No description available.

[pt] O conhecimento do comportamento geológico-geotécnico de solos formados em ambientes tropicais, em particular na região Amazônica, ainda é escasso tanto no país quanto no exterior. Visando contribuir para tal, o presente trabalho apresenta resultados de uma extensa campanha experimental envolvendo ensaios de laboratório em amostras amolgadas e indeformadas coletadas nos platôs dissecados do município de Oriximiná, localizado no norte do Pará, Brasil. O material foi extraído do horizonte mais inferior do perfil de solo local, chamado de argila variegada, assim definida por apresentar uma coloração variada (do vermelho ao branco). Tal tipo de solo argiloso, não saturado, constitui o principal material de fundação dos platôs de exploração e de armazenamento de rejeitos oriundos da atividade mineradora da região sendo, portanto, relevante um entendimento cientificamente embasado acerca de seu comportamento sob o ponto de vista de engenharia. Para subsidiar um melhor entendimento desse comportamento, o trabalho apresenta resultados de ensaios físicos (ensaios geotécnicos básicos tais como de granulometria, densidade relativa dos grãos e limites de Atterberg); análises químicas total e parcial, pH e de matéria orgânica; ensaios mineralógicos por difração de raios X e utilizando lupa binocular; ensaios de retenção de umidade (papel filtro) e ensaios de micro-morfologia dos solos, como de porosimetria, tomografia computadorizada e microscopia eletrônica de varredura (MEV). Os resultados obtidos sugerem que este solo é de origem residual, essencialmente composto por caulinita, com traços de gibbsita e cimentações ferruginosas, com uma microestrutura que pode explicar um caráter fortemente anisotrópico de permeabilidade, ajudando a justificar o que é evidenciado em resultados de investigações de campo efetuadas na área. / [en] Knowledge of the geological-geotechnical behaviour of soils formed in tropical environments, particularly in the Amazon region, is still scarce both in Brazil and abroad. In order to understand this behaviour, an extensive experimental campaign was carried out with laboratory tests on disturbed and undisturbed samples collected from the dissected plateaus of the municipality of Oriximiná, located in the north of Pará, Brazil. The material was extracted from the lowest horizon of the local lithological profile, called variegated clay, characterized by its varied colour (from red to white). This type of clayey soil constitutes the main foundation material of the plateaus for exploration and storage of tailings from the mining activity in the region, which demands a scientifically based understanding of its behaviour from an engineering point of view. Therefore, the work presents results of physical tests, including measurements of material suction through characteristic retention curves, chemical tests of grain composition, pH and presence of organic matter, mineralogical tests of X-ray diffraction and binocular observation, and soil micromorphology tests, such as porosimetry, computed tomography and scanning electron microscopy (SEM). The results suggest that this soil is of residual origin, essentially composed of kaolinite, with traces of gypsum and ferruginous cementations, with a microstructure that can explain a strongly anisotropic character of permeability evidenced by results of field investigations carried out in the area.

Pharmaceuticals with suitable therapeutic properties often found to encounter challenges with dosage form development due to their poor physicochemical properties. Aim of thesis is to evaluate potential of crystal engineering directed cocrystallisation of active ingredients in modulating their physical attributes. The model compounds considered are isoniazid, caffeine, nifedipine, glyburide, chlorpropamide and riboflavin. Co-formers selected are based on the suitability of functional groups for hydrogen bond formation. Co-crystal screening and preparation methods used include neat grinding (NG), liquid assisted grinding (LAG) and solution crystallisation. Antituberculosis drug, isoniazid, upon cocrystallisation with melamine, solubility has reduced as per high performance liquid chromatography assay, however, antimicrobial properties determined using REMA assay confirms that cocrystal anti-mycobacterial activity is not compromised. Next, caffeine-glutaric acid cocrystal polymorphic forms (Forms I and II) subjected to mechanical property evaluations in multiple faces using nanoindentation and correlated relationship between crystal structure and mechanical property. The results suggest that metastable form, Form I, could display suitable tablet properties to that of thermodynamically stable form, Form II. Subsequently, photosensitive drug, nifedipine, cocrystallised with theophylline and caffeine. Notably, photochemical stability along with solubility and drug release of cocrystals is found to be superior to that of nifedipine. Lastly, crystal engineering principles utilised in preparation of multicomponent crystals of antidiabetic model drugs, glyburide and chlorpropamide with various coformers. Interestingly, during the preparation of chlorpropamide-2-nitrobenzyl alcohol, high Z prime crystal (Z’=3) of 2- nitrobenzyl alcohol is serendipitously identified. In conclusion, crystal engineering based cocrystallisation is a viable technology for modulating physicochemical properties of pharma and nutraceuticals.

No / The electrophoretic mobilities of three beta-blocker drug practolol, timolol and propranolol, have been measured in electrolyte systems with mixed binary and ternary water-methanol-ethanol solvents with acetic acid/sodium acetate as buffer using capillary electrophoresis. The highest mobilities for the analytes studied have been observed in pure aqueous. the lowest values in ethanolic buffers The measured electrophoretic mobilities have been used to evaluate the accuracy of a mathematical model based on a mixture response surface method that expresses the mobility as a function of the solvent composition. Mean percentage error (MPE) has been computed considering experimental and calculated mobilities as an accuracy criterion. The obtained MPE for practolol, timolol and propranolol in the binary mixtures are between 0.9 and 2.6%, in the ternary water-methanol-ethanol solvent system the MPE was about 2.7%. The MPE values resulting from the proposed equation lie within the experimental relative standard deviation values and can he considered as an acceptable error.

Surface water pollution is prevalent in numerous areas of central Roodepoort mainly due to gold mining activities. The surface water quality for the Bosmontspruit, Russell’s Stream and the New Canada Dam was assessed from October 2010 to March 2011. Physical, chemical and biological characteristics of the water were determined for 8 monitoring points and the results obtained were compared with the In-stream water quality guidelines for the Klip River catchment and the South African Water Quality Guidelines. A trend noticed throughout the sampling period was the non-compliance in the levels of total dissolved solids (TDS) and dissolved oxygen. The results indicated that concentrations of iron, aluminium, nickel, manganese and potassium were above the limit across the Bosmontspruit and Russell’s stream. There was also significant evidence of excessive faecal coliform and ammonium pollution in the Bosmontspruit. During the monitoring period it was noted that water from these streams were utilised for crop irrigation, bathing, livestock and human consumption and may pose a health hazard due to poor water quality. / Environmental Sciences / M.Sc. (Environmental Science)

Durant les cultures cellulaires en bioréacteur, la physiologie des micro-organismes et les paramètres physico-chimiques (alimentations en gaz et en substrat, agitation, température, pH, pression) interagissent très fortement. La spécificité des bioréactions microbiennes, en relation avec les couplages irréductibles entre les transferts de chaleur, de matière et de quantité de mouvement, réside dans la complexité (milieu triphasique) et la dynamique (bioréaction autocatalysé) de ces systèmes. L’objectif de ce travail est de progresser dans la compréhension et le contrôle dynamique des intéractions entre les aspects biologiques et les aspects physiques à différentes échelles (macro, micro et moléculaire) pour conduire la réaction biologique vers l’objectif défini (production de biomasse, de métabolites intra ou extra cellulaires, …) et l’optimiser. Les cellules (concentration, forme, dimension, physiologie, …) affectent fortement les propriétés physico-chimiques des moûts et par conséquent, les performances des bioprocédés (vitesses spécifiques, rendements, productivité). Le comportement rhéologique particulier du moût est souvent utilisé pour comprendre l’impact de la biomasse microbienne sur le rendement et les performances du bioprocédé.Dans ce travail, des cultures axéniques, définies comme des cultures pures de microorganismes unicellulaires procaryote et eucaryote, sont considérées. Notre approche s’appuie sur des mesures physiques et physico-chimiques en ligne et hors ligne réalisées sur un bioréacteur instrumenté, mesures qui sont mises en place de façon à respecter les conditions imposées par les contraintes biologiques propres aux microorganismes et à la stratégie de culture choisie. Des cultures d’Escherichia coli et d’Yarrowia. lipolytica, à taux de croissance controlé par l’apport de substrat, ont été réalisées dans une gamme de concentration allant de 0.1 à 100 g l-1. Le bilan qui peut être dressé pour ce travail, tant sur les aspects scientifiques que technologiques, est le suivant :- conception et réalisation d’un outil d’investigation original construit sur la base d’un bioréacteur (20 l) et pourvu d’une boucle de recirculation instrumentée pour la mesure,- identification hydrodynamique (courbes de frottement) de conduites calibrées permettant la viscosimétrie en ligne durant une culture cellulaire, - conception, développement et validation d’un code, LoCoPREL, permettant simultanément le contrôle de la culture cellulaire suivant une stratégie définie, la gestion de séquences de débit dans la boucle de dérivation et l’acquisition des données issues de l’instrumentation spécifique employée,- comparaison des mesures réalisées en ligne à débit constant ou selon des séquences de débit,- mise en évidence du comportement non newtonien des moûts et d’écarts entre les mesures en ligne et hors ligne,- analyse des mesures physiques réalisées en ligne et hors ligne, en lien avec les performances de la culture / During cell cultures in bioreactors, micro-organism physiology closely interacts with physico-chemical parameters such as gas and feed flowrates, mixing, temperature, pH, pressure. The specificity of microbial bioreactions in relation with irreductible couplings between heat and mass transfers and fluid mechanics, led into complex (three-phase medium) and dynamic (auto-biocatalytics reaction) systems. Our scientific approach aims to investigate, understand and control dynamic interactions between physical and biological systems at different scales (macro, micro and molecular) for molecules, strains and/or bioprocess innovation. Cells (concentration, shape, dimension, physiology…) strongly affect physico-chemical properties of broth. Then the modification of these characteristics interacts with bioprocess performances (specific rates, yields…) with an improvement or, more frequently, a decrease of yields. Among these properties, rheological behaviour is a strategy widely used to understand the impact of cells and the derivation of bioprocess performances.In this manuscript, axenic cultures, defined as cultures of a pure and unicellular Prokaryote and Eukaryote microorganisms in bioreactors, are considered. Our approach is based on physical and physico-chemical on-line and off-line measurements in respect with accurate and stringent conditions imposed by cell culture strategy. Escherichia coli and Yarrowia lipolytica cultures were investigated with a control of growth rate by carbon feed in the range from 0.1 up to 100 g l-1. Our scientific and technical actions and results led:- to design and realize an original pilot based on a bioreactor (20 l) with a derivation loop including a specific on-line rheometric device as well as additional physical and biological measurements,- to identify, from a hydrodynamic standpoint, the generalized friction curves of calibrated ducts enabling on-line viscosimetry during cell cultures,- to conceive and validate a homemade software, named LoCoPREL, enabling simultaneously to control cell cultures under defined strategy and to manage flow sequences within the derivation loop,- to discuss and compare on-line physical measurements under constant flow rate and various sequence strategy related to investigated shear-rates,- to highlight about the non-newtonian rheological behaviour of broths and the gap between on-line and off-line measurements,- to analyse on-line and off-line physical measurements in the light of biological performances during fed-batch cultures (mass balance, specific rate, yield).

Anopheles gambiae sensu lato mosquitoes are among the dominant malaria vectors in sub-Saharan Africa. However, not much is known about the oviposition behaviour of these species necessary for the development of malaria vector control strategies. With the aim of investigating cues associated with selected oviposition sites, artificial oviposition sites- ponds (soil mixed with water) were set-up in an open field at Mbita, Western Kenya in 2012 and 2013. Ponds were allowed to be colonized by wild An. gambiae s.l.. The numbers of Anopheles early instar larvae were counted and used as a proxy for oviposition preference. Water samples were then analysed for physicochemical, bacterial and chemical profiles. The bacterial profiles were analysed using denaturing gradient gel electrophoresis (DGGE) and the chemical profiles with gas chromatography-mass spectrometry (GC-MS). The detection of possible oviposition cues from oviposition substrates requires sensitive analytical methods. Volatiles detection was improved seven times. The detection of bacteria deoxyribonucleic acid (DNA) bands with DGGE was also improved to a minimum DNA concentration of 50 ng/µl. Results showed that ponds were colonized differently. Fresh ponds were preferred over slightly older ponds. Bacterial analysis revealed a low number of bacteria colony forming units (CFU) in preferred ponds. Some volatiles, including: 6,10-dimethyl-5,9-undecadien-2-one (geranylacetone) and 4-ethylbenzaldehyde, were associated with the oviposition preferred pond. In addition, low pH and high turbidity were associated with the ponds selected for oviposition. Finally, fungi isolated from the rhizomes of nut grass yielded a promising array of volatiles of which one is known to attract oviposition site seeking malaria mosquitoes. This finding opens the door for a cost effective and environmental friendly method of using fungi in an “attract and kill” strategy targeting malaria vectors. / Myggor i Anopheles gambiae sensu lato komplexet tillhör de myggor som är bäst på att sprida malaria parasiter i afrika söder om Sahara. Kunskapen om de här myggornas äggläggningsbeteende är begränsad. Den här kunskapen behövs för att kunna utveckla nya och förbättra tillgängliga malaria vektor kontroll metoder. Nya metoder som kan komplettera de som används idag (insecticides treated nets (ITNs) och indoor residual spraying (IRS)) behövs eftersom de metoderna har problem med resistensutveckling. Två studier utfördes på icipe fältstation i Mbita västra Kenya under 2012 och 2013 med målet att identifiera faktorer som påverkar myggornas äggläggningsbeteende. Baljor fyllda med en blandning av jord och vatten (äggläggningssubstrat) användes för att tillverka artificiella äggläggningsplatser som liknar de vattenpölar som de här myggarterna gärna lägger ägg i. Baljorna koloniserades av vilda myggor och antalet mygglarver som detekterades i baljorna jämfördes och användes som en proxy för äggläggningspreferens. Fysikaliska och kemiska parametrar mättes på jordvattenblandningarna i baljorna och prover togs för att analysera bakteriepopulationer med hjälp av denaturing gradient gel electrophoresis (DGGE) och flyktiga ämnen med hjälp av gas-kromatografi kopplat till mass-spektrometri (GC-MS). För att kunna detektera de låga halter av flyktiga ämnen och bakterier som fanns i de här proverna krävdes det känsliga metoder. Antalet flyktiga ämnen som kunde detekteras ökades sju gånger genom att tillsätta NaCl till vattenproverna innan doften insamlades och termisk desorption användes istället för lösningsmedels desorption. För att förbättra detektionsgränsen för bakterier amplifierades bakterie-DNA i två PCR reaktioner som sedan mixades och koncentrerades. Resultaten från fältstudierna med baljorna visade att de koloniserades olika av Anopheles myggorna. Baljor med nyblandat substrat innehöll dubbelt så många mygglarver som baljor med jord-vattensubstrat som åldrats under en längre tid. Lägre mängd bakterier, lägre pH och högre grumlighet var gemensamt för de baljor som myggorna föredrog. De flyktiga ämnen som detekterades i de olika baljor varierade mellan olika försök och inget ämne fanns med i alla upprepningar av ett försök. Trots det detekterades några ämnen oftare i de baljor som myggorna föredrog att lägga ägg jämfört med de med en mindre mängd mygglarver. De inkluderar geranylacetone och 4-ethylbenzaldehyde. Svampar isolerades från rotstockar av gräs som fanns i den jord som användes för att göra äggläggningssubstraten i fältstudierna. De flyktiga ämnen som avgavs från svampkulturerna analyserades. Bland annat så identifierades ett ämne som fungerar som en äggläggningsattrahent för An. gambiae s.l. myggor.Resultaten från den här avhandlingen kommer att kunna användas för att utveckla miljövänliga ”attract and kill” metoder för att kontrollera malaria myggor. / <p>QC 20160211</p>

A família dos culicídeos é diversa e possui muitas espécies com alta relevância epidemiológica e que transmitem os patógenos causadores de doenças como dengue, febre amarela e malária. Os imaturos se criam exclusivamente na água e nos mais diversos tipos de criadouros, podendo ser influenciados por fatores biológicos e fatores físico-químicos, que incluem pH, salinidade, condutividade, sólidos totais dissolvidos, entre outros. Entender as variações das condições dos criadouros é importante para entender e esclarecer como esses fatores agem no desenvolvimento dos imaturos, na sua fisiologia e nas relações interespecíficas, que influenciam o desenvolvimento larval e a sobrevivência dos mosquitos. Portanto, o objetivo principal desse trabalho foi investigar a influência de fatores físico-químicos e do tipo de criadouro sobre a ocorrência das espécies de culicídeos em dois remanescentes de Mata Atlântica no município de São Paulo. As coletas dos imaturos ocorreram em três diferentes pontos no Parque Estadual da Cantareira e quatro diferentes pontos na Área de Proteção Ambiental Capivari-Monos, remanescentes de Mata Atlântica inseridos na Grande São Paulo, durante vinte e sete meses para as coletas de diversidade geral e doze meses para as coletas de diversidade juntamente com fatores físico químicos da água. Os imaturos foram coletados em bromélias epífitas e de solo, bambus, poças d\'água no solo e em pedras, ocos de árvore, lagos e recipientes artificiais. As análises dos dados foram feitas através do cálculo do coeficiente de variação das variáveis para os tipos de criadouros, Análise Restrita de Proximidade (CAP), Análise de Correspondência Canônica (CCA) e boxplots sem outliers. Os resultados indicaram que há uma diferença estatisticamente significante na composição de espécies em função dos diferentes tipos de criadouros e que o pH possui influência sobre a ocorrência das espécies, tanto para a variável tipo de criadouro quanto para situações em que se retira essa variável. As espécies com importância epidemiológica coletadas foram: Aedes aegypti, Aedes albopictus, Anopheles cruzii, Haemagogus leucocelaenus, Psorophora ferox e Sabethes purpureus, com ocorrência das duas espécies de Aedes e Haemagogus no mesmo criadouro. Esses resultados são importantes para reforçar a necessidade do monitoramento de criadouros das espécies vetoras de patógenos e para um melhor entendimento da ecologia das espécies. / The Culicidae family is diverse and has many species of high epidemiological relevance that transmit the pathogens that cause diseases such as dengue fever, yellow fever and malaria. The immatures are created exclusively in the water and in the most diverse types of breeding places, being able to be influenced by biological factors and physicochemical factors, that include pH, salinity, conductivity, total solids dissolved, among others. Understanding variations in breeding conditions is important in understanding and clarifying how these factors affect the development of immatures, their physiology, and interspecific relationships that influence larval development and mosquito survival. Therefore, the main objective of this work was to investigate the influence of physical-chemical factors and breeding type on the occurrence of Culicidae species in two remnants of Atlantic Forest in the city of São Paulo. Immature collections occurred at three different points in the Cantareira State Park and four different points in the Capivari-Monos Environmental Protection Area, remnants of the Mata Atlântica, located in Greater São Paulo, during twenty-seven months for collections of general diversity and twelve months for collections of diversity along with physical chemical factors of water. The immatures were collected in epiphytic and soil bromeliads, bamboos, pools of water in the soil and stones, tree hollows, lakes and artificial containers. Data analysis was done by calculating the coefficient of variation of the variables for breeding types, Restricted Proximity Analysis (CAP), Canonical Correspondence Analysis (CCA) and boxplots without outliers. The results indicated that there is a statistically significant difference in species composition as a function of the diverse types of breeding sites and that pH has an influence on the occurrence of species, both for the type of breeder variable and for situations in which this variable is removed. The species with epidemiological importance were: Aedes aegypti, Aedes albopictus, Anopheles cruzii, Haemagogus leucocelaenus, Psorophora ferox and Sabethes purpureus, with occurrence of both Aedes and Haemagogus species in the same breeding ground. These results are important to reinforce the need to monitor breeding sites of pathogen vector species and to better understand species ecology.

A família dos culicídeos é diversa e possui muitas espécies com alta relevância epidemiológica e que transmitem os patógenos causadores de doenças como dengue, febre amarela e malária. Os imaturos se criam exclusivamente na água e nos mais diversos tipos de criadouros, podendo ser influenciados por fatores biológicos e fatores físico-químicos, que incluem pH, salinidade, condutividade, sólidos totais dissolvidos, entre outros. Entender as variações das condições dos criadouros é importante para entender e esclarecer como esses fatores agem no desenvolvimento dos imaturos, na sua fisiologia e nas relações interespecíficas, que influenciam o desenvolvimento larval e a sobrevivência dos mosquitos. Portanto, o objetivo principal desse trabalho foi investigar a influência de fatores físico-químicos e do tipo de criadouro sobre a ocorrência das espécies de culicídeos em dois remanescentes de Mata Atlântica no município de São Paulo. As coletas dos imaturos ocorreram em três diferentes pontos no Parque Estadual da Cantareira e quatro diferentes pontos na Área de Proteção Ambiental Capivari-Monos, remanescentes de Mata Atlântica inseridos na Grande São Paulo, durante vinte e sete meses para as coletas de diversidade geral e doze meses para as coletas de diversidade juntamente com fatores físico químicos da água. Os imaturos foram coletados em bromélias epífitas e de solo, bambus, poças d\'água no solo e em pedras, ocos de árvore, lagos e recipientes artificiais. As análises dos dados foram feitas através do cálculo do coeficiente de variação das variáveis para os tipos de criadouros, Análise Restrita de Proximidade (CAP), Análise de Correspondência Canônica (CCA) e boxplots sem outliers. Os resultados indicaram que há uma diferença estatisticamente significante na composição de espécies em função dos diferentes tipos de criadouros e que o pH possui influência sobre a ocorrência das espécies, tanto para a variável tipo de criadouro quanto para situações em que se retira essa variável. As espécies com importância epidemiológica coletadas foram: Aedes aegypti, Aedes albopictus, Anopheles cruzii, Haemagogus leucocelaenus, Psorophora ferox e Sabethes purpureus, com ocorrência das duas espécies de Aedes e Haemagogus no mesmo criadouro. Esses resultados são importantes para reforçar a necessidade do monitoramento de criadouros das espécies vetoras de patógenos e para um melhor entendimento da ecologia das espécies. / The Culicidae family is diverse and has many species of high epidemiological relevance that transmit the pathogens that cause diseases such as dengue fever, yellow fever and malaria. The immatures are created exclusively in the water and in the most diverse types of breeding places, being able to be influenced by biological factors and physicochemical factors, that include pH, salinity, conductivity, total solids dissolved, among others. Understanding variations in breeding conditions is important in understanding and clarifying how these factors affect the development of immatures, their physiology, and interspecific relationships that influence larval development and mosquito survival. Therefore, the main objective of this work was to investigate the influence of physical-chemical factors and breeding type on the occurrence of Culicidae species in two remnants of Atlantic Forest in the city of São Paulo. Immature collections occurred at three different points in the Cantareira State Park and four different points in the Capivari-Monos Environmental Protection Area, remnants of the Mata Atlântica, located in Greater São Paulo, during twenty-seven months for collections of general diversity and twelve months for collections of diversity along with physical chemical factors of water. The immatures were collected in epiphytic and soil bromeliads, bamboos, pools of water in the soil and stones, tree hollows, lakes and artificial containers. Data analysis was done by calculating the coefficient of variation of the variables for breeding types, Restricted Proximity Analysis (CAP), Canonical Correspondence Analysis (CCA) and boxplots without outliers. The results indicated that there is a statistically significant difference in species composition as a function of the diverse types of breeding sites and that pH has an influence on the occurrence of species, both for the type of breeder variable and for situations in which this variable is removed. The species with epidemiological importance were: Aedes aegypti, Aedes albopictus, Anopheles cruzii, Haemagogus leucocelaenus, Psorophora ferox and Sabethes purpureus, with occurrence of both Aedes and Haemagogus species in the same breeding ground. These results are important to reinforce the need to monitor breeding sites of pathogen vector species and to better understand species ecology.

O desafio das indústrias de alimentos na substituição da gordura trans em diversos produtos reside no desenvolvimento de formulações e processos que apresentem funcionalidade equivalente e viabilidade econômica. A interesterificação química representa uma opção tecnológica importante para a produção de gorduras visando diversas aplicações comerciais, sem a formação de ácidos graxos trans. O óleo de palma contém quantidades aproximadamente iguais de ácidos graxos saturados e insaturados e pelo seu fracionamento obtêm-se duas frações: a estearina (fração sólida) e a oleína (fração líquida). A estearina e oleína de palma são opções interessantes para a produção de grande variedade de produtos como margarinas e shortenings. Assim, o objetivo deste trabalho foi modificar as propriedades físico-químicas de misturas de estearina e oleína de palma pelo uso da interesterificação química. As amostras foram analisadas quanto à composição em ácidos graxos e triacilgliceróis, distribuição regioespecífica dos ácidos graxos nos triacilgliceróis, índice de iodo, pontos de amolecimento e de fusão, conteúdo de gordura sólida, consistência e estrutura cristalina. Os ácidos graxos saturados são predominantes na estearina (71,9%), sendo que 65,5% correspondem ao ácido palmítico. A oleína tem como principal constituinte o ácido oléico, que representa 45,4%. À medida que aumenta a proporção de oleína de palma nas misturas, aumentam a quantidade de ácidos graxos insaturados e o índice de iodo e diminui a quantidade de ácidos graxos saturados. Após a interesterificação química, os pontos de fusão e amolecimento, a consistência e o conteúdo de gordura sólida aumentaram nas misturas que apresentavam maior proporção de oleína em função do aumento no teor de triacilgliceróis trissaturados. Por outro lado, estas propriedades não se modificaram nas misturas com maior proporção de estearina. Este comportamento se deve à distribuição aleatória dos ácidos graxos nos triacilgliceróis após a interesterificação, que forma triacilgliceróis em proporções diferentes das existentes originalmente. Os principais triacilgliceróis nas misturas foram PPP, PPO e POO. Antes da interesterificação os ácidos graxos saturados foram encontrados principalmente nas posições sn-1,3. Mudanças significativas na composição dos ácidos graxos na posição sn-2 após a interesterificação química foram encontradas em misturas com mais de 60% de oleína de palma. A mistura e a interesterificação permitiram obter gorduras com diferentes graus de plasticidade, aumentando as possibilidades de uso das frações estearina e oleína de palma. / The challenge of the food industries for the replacement of trans fat in various products lies in the development of formulations and processes which have equivalent functionality and economic viability. The chemical interesterification of palm stearin and palm olein is an important technological option for the production of fats targeting commercial applications, without formation of trans fatty acids Palm oil contains similar amounts of saturated and unsaturated fatty acids. After fractionation two fractions are obtained: stearin (solid fraction) and olein (liquid fraction). Palm stearin and palm olein are alternatives for the production of many products, such as margarines and shortenings. The objective of this work was to modify the physical and chemical properties of mixtures of palm stearin and palm olein by using chemical interesterification. The following properties were analyzed: fatty acid and triacylglycerol compositions, regiospecific distribution of fatty acids in triacylglycerols, iodine value, softening and melting points, solid fat content, consistency and crystal microstructure. Saturated fatty acids are predominant in palm stearin (71.9%), which corresponds to 65.5% of palmitic acid. Palm olein has as its main constituent the oleic acid, which represents 45.4% of the unsaturated fatty acids. The increase of the proportion of palm olein in the mixture causes increase on the amount of unsaturated fatty acids and iodine value and decrease on the content of saturated fatty acids. After chemical interesterification, melting and softening points, consistency and solid fat content increased in the blends that had higher proportion of palm olein, as a consequence of the increase in the trisaturated triacylglycerols. On the other hand, these properties did not alter in the blends with higher proportion of palm stearin. This behavior is due to the random distribution of fatty acids in triacylglycerols after interesterification, which forms triacylglycerols in proportions that are different from those originally present. The major triacylglycerols in the blends were PPP, PPO and POO. Before interesterification the saturated fatty acids were found mainly in the sn-1,3 positions. Significant changes in the fatty acid composition in the sn-2 position after chemical interesterification were found in blends with more than 60 % of palm olein. Blending and interesterification of fats resulted in structured lipids with different degrees of plasticity, increasing the possibilities of use of stearin and olein fractions.