O dióxido de carbono no estado supercrítico (CO2-SC) tem despertado considerável interesse nos últimos anos como um novo solvente para reações orgânicas. Nesta tese foi investigada a influência do uso de CO2 supercrítico, associado ou não a líquidos iônicos ou cossolventes, como solvente em reações químicas visando à obtenção de precursores quirais. Foram estudadas as reações de condensação Aldólica, de Morita-Baylis-Hillman (MBH) e do tipo adição de Michael, empregando Organocatálise quando conveniente, isto é, catalisadores provenientes de aminoácidos e ácidos carboxílicos. As reações de MBH foram otimizadas através de um planejamento experimental e sua condição ótima se deu a 70°C, 110 bar, com 6 equivalentes de H2O, tempo reacional de 2h30 min e sem a presença de liquido iônico, tendo um rendimento de 84,6%. Para as condensações aldólicas os melhores resultados com acetona e p-nitrobenzaldeido como materiais de partida foram obtidos a 150 bar e 40°C, com a presença de liquido iônico, em 2 horas de tempo reacional com um rendimento de 54,0% e um excesso enantiomérico de 79,0% utilizando o catalisador (2S,4R)-4-(terc-butildimetilsililoxi)pirrolidina-2-ácido carboxílico. Com ciclohexanona como material de partida foram obtidos a 150 bar e 40°C com a presença de um doador de prótons (resina de troca iônica) em 2 horas de tempo reacional com um rendimento de 70,9% e um excesso enantiomérico de 91,2%, utilizando o catalisador (2S,4R)-4-(terc-butildimetilsililoxi)pirrolidina-2-ácido carboxílico. Outros aldeídos e cetonas utilizados como materiais de partida apresentaram rendimentos menores. Estudos de comportamento de fases foram feitos para os materiais de partida, catalisadores e produtos da reação de condensação Aldólica. Os melhores rendimentos foram obtidos em situações em que os materiais de partida e os catalisadores eram solúveis na fase supercrítica, mas os produtos não, formando uma segunda fase. / Supercritical carbon dioxide (sc-CO2) has attracted considerable interest in the last years as a new solvent for organic reactions. In this thesis, the influence of supercritical CO2 use, associated or not to ionic liquids or cosolvents, as a solvent for chemical reactions aiming at the synthesis of chiral precursors was studied. Aldol condensation, Morita-Baylis-Hillman (MBH) and Michael addition reactions were studied, employing organocatalysis when it was convenient, i.e., catalysts derived from aminoacids or carboxylic acids. MBH reactions were optimized through experimental design, resulting in a maximum yield of 84.6% for the optimal condition at 70°C, 110 bar, and 6 equivalents of H2O, reaction time of 2h30 min and the absence of ionic liquids. For the Aldol condensation reactions employing acetone and p-nitrobenzaldehyde, a maximum yield of 54.0%, with an enantiomeric excess of 79.0% was obtained at 150 bar, 40°C, 2h reaction time, in the presence of ionic liquid, using the catalyst (2S,4R)-4-(terc-butyldimethylsililoxy)pirrolidine-2-carboxylic acid. The yields were significantly lower for other aldehydes and ketones. Yields for Michael addition reactions were very low and their study was discontinued. Phase behavior studies were performed with starting materials, catalysts and products for the Aldol condensation reactions. The best yields were obtained for situations where the starting materials and catalysts were soluble in the supercritical phase and the products were not, forming a second phase.

Fish oil is an excellent source of long chain polyunsaturated fatty acids (LC-PUFA), which can reduce the risk of cardiovascular disease in addition to other health benefits. However, the average intake of LC-PUFA in the Western diet is much lower than the recommended levels. Fish oil is prone to oxidative deterioration when exposed to oxygen and thus must be protected in order to be used in food products. Microencapsulation is one possibility that is already applied by the industry to protect fish oil. However, most of the conventional microencapsulation techniques suffer from shortcomings such as harsh processing conditions or the use of numerous chemicals. The main objective of this thesis was to develop a novel spray process to microencapsulate fish oil based on supercritical fluid (SCF) technology using supercritical carbon dioxide (SC-CO2) and CO2-expanded ethanol (CX EtOH). Fundamental physicochemical properties essential for optimal process design were lacking in the literature; therefore, density, interfacial tension (IFT) and viscosity of fish oil in the form of triglycerides and fatty acid ethyl esters were determined at different temperatures and pressures. Fish oil when equilibrated with SC-CO2 at elevated pressure expanded by up to about 40% in volume and increased in density by up to about 5%. Furthermore, IFT of fish oil in contact with SC-CO2 decreased substantially by an order of magnitude with an increase in CO2 pressure. When fish oil was in contact with CX EtOH, IFT decreased to ultra low levels at pressures of less than 10 MPa. Viscosity of fish oil equilibrated with SC-CO2 decreased substantially with pressure but increased with shear rate. Based on the physicochemical properties determined in this research, a novel process to produce micro- and nano-sized particles containing fish oil was developed based on a SCF spray-drying method. Key processing parameters have been evaluated and can be further optimized to improve encapsulation efficiency. Determination of physicochemical properties contributed to the fundamental understanding of the behavior of the fish oil+CO2 system with and without ethanol under high pressure conditions. The new microencapsulation process shows great potential for the delivery of bioactives in various product applications. / Bioresource and Food Engineering

Los materiales compuestos nanoestructurados son considerados una opción prometedora para la concepción de materiales multifuncionales. Sin embargo, la falta habitual de interacción entre los componentes orgánicos e inorgánicos en los materiales híbridos nanoestructurados comporta unas propiedades macroscópicas anisotrópicas que limitan su uso. Por ello, se hace necesario el diseño de la interfase formada entre los componentes mencionados a fin de mejorar sus prestaciones. En esta Tesis Doctoral se ha optado por el uso de dióxido de carbono supercrítico (scCO2) para la modificación superficial de nanopartículas inorgánicas y para la preparación de materiales híbridos nanoestructurados. Estos procesos supercríticos, diseñados como sostenibles, se proponen como sustitutos de técnicas convencionales que empleen disolventes orgánicos. El tratamiento superficial de nanopartículas de dióxido de titanio (TiO2) con octiltrietoxisilano se ha empleado como sistema de estudio para evaluar el uso de recubrimientos de alcoxisilanos bifuncionales como promotores de adhesión de partículas inorgánicas nanométricas. El scCO2 se emplea como disolvente del alcoxisilano para la silanización del TiO2. También se han llevado a cabo estudios fundamentales de solubilidad de octiltrietoxisilano en CO2 y de la cinética del proceso de silanización del TiO2. La modulación de las propiedades fisicoquímicas del scCO2 con la presión y la temperatura permite el control de las características del recubrimiento con silano. El proceso de silanización supercrítico se ha extendido a diferentes sistemas alcoxisilano-nanopartículas inorgánicas. Asimismo, se ha evaluado la tecnología de scCO2 para la preparación de materiales híbridos nanoestructurados que contengan nanopartículas inorgánicas silanizadas. El tratamiento superficial de las nanopartículas favorece la distribución homogénea de éstas en el material híbrido y mejora la interacción relleno-matriz orgánica. Se han procesado matrices biopoliméricas de interés en ingeniería tisular, compuestas de ácido poliláctico o la mezcla iv polimetilmetacrilato/policaprolactona, con adiciones de nanopartículas de TiO2 o hidroxiapatita, respectivamente. Para su procesado, se ha empleado scCO2 como no-disolvente utilizando la técnica Particles from a Compressed Anti-Solvent (PCA). Además, se han preparado partículas híbridas formadas por una mezcla lipídica de aceite de ricino hidrogenado y glicerilmonoestearato con adiciones de TiO2 y cafeína, con posibles aplicaciones en cremas para uso tópico. Estas partículas sólidas lipídicas se han obtenido usando la técnica Particles from Gas Saturated Solutions (PGSS) que emplea scCO2 como soluto. Por último, el proceso de silanización supercrítico se ha ensayado para materiales híbridos complejos multiescalados. Se han procesado materiales de base cemento empleando un proceso supercrítico de carbonatación-silanización en dos etapas. Primero, el cemento se carbonata de manera acelerada usando scCO2 como agente de carbonatación. Este cemento, ya carbonatado, se somete, finalmente, a un tratamiento hidrofóbico mediante silanización supercrítica, para su posible aplicación en confinamiento de residuos peligrosos en ambientes húmedos o como material de construcción duradero. / Nowadays, society is asking for a global changing in the way of manufacturing goods in a more sustainable manner. Indeed, the weight of the classical factors (cost, quality, appearance) influencing the acceptance of a certain good in the market have currently changed. Manufacturing requirements and regulations concerning environment protection (e.g., resource consumption, sustainability, toxicity, CO2 footprint, recycling potential) and quality features (e.g., product guarantees, durability against aggressive environments, corporate vision) are aspects of increasing concern. The competitive position of a company is influenced by seizing the opportunities and challenges and by managing the risks that the changeable market has. As a consequence, the industry is continuously looking for smart and innovative solutions for the design and manufacturing of materials with novel properties and increased added value, and for the production of materials already existing in the market in a more efficient manner. Nanostructured hybrid composites have emerged as a promising class of innovative materials for many industrial sectors (e.g., energy, optoelectronics, biomedicine, cosmetics). The multicomponent composition of these materials provides them with unique properties arising from the synergistic combination of the characteristics of their individual components structured at the nanolevel. Nevertheless, in numerous hybrid materials, the lack of coupling or bonding between the components often leads to anisotropic macroscopic properties, limiting their use. Hence, the interaction at the interphase between hybrid components must be properly engineered to enhance materials properties. In this PhD Thesis, the quest for sustainable and environmentally friendly processes led to the use of supercritical carbon dioxide (scCO2) for both the surface modification of nanometric inorganic particles and the preparation of nanostructured hybrid materials. These processes are designed for the replacement of conventional methods using organic solvents. vi Bifunctional alkoxysilane molecules, acting as adhesion promoters, are, herein, investigated for the surface modification of nanometric inorganic particles. The surface treatment of titanium dioxide (TiO2) nanoparticles with octyltriethoxysilane is taken as the model system for study. In terms of processing, scCO2 is used as the solvent of choice for alkoxysilanes for the surface modification of TiO2. Fundamental studies on the solubility of the used silane in CO2 in the pressure range 8-18 MPa at two different temperatures (318 and 348 K) and on the kinetics of the TiO2 silanization process are performed. For the scCO2-aided silanization process, studies are conducted to ascertain the effects and interactions of the operating variables on the properties of the final material. Results show that the tunable physicochemical properties of scCO2 with pressure and temperature (e.g., density, solvation power) allows the engineering control of the characteristics of the silane coating. Examples of the extension of the application of the supercritical silanization process to other sets of alkoxysilanes and inorganic nanoparticles are also presented. The preparation of hybrid materials including silanized inorganic nanoparticles and organic matrices is further tested using scCO2 technology. Surface treated nanoparticles are used to facilitate the homogeneous distribution of the nanoparticles within the matix and to improve the inorganic filler-organic matrix interaction. Biopolymeric matrices of either poly(L-lactic acid) (L-PLA) or the blend poly(methylmethacrylate)/poly(ε-caprolactone) (PMMA/PCL) loaded with nanometric titanium dioxide or hydroxyapatite, respectively, are prepared. To obtain these hybrid materials, scCO2 is employed as an anti-solvent, using the Particles from a Compressed Anti-Solvent (PCA) technique. Studies are performed to pursue the effect of the processing conditions on the morphology of the precipitated hybrid materials. The resulting material, obtained in the form of fibers, has suitable properties for its potential application in tissue engineering. In a different system, hybrid particles composed of a lipidic matrix (hydrogenated castor oil/glyceryl monostearate) loaded with silanized titanium dioxide and caffeine are prepared. The Particles from Gas Saturated Solutions (PGSS) technique, assisted by the use of scCO2 as a solute, is employed for the production of these solid lipid particles. The obtained hybrid material is evaluated concerning the drug carrier and release ability and the UV-shielding capacity. The UV-light protection and photoaging prevention capacity of the lipid-based hybrid material provide excellent properties for the use of these particles in the formulation of sunscreens and pharmaceutical dermal products. vii Finally, the possibility of extending the supercritical silane treatment to multiscale complex hybrid materials is assessed. The technology based on the use of scCO2 is presented for the two-step carbonation-silanization process of cement-based materials. In the first step, the carbonation of cement is accelerated using scCO2 as the carbonation agent. The effects of the cement formulation and process operation conditions on the microstructure and physicochemical properties of carbonated samples are evaluated. The carbonation process is followed by the hydrophobic treatment of the carbonated samples using a supercritical silanization method. The surface modification of carbonated cement with octyltriethoxysilane confers water repellence to the material. The carbonation-silanization process is scheduled and integrated to mitigate the consumption of raw materials and the use of facilities.

As feature sizes in semiconductor devices become smaller and newer materials are incorporated, current methods for photoresist and post plasma etch residue removal face several challenges. A cleaning process should be environmentally benign, compatible with dielectric materials and copper, and provide residue removal from narrow and high aspect ratio features. In this work, sub-critical CO2 based mixtures have been developed to remove the etch residues; these mixtures satisfy the above requirements and can potentially replace the two step residue removal process currently used in the integrated circuit (IC) industry. Based on the chemical nature of the residue being removed, additives or co-solvents to CO2 have been identified that can remove the residues without damaging the dielectric layers. Using the phase behavior of these additives as a guide, the composition of the co-solvent was altered to achieve a single liquid phase at moderate pressures without compromising cleaning ability. The extent of residue removal has been analyzed primarily by x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Various techniques such as attenuated total reflection - Fourier transform infrared (ATR-FTIR) spectroscopy, angle-resolved XPS (ARXPS), and interferometry were used to probe the interaction of cleaning fluids with residues. Model films of photoresists and plasma deposited residues were used to assist in understanding the mechanism of residue removal. From these studies, it was concluded that residue removal takes place primarily by attack of the interface between the residue and the substrate; a solvent rinse then lifts these residues from the wafer. It has been shown that transport of the additives to the interface is enhanced in the presence of CO2. From positronium annihilation lifetime spectroscopy (PALS) studies on a porous dielectric film, it has been shown that these high pressure fluids do not cause significant changes to the pore sizes or the bonding structure of the film. Hence, this method can be used to remove post etch residues from low-k dielectric films.

Non-conventional techniques for polymerization and depolymerization were investigated. The rates of polymerization were enhanced higher in ultrasonic, supercritical fluids and microwaves. However in these system under certain conditions, simultaneous degradation also occurred. Depolymerization was studied by various methods like thermal degradation in supercritical fluids and in presence of oxidizers, Lewis acid and other organic acids. Degradation by ultrasound and thermal degradation of polymer mixtures were also investigated. The scission of the polymer backbone is random for thermal degradation while the scission occurs at the midpoint for ultrasonic degradation. The degradation rates in all the investigated techniques were higher than the degradation rates observed for pyrolysis. Degradation was possible at low temperature (< 50°C) for oxidative and ultrasound degradation while the degradation rates were two orders of magnitude higher in supercritical conditions. The molecular weight distribution was obtained by GPC analysis and the continuous distribution models were used to obtain the rate coefficients. The activation energies were calculated from the temperature dependence of the rate coefficients.

No description available.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work aimed to study the enzymatic hydrolysis of malt bagasse, using mechanical agitation, ultrasonic probe and supercritical CO2. Enzymatic hydrolysis was performed on granular starch. For this, was used a commercial amylolytic complex suitable for this type of hydrolysis, STARGENTM 002. For each technology were studied different variables. The first planning was carried out for the hydrolysis assisted by mechanical agitation and the variables studied were temperature (°C), enzyme concentration (%, m/m) and substrate concentration in the medium (m/m). TRS concentrations were found up to 75.5 g per kg of substrate and all variables had a significant effect on the response. This concentration of TRS was defined as mass yield of the process and this yield was corroborated by a kinetic, developed under the same conditions, with slight increase in temperature (70°C). From this initial planning, the temperature variables (70°C), enzyme concentration (8.2%) and substrate concentration (170 g.L-1) were fixed to carry out the hydrolysis assisted by direct and indirect ultrasound. The variables were investigated in the second planning were amplitude (%) and pulse factor (-) for 2 hours of reaction. With the application of direct sonication, it was possible to achieve 100% efficiency in the starch conversion process. The TRS for the best essay (5) was 370.86 g.kg-1. For indirect sonication TRS concentration at the best condition (run 6) was 162.96 g / kg of substrate. A kinetic assay for the best condition under direct sonication was carried out for 3 hours, confirming that the ultrasound increases the reaction rate resulting in better yields in less time compared to the other techniques. For reactions with supercritical CO2 was studied the influence of the moisture content, temperature and pressure, where the best result among all the reactions was using at pressure 175 bar, 40 °C for temperature and moisture content of 80%, resulting in 104.28 g of TRS per kg of dry pulp. Ultrasound showed better results than other technologies investigated in this study. / Este trabalho teve como objetivo estudar a hidrólise enzimática do bagaço de malte, utilizando agitação mecânica, sonda de ultrassom e CO2 supercrítico. A hidrólise enzimática foi realizada sobre o amido granular. Para tanto, foi utilizado um complexo amilolítico comercial próprio para este tipo de hidrólise, STARGENTM 002. Para cada tecnologia foram estudadas diferentes variáveis. O primeiro planejamento foi realizado para a hidrólise assistida por agitação mecânica e as variáveis estudadas foram temperatura (ºC), concentração de enzima (%, m/m) e concentração de substrato no meio (m/m). Foram encontradas concentrações de ART de até 75,5 g por kg de substrato e todas as variáveis apresentaram efeito significativo sobre a resposta. Essa concentração de ART, foi definida como rendimento mássico do processo e este valor foi corroborado com uma cinética, desenvolvida nas mesmas condições do melhor ensaio, com leve aumento apenas na temperatura (70ºC), e indicou valor concernente ao anterior além de provar que o tempo de 4 horas de hidrólise foi suficiente. A partir deste primeiro planejamento, as variáveis temperatura (70°C), concentração de enzima (8,2%) e concentração de substrato (170 g.L-1) foram fixadas para a realização da hidrólise assistida por ultrassom, de forma direta e indireta. As variáveis investigadas neste segundo planejamento foram amplitude (%) e fator de pulso (-) durante 2 horas de reação. Com aplicação de sonicação direta, foi possível alcançar 100% de eficiência no processo de conversão do amido. A resposta encontrada para o melhor ensaio (5) foi de 370,86 g.kg-1. Já com aplicação de sonicação indireta, a eficiência do processo caiu pela metade e o melhor resultado foi para o ensaio de número 6, com concentração de 162,96 g ART/ kg de substrato. Uma cinética para o melhor ensaio de sonicação direta foi desenvolvida durante 3 horas, atestando que o ultrassom aumenta a velocidade da reação resultando no melhor rendimento em menor tempo comparado às outras técnicas. Para as reações com CO2 supercrítico, foi estudada a influência da umidade, da temperatura e pressão, onde o melhor resultado obtido, entre todas as reações, foi com a utilização de pressão de 175 bar, temperatura de 40ºC e 80% de água adicionada ao bagaço, resultando em 104,28 g de ART por kg de bagaço seco. Esse valor corresponde a 11,53% de eficiência da reação de hidrólise do amido em açúcares redutores totais. De um modo geral, os processos obtiveram um bom desempenho na obtenção de açúcares fermentescíveis, destacando-se o ultrassom em relação as demais tecnologias testadas.

Orientador: Lireny Aparecida Guaraldo Gonçalves / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-05T16:44:27Z (GMT). No. of bitstreams: 1 Moura_JulianaMariaLeiteNobregade_D.pdf: 12204260 bytes, checksum: 81d1e3e2a50ff11707866a644a4ad381 (MD5) Previous issue date: 2006 / Resumo: Lipídios estruturados específicos (LE) constituem uma fonte lipídica de elevado valor nutricional em função das modificações ocorridas em sua composição e distribuição específica de ácidos graxos na molécula do glicerol, visando aplicações médicas, nutricionais e alimentícias. Este trabalho teve como objetivo a obtenção enzimática de LE a partir da interesterificação entre triacilgliceróis de cadeia média (TCM) e ésteres etílicos de ácidos graxos de cadeia longa (EEAGCL), aplicando a tecnologia de membranas, associada ou não à tecnologia de fluido supercrítico, durante a síntese e/ou purificação dos LE. As condições de obtenção dos EEAGCL, utilizados como substratos na obtenção dos LE, foram otimizadas através de planejamento experimental 23. Obteve-se taxa de conversão máxima de 95%, a 40°C, 1% de NaOH, 36% de etanol anidro, tempo de reação de 5 minutos e agitação de 600 rpm. Parâmetros reacionais como, diferentes valores de atividade de água (aw), uso de peneira molecular (10%p/p), razão molar de substratos de 1:2 e 1:4 (TCM/EEAGCL) e diferentes enzimas (Lipozyme TL 1Me RM 1M)foram avaliados na cinética de interesterificação do LE em reator por batelada, a 60°C. Verificou-se maior cinética para a enzima Lipozyme TL 1M,para aw entre 0,30 - 0,43 e razão molar de 1:4. O uso de peneira molecular (10% p/p) conferiu discreto aumento na incorporação de EEAGCL nos TCM. No sistema de reator de interesterificação piloto foram avaliados o efeito do condicionamento da enzima na mistura reacional (TCM + EEAGCL) e a influência da razão molar de substratos. A enzima agindo com aw original (0,33) conferiu maior incorporação quando comparada com a enzima previamente condicionada na mistura reacional, para 30 horas de reação, 67 e 48%, respectivamente. Quando se passou a razão molar dos substratos de 1:3 para 1:4 houve aumento no percentual de incorporação e o tempo necessário para a incorporação máxima no TCM (-66,6%) foi reduzido de 30 para 10 horas. A aplicação da tecnologia de membranas no sistema de obtenção enzimático de LE foi avaliada em reator de membrana plana (poliméricas) a 60°C, com agitação de 600 rpm, utilização da enzima Lipozyme TL 1M (5% peso/substrato) e razão molar de 1:3 - TCM/EEAGCLo. uso de membranas favoreceu a incorporação de EEAGCL nos TCM a partir de 54 horas de reação e ao final de 102 horas foi de 70 e 57%, com e sem membrana, respectivamente. Os teores de AGE w-6 e w-3 observados foram de 23,5 e 11,7%, respectivamente. No entanto, a razão entre os AGE ro-6/ro-3 não apresentou variação significativa. A associação do processo de membrana enzimática e fluidificação por dióxido de carbono supercrítico (C02SC) também foi avaliada. A enzima Candida antartica foi imobilizada por ligação covalente a uma camada de biopolímero (Gelatina/PEI), adsorvida na membrana tubular (aalumina). Os experimentos foram conduzidos a 60°C e pressão transmembrana de 0,05MPa. Pressões de C02 (PC02) de 6, 12 e 18MPa foram avaliadas. Verificou-se uma grande influência da PC02 sobre a cinética de interesterificação, tendo a PC02 de 18MPa permitido incorporação máxima de 34,5% de EEAGCL no TCM; dentre os quais 24,7% de ácidos graxos essenciais. Experimentos foram conduzidos com o objetivo de purificar o LE através da extração por C02SC dos subprodutos do meio reacional e retenção seletiva do LE através de membrana de osmose reversa. Foram avaliadas diferentes pressões de CO2 (9, 11 e 13MPa) e pressões transmembranas (1, 2, 3 e 4MPa), a 40°C. A membrana de osmose reversa BW-30 apresentou boa resistência às pressões utilizadas e maior retenção de triacilgliceróis nos testes seletivos. Incrementos na PC02 de 9 a 13MPa ocasionaram decréscimos no fator de retenção de triacilgliceróis devido ao aumento na solubilização dos solutos e consequente redução na seletividade da extração. O fator máximo de retenção de triacilgliceróis foi obtido com baixa PCO2 (9MPa) e baixa pressão transmembrana (0,7MPa). A membrana apresentou, no período de estabilização, um fator de retenção de triacilgliceróis médio de 95% e máximo a partir de 3 horas de filtração. A utilização de baixa temperatura (40°C) na extração e purificação do LE confere boa proteção aos ácidos graxos poliinsaturados contra a oxidação e migração acila / Abstract: Specific-structured lipids (SL) are a lipid source with high nutritional value due to changes in its glycerol backbone's fatty acid composition and specific distribution aiming medical, nutritional and food applications. This study had as objective the production of SL through enzymatic interesterification between medium chain triacylglycerol (MCT) and long chain fatty acid ethyl esters (LCFAEt) applying membrane technology, with or without supercritical fluid technology for synthesis and/or SL purification. The production conditions of LCFAEt, used to obtain SL, were optimized according to an experimental planning (23). Ethyl esters' conversion rate was 95%, at 40°C, 1% NaOH, 36% ethanol, running 5 minutes under 600rpm stirring speed. Reaction parameters like water activity (aw), moisture absorbent (10%w/w), molar ratio between substrates of 1:2 e 1:4 (MCT/LCFAEt) and types of enzymes (Lipozyme TL 1Mand RM 1M)were evaluated according to their influences on the SL interesterification in the batch reactor, at 60°C. The best incorporation results were obtained using Lipozyme TL 1Mwith aw between 0,30- 0,43.and molar ratio of 1:4. 10% (p/p) of moisture absorbent the interesterification kinetic presented a discreet increase. The impact of the enzyme conditioning process in the blend and the influence of the molar ratio of substrates were evaluated in the pilot reactor system. The usage of the enzyme with original water activity (0,33) provided higher kinetic incorporation in comparison with the conditioned enzyme, for a reaction time of 30 hours, 67 and 48%, respectively. The increase in the molar ratio of substrates from 1:3 to 1:4 improved the kinetic incorporation and reduced the maximum incorporation reaction time (66,6%) from 30 to 10 hours. The usage of membrane technology in the enzymatic system to obtain SL was evaluated in a plain membrane reactor (polymeric) under 60°C temperature; 600rpm stirring speed; Lipozyme TL 1M enzyme (5% based on substrates' weight) and molar ratio of substrates of 1:3(MCT/LCFAEt). The application of membranes increased the kinetic incorporation of LCFAEt in the MCT afier 54 hours of reaction. In the end of 102 hours incorporation was 70 and 57%, with and without membrane in the reactor, respectively. The final SL, obtained with and without membrane, showed fatty essential acids composition of 23,5 and 11,7%, respectively. However, the ratio between the essential fatty acids 00-6/00-3was not significantly different. The coupling of the membrane filtration process and fluidification by supercritical carbon dioxide (SCCO2) was also evaluated. The enzyme (Candida antartica) was immobilized on the membrane support (a-alumina) by covalent attachment to a gelatin/PEI layer previously adsorbed. Tests were performed at 60°C and O,O5MPa of transmembrane pressure. CO2 pressures (PCO2) of 6, 12 and 18MPa were evaluated. This parameter showed a high influence in the kinetic interesterification, with highest incorporation value of LCFAEt in the MCT (34,5%) at 18MPa, being 24,7% of essential fatty acids. Tests to purify the SL by SCCO2extraction of the undesired solutes and triacylglycerol retention by reverse osmosis and nanofiltration membrane were also performed. PCO2 of 9, 11 and 13MPa and transmembrane pressure of 1, 2, 3 and 4MPa were evaluated at temperature of 40°C. Reverse osmosis membrane (BW-30) demonstrated good resistance to the pressure conditions and higher triacylglycerol retention. The increment in the PCO2 from 9 to 13MPa reduced the triacylglycerol retention factor by increasing solute's solubilization. The highest triacilglicerol retention factor was obtained at the lowest PCO2 (9MPa) and at low transmembrane pressure (O,7MPa). The membrane showed, in the initial time, triacylglycerol retention factor of 95% and the maximum value with 3 hours of filtration. The low temperature (40°C) usage in SL extraction and purification reactions provided good protection to the polyunsaturated fatty acids against the oxidation and acyl migration / Doutorado / Doutor em Tecnologia de Alimentos

Orientador: Fernando Antonio Cabral / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-03T17:19:57Z (GMT). No. of bitstreams: 1 Correa_AnaPaulaAntunes_M.pdf: 600105 bytes, checksum: 4dfea2d144baade07682ceb2cd366861 (MD5) Previous issue date: 2003 / Resumo: Os ácidos graxos polinsaturados ômega-3 (EPA, DHA) são compostos com propriedades terapêuticas no tratamento e prevenção de doenças coronárias, hipertensão, arteriosclerose e artrite, além de serem essenciais para o desenvolvimento e manutenção das funções do sistema nervoso central. Os óleos de peixes de origem marinha são as fontes mais ricas em ômega-3 e por isso têm sido usados com freqüência para a obtenção de concentrados destes ácidos graxos. A deficiência de ômega-3 na dieta da população causada pela baixa ingestão destes ácidos graxos, através do consumo de peixes, toma interessante o enriquecimento de alimentos mais populares como a margarina, pães e produtos lácteos com esses ácidos graxos. A extração com fluido supercrítico é um processo de separação relativamente novo que traz vantagens em relação às técnicas convencionais. Para alimentos, o dióxido de carbono tem sido o solvente mais empregado, por ser inerte, relativamente barato e não inflamável e por possuir pressão e temperatura crítica moderadas (304,15 K, 7,38 MPa), evitando problemas de degradação térmica. Neste trabalho, estudou se o fracionamento com dióxido de carbono supercrítico do óleo de peixe em diferentes condições de temperatura e pressão. Os experimentos foram realizados de 14,7 a 29,4 Mpa e de 301,15 a 323,15 K. O procedimento experimental consistiu em promover o contato entre o óleo de peixe aderido à esferas de vidro e o CO2 supercrítico, em um processo dinâmico, de forma a promover o equilíbrio de fases. O corpo do sistema permanecia imerso dentro de um banho termostatizado. O extrato do óleo de peixe (amostra da fase leve) foi coletado no final do extrator em condições de equilíbrio com a fa_e pesada e a sua composição em ácidos graxos foi determinada através de cromatografia em fase gasosa. A altas pressões (14,7 a 29,4 MPa), o extrato apresentou pouca diferença na sua composição em ácidos graxos em relação a fase pesada. A 7,8 MPa e 301,15 K um pequeno fracionamento foi obtido para o ácido docosahexaenóico (DHA). O ácido eicosapentaenóico (EPA) foi o ácido graxo que mostrou maior resistência ao fracionamento em todas as condições estudadas. Logo, neste estudo o dióxido de carbono supercrítico não se mostrou efetivo para o fracionamento do óleo de peixe rico em ácidos graxos polinsaturados. Estas dificuldades podem ser atribuídas à complexidade da composição do óleo de peixe em triacilgliceróis, os quais apresentam-se distribuídos em muitas frações com baixa porcentagem mássica no óleo e por serem formados por ácidos graxos de diferentes tamanhos de moléculas / Abstract: The omega-3 (EPA and DHA) polyunsaturated fatty acids are compounds with therapeutic properties, that may play an important role in the prevention and treatment of cardiovascular disease, hypertension, atherosclerosi, and arthriti. Furthermore, they are essencial for development and maintaince of central nervous system. Because there is a gap between intake of n-3 fatty acids by fish consumption and the recommended amount, it would be useful to enrich ordinary foods as margarine, bread and dairy foods with this fatty acids. The marine fish oils are the richest source of n-3 and it has been used as raw material for preparation of this fatty acid concentrate. Supercritical fluid extraction is a relatively new separation process that may circumvent some of the problems associated with the use of conventional separation techniques. In foods processes, carbon dioxide is the most used solvent, because it is inert, inexpensive and non-flamable and it has moderate critical temperature and pressure (304,15 K, 7,38 MPa), which avoid problems of thermo degradation. In the present work, the fractionation of fish oil with supercritical carbon dioxide at different conditions of temperature and pressure: pressure ranged from from 14,7 to 29,4 MPa and temperature ranged from 301,15 to 323,15 K. A known amount of fish oil was mixed with glass spheres and put inside the column extraction. The supercritical carbon dioxide was contacted with the fish oil in a dynamic system and the oil present in the light phase was collected in the end columm, which was in equilibrium conditions with the heavy phase. All the experimental body system was immersed in water bath to ensure isothermal conditions. The oil present in the light phase was trapped in a flask and its fatty acids composition was determined by gas phase chromatography. At higher pressures the extract obtained (Iight phase) showed similar composition in poliunsatured fatty acids when compared with heavy phase, so no fractionation effect was observed at this conditions. At 7,8 MPa and 301,15 K a modest fractionation was obtained for docosahexaenoic acid (DHA). The eicosapentaenoic acid (EPA) was the most difficult one to fraction at the studied conditions. So, in the present work, the supercritical carbon dioxide didn't show effective in the fractionation of fish oil rich in polyunsaturated fatty acids. This difficult can be explained by the complex composition of fish oil in triacylglicerols with different chain length fatty acids ligants and by similar molecular mass / Mestrado / Mestre em Engenharia de Alimentos

Les biopolymères constituent une alternative crédible à l’utilisation des plastiques issus de ressources pétrolières. Dans cette étude, la transformation de l’amidon et de l’acétate de cellulose en présence de liquides ioniques en voie fondue (par extrusion) a été réalisée. Les caractéristiques physico-chimiques des formulations obtenues ont montré une dépendance vis-à-vis du type et de la concentration de plastifiant utilisé, mais aussi de l’humidité relative appliquée. De manière générale, les liquides ioniques ont présenté comparativement à des plastifiants usuels: une interaction plus privilégiée avec les deux polymères, une réduction beaucoup plus importante de la cristallinité, une diminution significative de la température de transition vitreuse et une plastification efficace des deux matrices polymères étudiées. Dans un deuxième temps, on s’est intéressé à associer le pouvoir de solvatation et de plastification du dioxyde de carbone supercritique (CO2Sc) sur la mise en oeuvre de l’amidon par les liquides ioniques. Les résultats les plus importants ont montré que le CO2Sc est capable d’interagir sur l’amidon et sur les liquides ioniques, de sorte qu’il peut induire une diminution de la température de la transition vitreuse de l’amidon plastifié / Biopolymers are viable alternatives to the use of conventional plastics derived from fossil fuels resources. In this study, our objective, beyond doing the melt processing ionic liquids plasticized starch and cellulose acetate in laboratory scale microcoumpounder which simulate the performance of a co-rotating twin screw extruder, are to investigate the effects and influence of ionic liquids and water on the intrinsic properties of the materials which are prepared. In general ways, processing with ionic liquids compared with conventional plasticizers, presents: a better interaction with starch and cellulose acetate, a more efficient depressor of glass transition temperature and allows the production of processed materials with efficient crystallinity destruction and plasticization. In the second step, we investigate the effects of supercritical carbon dioxide on the processing of starch with ionic liquid and the effects of the processing pressure, temperature and duration of supercritical carbon dioxide (ScCO2), which is an environmentally-friendly component, on the properties of plasticized starch. The significant results show that ScCO2 is capable of interacting with starch chains and with ionic liquids, so that it may induce a decrease in the glass transition temperature of the plasticized starch