Efeito da adição de extrato de casca de jabuticaba nas características físico-químicas e sensoriais de queijo petit suisse

A busca pela melhoria da qualidade de vida e a procura por alimentos naturais e funcionais são crescentes. A incorporação de prebióticos e corantes naturais pode agregar valor ao produto, por serem capazes de melhorar sua qualidade e por apresentarem grandes atrativos tecnológicos. Portanto, o objetivo deste trabalho foi avaliar o efeito da adição de prebióticos (inulina e oligofrutose) e corante natural (extrato de casca de jabuticaba) nas características de queijo petit suisse. Foi realizada análise da composição físico-química (extrato seco total, cinzas, proteínas, lipídeos, carboidratos e acidez titulável) logo após o processamento, análise do pH, colorimetria, teor de compostos bioativos e atividade antioxidante em diferentes tempos de armazenamento (0, 7, 14, 21 e 28 dias), análise do teor de fibras alimentares da formulação de queijo petit suisse com maior atividade antioxidante ao final da vida de prateleira e análises microbiológica e sensorial. O queijo petit suisse elaborado foi dividido em cinco formulações, de acordo com a concentração de corante natural incorporado, que foram 0%, 1,5%, 2,0%, 2,5% e 3,0%. Os dados obtidos com as análises realizadas logo após o processamento e análise sensorial foram submetidos à análise de variância e teste de Tukey, os dados obtidos com as análises realizadas em diferentes tempos de armazenamento foram submetidos à análise de variância e estudo do comportamento cinético, e a análise de fibras e microbiológica foi analisada por meio de estatística descritiva. Os valores de extrato seco total, proteínas, lipídeos, cinzas e carboidrato não diferiram significativamente (p>0,05) entre as formulações. A formulação sem adição de corante natural apresentou menor acidez (p≤0,05), e com o aumento da concentração de corante natural, maior foi a acidez do queijo. Os teores de antocianinas, fenólicos totais e capacidade antioxidante foram maiores com o aumento da concentração de corante incorporado, sendo que o teor de antocianinas reduziu com o decorrer do tempo de armazenamento. O valor encontrado de fibras para a formulação contendo 3,0% de corante natural foi baixo, e o produto não apresentou alegação de propriedade funcional. A fim de verificar se o queijo estava próprio para o consumo, foi realizada análise microbiológica para coliformes termotolerantes, estando todas as formulações de queijo petit suisse em condições sanitárias satisfatórias. A análise sensorial foi realizada em duas etapas. Na primeira etapa foi realizado teste de aceitação com avaliação dos atributos cor, sabor, consistência e impressão global, e intenção de compra para todas as formulações com incorporação de corante natural. Na segunda etapa foi realizado o teste de aceitação com informação nutricional do produto para a amostra mais aceita na primeira etapa. Como resultado, foi observado que o atributo cor foi o único que apresentou diferença significativa (p≤0,05) entre as formulações, sendo as mais aceitas com concentração 2,5% e 3,0%. De forma geral, todas as formulações foram bem aceitas, porém, a formulação com maior adição de corante natural foi a que xiii apresentou maiores notas. Assim, o queijo com maior concentração de corante natural foi o utilizado na segunda etapa sensorial, sendo observada influência das informações nos atributos cor e consistência (p≤0,05). Dessa forma, a utilização de prebióticos e corante natural de casca de jabuticaba em queijo petit suisse foi viável por não alterar a composição centesimal do produto, além de conferir ao produto uma coloração atrativa.

Elaboração e análise de extrato hidrossolúvel de gergelim (Sesamum indicum)

O objetivo do presente estudo foi elaborar e caracterizar um extrato hidrossolúvel à base de gergelim para ser usado como possível substituto do leite de vaca e extrato de soja. Foi proposto um modelo de cinética de absorção de água durante a etapa de maceração no qual estimou o tempo ideal de batimento do gergelim macerado e se essa etapa influencia no rendimento do produto. Posteriormente com o objetivo de saber a influência do tempo de batimento (0,45 min a 14,55 min) e a concentração do extrato (1,925% a 23,07%) foram avaliadas através de um delineamento composto central rotacional (DCCR), ou seja, um delineamento 22 incluindo 4 ensaios nas condições axiais e 5 repetições no ponto central, totalizando 13 experimentos. Para todos os ensaios do delineamento realizou-se análises de viscosidade, cor, sólidos solúveis totais e rendimento. As mesmas análises foram realizadas em amostras comerciais de leite de vaca e extrato hidrossolúvel de soja com o intuito de comparação. Após a realização dessa etapa foi possível à seleção de algumas amostras para elaboração do extrato hidrossolúvel de gergelim e então realizou-se análises físico-químicas (proteína, cinzas, lipídios, carboidratos) e determinou-se a capacidade antioxidante por ABTS e teor de compostos fenólicos de tais amostras. Quanto à análise de rendimento não houve diferença significativa da quantidade de extrato obtido em diferentes temperaturas de maceração pelo teste de Tukey (p> 0,05). O DCCR foi realizado no programa Statistica e selecionaram-se os ensaios 1, 2, 6, 7, PC (ponto central) que foram as amostras que mais se assemelharam com as amostras comerciais estudadas. Nessas amostras realizou-se as análises físico-químicas além de capacidade antioxidante e compostos fenólicos. O conteúdo de sólidos totais na amostra 6 foi superior as demais amostras, diferindo estatisticamente das demais amostras (p> 0,05). Já para o teor de lipídios, cinzas e proteínas encontrados nas amostras 6 e PC foram maiores que as demais amostras, enquanto a amostra 7 exibiu o menor teor de lipídios e proteínas, considerando que o teor de cinzas das amostras 1, 2 e 7 foram estatisticamente iguais. O teor de carboidratos calculado por diferença foi superior nas amostras 1, 2 e 7 e com o menor valor na amostra 6. Os valores de capacidade antioxidante e compostos fenólicos não se diferenciaram estatisticamente entre si ao nível de 5% de probabilidade. Concluiu-se portanto que a etapa de maceração não influenciou no rendimento do produto final. A partir das análises físico-químicas pode-se concluir que o extrato hidrossolúvel de gergelim em determinadas amostras apresentou um melhor desempenho quanto ao valor nutricional comparado ao extrato de soja.

Surface plasmon resonance as a tool in the functional analisys of an immunodominant site in foot-and-mouth disease virus

A fast and direct surface plasmon resonance (SPR) method for the kinetic analysis of the interactions between peptide antigens and immobilised monoclonal antibodies (mAb) has been established. Protocols have been developed to overcome the problems posed by the small size of the analytes (< 1600 Da). The interactions were well described by a simple 1:1 bimolecular interaction and the rate constants were self-consistent and reproducible. The key features for the accuracy of the kinetic constants measured were high buffer flow rates, medium antibody surface densities and high peptide concentrations. The method was applied to an extensive analysis of over 40 peptide analogues towards two distinct anti-FMDV antibodies, providing data in total agreement with previous competition ELISA experiments. Eleven linear 15-residue synthetic peptides, reproducing all possible combinations of the four replacements found in foot-and-mouth disease virus (FMDV) field isolate C-S30, were evaluated. The direct kinetic SPR analysis of the interactions between these peptides and three anti-site A mAbs suggested additivity in all combinations of the four relevant mutations, which was confirmed by parallel ELISA analysis. The four-point mutant peptide (A15S30) reproducing site A from the C-S30 strain was the least antigenic of the set, in disagreement with previously reported studies with the virus isolate. Increasing peptide size from 15 to 21 residues did not significantly improve antigenicity. Overnight incubation of A15S30 with mAb 4C4 in solution showed a marked increase in peptide antigenicity not observed for other peptide analogues, suggesting that conformational rearrangement could lead to a stable peptide-antibody complex. In fact, peptide cyclization clearly improved antigenicity, confirming an antigenic reversion in a multiply substituted peptide. Solution NMR studies of both linear and cyclic versions of the antigenic loop of FMDV C-S30 showed that structural features previously correlated with antigenicity were more pronounced in the cyclic peptide. Twenty-six synthetic peptides, corresponding to all possible combinations of five single-point antigenicity-enhancing replacements in the GH loop of FMDV C-S8c1, were also studied. SPR kinetic screening of these peptides was not possible due to problems mainly related to the high mAb affinities displayed by these synthetic antigens. Solution affinity SPR analysis was employed and affinities displayed were generally comparable to or even higher than those corresponding to the C-S8c1 reference peptide A15. The NMR characterisation of one of these multiple mutants in solution showed that it had a conformational behaviour quite similar to that of the native sequence A15 and the X-ray diffraction crystallographic analysis of the peptide ? mAb 4C4 complex showed paratope ? epitope interactions identical to all FMDV peptide ? mAb complexes studied so far. Key residues for these interactions are those directly involved in epitope ? paratope contacts (141Arg, 143Asp, 146His) as well as residues able to stabilise a particular peptide global folding. A quasi-cyclic conformation is held up by a hydrophobic cavity defined by residues 138, 144 and 147 and by other key intrapeptide hydrogen bonds, delineating an open turn at positions 141, 142 and 143 (corresponding to the Arg-Gly-Asp motif).

Cristalização de Biomateriais Vitrocerâmicos e Mineralização em Meio Fisiológico Simulado

We propose new theoretical models, which generalize the classical Avrami-Nakamura models. These models are suitable to describe the kinetics of nucleation and growth in transient regime, and/or with overlapping of nucleation and growth. Simulations and predictions were performed for lithium disilicate based on data reported in the literature. One re-examined the limitations of the models currently used to interpret DTA or DSC results, and to extract the relevant kinetic parameters. Glasses and glass-ceramics with molar formulation 0.45SiO2? (0.45-x)MgO?xK2O?0.1(3CaO.P2O5) (0?x?0.090) were prepared, crystallized and studied as potential materials for biomedical applications. Substitution of K+ for Mg2+ were used to prevent devritification on cooling, to adjust the kinetics of crystallization and to modify the in vitro behaviour of resulting biomaterials. The crystallization of the glass frits was studied by DTA, XRD and SEM. Exothermic peaks were detected corresponding to bulk crystallization of whitlockite-type phosphate, Ca9MgK(PO4)7, at approximately 900ºC, and surface crystallization of a predominant forsterite phase (Mg2SiO4) at higher temperatures. XRD also revealed the presence of diopside (CaMgSi2O6 in some samples. The predominant microstructure of the phosphate phase is of the plate-type, seemingly crystallizing by a 2-dimensional growth mechanism. Impedance spectroscopy revealed significant changes in electrical behaviour, associated to crystallization of the phosphate phase. This showed that electrical measurements can be used to study the kinetics of crystallization for cases when DTA or DSC experiments reveal limitations, and to extract estimates of relevant parameters from the dependence of crystallization peak temperature, and its width at half height. In vitro studies of glasses and glass-ceramics in acelular SBF media showed bioactivity and the development of apatite layers The morphology, composition and adhesion of the apatite layer could be changed by substitution of Mg2+ by K+. Apatite layers were deposited on the surface of glass-ceramics of the nominal compositions with x=0 and 0.09, in contact with SBF at 37ºC. The adhesion of the apatite layer was quantified by the scratch test technique, having been related with SBF?s immersion time, with composition and structure of the glass phase, and with the morphology of the crystalline phase of the glass-ceramics. The structure of three glasses (x=0, 0.045 and 0.090) were investigated by MAS-NMR ( 29Si and 31P), showing that the fraction of Q3 structural units increases with the contents of Mg, and that the structure of these glasses includes orthophosphate groups (PO43-) preferentially connected to Ca2+ ions. Mg2+ ions show preference towards the silicate network. Substitution of Mg2+ by K+ allowed one to change the bioactivity. FTIR data revealed octacalcium phosphate precipitation (Ca8H2(PO4)6.5H2O) in the glass without K, while the morphology of the layer acquires the shape of partially superimposed hemispheres, spread over the surface. The glasses with K present a layer of acicular hidroxyapatite, whose crystallinity and needles thickness tend to increase along with K content.

Predictive Optimal Matrix Converter Control for a Dynamic Voltage Restorer with Flywheel Energy Storage

This paper presents a predictive optimal matrix converter controller for a flywheel energy storage system used as Dynamic Voltage Restorer (DVR). The flywheel energy storage device is based on a steel seamless tube mounted as a vertical axis flywheel to store kinetic energy. The motor/generator is a Permanent Magnet Synchronous Machine driven by the AC-AC Matrix Converter. The matrix control method uses a discrete-time model of the converter system to predict the expected values of the input and output currents for all the 27 possible vectors generated by the matrix converter. An optimal controller minimizes control errors using a weighted cost functional. The flywheel and control process was tested as a DVR to mitigate voltage sags and swells. Simulation results show that the DVR is able to compensate the critical load voltage without delays, voltage undershoots or overshoots, overcoming the input/output coupling of matrix converters.

Extraction of hemoglobin with calixarenes and biocatalysis in organic media of the complex with pseudoactivity of peroxidase

The present work involves the use of p-tert-butylcalix[4,6,8]arene carboxylic acid derivatives ((t)Butyl[4,6,8]CH2COOH) for selective extraction of hemoglobin. All three calixarenes extracted hemoglobin into the organic phase, exhibiting extraction parameters higher than 0.90. Evaluation of the solvent accessible positively charged amino acid side chains of hemoglobin (PDB entry 1XZ2) revealed that there are 8 arginine, 44 lysine and 30 histidine residues on the protein surface which may be involved in the interactions with the calixarene molecules. The hemoglobin-(t)Butyl[6]CH2COOH complex had pseudoperoxidase activity which catalysed the oxidation of syringaldazine in the presence of hydrogen peroxide in organic medium containing chloroform. The effect of pH, protein and substrate concentrations on biocatalysis was investigated using the hemoglobin-(t)Butyl[6]CH2COOH complex. This complex exhibited the highest specific activity of 9.92 x 10(-2) U mg protein(-1) at an initial pH of 7.5 in organic medium. Apparent kinetic parameters (V'(max), K'(m), k'(cat) and k'(cat)/K'(m)) for the pseudoperoxidase activity were determined in organic media for different pH values from a Michaelis-Menten plot. Furthermore, the stability of the protein-calixarene complex was investigated for different initial pH values and half-life (t(1/2)) values were obtained in the range of 1.96 and 2.64 days. Hemoglobin-calixarene complex present in organic medium was recovered in fresh aqueous solutions at alkaline pH, with a recovery of pseudoperoxidase activity of over 100%. These results strongly suggest that the use of calixarene derivatives is an alternative technique for protein extraction and solubilisation in organic media for biocatalysis.

Influence of growth temperature and carrier flux on the structure and transport properties of highly oriented CrO2 on Al2O3 (0001)

In this work we report on the structure and magnetic and electrical transport properties of CrO2 films deposited onto (0001) sapphire by atmospheric pressure (AP)CVD from a CrO3 precursor. Films are grown within a broad range of deposition temperatures, from 320 to 410 degrees C, and oxygen carrier gas flow rates of 50-500 seem, showing that it is viable to grow highly oriented a-axis CrO2 films at temperatures as low as 330 degrees C i.e., 60-70 degrees C lower than is reported in published data for the same chemical system. Depending on the experimental conditions, growth kinetic regimes dominated either by surface reaction or by mass-transport mechanisms are identified. The growth of a Cr2O3 interfacial layer as an intrinsic feature of the deposition process is studied and discussed. Films synthesized at 330 degrees C keep the same high quality magnetic and transport properties as those deposited at higher temperatures.

Relatório de estágio. Terapia manual ortopédica

Este estudo refere-se a uma paciente de 33 anos com paralisia do nervo toráxico longo direito e consequente atrofia do grande dentado A paciente foi acompanhada durante 7 meses no serviço de Fisioterapia e tratada segundo as guidelines para o tratamento desta patologia. Após estabilização de resultados, por não apresentar mais melhoria, foi sujeita a análise electromigráfica no sentido de perceber quais as estratégias utilizadas pela paciente para compensar o défice do grande dentado, na manutenção de 4 movimentos: Elevação anterior a 90º, elevação lateral a 90º, elevação lateral no plano da omoplata a 90º e no push-up contra a parede. Foram avaliados o trapézio superior, médio e inferior, bem como o grande dentado. Verificou-se que não existe um padrão de activação consistente dos estabilizadores da omoplata em cadeia cinética aberta, sendo que o padrão é mantido em cadeia cinética fechada.

Bioconversion of D-glucose into D-glucosone by Glucose 2-oxidase from Coriolus versicolor at Moderate Pressures

Glucose 2-oxidase (pyranose oxidase, pyranose: oxygen-2-oxidoreductase, EC 1.1.3.10) from Coriolus versicolor catalyses the oxidation of D-glucose at carbon 2 in the presence of molecular O(2) producing D-glucosone (2-keto-glucose and D-arabino-2-hexosulose) and H(2)O(2). It was used to convert D-glucose into D-glucosone at moderate pressures (i.e. up to 150 bar) with compressed air in a modified commercial batch reactor. Several parameters affecting biocatalysis at moderate pressures were investigated as follows: pressure, [enzyme], [glucose], pH, temperature, nature of fluid and the presence of catalase. Glucose 2-oxidase was purified by immobilized metal affinity chromatography on epoxy-activated Sepharose 6B-IDA-Cu(II) column at pH 6.0. The rate of bioconversion of D-glucose increased with the pressure since an increase in the pressure with compressed air resulted in higher rates of conversion. On the other hand, the presence of catalase increased the rate of reaction which strongly suggests that H(2)O(2) acted as inhibitor for this reaction. The rate of bioconversion of D-glucose by glucose 2-oxidase in the presence of either nitrogen or supercritical CO(2) at 110 bar was very low compared with the use of compressed air at the same pressure. The optimum temperature (55 degrees C) and pH (5.0) of D-glucose bioconversion as well as kinetic parameters for this enzyme were determined under moderate pressure. The activation energy (E(a)) was 32.08 kJmol(-1) and kinetic parameters (V(max), K(m), K(cat) and K(cat)/K(m)) for this bioconversion were 8.8 Umg(-1) protein, 2.95 mM, 30.81 s(-1) and 10,444.06 s(-1)M(-1), respectively. The biomass of C. versicolor as well as the cell-free extract containing glucose 2-oxidase activity were also useful for bioconversion of D-glucose at moderate pressures. The enzyme was apparently stable at moderate pressures since such pressures did not affect significantly the enzyme activity.

Bioconversion of D-glucose into D-glucosone by immobilized glucose 2-oxidase from Coriolus versicolorat moderate pressures

The immobilized glucose 2-oxidase (pyranose oxidase, pyranose:oxygen-2-oxidoreductase, EC 1.1.3.10) from Coriolus versicolor was used to convert D-glucose into D-glucosone at moderate pressures, up to 150 bar, with compressed air in a modified commercial batch reactor. Several parameters affecting biocatalysis at moderate pressures were investigated as follows: pressure, different forms of immobilized biocatalysts, glucose concentration, pH, temperature and the presence of catalase. Glucose 2-oxidase (GOX2) was purified by immobilized metal affinity chromatography on epoxy-activated Sepharose 6B-IDA-Cu(II) column at pH 6.0. Purified enzyme and catalase were immobilized into a polyethersulfone (PES) membrane in the presence of glutaraldehyde and gelatin. Enhancement of the bioconversion of D-glucose was done by the pressure since an increase in the pressure with compressed air increases the conversion rates. The optimum temperature and pH for bioconversion of D-glucose were found to be 62 degrees C and pH 6.0, respectively and the activation energy (E(a)) was 28.01 kJ mol(-1). The apparent kinetic constants (V(max)' K(m)', K(cat)' and K(cat)/K(m)') for this bioconversion were 2.27 U mg(-1) protein, 11.15 mM, 8.33 s(-1) and 747.38 s(-1) M(-1), respectively. The immobilized biomass of C. versicolor as well as crude extract containing GOX2 activity were also useful for bioconversion of D-glucose at 65 bar with a yield of 69.9 +/- 3.8% and 91.3 +/- 1.2%, respectively. The immobilized enzyme was apparently stable for several months without any significant loss of enzyme activity. On the other hand, this immobilized enzyme was also stable at moderate pressures, since such pressures did not affect significantly the enzyme activity. (C) 2010 Elsevier Ltd. All rights reserved.

Development of a biosensor for urea assay based on amidase inhibition, using an ion-selective electrode

A biosensor for urea has been developed based on the observation that urea is a powerful active-site inhibitor of amidase, which catalyzes the hydrolysis of amides such as acetamide to produce ammonia and the corresponding organic acid. Cell-free extract from Pseudomonas aeruginosa was the source of amidase (acylamide hydrolase, EC 3.5.1.4) which was immobilized on a polyethersulfone membrane in the presence of glutaraldehyde; anion-selective electrode for ammonium ions was used for biosensor development. Analysis of variance was used for optimization of the biosensorresponse and showed that 30 mu L of cell-free extract containing 7.47 mg protein mL(-1), 2 mu L of glutaraldehyde (5%, v/v) and 10 mu L of gelatin (15%, w/v) exhibited the highest response. Optimization of other parameters showed that pH 7.2 and 30 min incubation time were optimum for incubation ofmembranes in urea. The biosensor exhibited a linear response in the range of 4.0-10.0 mu M urea, a detection limit of 2.0 mu M for urea, a response timeof 20 s, a sensitivity of 58.245 % per mu M urea and a storage stability of over 4 months. It was successfully used for quantification of urea in samples such as wine and milk; recovery experiments were carried out which revealed an average substrate recovery of 94.9%. The urea analogs hydroxyurea, methylurea and thiourea inhibited amidase activity by about 90%, 10% and 0%, respectively, compared with urea inhibition.

Influence of an unstable shoe on compensatory postural adjustments: an experimental evaluation

This study attempted to evaluate the influence of using an unstable shoe in muscle re-cruitment strategies and center of pressure (CoP) displacement after the application of an external perturba-tion. Fourteen healthy female subjects participated in this study. The electromyographic activity of medial ga-strocnemius, tibialis anterior, rectus femoris, biceps femoris, rectus abdominis and erector spinae muscles and the kinetic values to calculate the CoP were collected and analyzed after the application of an external pertur-bation with the subject in standing position, with no shoes and using unstable footwear. The results showed increased in medial gastrocnemius activity during the first compensatory postural adjustments and late com-pensatory postural adjustments when using an unstable shoe. There were no differences in standard deviation and maximum peak of anteroposterior displacement of CoP between measurements. From the experimental findings, one can conclude that the use of an unstable shoe leads to an increase in gastrocnemius activity with no increase in CoP displacement following an unexpected external perturbation.

A marcha humana: uma abordagem biomecânica

A análise biomecânica da marcha engloba, entre outros, dados cinemáticos, cinéticos e sinais electromiográficos, que, em conjunto, promovem a descrição do fenómeno da marcha. Neste trabalho é efectuada uma revisão dos estudos existentes que versam sobre os aspectos biomecânicos da marcha, de forma a perceber-se os componentes a ter em consideração na referida análise, bem como os modelos comuns que suportam achados experimentais. A análise efectuada permitiu verificar que a necessidade de redirecção da velocidade do centro de massa entre passos prediz um forte componente do dispêndio energético na marcha e que este, por sua vez, está associado à velocidade.

Avanços da ressonância magnética mamária no diagnóstico do carcinoma da mama

A Ressonância Magnética Mamaria (RMM), ao longo da década, tem demonstrado um franco desenvolvimento no diagnóstico e caracterização do Carcinoma Mamário. O objectivo deste trabalho científico é demonstrar, através de uma revisão bibliográfica, os avanços desta modalidade na avaliação das lesões da mama, tendo em conta as características: elasticidade (Elastografia), bioquímicas (Espectroscopia), celularidade (Difusão) e vascularização (Perfusão). A avaliação destas em consonância com as morfológicas e cinéticas (RMM), permitem um aumento da especificidade da RMM, reduzindo assim o número de biopsias desnecessárias. Contudo estas evoluções técnicas devem estar em consonância com a inovação em questões de software de processamento de Imagem e hardware dos equipamentos de Ressonância Magnética.

Comparison of Py-GC/FID and Wet Chemistry Analysis for Lignin Determination in Wood and Pulps from Eucalyptus globulus

The kraft pulps produced from heartwood and sapwood of Eucalyptus globulus at 130 degrees C, 150 degrees C, and 170 degrees C were characterized by wet chemistry (total lignin as sum of Klason and soluble lignin fractions) and pyrolysis (total lignin denoted as py-lignin). The total lignin content obtained with both methods was similar. In the course of delignification, the py-lignin values were higher (by 2 to 5%) compared to Klason values, which is in line with the importance of soluble lignin for total lignin determination. Pyrolysis analysis presents advantages over wet chemical procedures, and it can be applied to wood and pulps to determine lignin contents at different stages of the delignification process. The py-lignin values were used for kinetic modelling of delignification, with very high predictive value and results similar to those of modelling using wet chemical determinations.