L'acide ascorbique (AsA, vitamine C) est l'un des composés parmi les plus importants chez les eucaryotes. En raison de son potentiel antioxydant élevé, l'AsA représente un trait important de la qualité nutritionnelle des végétaux. Au-delà de sa valeur bénéfique pour la santé, une augmentation de la teneur en AsA des fruits bénéficierait probablement à la qualité post-récolte et à la résistance aux pathogènes. Pour mieux comprendre ces régulations chez les plantes et leurs impacts sur la qualité des fruits, une collection de tomates EMS hautement mutée (cv. Micro-Tom) a été criblée pour identifier des mutants dont les fruits sont enrichis en AsA. Cette stratégie de génétique directe associant le criblage à une approche de cartographie par séquençage devait permettre d’identifier de nouveaux gènes liés au caractère AsA+. L'un des mutants, noté P21H6, présentait un enrichissement en AsA de 2 à 4 fois supérieur à celui du WT, et fut le premier à être génétiquement caractérisé. Cette étude a permis de mettre en évidence une nouvelle classe de photorécepteurs impliqués dans la détection de la lumière bleue, appelée SlPLP, en tant que régulateur négatif de l'accumulation d'AsA dans la tomate. Le rôle de PLP dans le phénotype AsA+ du fruit a été confirmé par une stratégie de mutagenèse dirigée, avant d’entreprendre sa caractérisation fonctionnelle. Nous avons démontré que SlPLP interagit avec SlGGP (GDP-L-galactose phosphorylase), une enzyme clé de la voie du L-Galactose, sous contrôle de la lumière bleue et que cette interaction a lieu dans le cytoplasme et le noyau. Nos résultats renforcent le rôle central du GGP dans la biosynthèse de l'AsA et suggèrent un nouveau mécanisme de régulation par la lumière bleue de la fonction du GGP, en plus de son activité métabolique. Parallèlement, nous avons entrepris la caractérisation d’un autre mutant, le P17C5-3, qui présentait le plus fort taux d'AsA (jusqu'à 10 fois le WT). Outre le phénotype AsA+, le mutant P17C5 présentait de fortes altérations morphologiques, notamment l’absence de graines, rendant la mise en place de la stratégie de cartographie difficile. Grâce à un croisement avec la variété commerciale M82, la mutation causale pu être identifiée dans un ORF cis-régulateur en amont de GGP. Ce résultat confirme le rôle clé de GGP dans la voie L-Galactose. Des études préliminaires liées au phénotype parthénocarpique suggèrent un problème de stérilité mâle associé aux processus de développement du pollen. Enfin, dans l’étude de la qualité des fruits après la récolte, des expériences de stress froid effectuées avec les fruits P21H6 semblent démontrer que l’augmentation de la teneur en AsA améliore la durée de conservation et la capacité de maturation des fruits. Dans l'ensemble, nos résultats confirment la position clé de la protéine GGP dans la voie de biosynthèse de l'AsA, et fournissent des outils et du matériel végétal précieux pour décortiquer la régulation de l'AsA et son rôle physiologique dans la qualité des fruits et les caractères post-récolte. / Ascorbic acid (AsA, vitamin C) is one of the most important biochemical in living organisms. Due to its high antioxidant potential, AsA represents an important trait of nutritional quality in fruits and vegetables. In addition to its beneficial health value in fruit consumption, increasing fruit AsA content would likely affect postharvest quality and resistance to pathogens. Thus, understanding the regulation of AsA accumulation in order to improve crop species of agronomical interest is an important issue in plant breeding for many fleshy fruit species. To get a better understanding of the regulation of AsA level in plants and its impact on fruit quality, a highly mutagenized EMS tomato collection (cv. Micro-Tom) was screened for AsA+ fruit mutants. This forward genetic strategy combined with a mapping-by-sequencing approach, had allowed identifying new genes related to the AsA+ trait. One of the mutant line named P21H6, displayed an AsA-enrichment 2 to 4 fold that of the WT, and was the first to be genetically characterized. It allowed highlighting a new class of photoreceptor involved in blue light sensing named SlPLP as a negative regulator of AsA accumulation in tomato. We confirmed the role of the PLP in the fruit AsA+ phenotype using a directed mutagenesis strategy, undertaking its functional characterization. We demonstrate that PLP interacts with GGP (GDP-L-galactose phosphorylase), a key enzyme of the L-Galactose pathway, under blue light control and that this interaction takes place in the cytoplasm and the nucleus. Our results strengthen the central role of GGP in the AsA biosynthesis and suggest a new regulation mechanism by blue light of the GGP function in addition to its metabolic activity. Besides we started the characterization another mutant, the P17C5-3, which displayed the highest level of AsA (up to 10 times the WT). Beyond its AsA+ content, the P17C5 mutant showed strong morphological alterations including a seedless phenotype making the mapping difficult at first. Thanks to the crossing with the commercial M82 tomato cultivar, the causal mutation was identified in a cis-acting ORF, upstream of the GGP gene. This result confirmed the key role of GGP in the L-Galactose pathway. Preliminary studies related to the parthenocarpic phenotype suggest a problem of male sterility associated with pollen development processes. Finally, in the study of the post-harvest fruit quality, chilling stress experiments carried out with the P21H6 fruits seem to demonstrate that increasing AsA content improve the fruit shelf life and its maturation capacity. Taken as a whole, our results confirmed the key position of the GGP protein in the AsA biosynthesis pathway and they provided precious tools and plant material for deciphering the regulation of AsA and its physiological role in fruit quality and post-harvest traits.

Acredita-se que o uso de agentes antioxidantes poderia auxiliar na restituição da resistência adesiva diminuída após o clareamento dental. O objetivo deste estudo in vitro foi avaliar o efeito do hidrogel de ascorbato de sódio a 10% e 20% e hidrogel de ácido ascórbico a 10%, aplicados por 15 minutos imediatamente após o clareamento com peróxido de hidrogênio a 35% (Lase Peroxide Sensy-DMC) (PH) na resistência adesiva imediata (24 horas) e tardia (7 dias) de uma resina composta (RC) ao esmalte bovino. Foram utilizadas 45 superfícies de esmalte de incisivos bovinos e distribuídas em 9 grupos com 5 em cada uma, sobre as quais foram confeccionados 4 corpos de prova (n= 20), de acordo com o tratamento: G1: sem clareamento (controle) + RC; G2: PH + 24h + RC; G3: PH + 7 d + RC; G4: PH + hidrogel de ascorbato de sódio 10% + 24h + RC; G5: PH + hidrogel de ascorbato de sódio a 10% + 7 d + RC; G6: PH + hidrogel de ascorbato de sódio a 20% + 24h + RC; G7: PH + hidrogel de ascorbato de sódio a 20% + 7 d + RC; G8: PH + hidrogel de ácido ascórbico a 10% + 24h + RC; G9: PH + hidrogel de ácido ascórbico a 10% + 7 d + RC. Foram confeccionados cilindros de (0.8x1mm), utilizando o sistema adesivo Single Bond 2 e a resina composta Z100 (3M ESPE) e submetidos ao teste de resistência adesiva ao microcisalhamento na máquina de ensaios universal (EMIC) com célula de carga de 50N a uma velocidade de (0,5mm/min). Posteriormente foram observados os tipos de fraturas em um estereomicroscópio com aumento de 40x. A seguir, os valores de resistência adesiva ao microcisalhamento foram avaliados estatisticamente através da Análise de Variância a um critério (ANOVA) e do teste de Tukey para comparações múltiplas, com nível de significância de 5%. Os resultados foram: G1: 24,34ab ± 5,182; G2: 15,27c ± 7,170; G3: 16,65c ± 7,614; G4: 20,30bc ± 7,071; G5: 17,77bc ± 8,135; G6: 18,03bc ± 4,016; G7: 19,60bc ± 6,396; G8: 20,03bc ± 3,941; G9: 17,63bc ± 3,390. De acordo com os resultados obtidos na presente pesquisa pode-se concluir que: a técnica de clareamento dental com peróxido de hidrogênio a 35% promoveu uma diminuição estatisticamente significante na resistência adesiva da resina composta ao esmalte bovino nos procedimentos realizados 24 horas e 7 dias após o clareamento dental. Tanto o tratamento com hidrogel de ascorbato de sódio como com o hidrogel de ácido ascórbico, independente da concentração e tempo de espera, foram capazes de melhorar a resistência adesiva da resina composta ao esmalte bovino clareado. Entretanto, ambos os tratamentos com agentes antioxidantes não foram capazes de recuperá-la. / It is referred that the use of antioxidants may improve the decreased bond strength after bleaching treatment. The aim of this in vitro study was to evaluate the effect of 10% and 20% sodium ascorbate hydrogel and 10% ascorbic acid hydrogel applied for 15 minutes immediately after 35% hydrogen peroxide bleaching (HP) (Lase Peroxide Sensy-DMC). 45 bovine incisors enamel surfaces divided into 9 groups were used. Four specimens were made on each surface (n = 20) according to the different treatments: G1: without bleaching (control group) + RC; G2 : HP + 24 h + RC; G3: HP + 7 d+ RC; G4: HP + 10% sodium ascorbate hydrogel + 24 h + RC; G5: HP + 10% sodium ascorbate hydrogel + 7 d + RC; G6: HP + 20% sodium ascorbate hydrogel + 24h + RC; G7: HP + 20% sodium ascorbate hydrogel + 7 d + RC; G8: HP + 10% ascorbic acid hydrogel + 24 h + RC; G9: HP + 10% ascorbic acid hydrogel + 7 d + RC. Cylinder restorations (0.8x1mm) were made using Single Bond 2 and Z100 (3M ESPE). Microshear bond strength test was performed using a universal testing machine (EMIC) with a 50N load at a crosshead speed of 0.5mm/min. Failure modes were assesed using a stereomicroscope (40x) showing mainly adhesive failures. Data were analyzed by ANOVA and Tukey analysis for multiple comparisons at the significance level of 5%. The results were: G1: 24.34 ± 5.182 ab G2: 15.27 ± 7.170 c; G3: 16.65 ± 7.614 c, G4: 20.30 ± 7.071 bc; G5: 17.77 ± 8.135 bc G6: ± 18.03 bc 4.016; G7: 19.60 bc ± 6.396; G8: 20.03 bc ± 3.941; G9: 17.63 ± 3.390 bc. According to the results obtained it can be concluded that: the 35% hydrogen peroxide tooth whitening technique promoted a statistically significant decrease in bond strength of resin composite to enamel performed 24 hours and 7 days after bleaching. Both treatment with sodium ascorbate hydrogel and ascorbic acid hydrogel, independent of concentration and time, were able to improve the bond strength of composite resin to bleached bovine enamel, however, both antioxidants were not able to retrieve it.

A lesão de isquemia/reperfusão(I/R) do intestino delgado é de importância fundamental em procedimentos cirúrgicos. Alguns radicais livres de oxigênio gerados atuam durante este período. Utilizamos o ácido ascórbico para atenuar as lesões de I/R. Cinqüenta ratos foram separados e cinco grupos, cada grupo com 10 ratos. Os grupos foram sumetidos à isquemia mesentérica e isquemia/reperfusão. Os grupos experimentos receberam ácido ascórbico. Foi realizada a análise histológica morfométrica. Os grupos com ácido ascórbico mostraram uma redução significativa do infarto anti-mesentérico. (p = 0,009) na isquemia/reperfusão e redução da necrose das vilosidades na isquemia. O ácido ascórbico é eficaz na redução dos danos intestinais causados pela I/R em ratos / Intestinal injury resulting from ischemia-reperfusion (I/R) is of fundamental importance in surgical procedures. Some oxygen-derived free radicals generated during this time possibly play an important role. We used ascorbic acid to attenuate I/R injury. Fifty male rats were divided into five groups, each containing 10 rats. The groups were submitted to mesenteric ischemia and ischemia/reperfusion, experimental groups received ascorbic acid. The intestinal histological morphometric analysis was performed. The ascorbic acid groups showed a significant reduction of antimesenteric villous infarct (p=0,009) in the /R and reduction of villous necrosis ischemia groups. The ascorbic acid is effective in reducing the intestinal damage caused by I/R in the rats

Made available in DSpace on 2017-07-24T19:38:03Z (GMT). No. of bitstreams: 1 Tatiane Skeika.pdf: 2364306 bytes, checksum: 8d6414f80c21a8f934352d23ededc5ff (MD5) Previous issue date: 2010-05-11 / The study of carbon-based ceramic electrodes (CCE) has been significantly increased due to advantages over other electrodes. The CCE features as large surface area, high electrical conductivity and higher mechanical strength, increases their stability and durability. Different parameters of CCE preparation, such as type of precursor, carbon material, catalyst amount, among others, significantly influence the morphological properties and consequently their electrochemical responses. Based on these factors this work presents a 23 factorial design (2 levels and 3 factors) which the factors analyzed were catalyst amount (HCl 12 mol L-1), graphite / precursor ratio, and precursor type (TEOS - tetraethoxysilane and MTMOS - methyltrimetoxysilane). These variables were optimized by analyzing the electrochemical responses obtained in presence of potassium ferrocyanide (at fixed concentration of 1.0 x10-3 mol L-1). The design resulted in a significant third order interaction for anodic peak current values (Ipa), and also to the potential difference (E) between the factors studied which could not be observed using an univariated study. The optimized electrode was modified with ferrocenecarboxylic acid (designated as CCE/Ferrocene) mainly aiming at the increase the sensitivity to the unmodified one. SEM images indicated that the components are homogeneously dispersed in the sample but with some little agglomeration of segregated ferrocene particles. From cyclic voltammetric experiments, it was observed that the CCE/Ferrocene presented a redox pair at Epa = 390.3 mV and Epc = 298.7 mV (E = 91.7 mV), related to the ferrocene/ferrocenium process, since the non- modified CCE did not presented any redox peaks. Studies of the modified electrode in different scan rates resulted in a linear relationship between the anodic peak current values and the scan rate, a characteristic behavior for confined species in the surface electrode. In order to verify the possibility of using the CCE/Ferrocene as an electrochemical sensor, studies in presence of dopamine (DA) were carried out. In this case, it was observed that after DA addition in the electrolyte solution, a considerably increase in the redox currents were observed at same oxidation potential of ferrocene (Epa= 408.0 mV vs Ag/AgCl), different from the observed when using only CCE as electrode material, which the increase in the anodic peak was considerably lower and slightly dislocated to higher positive potential (Epa= 446.1 mV vs Ag/AgCl). Square wave voltammetry (SWV) experiments were evaluated in presence of DA, with optimized parameters. In these conditions, the proposed sensor has shown a linear response range from 0.2 to 1.0 molL-1 with a detection limit of 1.5 mol L-1 to CCE and 0.43 mol L-1 for CCE/Ferrocene. From SWV experiments, it was observed that the AA oxidation at CCE/Ferrocene occurred in a different potential of DA oxidation, with a peak separation of approximately 170.5 mV. Moreover, CCE/Ferrocene did not respond to different AA concentrations indicating that is possible with this electrode determine DA without the interference of AA. / O estudo de eletrodos a base de carbono cerâmico (ECC), tem aumentado significativamente devido às vantagens sobre os demais eletrodos. Os ECC apresentam grande área superficial, alta condutividade elétrica, além de uma maior resistência mecânica, o que aumenta a estabilidade e durabilidade desses eletrodos. Os diferentes parâmetros utilizados na preparação dos ECC, tais como, tipo de precursor, material de carbono, quantidade de catalisador, entre outros, influenciam significativamente nas propriedades morfológicas e consequentemente nas respostas eletroquímicas dos mesmos. Baseando-se nisto, esse trabalho apresenta um planejamento fatorial 23 (2 níveis e 3 fatores) onde os fatores analisados foram a quantidade de catalisador (HCl 12 mol L-1), proporção grafite/precursor, e o tipo de precursor (TEOS - tetraetoxisilano e MTMOS - metiltrimetoxisilano). Tais variáveis foram otimizadas analisando-se as respostas eletroquímicas obtidas na presença de ferrocianeto de potássio (na concentração fixa de 1,0 x10-3 mol L-1). O planejamento resultou numa interação significativa de terceira ordem para os valores de corrente de pico anódico (Ipa) e também para a diferença de potencial (E), entre os fatores estudados o que não poderia ser observado utilizando-se um estudo univariado. O eletrodo otimizado foi modificado com ácido ferrocenocarboxílico (denominado ECC/Ferroceno) visando principalmente o aumento da sensibilidade em relação ao eletrodo não modificado. As imagens de MEV indicaram que os componentes do eletrodo estão homogeneamente dispersos na amostra, mas com pequena aglomeração de partículas segregadas do ferroceno. Através dos estudos de voltametria cíclica (VC), observou-se que o ECC/Ferroceno apresentou um par redox em Epa = 390,3 mV e Epc = 298,7 mV (E = 91,7 mV), relacionados ao processo ferroceno / íon ferroceno já que o ECC sem modificação não apresentou picos redox. O estudo do eletrodo modificado em diferentes velocidades de varredura resultou em uma relação linear entre os valores de corrente de pico anódica e, sendo esse um comportamento típico de espécies confinadas na superfície do eletrodo. Para verificar a possibilidade da aplicação do ECC/Ferroceno como sensor eletroquímico foram realizados estudos na presença de dopamina (DA). Neste caso, foi observado que após a adição de DA na solução eletrolítica, um considerável aumento nas correntes redox foram observados no mesmo potencial de oxidação do ferroceno (Epa = 408,0 mV vs Ag / AgCl), diferente do que foi observado para o ECC. Nesse último caso, a corrente de pico anódica foi consideravelmente mais baixa além do potencial de pico anódico ligeiramente deslocado para regiões mais positivas (Epa = 446,1 V vs Ag / AgCl). A técnica de voltametria de onda quadrada (VOQ) foi aplicada para a determinação de DA, com os parâmetros otimizados. Nessas condições, os sensores propostos apresentaram uma faixa de resposta linear de 0,2 a 1,0 mol L-1 e um limite de detecção de 1,5 mol L-1 para o ECC e 0,43 mol L-1 para o ECC/Ferroceno. A partir dos estudos de VOQ, foi observado ainda que a oxidação de ácido ascórbico (AA) no ECC/Ferroceno ocorreu em um potencial diferente da oxidação de DA, com separação de pico de aproximadamente 170,5 mV. Além disso, o ECC/Ferroceno não apresentou aumento da corrente de pico com a variação da concentração de AA, indicando uma possível aplicação deste eletrodo na determinação de DA sem a interferência do AA.

by Chan Tak Yee Bonita. / "July 2004." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (p. 121-137). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / The objective of this study was to develop a probiotic cashew apple juice ready to drink and in the dehydrated form through spray drying. The first stage of the study was the optimization of Lactobacillus casei NRRL B-442 cultivation in cashew apple juice, to optimize the proper inoculum amount and the fermentation time. The optimum conditions for probiotic cashew apple juice production were: initial pH 6.4, fermentation temperature of 30ÂC, inoculation level of 7.48 log CFU/mL (L. casei) and 16 h of fermentation process. Cashew apple juice showed to be as efficient as dairy products for L. casei growth. In a second stage, the stability of probiotic cashew apple juice stored for 42 days at 4ÂC was evaluated. Analyses were conducted in the non fermented cashew apple juice (control), and in the fermented juices with L. casei NRRL B-442, with 8% (w/v) of sucrose (sugar table), after fermentation, and without the addition of sugar. The viability of the probiotic bacteria, sugars and organic acids content, color, antioxidant and enzymatic activity, and sensory characteristics were evaluated during the storage. Viable cell counts increased in the probiotic cashew apple containing sucrose along the storage period. Moreover, the fermentation lead to the preservation of the ascorbic acid content, which had a less intense reduction in the fermented cashew apple juices compared to the non fermented sample. The antioxidant activity and total polyphenolic compounds of cashew apple juice had a similar trend. Browning reactions and nutritional breakdown caused by enzymes were minimized in the fermented samples during storage. In these samples, a higher reduction of the enzymatic activity of polyphenoloxidase and peroxidase activity was observed. During the storage, the increase in the chroma values indicated that yellowness was reinforced, being well accepted by consumers. The sensory attributes (aroma, flavor, acidity and color) of probiotic cashew apple juice were positively influenced by storage under refrigeration for 42 days. In the third stage of the research, the effects of dehydration by spray drying in cashew apple juice containing L. casei NRRL B-442 was assessed and the influence of storage temperature on the viability of L. casei NRRL B-442 and physical properties of the powder were evaluated during 35 days of storage. The drying agents used were: 20% (w/v) maltodextrin or 10% (w/v) maltodextrin + 10% (w/v) arabic gum. The powder of probiotic cashew apple juice showed satisfactory levels of L. casei survival, during drying. During storage, the addition of 10% (w/v) maltodextrin + 10% (w/v) arabic gum kept microbial viability within satisfactory levels when the powder was subjected to cooling at 4ÂC. However, greater differences in the reconstituted powder color and higher rehydration time were obtained in this condition. On the other hand, the addition of 20% (w/v) maltodextrin provided better yield. In conclusion, cashew apple juice is a good substrate for the probiotic beverage production, and the condition of drying agents 10% maltodextrin + 10% arabic gum is adequate to maintain satisfactory levels of L. casei NRRL B-442 survival for 35 days, in the powder of probiotic cashew juice stored at 4ÂC. / O objetivo desta pesquisa foi elaborar um produto probiÃtico à base de suco de caju pronto para beber, como tambÃm, na forma desidratada obtida pela secagem por aspersÃo (spray drying). A primeira etapa da pesquisa consistiu em otimizar as condiÃÃes de crescimento do Lactobacillus casei NRRL B-442 em suco de caju, a quantidade adequada de inÃculo e o tempo de fermentaÃÃo. As condiÃÃes Ãtimas para produÃÃo do suco de caju probiÃtico foram: pH inicial de 6,4, temperatura de fermentaÃÃo de 30ÂC, quantidade de inÃculo de 7,48 log UFC/mL (L. casei) e 16 h de fermentaÃÃo. O suco de caju mostrou ser tÃo eficiente quanto os produtos lÃcteos para o crescimento de L. casei. Em uma segunda etapa, foi avaliada a estabilidade da bebida probiÃtica de caju estocada por 42 dias a 4ÂC. Foram realizadas anÃlises no suco de caju nÃo fermentado (controle) e nos sucos fermentados com L. casei NRRL B-442, adicionado ou nÃo de 8% (p/v) de sacarose depois da fermentaÃÃo. Durante a estocagem, foram realizadas as determinaÃÃes de viabilidade de L. casei NRRL B-442, conteÃdo de aÃÃcares e Ãcidos orgÃnicos, cor, atividade antioxidante e enzimÃtica e aceitaÃÃo sensorial. Foi observado que o nÃmero de cÃlulas viÃveis aumentou no suco de caju contendo sacarose ao longo da estocagem. AlÃm disso, a fermentaÃÃo proporcionou um efeito conservante no conteÃdo de Ãcido ascÃrbico que teve uma reduÃÃo menos intensa, com a estocagem, nos sucos fermentados, quando comparados com o controle. A atividade antioxidante e o conteÃdo de polifenÃis apresentaram similar tendÃncia. ReaÃÃes que reduzem o valor nutricional causadas por enzimas foram minimizadas nas amostras fermentadas durante a estocagem. Nessas amostras foi observada maior reduÃÃo da atividade enzimÃtica da polifenoloxidase e peroxidase. Durante a estocagem, o aumento do croma indicou que a cor amarela foi intensificada, sendo bem aceita pelos consumidores. Os atributos sensoriais (aroma, sabor, acidez e cor) do suco de caju probiÃtico foram positivamente influenciados pela estocagem sob refrigeraÃÃo por 42 dias. Na terceira etapa da pesquisa, foi avaliado o efeito da desidrataÃÃo por spray drying no suco de caju contendo L. casei NRRL B-442, alÃm de avaliar a influÃncia da temperatura de estocagem sobre a viabilidade de L. casei e nas propriedades fÃsicas do pÃ, durante 35 dias de estocagem. Os agentes de secagem usados foram: 20% (p/v) de maltodextrina ou 10% (p/v) de maltodextrina + 10% (p/v) de goma arÃbica. O suco de caju probiÃtico desidratado por spray drying apresentou nÃveis satisfatÃrios de sobrevivÃncia de L. casei NRRL B-442, durante a secagem. Durante a estocagem, a adiÃÃo de 10% (p/v) de maltodextrina + 10% (p/v) de goma arÃbica manteve a viabilidade microbiana dentro de nÃveis satisfatÃrios quando o pà foi submetido à refrigeraÃÃo a 4ÂC. Entretanto, maiores diferenÃas na coloraÃÃo do pà reconstituÃdo e maior tempo de reidrataÃÃo foram obtidos nesta condiÃÃo. Jà a adiÃÃo de 20% (p/v) de maltodextrina proporcionou melhor rendimento. Em conclusÃo, o suco de caju pode ser utilizado como substrato para o desenvolvimento de bebida probiÃtica, e a condiÃÃo dos agentes de secagem de 10% de maltodextrina + 10% de goma arÃbica mostra-se adequada para manter os nÃveis satisfatÃrios de L. casei NRRL B-442 por atà 35 dias, no suco de caju probiÃtico desidratado estocado a 4ÂC.

A lesão de isquemia/reperfusão(I/R) do intestino delgado é de importância fundamental em procedimentos cirúrgicos. Alguns radicais livres de oxigênio gerados atuam durante este período. Utilizamos o ácido ascórbico para atenuar as lesões de I/R. Cinqüenta ratos foram separados e cinco grupos, cada grupo com 10 ratos. Os grupos foram sumetidos à isquemia mesentérica e isquemia/reperfusão. Os grupos experimentos receberam ácido ascórbico. Foi realizada a análise histológica morfométrica. Os grupos com ácido ascórbico mostraram uma redução significativa do infarto anti-mesentérico. (p = 0,009) na isquemia/reperfusão e redução da necrose das vilosidades na isquemia. O ácido ascórbico é eficaz na redução dos danos intestinais causados pela I/R em ratos / Intestinal injury resulting from ischemia-reperfusion (I/R) is of fundamental importance in surgical procedures. Some oxygen-derived free radicals generated during this time possibly play an important role. We used ascorbic acid to attenuate I/R injury. Fifty male rats were divided into five groups, each containing 10 rats. The groups were submitted to mesenteric ischemia and ischemia/reperfusion, experimental groups received ascorbic acid. The intestinal histological morphometric analysis was performed. The ascorbic acid groups showed a significant reduction of antimesenteric villous infarct (p=0,009) in the /R and reduction of villous necrosis ischemia groups. The ascorbic acid is effective in reducing the intestinal damage caused by I/R in the rats

Background: The adequacy of serum ascorbic acid (vitamin C) concentrations in young Canadian adults is unknown. Individuals have varied serum ascorbic acid response to dietary vitamin C, possibly due to genetic variation. Objective: To investigate the prevalence of serum ascorbic acid deficiency in young Canadians and to determine whether common genotypes modify the association between dietary vitamin C and serum ascorbic acid. Methods: Subjects were 1277 men and women aged 20-29 years from the Toronto Nutrigenomics and Health study. Vitamin C intakes were estimated by a 196-item FFQ. Fasting blood was collected to measure serum ascorbic acid by HPLC and to genotype for common polymorphisms in genes that code for glutathione S-transferase (GST) (GSTM1, GSTT1 and GSTP1), haptoglobin (Hp), and vitamin C transporters (SLC23A1 and SLC23A2). Results: 53% of subjects had adequate, 33% had suboptimal and 14% had deficient serum ascorbic acid. Subjects with deficiency had higher mean C-reactive protein, waist circumference, BMI and blood pressure than subjects with adequate serum ascorbic acid. The odds ratio (95% confidence interval) for serum ascorbic acid deficiency was 3.43 (2.14, 5.50) for subjects who did not meet the vitamin C recommendation compared to those who did. The corresponding odds ratios were 2.17 (1.10, 4.28) and 12.28 (4.26, 33.42) for individuals with the GSTT1 functional and null genotypes respectively (interaction p=0.01), and 2.29 (0.96, 5.45) and 4.03 (2.01, 8.09) for the GSTM1 functional and null genotypes (interaction p=0.04). These odds ratios were 4.77 (2.36, 9.65) for the Hp2-2 genotype, but 1.69 (0.80, 3.63) for carriers of the Hp1 allele (interaction p=0.02). Serum ascorbic acid concentrations (mean +/- SE) differed among SLC23A1 rs4257763 genotypes (GG: 24.4 +/- 1.3, GA: 26.8 +/- 1.1, AA: 29.7 +/- 1.4, p=0.002). Conclusions: Serum ascorbic acid deficiency is prevalent and associated with markers of chronic disease. Individuals with GST null or Hp2-2 genotypes had an increased risk of deficiency if they did not meet the recommendation for vitamin C, suggesting that GSTs and haptoglobin may spare ascorbic acid when dietary vitamin C is insufficient, thus protecting against serum ascorbic acid deficiency.

Background: The adequacy of serum ascorbic acid (vitamin C) concentrations in young Canadian adults is unknown. Individuals have varied serum ascorbic acid response to dietary vitamin C, possibly due to genetic variation. Objective: To investigate the prevalence of serum ascorbic acid deficiency in young Canadians and to determine whether common genotypes modify the association between dietary vitamin C and serum ascorbic acid. Methods: Subjects were 1277 men and women aged 20-29 years from the Toronto Nutrigenomics and Health study. Vitamin C intakes were estimated by a 196-item FFQ. Fasting blood was collected to measure serum ascorbic acid by HPLC and to genotype for common polymorphisms in genes that code for glutathione S-transferase (GST) (GSTM1, GSTT1 and GSTP1), haptoglobin (Hp), and vitamin C transporters (SLC23A1 and SLC23A2). Results: 53% of subjects had adequate, 33% had suboptimal and 14% had deficient serum ascorbic acid. Subjects with deficiency had higher mean C-reactive protein, waist circumference, BMI and blood pressure than subjects with adequate serum ascorbic acid. The odds ratio (95% confidence interval) for serum ascorbic acid deficiency was 3.43 (2.14, 5.50) for subjects who did not meet the vitamin C recommendation compared to those who did. The corresponding odds ratios were 2.17 (1.10, 4.28) and 12.28 (4.26, 33.42) for individuals with the GSTT1 functional and null genotypes respectively (interaction p=0.01), and 2.29 (0.96, 5.45) and 4.03 (2.01, 8.09) for the GSTM1 functional and null genotypes (interaction p=0.04). These odds ratios were 4.77 (2.36, 9.65) for the Hp2-2 genotype, but 1.69 (0.80, 3.63) for carriers of the Hp1 allele (interaction p=0.02). Serum ascorbic acid concentrations (mean +/- SE) differed among SLC23A1 rs4257763 genotypes (GG: 24.4 +/- 1.3, GA: 26.8 +/- 1.1, AA: 29.7 +/- 1.4, p=0.002). Conclusions: Serum ascorbic acid deficiency is prevalent and associated with markers of chronic disease. Individuals with GST null or Hp2-2 genotypes had an increased risk of deficiency if they did not meet the recommendation for vitamin C, suggesting that GSTs and haptoglobin may spare ascorbic acid when dietary vitamin C is insufficient, thus protecting against serum ascorbic acid deficiency.

¤@¡BRole of 5-thio-(2-nitrobenzoic acid)-capped gold nanoparticles in the sensing of chromium(VI): remover and sensor This study describes a simple, rapid method for sensing Cr(VI) using 5-thio-(2-nitrobenzoic acid) modified gold nanoparticles (TNBA-AuNPs) as a remover for Cr(III) and as a sensor for Cr(VI). We discovered that TNBA-AuNPs were dispersed in the presence of Cr(VI), whereas Cr(III) induced the aggregation of TNBA-AuNPs. Due to this phenomenon, TNBA-AuNPs can be used as a sorbent material for the removal of > 90% Cr(III), without removing Cr(VI). After centrifuging a solution containing Cr(III), Cr(VI), and TNBA-AuNPs, Cr(III) and Cr(VI) were separately present in the precipitate and supernatant. In other words, TNBA-AuNPs are capable of separating a mixture of Cr(III) and Cr(VI). The addition of ascorbic acid to the supernatant resulted in a reduction of Cr(VI) to Cr(III), driving the aggregation of TNBA-AuNPs. The selectivity of this approach is more than 1000-fold for Cr(VI) over other metal ions. The minimum detectable concentration of Cr(VI) was 1 £gM using this approach. Inductively coupled plasma mass spectrometry provided an alternative for the quantification of Cr(III) and Cr(VI) after a mixture of Cr(III) and Cr(VI) had been separated by TNBA-AuNPs. The applicability of this approach was validated through the analysis of Cr(VI) in drinking and tap water. ¤G¡BFluorescent Sensing of Total, Protein-bound, Free, and Oxidized Homocysteine in Plasma through the Combination of Tris(2-carboxyethyl)Phosphine Reduction, Fluorosurfactant-Capped Gold Nanoparticles Extraction, and o-Phthaldialdehyde Derivatization This study reports a simple, selective, and sensitive method for fluorescent detection of total, protein-bound, free, and oxidized homocysteine (HCys) using tris(2-carboxyethyl)phosphine (TCEP) as a reducing agent, fluorosurfactant-capped gold nanoparticles (FSN-AuNP) as a preconcentrating probe, and o-Phthaldialdehyde (OPA) as a derivatizing agent. TCEP was used to reduce the disulfide bonds of protein-bound and oxidized HCys. FSN-AuNPs were capable of extracting HCys from a complicated complex because the FSN capping layer can stabilize the AuNPs in a high-salt solution and inhibit non-specific adsorption. HCys was selectively derivatized with OPA in the absence of a nucleophile. By taking advantage of these features, the selectivity of the proposed system is greater than 100-fold for HCys and homocystine (HCys-HCys disulfide; diHCys) compared to any aminothiols. The limits of detection (LODs) for HCys and diHCys were 4.4 and 4.6 nM, respectively. Compared to other sensors, the proposed system provides an approximately 3-300-fold improvement in the detection of HCys. Different forms of plasma HCys were determined by varying the order of disulfide reduction with TCEP. The proposed system was successfully applied to determine the total, protein-bound, free, and oxidized HCys in plasma. To the best of our knowledge, the proposed system not only provides the first method for detecting various forms of plasma HCys, but also has the lowest LOD value for HCys when compared to other sensors.