. This thesis shows that thermal stability is an indicator of dimensional stability. The aim of Part B of this investigation was therefore to adapt thermal analysis techniques to dental alginates, and develop a method to measure their thermal stability. These results were then compared with those for dimensional stability measured by the Optical Method to determine the relationship between thermal and dimensional stability for dental alginates. The results show that current thermal analysis methods of TGA and DSC can be adapted to measure relative dental alginate dimensional stability, and are both rapid and convenient. This study also provides evidence that commercial products differ as regards the property of dimensional stability, and can be ranked accordingly. C. Practical Application of the Methods The aim of part C of this thesis was to validate the methods (both optical and thermal) developed in this study by using them to investigate the effect of varying the water/powder ratio on the dimensional stability of dental alginates. It was shown that dimensional stability is affected by changes to the recommended water/powder ratio, that both the methods detected and measured the changes, and that the results were proportional, in that any percentage change detected by the optical method, was mirrored by the thermal method, confirming that the more convenient thermal methods can be used to measure dimensional stability.

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27

Carulo, Marcelle Fernanda. "Desenvolvimento e caracterização de biofilmes ativos contendo sorbato de potassio, feitos de alginato de calcio e acidos graxos." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266284.

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Orientador: Theo Guenter Kieckbusch
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Quimica
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Resumo: O desenvolvimento da tecnologia para a fabricação de embalagens biodegradáveis é recente e sua importância cresce com o consumidor mais preocupado com o meio ambiente. Filmes para embalagens biodegradáveis são obtidos a partir de polímeros naturais como polissacarídeos, proteínas e lipídios. Neste trabalho, o polissacarídeo utilizado foi o alginato de sódio e a reticulação foi obtida com íons 'CA POT. ++¿. Glicerol e sorbitol foram ensaiados como plastificantes. Para conferir hidrofobicidade ao filme, investigou-se a incorporação de ácidos graxos saturados (C:4 a C:18) tendo sido dado consideração especial ao ácido caprílico (C:8), por formar filmes transparentes (não emulsionados). As propriedades de filmes contendo 5% e 10% de ácido caprílico (em relação a massa de alginato) foram caracterizadas e comparadas com filmes sem o lipídio. A solubilidade em água aumentou ligeiramente em filmes contendo ácido caprílico e sua resistência mecânica (tensão na ruptura e elongação) diminuiu. A adição de ácido caprílico melhora as propriedades de barreira ao vapor d¿água e reduziu o grau de intumescimento com água. A análise morfológica (MEV) de fratura dos filmes contendo lipídios confirmou sua estrutura interna contínua. Para a confecção de filme ativo utilizou-se sorbato de potássio como agnte antimicótico. Ensaios de liberação indicaram que a difusividade do sorbato é significativamente menor, na presença do ácido caprílico, tendência que foi confirmada em relação à permeabilidade desse soluto no filme
Abstract: The relevance of suitable developments of biodegradable packaging is becoming vital due to consumers awareness and demand for safer and cleaner environment. Biodegradable films used for food packaging can be produced from natural polymers, like proteins, polysaccharides and/or lipids. In this work sodium alginate ws used and the reticulation of the polymeric matrix was strengthened with 'CA POT. ++¿. Glycerol and sorbitol were lested as plasticizers. To impart the hydrophobicity of the film, saturated fatty acids (C:4 to C:18) were incorporated in the film-forming solution, with special consideration to caprilic acid, (C:8), due to its ability to form transparent films (non emulsionated). The properties of films containing 5% or 10% caprilic acid (relative to the mass of alginate) were characterized and compared to films without the lipid. The water solubility increased slightly in films with caprilic acid and their mechanical resistance (tension and elongation at break) decreased. The addition of caprilic acid improved the water vapor barrier capacity and reduced the degree of swelling. Morphological analyses (SEM) of fractures of films with caprilic acid confirmed a continuous internal structure. Active films were manufactured with potassium sorbate as antimicotic agent. Release tests indicate that the sorbate diffusivity inside the film is significantly reduced in the presence of caprilic acid and this tendency was confirmed with sorbate permeation data
Mestrado
Engenharia de Processos
Mestre em Engenharia Química

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28

Silva, Mariana Altenhofen da. "Desenvolvimento e caracterização de filmes compostos de alginato e quitosana contendo natamicina como agete antimicotico." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266051.

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Orientador: Theo Guenter Kieckbusch
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: Filmes simples de alginato (FA) e filmes compostos de alginato e quitosana nas proporções 82,5:17,5 (FC1) e 65:35 (FC2), de baixo grau de reticulação com cálcio (0,04 g CaCl2.2H2O/g alginato) contendo glicerol como plastificante, foram confeccionados pela técnica de casting. Esses filmes foram submetidos a uma reticulação complementar por imersão durante 30 minutos em uma solução contendo 5g CaCl2.2H2O/100 mL. Filmes FA, FC1 e FC2 com espessura média de 48, 54 e 62 µm, respectivamente, apresentaram massa solubilizada em água de 0,15, 0,19 e 0,23 g/g massa seca, coeficientes de permeabilidade ao vapor de água de 4,04, 4,91 e 7,41 g.mm/m2.dia.kPa, intumescimento em água de 68, 102 e 195% (em massa), tensão na ruptura de 96, 75 e 59 MPa e alongamento na ruptura de 8,4, 12,5 e 17,1%. Esses valores assim como o conteúdo de cálcio e os espectros de FTIR indicaram que, nas condições experimentais utilizadas, a interação do alginato com os íons cálcio foi mais efetiva do que com a quitosana, não havendo indícios de formação de ligação amídica entre o alginato e a quitosana. A análise da Tg por DMA também indicou separação de fases entre os dois polímeros. Os filmes com 35% de quitosana apresentaram estrutura polimérica mais rugosa e heterogênea. As três formulações receberam sorbato de potássio (até 17 g/100g biopolímero) e natamicina (0, 0,5, 1, 2, 4 e 8 g/100g biopolímero) como agentes antimicrobianos, e o efeito antimicótico destes filmes frente às espécies Penicillium roqueforti, Penicillium commune e Debaromyces hansenii foi avaliado através do teste de difusão em ágar. O sorbato de potássio não apresentou efeito inibitório, e a natamicina foi eficiente a partir da concentração de 0,5 g/100g biopolímero para o filme de alginato puro e 1 g/100g biopolímero para os filmes compostos. Ensaios de liberação em água indicaram uma cinética muito lenta de liberação do antimicrobiano, sendo mais lenta para os filmes compostos, provavelmente devido à interações eletrostáticas entre a natamicina e a quitosana. Os coeficientes de difusão da natamicina encontrados foram da ordem de 10-11 cm2/s para FA e FC2 e de 10-12 cm2/s para FC1. A estrutura física menos compacta da matriz polimérica do FC2 acelerou a liberação da natamicina. Nas concentrações testadas, a adição da natamicina influenciou principalmente a cor, transparência, rugosidade e morfologia dos filmes. Os resultados obtidos permitem afirmar que os filmes desenvolvidos contendo natamicina apresentam excelente perspectiva de atuação como filmes ativos (antimicrobianos) para alimentos
Abstract: Films composed solely by alginate (FA) and two composite films with different mass proportions of alginate and chitosan, 82.5:17.5 (FC1) and 65:35 (FC2), were obtained by casting. Using glycerol as plasticizer, the films were partially crosslinked by adding calcium chloride (0.04 g CaCl2.2H2O/g alginate) to the film forming solution. The resulting soluble films were further crosslinked by total immersion in a CaCl2 solution (5g CaCl2.2H2O/100 mL) for 30 minutes. FA, FC1 and FC2 with an average thickness of 48, 54 and 62 µm, respectively, exhibited soluble mass in water of 0.15, 0.19 and 0.23 g/g dry matter, water vapor permeability coefficient of 4.04, 4.91 and 7.41 g.mm/m2.day.kPa, swelling in water of 68, 102 and 195% (mass basis), tensile strength of 96, 75 and 59 MPa and elongation at break of 8.4, 12.5 and 17.1%. The tendencies found for the physical properties, complemented with values of calcium content in the films and results of FTIR analysis indicated that under the experimental conditions used, ionic binding of alginate chains with calcium ions was more effective than with chitosan, and no evidence of amidic bonding between alginate and chitosan was found. DMA thermograms also indicated phase separation between the two polymers, showing two Tg's for composite films. Films with higher content of chitosan showed rougher surfaces and less homogeneous polymeric structure. The film formulations received potassium sorbate (up to 17 g/100g biopolymer) and natamycin (0, 0.5, 1, 2, 4 and 8 g/100g biopolymer) as antimicrobial agents, and their antimycotic effect against Penicillium roqueforti, Penicillium commune and Debaromyces hansenii was evaluated by the agar diffusion test. Potassium sorbate did not show inhibitory effect. Natamycin was effective at concentrations as low as 0.5 g/100g biopolymer for alginate film and 1 g/100g biopolymer for composite films. Diffusion experiments in water indicated very slow release kinetics of the antimicrobial, being markedly hindered for the composite films, probably due to electrostatic interactions between chitosan and natamycin. Diffusion coefficients in films were in the order of 10-11 cm2/s for FA and FC2, and 10-12 cm2/s for FC1. The addition of natamycin affected mainly the color, transparency, roughness and morphology of the films, in the tested concentration range. The results showed that the films containing natamycin obtained in the present work show excellent perspectives for acting as active films intended for food applications
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Engenharia de Processos
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29

Kleinübing, Sirlei Jaiana. "Bioadsorção competitiva dos ions niquel e cobre em alginato e alga marinha Sargassum filipendula." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267115.

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Orientador: Meuris Gurgel Carlos da Silva
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: Estudos no campo da biotecnologia ambiental tem buscado encontrar materiais alternativos para o tratamento de efluentes industriais, dentre os quais se destacam as algas marinhas marrons. O alginato e o seu principal polissacarídeo e a presença dos ácidos manuronico (M) e guluronico (G) neste biopolimero esta diretamente relacionada a capacidade de bioadsorcao de íons metálicos. As propriedades de adsorção de diferentes espécies metálicas individuais vem sendo largamente estudadas, embora a maioria dos efluentes industriais contenha varias espécies metálicas em mistura. Este trabalho teve como objetivo investigar o fenômeno de bioadsorcao em sistemas simples e binário, constituídos dos íons Cu2+ e Ni2+, utilizando alginatos comerciais e alga marinha Sargassum filipendula como bioadsorventes. O estudo com alginatos comerciais visou auxiliar na compreensão dos mecanismos envolvidos no processo de bioadsorcao pelas algas marrons. Dois tipos de alginatos com diferentes relações M/G foram avaliados em sistemas monocomponentes. O alginato com menor relação M/G apresentou maior capacidade de bioadsorcao de ambos os íons metálicos. Seguiu-se então o estudo com a alga marinha Sargassum filipendula como bioadsorvente. Inicialmente, foi feita a extração do acido alginico e sua caracterização quanto a relação M/G. Em seguida, foi realizada a identificação dos grupos funcionais presentes na alga que poderiam estar envolvidos no processo de bioadsorcao. Verificou-se que os grupos carboxílicos e álcoois presentes no alginato, grupos sulfatos presentes na fucoidana, e grupos aminos nos aminoácidos, são responsáveis pelas ligações com estes íons. Para a obtenção dos dados de equilíbrio, foram realizados experimentos de remoção individual e da mistura dos íons Cu2+ e Ni2+ pela alga marinha Sargassum filipendula em coluna de leito fixo. Diferentes modelos foram aplicados para ajustar o equilíbrio e o modelo desenvolvido por Silva (2001) para simular a dinâmica de bioadsorcao. A bioadsorcao dos íons metálicos quando puros em solução apresentou capacidades adequadas tanto para o Cu2+ como para o Ni2+. Para a condição binária, o fenômeno de troca seqüencial foi observado, onde o íon Cu2+ desloca o Ni2+ anteriormente bioadsorvido. O modelo de Silva (2001) se ajustou aos dados experimentais obtidos tanto na condicao simples como na binária. Foram estudados, ainda, três ciclos de bioadsorção/dessorção, sendo verificado que a alga manteve suas características de bioadsorcao, assim como o efeito competitivo entre os íons durante os três ciclos avaliados.
Abstract: Environmental biotechnology studies have been conducted using alternative materials in order to eliminate heavy metal ions from industrial effluents. Brown algae are an attractive materials, due to their large availability and their reduced participation in the vital functions of marine ecosystems. The main structural polysaccharide of the brown algae is alginate, constituted of two uronic acids, mannuronic (M) e guluronic (G), and these groups are directly related to its bioadsorption capacity. The adsorption of different heavy metal ions in single systems has been investigated. However, in real systems it is more common to observe several ions in solution, which may interfere and compete for adsorption sites. The aim of this work was to study the bioadsorption of Cu2+ and Ni2+ ions on Sargassum filipendula seaweed and on commercial alginate (single and binary systems), in order to evaluate the competition of different metallic ions for the adsorption sites of bioadsorbents. Two types of alginates with different M / G ratio were evaluated in single component systems. Alginate with the lower M / G ratios showed a higher biosorption capacity of both metal ions. Next, a study with the seaweed Sargassum filipendula as biosorbent was performed. Initially, the alginic acid was extracted and its M / G ratio was characterized. The functional groups present in the algae that could be involved in the process of biosorption were identified. These results indicated that the alcohols and carboxylic groups present in alginate, sulphate groups present in fucoidan, and amino groups in amino acids, are responsible for binding these ions. To obtain equilibrium data, experiments were carried out to remove ions Cu2+ and Ni2+ individuales or in mixture by Sargassum filipendula seaweed in fixed bed column. Different equilibrium models were used to adjust the experimental data and the model developed by Silva (2001) was employed to simulate the dynamic of biosorption. The biosorption of pure ions in solution showed adequate capacity for Cu2+ and Ni2+. For the binary condition, the phenomenon of sequential exchange was observed, where the Cu2+ ion displaces the previously bioadsorbed Ni2+ ion. The mathematical model of Silva (2001) was able to describe satisfactorily the experimental data obtained for single and binary conditions. With regard to biosorption performance for sorption/desorption cycles, metal uptake remained practically unaltered as well as the competition effect between the ions during three successive cycles.
Doutorado
Engenharia de Processos
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30

Vaz, Juliana Miguel 1979. "Preparação e caracterização de biofilmes ativos à base de alginato de diferentes estruturas poliméricas reticuladas com cálcio." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266693.

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Orientadores: Theo Guenter Kieckbusch, Mariana Altenhofen da Silva
Dissertação (mestrado) - Universidade Estadual de Campínas, Faculdade de Engenharia Química
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Resumo: Alginatos são polissacarídeos compostos pela co-polimerização de unidades de beta-D-manuronato (M) e alfa-L-guluronato (G), arranjados em bloco homopoliméricos (poli-M ou poli-G) ou blocos em sequencia alternada, capazes de formar filmes resistentes quando reticulados com cálcio. ...Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital
Abstract: Alginates are linear copolymers of (1,4)-linked beta-D-mannuronate (M) and alfa-L-guluronate (G) units, arranged as homopolymeric blocks (poly-M and poly-G) and blocks with alternating sequence....Note: The complete abstract is available with the full electronic document
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31

Miralles, Grégory. "Biomatériaux de comblement pour la réparation de lésions ostéochondrales : intérêt deséponges polysaccharidiques à base de hyaluronate de sodium." Nancy 1, 2001. http://www.theses.fr/2001NAN11307.

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32

Palluault, Vincent. "Nouveaux traitements de surface respectueux de l’environnement par des gels polymères réticulables : application à la préparation des surfaces d’usage dans le secteur aéronautique." Thesis, Bordeaux 1, 2010. http://www.theses.fr/2010BOR14196/document.

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Les alginates sont des polysaccharides naturels extraits des algues brunes, capables de réticuler instantanément en formant un gel au contact des ions calcium. L'objet de cette thèse est d'utiliser ces alginates au sein de formulations détergentes capables de dégraisser les surfaces de matériaux composites usinés. Les solutions détergentes sont spécifiquement formulées pour être compatibles avec les alginates afin d'empêcher leur dégradation tout en permettant leur réticulation après action détergente. La faisabilité du procédé a été démontrée et ses paramètres critiques ont été identifiés et étudiés.Le principal avantage de ce procédé est qu'il permet, contrairement aux solutions de dégraissage lessivielles traditionnelles, de ne pas gaspiller d'eau tout en offrant un moyen rapide et efficace de dégraisser les surfaces
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33

Sinquin, Anne. "Alginates associatifs : synthèse et étude physico-chimique en milieu aqueux." Vandoeuvre-les-Nancy, INPL, 1995. http://www.theses.fr/1995INPL035N.

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La synthèse de polymères hydrosolubles présentant un caractère associatif a été effectuée, par réaction de diverses alkylamines à chaine longue (Cn-NH2, 8≤n≤16) sur l'alginate de propylène glycol (PGA), un dérivé partiellement estérifié d'un polysaccharide extrait des algues. Les propriétés physico-chimiques des dérivés hydrophobisés résultants ont été étudiées, comparativement à celles des polymères parents, en rhéologie, en spectrophotométrie de fluorescence et par des mesures de tension superficielle, dans l'eau pure ou en présence de sels. De façon générale, on observe que le caractère associatif des dérivés synthétisés augmente avec le taux et la longueur des segments hydrophobes immobilisés sur le PGA. Ainsi, si les effets d'interactions hydrophobes ne sont pas mis en évidence pour le dérivé en C8, les dérivés hydrophobisés par des chaines alkyles longues (C12 et C14) présentent, quant à eux, d'importantes variations de comportement par rapport aux polymères parents. Celles-ci résultent de la mise en place d'interactions hydrophobes entre les chaines alkyles immobilisées sur le squelette polysaccharidique. Ces interactions sont essentiellement de nature intramoléculaire en solution diluée tandis que les associations intermoléculaires deviennent prépondérantes en régime semi-dilué. Des entités de volume hydrodynamique élevé apparaissent alors et conduisent à une augmentation spectaculaire de la viscosité, pouvant aller jusqu'à la formation d'un réseau tridimensionnel ayant une structure de gel physique

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34

Bierhalz, Andréa Cristiane Krause 1981. "Confecção e caracterização de biofilmes ativos à base de pectina BTM e pectina BTM/alginato reticulados com cálcio." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266966.

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Orientador: Theo Guenter Kieckbusch
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química
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Resumo: Pectinas e alginatos são polímeros naturais com grande potencial de aplicação no desenvolvimento de filmes biodegradáveis, por serem materiais renováveis e obtidos a partir de diversas fontes a baixo custo. Atualmente, diversos estudos estão voltados ao desenvolvimento de tecnologia que controle o crescimento indesejável de microorganismos, pelo uso de embalagens ativas. Na presente pesquisa, foram desenvolvidos filmes simples de pectina e filmes compostos de pectina e alginato em diferentes proporções, reticulados com cálcio e contendo glicerol como plastificante. Foi avaliada a influência das concentrações de cálcio e do plastificante e do tempo de reticulação sobre as propriedades características dos filmes. A adição de natamicina como agente antimicrobiano também foi investigada. Os filmes foram preparados por casting, isto é, alíquotas da solução filme-formadora foram vertidas em moldes de acrílico e submetidas à gelificação e secagem. Devido ao alto poder gelificante do Ca++, filmes com baixo grau de reticulação foram inicialmente confeccionados (1º estágio). Estes préfilmes foram submetidos a uma reticulação complementar com imersão em uma solução mais concentrada de íons cálcio contendo plastificante. O alginato e a pectina mostraram-se compatíveis em todas as proporções, resultando em filmes com bom aspecto visual. O aumento da concentração de alginato diminuiu a solubilidade em água e o grau de intumescimento e aumentou a espessura, a resistência à tensão, a flexibilidade, a opacidade e a temperatura de transição vítrea dos filmes. Filmes pré-reticulados com 1% CaCl2.2H2O (13,60 mg Ca++/g biopolímero) na solução do 1º estágio, imersos durante 20 minutos em uma solução contendo 5% CaCl2.2H2O e 3% glicerol (2º estágio) apresentaram um compromisso entre alta resistência mecânica, boa aparência e baixa solubilidade em água. Esta formulação foi selecionada para a confecção dos filmes ativos contendo natamicina. A adição da natamicina provocou um aumento na permeabilidade ao vapor de água, na solubilidade em água e na opacidade, e uma redução na tensão na ruptura em relação aos filmes sem antimicrobiano. Determinações experimentais da massa de natamicina liberada em ensaios nos quais os filmes eram imersos em água apresentaram bom ajuste ao modelo difusional da segunda Lei de Fick, com valores de difusividade efetiva variando entre 9,53.10-9 e 9,22.10-12 cm2/s. A difusividade aumentou com a espessura e diminuiu com o aumento da concentração de alginato no filme
Abstract: Pectin and alginate are natural polymers with potential applications in the development of biodegradable package films, since they can be obtained at low cost from a large variety of renewable sources. There is a growing interest concerning the control of microbial activity in prepared food using active packaging. In this work, single and composite films based on alginate and pectin crosslinked with calcium ions and containing glycerol as plasticizer were prepared. The influence of calcium and glycerol concentrations and of the time of reticulation on the film characteristics was evaluated and the addition of natamycin as an active agent was investigated. The strong gelling power of Ca++ ions hinders smooth casting procedures so that a film with low degree of reticulation has to be initially confectioned by casting (1st stage). These pre-films are further crosslinked in a second contact with a more concentrated Ca++ solution containing plasticizer (2nd stage). Alginate and pectin were compatible in all proportions studied resulting in visually attractive films. Increasing the alginate concentration decreased film solubility in water and the swelling degree and increased the thickness, resistance to tensile stress, flexibility, water vapor permeability, opacity and glass transition temperature. Films pre-reticulated with 1% CaCl2.2H2O (13.60 mg Ca++/g biopolymer) in the solution of the 1st stage, immersed for 20 minutes in a 5% CaCl2.2H2O and 3% glycerol solution (2nd stage) showed a good compromise between high mechanical resistance, attractive appearance and low solubility in water. This formulation was selected for the manufacture of active films containing natamycin. Addition of natamycin promoted an increase in water vapor permeability, solubility in water and opacity and decreased the tensile strength when compared to films without the added anti-microbial agent. Experimental data of mass of natamycin released by immersion of the film in water were well fitted to Fick's second law diffusional model, with effective diffusivity values ranging from 9.53. 10-9 e 9.22.10-12 cm2/s. The diffusivity increased with the thickness and decreased with alginate concentrations in the film
Mestrado
Engenharia de Processos
Mestre em Engenharia Química

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35

Abbas, Assef. "Proprietes et potentialites de valorisation de nouveaux alginates a haute viscosite." Aix-Marseille 1, 2000. http://www.theses.fr/2000AIX11015.

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L'utilisation des plans d'experiences, appliquee a la methode d'extraction des alginates basee sur leur solubilisation par le carbonate de sodium nous a permis d'obtenir une gamme d'alginates par la modelisation de trois facteurs : la temperature, la concentration en carbonate de sodium et la duree d'extraction. Des modifications apportees a cette methode, nous ont conduit a (1) augmenter le rendement d'extraction, (2) moduler le rapport m/g, (3) decupler la viscosite des solutions d'alginates a 1% a 20\c et reduire la coloration des alginates. Les proprietes de ces alginates a haute viscosite, stabilite aux variations de ph, variations de la viscosite en fonction de la temperature, force de gel de la retexturation d'une compote de fruit ont ete comparees a celles d'alginates et de polymeres utilises industriellement.

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36

Li, Zhensheng. "Hybrid chitosan-alginate scaffolds for bone and cartilage tissue engineering /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/10609.

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Cathell, Matthew David Schauer Caroline L. "Structurally colored biopolymer thin films for detection of dissolved metal ions in aqueous solution /." Philadelphia, Pa. : Drexel University, 2008. http://hdl.handle.net/1860/2843.

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Rothenbuhler, Éric. "L'alginate : variation du pH au moment de la prise." Nantes, 1985. http://www.theses.fr/1985NANT1510.

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39

Sfayhi, Dorra. "Propriétés tensioactives et rhéologiques du caprate de tréhalose : influence des interactions en solutions avec l'alginate associatif." Vandoeuvre-les-Nancy, INPL, 2004. http://docnum.univ-lorraine.fr/public/INPL_T_2004_SFAYHI_D.pdf.

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Ce travail a pour objectif d'étudier les propriétés tensioactives et rhéologiques d'abord de solutions aqueuses d'un mélange équimolaire de mono- et de dicaprate de tréhalose synthétisé par voie enzymatique, puis de mélanges de ce tensioactif avec des alginates associatifs. A 20°C, le caprate de tréhalose a une CMC de 50 mM et une viscosité de 1 mPa. S en dessous de 0. 8 % qui augmente fortement entre 0. 8 et 23 % et se stabilise aux concentrations plus élevées. Ce comportement suggère une organisation des micelles du tensioactif en des micelles type "worm-like" branchées, puis en réseau multitubulaire. En mélange avec l'alginate associatif à 13 g/l, la viscosité de plateau présente une variation en trois domaines qui d'abord augmente fortement. Puis diminue autour de la CMC du tensioactif et enfin augmente à nouveau aux concentrations plus élevées. Cette variation peut être interprétée en terme d'interactions entre les groupements hydrophobes du polymère et du tensioactif
The present study aims at determining first the surface and rheological properties of a novel sugar ester, the trehalose caprate synthesized by enzymatic catalysis. The interaction with alginate associative polymer solution is then studied. At 20°C, trehalose caprate has a CMC of 50 mM and a viscosity of 1 mPa under 0. 8 wt%. For concentrations around 0. 8 and 23 wt%, the viscosity increased and stabilized at higher concentrations. This behavior suggests the formation of worm-like micelles and multiconnected tubular network. Ln addition to the alginate associative polymer and at 13 g/l, the zero-shear viscosity ofpolymer solution shows a three domain variation: As the trehalose caprate concentration increased, the zero shear viscosity first increased then decreased. At higher trehalose caprate concentrations, the zero-shear viscosity presented a second increase. This variation was attributed to the interaction between the surfactant and the hydrophobic alkyl chains of alginate

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40

Chtchigrovsky, Mélanie. "Préparation, criblage et utilisation de catalyseurs hétérogènes à base de polysaccharides." Paris 11, 2010. http://www.theses.fr/2010PA112144.

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Les contraintes environnementales poussent les chimistes à développer de nouveaux systèmes générant un minimum de déchets. La mise au point de catalyseurs hétérogènes bien définis permet de répondre à ces contraintes notamment par la récupération et le recyclage du catalyseur. Alors que de nombreux systèmes catalytiques hétérogènes à base de supports inorganiques ou organiques, sont d’ores et déjà rapportés dans la littérature, peu de travaux mettent en œuvre des systèmes à base de matériaux biologiques, tels que des macrostructures polymériques naturelles. Dans cette optique, nous avons entrepris de développer des catalyseurs hétérogènes à base de polysaccharides, en tant que supports renouvelables, sous la forme de billes macroscopiques poreuses. Les différents catalyseurs obtenus ont été criblés à l’aide de tests fluorescents. Dans un premier temps, l’efficacité catalytique d’une douzaine de systèmes hétérogènes à base de chitosane comme support pour des complexes « cuivre-ligand » a pu être étudiée via la réaction de cycloaddition 1,3-dipolaire de Huisgen. Puis dans un second temps, l’efficacité catalytique d’une quarantaine de systèmes hétérogènes à base de nanoparticules de palladium supportées sur alginate a pu être étudiée via la réaction de couplage de Suzuki. Nos résultats montrent que des systèmes hétérogènes fortement actifs peuvent être obtenus en combinant les propriétés texturales des polysaccharides et les propriétés catalytiques de métaux de transition ou de complexes « métal-ligand »
Environmental constraints push chemists to develop new systems for generating minimal waste. The development of well-defined heterogeneous catalysts can respond to these constraints in particular by the recovery and the recycling of catalyst. While many heterogeneous catalytic systems based on inorganic or organic materials are already reported in the literature, few works implement systems based on biological materials such as natural polymeric macrostructures. In this context, we have undertaken to develop heterogeneous catalysts based on polysaccharides as renewable materials, in the form of macroscopic porous beads. Different catalysts obtained were screened using fluorescent test. Firstly, the catalytic efficiency of a dozen heterogeneous catalysts based on chitosan as support for « copper-ligand » complexes has been studied through the 1,3-dipolar Huisgen’s cycloaddition. Secondly, the catalytic efficiency of around forty heterogeneous systems based on palladium nanoparticles supported on alginate have been studied through the Suzuki’s coupling reaction. Our results show that highly active heterogeneous systems can be obtained by combining the structural properties of polysaccharides and catalytic properties of transition metals or « metal-ligand » complexes

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Graff, Sandrine. "Formes galéniques protectrices de "Saccharomyces boulardii"." Paris 5, 2007. http://www.theses.fr/2007PA05P609.

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S. Boulardii est une levure probiotique utilisée comme anti-diarrhéique. Cependant, moins de 1% de levures viables est recouvré dans les fèces après administration orale. Le but de l’étude a été de protéger la levure de sa dégradation durant le transit gastro-intestinal. Après avoir étudié les conditions de survie de la levure, des comprimés et des microsphères ont été préparés et évalués. In vitro, la viabilité de la levure est stable pendant 6h à pH6,8 mais diminue significativement dès 5min à pH1,1. Dans ces mêmes conditions, les microsphères et les comprimés protègent la levure de la dégradation à pH1,1, et la libèrent viable à pH6,8. En raison de la mortalité engendrée par la compression, seules les microsphères ont été retenues et enrobées par du chitosan. In vivo, la microencapsulation augmente la libération intestinale du probiotique viable d’un facteur 5,5. En conclusion, les microsphères pourraient présenter un intérêt majeur pour les applications thérapeutiques de la levure
S. Boulardii is a probiotic yeast used as an anti-diarroheal agent. However, less than 1% of the viable yeast is recovered in feaces after an oral administration. The aim of this study was to protect the yeast from its degradation during the gastrointestinal transit. Following determination of the survival conditions of S. Boulardii, tablets and microspheres were prepared and evaluated. In vitro, the viability of the yeast remained stable for 6h at pH6. 8 but significantly decreased as soon as 5 minutes at pH1. 1. In similar conditions, tablets and microspheres enabled to protect the yeast from degradation in HCl and to release it viable at pH6. 8. Because of the mortality due to the compression, only microspheres were selected and further coated with chitosan. In vivo, the microencapsulation increased the intestinal delivery of the viable probiotic about 5. 5 fold. In conclusion, microspheres could present a major interest in the therapeutic applications of the yeast

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Almeelbi, Talal Bakheet. "Phosphate Removal and Recovery Using Iron Nanoparticles and Iron Cross-Linked Biopolymer." Diss., North Dakota State University, 2012. https://hdl.handle.net/10365/26517.

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Nanoscale zero-valent iron (NZVI) particles and iron cross-linked alginate (FCA) beads were successfully used for the first time for phosphate removal and recovery. NZVI was successfully used for phosphate removal and recovery. Batch studies indicated a removal of ~96 to 100% phosphate in 30 min (1, 5, and 10 mg PO43--P/L with 400 mg NZVI/L). Phosphate removal efficiency by NZVI was 13.9 times higher compared to Microscale ZVI (MZVI) particles. The successful rapid removal of phosphate by NZVI from aqueous solution is expected to have great ramification for cleaning up nutrient rich waters. The presence of sulfate, nitrate, and humic substances and the change in ionic strength in the water marginally affected phosphate removal by NZVI. A maximum phosphate recovery of ~78% was achieved in 30 min at pH 12. Novel iron cross-linked alginate (FCA) beads were synthesized, characterized and used for phosphate removal. The beads removed up to 37-100% phosphate from aqueous solution in 24 h. Freundlich isotherm was found to most closely fit with experimental data and the maximum adsorption capacity was found to be 14.77 mg/g of dry beads. The presence of chloride, bicarbonate, sulfate, nitrate, and natural organic matters in aqueous solution did not interfere in phosphate removal by FCA beads. The phosphate removal efficacy FCA beads was not affected due to change in pH (4-9). Nanosacle zero-valent iron (NZVI) and iron cross-linked alginate beads were also tested for phosphate removal using actual wastewater treatment plant effluent and animal feedlot runoff. The FCA beads could remove ~63% and ~77% phosphate from wastewater and feedlot runoff in 15 min, respectively. Bioavailability of phosphate was examined using algae and higher plants. Phosphate and iron bioavailability of the NZVI sorbed phosphate was examined by supplying spent particles (NZVI with sorbed phosphate) to Tyee Spinach (Spinacia oleracea) and algae (Selenastrum capricornutum). Results revealed that the phosphate was bioavailable for both the algae and spinach. Also, presence of the nanoparticles enhanced the algae growth and plant growth and increases in biomass and plant length were observed. Iron (from spent NZVI) was found to be bioavailable for spinach.

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Vauchel, Peggy. "Optimisation de procédés innovants pour l'obtention de phycocolloïdes." Nantes, 2007. http://www.theses.fr/2007NANT2096.

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Abang, Sariah. "Immobilisation of porcine pancreatic lipase in liquid-core capsules." Nantes, Ecole nationale vétérinaire, 2011. https://doc-veto.oniris-nantes.fr/GED_CHN/193639191181/These_ABANG_Sariah_2011.pdf.

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Des capsules à cœur hydrophobe ont été produites par extrusion gouttes à gouttes d’une émulsion de chlorure de calcium/huile dans une solution d’alginate. Une gélification autour des gouttes d’huile se créée par la migration des ions calcium dans la solution d’alginate (gélification interne) permettant la formation d’une membrane. L’influence des conditions opératoires (concentrations en chlorure de calcium et en alginate et le temps de gélification) sur l'épaisseur de la membrane et la résistance mécanique des capsules ont été étudiées et ont permis d’obtenir des capsules stables et résistantes. Ces capsules ont été utilisées pour l'immobilisation de la lipase pancréatique porcine avec un taux d’encapsulation proche de 60% sans perte d’activité intrinsèque. L’immobilisation de la lipase a été étudiée en fonction du pH, de la température, des taux de réutilisation et de libération, de l?efficacité du stockage et des paramètres cinétiques de la réaction hydrolytique. Ce biocatalyseur a montré une activité catalytique plus élevée par rapport à l'enzyme libre. On observe toutefois une libération de la lipase à travers la membrane des capsules lors d?utilisations répétées et une faible stabilité au stockage à température ambiante et à 4°C. Pour y remédier, la porosité de la membrane d'alginate de calcium a été modifiée en utilisant une membrane composée d'alginate et de pectine. Ces nouvelles capsules ont montré une efficacité d'encapsulation supérieure et permettent de réduire la libération de la lipase au cours du temps. D’autre part, la stabilité du stockage de la lipase immobilisée dans ces capsules a été améliorée lorsqu’elles sont conservées dans un environnement présentant une faible activité de l’eau.

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Huguet, Marie Laure. "Étude de billes d'alginate de calcium recouvertes de polymère polycationique." Vandoeuvre-les-Nancy, INPL, 1994. http://www.theses.fr/1994INPL105N.

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L'encapsulation des produits biologiques est particulièrement intéressante pour préserver leur intégrité et permettre leur relargage de façon contrôlée. L'alginate, polysaccharide anionique, est souvent utilisé pour la microencapsulation. Il présente des propriétés de gélification en présence de cations divalents (Ca++, Mg++). La microencapsulation de molécules biologiques et de cellules dans des billes d'alginate de calcium présente l'avantage d'être très douce et de maintenir ainsi l'activité de ces produits. Cependant pour limiter le relargage du matériel encapsulé, il est parfois nécessaire d'établir une membrane à la surface de la bille par formation d'un complexe polyélectrolyte avec un polymère polycationique. Le chitosane, polysaccharide cationique naturel, ou le diéthylaminoethyl-dextrane peuvent donc être utilisés pour l'élaboration d'une membrane autour de la bille d'alginate de calcium. Deux techniques de production de billes d'alginate ont été testées, la méthode à l'extrusion et celle à l'émulsion, qui ont permis d'obtenir des billes d'alginate de calcium de diamètre moyen différent soit respectivement de 1mm et 70m. Nous avons étudié les propriétés de rétention de ces billes recouvertes d'une membrane polyélectrolyte vis à vis de différentes molécules, des protéines (hémoglobine, albumine de sérum bovin), des dextranes de masses molaires différentes, le benzène tetracarboxylate. Les conditions de formation de la membrane, pH et concentration de la solution de polymère polycationique et la nature du polycation ont une influence sur les propriétés de rétention de ces billes recouvertes d'une membrane. La nature des produits encapsulés à également une grande influence sur leur rétention. Leur taux de libération varie en fonction de leur masse molaire, leur conformation tridimensionnelle ainsi que de leur composition chimique

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Arlov, Øystein. "Heparin Analogs Created by Sulfation of Alginates Using a Chemoenzymatic Strategy." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for bioteknologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-16802.

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Alginates are a class of natural unbranched linear polysaccharides, and consist of the monomers β-D-mannuronic acid and α-L-guluronic acid. The inherent physical properties, relative ease of modification, wide availability and good biocompatibility of alginates have gained a great deal of attention with regards to therapeutic applications. Heparin is a highly negatively charged linear glycosaminoglycan that is widely used as an anticoagulant. The presence of carboxyl groups and several sulfate groups gives heparin its negative charge, while iduronic acid moieties confer a high degree of flexibility to the polysaccharide by being able to assume different stable conformations. Heparin shows diversity in molecular weight, monomer sequence and modification pattern, resulting in a vast range of biological effects. When administered therapeutically, this can in cause an unpredictable dose response and potentially severe adverse effects in certain patients. The main objective of this study was to create a structural analog of heparin exhibiting a more regular structure and distribution, through chemical sulfation of alginate using chlorosulfonic acid. Other important aims were to characterize the analog in terms of structure, distribution and sulfation degree, and assess protein binding and anticoagulating properties of the sulfated alginates in comparison with heparin and the unmodified alginate templates. Sulfation was performed using chlorosulfonic acid in formamide on a polymannuronic acid (poly-M) and a polyalternating alginate with a guluronic acid fraction of FG = 0.46 (poly-MG), introduced through enzymatic epimerization. FTIR, elemental analysis with HR-ICP-MS and carbon NMR were employed to detect the attached sulfate groups on the alginate. The average molecular weights and the mass distributions of the alginate samples were studied using SEC-MALLS. Elemental analysis was used to estimate the sulfation degrees of the alginates, and 13C NMR was employed to study substitution patterns, provide additional DS estimates and assess sample purity. The protein binding properties of the sulfated alginates were evaluated by studying their ability to release hepatocyte growth factor and osteoprotegerin bound to myeloma cells. Anticoagulating properties were studied by measuring prolongation of plasma coagulation time as a result of sulfated alginate supplementation. The alginates were successfully sulfated and exhibited different degrees of sulfation obtained by varying the chlorosulfonic acid concentration used (1 - 10 %), as estimated by elemental analysis. The poly-MG alginate showed increased solubility during the sulfation reaction, resulting in a higher estimated DS at lower chlorosulfonic acid concentrations compared with poly-M. No apparent degradation of the alginates as a result of the sulfation was observed, although preliminary acid hydrolysis resulted in a molecular weight disparity between poly-M and poly-MG samples. Analysis of carbon NMR spectra allowed characterization of novel peaks and secondary DS estimations for the sulfated poly-M samples, while the complexity of the sulfated poly-MG spectra prevented confident characterization of the structures. Sulfation resulted in a profound improvement of the protein binding properties of the alginates, and showed prolongation of the plasma coagulation time at high treatment concentrations.

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Banning, Douglas. "An investigation into the use of alginates as bioadhesive delivery systems." Thesis, University College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299936.

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Barbier, Lucile. "Hydrogels injectables thermostimulables : relations structure/propriétés." Electronic Thesis or Diss., Sorbonne université, 2022. http://www.theses.fr/2022SORUS394.

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Ce travail de thèse porte sur le développement d’hydrogels injectables thermostimulables. Dans le cadre de la délivrance de principes actifs, l’objectif est de partir d’une solution de polymère suffisamment fluide à température ambiante pour pouvoir être injectée à un endroit ciblé du corps et d’obtenir une gélification rapide de la formulation une fois introduite en milieu physiologique. Pour aborder cette étude, une large plateforme de copolymères greffés a été développée à partir de squelettes hydrophiles et de greffons thermosensibles caractérisées par leur LCST en milieu aqueux. Dans un premier temps, un système entièrement synthétique à base de poly(acide acrylique)-g-poly(N-isopropyl acrylamide) a été utilisé comme système modèle. Les relations structure/propriétés ont alors été établies en étudiant l’impact de la taille du squelette, de la taille des greffons et du taux de greffage sur la transition de phase et sur les propriétés rhéologiques dans le domaine linéaire (modules dynamiques) ainsi qu’aux grandes déformations (test d’adhésion). En régime enchevêtré, il a été montré que les propriétés élastiques générées à haute température pouvaient être décrites à partir d’un paramètre réduit prenant en compte la concentration en copolymère, la concentration d’enchevêtrement des chaînes ainsi que la fraction massique de greffons à LCST. Dans une seconde étape, cette étude a été élargie en utilisant des greffons de poly[oligo(éthylène glycol) méthyl éther méthacrylate]. Dans cette étude comparative, nous montrons que si la température de transition de phase des greffons est importante pour le déclenchement du processus associatif, les propriétés thermodynamiques des greffons gouvernent les propriétés élastiques à haute température. Dans une dernière partie, cette étude a été transposée à des squelettes polysaccharides de type alginate et acide hyaluronique afin d’améliorer la biocompatiblité. Avec ces copolymères de nature chimique pourtant très différente, la corrélation précédente entre module élastique et concentration réduite est de nouveau observée. Enfin, dans le cadre d’études plus appliquées, le caractère injectable des solutions a été vérifié pour les copolymères à base d’alginate, de même que leur cinétique de gélification extrêmement rapide en milieu physiologique qui permet de conserver l’intégrité des gels sur des temps longs tout en favorisant un relargage ralenti des molécules d’intérêt dans le milieu extérieur
This thesis work focuses on the development of thermoresponsive injectable hydrogels. In the context of drug delivery, the objective is to start from a polymer solution that is sufficiently fluid at room temperature to be injected into a targeted area of the body and to obtain a rapid gelation of the formulation once introduced in a physiological environment. To address this problem, a large platform of graft copolymers has been developed using hydrophilic backbones and thermoresponsive side-chains characterized by their LCST in aqueous medium. In a first step, a fully synthetic macromolecular architecture based on poly(acrylic acid)-g-poly(N-isopropyl acrylamide) was used as a model system. The structure/properties relationships were then established by studying the impact of the size of the backbone, the size of the grafts and the rate of grafting on the phase transition and on the rheological properties determined in the linear domain (dynamic moduli) as well as at large deformations (adhesion test). In the entangled regime, it was shown that the elastic properties triggered at high temperature could be described from a reduced parameter taking into account the copolymer concentration, the entanglement concentration of chains as well as the weight fraction of LCST grafts. In a second step, this study was extended to the same copolymers using poly[oligo(ethylene glycol) methyl ether methacrylate] as responsive grafts. In this comparative study, we show that while the association temperature of the grafts is important for triggering the associative process, their thermodynamic properties control the elastic properties at high temperature. In a last part, this study was transposed to polysaccharide backbones, alginate and hyaluronic acid, to improve their biocompatibility. With these copolymers of very different chemical nature, the previous correlation between elastic modulus and reduced concentration is still observed. Finally, in a more applicative context, the injectability of alginate-based copolymers solutions was verified, as well as their extremely rapid kinetics of gelation in a physiological environment, which leads to the conservation of the integrity of gels over long periods of time while favouring a slower release of the molecules of interest into the external environment

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Welter, Rosilene Andrea. "Estudo do equilibrio dos sistemas binarios e ternario de troca ionica dos ions cobre, cadmio e calcio pelo biopolimero alginato." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267090.

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Orientadores: Meuris Gurgel Carlos da Silva, Edson Antonio da Silva
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: Neste trabalho, estudou-se o processo de troca iônica envolvendo os íons Cobre, Cádmio e Cálcio, sendo que os metais pesados, Cobre e Cádmio, foram avaliados devido a alta toxicidade, à sua presença em efluente industriais e a dificuldade na sua remoção quando em baixas concentrações, entretanto, acima do permitido pela legislação vigente. O trocador iônico utilizado foi o Alginato, que na presença de íons divalentes possui a capacidade de gelificar-se formando partículas aptas à utilização em operações de troca iônica. As partículas foram obtidas por diferentes formas: gotejamento, atomização ou ainda, emulsificação, contudo, cada método apresentou partículas com propriedades físicas distintas. O método de emulsificação resultou em partículas com diâmetro e granulometria satisfatórios para o processo de troca iônica em leito poroso, além de, dentre os métodos analisados, apresentar maior capacidade de troca iônica para o ensaio realizado em banho finito sob as mesmas condições operacionais. Portanto, os ensaios de equilíbrio de troca iônica para os sistemas binários envolvendo os íons Cu-Ca, Cd-Ca e Cu-Cd e para o ensaio ternário Cu-Cd-Ca, foram realizados em leito poroso, utilizando partículas obtidas por emulsificação, a vazão de 3 mL/min e pH de 4,5, sendo estes parâmetros operacionais definidos por estudos prévios. Os dados experimentais para os sistemas binários foram avaliados utilizando Isotermas de Adsorção Monocomponente que apresentaram comportamento satisfatório, entretanto os modelos de Isotermas de Adsorção Binária apresentaram melhor ajuste. O tratamento dos sistemas binários utilizando LAM Ideal e LAM, foram satisfatórios para o comportamento dos dados experimentais, entretanto, houve uma variação considerável do valor de Keq. Os coeficientes de atividade envolvendo os íons ligados a fase sólida apresentaram-se próximos a 1, ou seja, o sistema Metal-Alginato, está próximo à idealidade. O sistema ternário apresentou resultado insatisfatório para seu tratamento utilizando Isotermas de Adsorção Binária e o modelo Preditivo de LAM, sendo que apenas os modelos de Isotermas de Adsorção Ternária, Langmuir 4 parâmetros, Langmuir 6 parâmetros e Langmuir-Freundlich apresentaram resultados satisfatórios.
Abstract: In this work, it was studied the ion exchange process involving copper, cadmium and calcium ions. The heavy metals, copper and cadmium, were evaluated due to its high toxicity, its presence in industrial effluent and difficulty in its removal when in low concentrations, however, above permitted levels by law. Alginate was used as ionic exchanger. In the presence of high affinity ions, such as calcium, it has the ability to gelate and form rigid particles which are suitable for ion exchange operations. These particles were obtained from different methods, such as dripping, atomization and emulsification, however, each method resulted in particles with different physical properties. Emulsification method resulted in particles of suitable diameter and size for the ion exchange process in porous bed. Among the considered methods, it showed to be the one with higher ion exchange capacity, under the same operating conditions, for batch system experiments. Therefore, ion exchange equilibrium experiments for binary systems, involving Cu-Ca, Cd-Ca and Cu-Cd ions, and ternary system Cu-Cd-Ca, were conducted in porous bed, using particles obtained by emulsification, at a flow rate of 3 mL/min and pH 4.5. These operational parameters were defined by previous studies. Binary systems experimental data were evaluated using monocomponent adsorption isotherms, which showed good behavior, however, binary adsorption isotherms models showed higher accuracy. Binary systems treatment using Ideal LAM and LAM, were satisfactory for the experimental data behavior, however, there was a considerable variation in Keq values. Activity coefficients involving ions attached to the solid phase were close to 1, which means that the alginate-metal system is close to ideality. The ternary system showed unsatisfactory results for its treatment using binary adsorption isotherms and LAM predictive model, where just ternary adsorption isotherms, Langmuir 4 parameters, Langmuir 6 parameters and Langmuir-Freundlich models showed satisfactory results.
Mestrado
Engenharia de Processos
Mestre em Engenharia Química

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50

Duarte, Juliana Canto 1984. "Estudo da imobilização de células de Saccharomyces cerevisiae em suportes no processo de fermentação alcoólica." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266827.

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Orientador: Gustavo Paim Valença
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química
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Resumo: A utilização de sistemas empregando células de levedura imobilizadas é uma técnica promissora para a produção de etanol. Este trabalho apresenta a proposta de imobilizar células de Saccharomyces cerevisiae em montmorilonita K10, em óxido de zircônio, em esferas de alginato de cálcio e em esferas de alginato de cálcio revestidas com quitosana, utilizando glicose e sacarose como fontes de carbono, a fim de observar o comportamento destas células nestes suportes. Estudos nesta área têm demonstrado que células imobilizadas apresentam maior resistência a variações de temperatura, atividade, concentração de substratos e metabólitos, além de um alto rendimento para fermentação alcoólica. A montmorilonita K10, o alginato de sódio e a quitosana que foram utilizados nos estudos tiveram origem comercial, enquanto que o óxido de zircônio foi sintetizado e caracterizado através de Difração de Raios-X (DRX) e área superficial B.E.T. (Brunauer, Emmet e Teller). Células de Saccharomyces cerevisiae liofilizada não aderiram aos suportes sólidos (montmorilonita K10, óxido de zircônio e óxido de zircônio com superfície modificada). Já a cepa JAY 270 de Saccharomyces cerevisiae foi imobilizada com sucesso em esferas de alginato de cálcio e em esferas de alginato de cálcio revestidas com quitosana. Estudos de fermentação em regime batelada foram conduzidos em shaker orbital para avaliação da produção de etanol, estabilidade, rendimento, taxa de consumo de substratos e taxa de produção de produto. O comportamento destes sistemas foi avaliado através de dados de concentração de substrato e produto em equipamento de HPLC (High-Performance Liquid Chromatograph). A imobilização celular em esferas de alginato de cálcio e em esferas de alginato de cálcio revestidas com quitosana permitiu a reutilização das esferas durante oito ciclos de fermentação de aproximadamente 10 horas cada. A produção de etanol para células livres foi 40 g/L e o rendimento foi de 78% e 74,3% utilizando a glicose e a sacarose como fontes de carbono, respectivamente. Para as células imobilizadas em esferas de alginato de cálcio, utilizando a glicose como fonte de carbono, a produção de etanol foi de 33 g/L e o rendimento foi de 64,6 %, utilizando a sacarose, a produção de etanol foi de 33 g/L e o rendimento foi de 61,3%. Para as células imobilizadas em esferas de alginato de cálcio revestidas com quitosana, utilizando a glicose como fonte de carbono, a produção de etanol foi de 31 g/L e o rendimento foi de 60,7 % e utilizando a sacarose, a produção de etanol foi de 32 g/L e o rendimento foi de 59,5%
Abstract: The use of immobilized yeast cells in supports systems is a promising technique for the ethanol production. This work proposes to immobilize Saccharomyces cerevisiae cells in montmorillonite K10, zirconium oxide, calcium alginate beads and chitosan covered calcium alginate beads, using glucose and sucrose as carbon sources, in order to observe the behavior of these cells in these media. Studies in this area have demonstrated that immobilized cells are more resistant to temperature, activity, concentration of substrates and metabolites, and a high yield for ethanol fermentation. The montmorillonite K10, sodium alginate and chitosan have been used in the studies had commercial origin, while the zirconium oxide was synthesized and characterized by X-ray Diffraction (XRD) and B.E.T. surface area (Brunauer, Emmet and Teller). Liofilized Saccharomyces cerevisiae did not adhere to solid supports (K10 montmorillonite, zirconium oxide and modified surface zirconium oxide). Since the strain of Saccharomyces cerevisiae, JAY 270, was successfully immobilized in calcium alginate beads and in chitosan covered calcium alginate beads. Studies under batch fermentation were conducted in orbital shaker for evaluation of ethanol production, stability, efficiency, substrate consumption rate and the product production rate. The behavior of these systems was assessed using concentration data of substrate and product in the HPLC equipment (High-performance liquid chromatography). The cell immobilization in calcium alginate beads and chitosan covered calcium alginate beads allowed reusing of the beads during fermentation of eight cycles every 10 hours. The production of ethanol to free cells was 40 g/L and 78% and 74.3% yield using the glucose and sucrose as carbon sources, respectively. For immobilized cells in calcium alginate beads, ethanol production was 33 g/L and 64.6% yield and 33 g/L and 61.3% yield, using glucose and sucrose, respectively. For immobilized cells in chitosan covered calcium alginate beads, ethanol production was 31 g/L and 60.7% yield and 32 g/L and 59.5% yield, using glucose and sucrose, respectively
Mestrado
Desenvolvimento de Processos Químicos
Mestre em Engenharia Química

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Dissertations / Theses on the topic 'Alginates'

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