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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Étude de la capacité antioxydante en lien avec la reproduction chez l'huître creuse Crassostrea gigas / Study of the antioxydant capacity in link with reproduction in the Pacific oyster Crassostrea gigas

Béguel, Jean-Philippe 20 December 2012 (has links)
Le “coût de la reproduction” est un concept qui définit qu’un investissement à la reproduction élevé a un prix qui se paye ultérieurement par une accélération de la sénescence. Cela peut notamment traduire des compromis entre la reproduction et d’autres fonctions physiologiques comme la défense antioxydante. Chez l’huître creuse Crassostrea gigas, la reproduction représente une fonction physiologique majeure. Dans le cadre des études effectuées pour comprendre les mortalités estivales affectant cette espèce, une corrélation négative entre effort reproducteur et survie a été observée. D’autre part, des gènes antioxydants ont été mis en évidence comme différentiellement exprimés entre les lignées d’huîtres sélectionnées pour leur résistance ou leur sensibilité aux mortalités estivales. Certaines études proposent que la susceptibilité au stress oxydant puisse représenter un coût de la reproduction participant au processus de sénescence. Dans ce contexte, nous avons analysé la capacité antioxydante des huîtres en fonction de leur investissement reproducteur. Pour cela, la technique d’ARN interférence a été utilisée pour manipuler l’effort reproducteur des huîtres. L’expression des principales enzymes antioxydantes (taux de transcrits et activités enzymatiques) et le dosage de dommages oxydatifs ont ensuite été mesurés dans différents tissus et cellules de l’organisme (branchies, gonade, hémocytes et gamètes). Les résultats obtenus dans le cadre de cette thèse suggèrent que la capacité antioxydante de C. gigas est particulièrement efficace et que la reproduction seule n’est pas suffisante pour induire un stress oxydant. Cette capacité antioxydante apparaît comme tissu-spécifique voire cellule-spécifique et le métabolisme du glutathion semble jouer un rôle majeur dans cette protection. Cette grande résistance au stress oxydant contribuerait à faire de C. gigas une espèce particulièrement adaptée à la vie dans des environnements stressants. / The “cost of reproduction” is a concept defining that a high reproductive investment has a price that is paid later by an acceleration of senescence. That may translate tradeoff between reproduction and other physiological functions such as antioxidant defense. In the Pacific oyster Crassostrea gigas, reproduction is a major physiological function. In a study led to understand the summer mortalities affecting this species, a negative correlation between reproductive effort and survival was observed. Moreover, some antioxidant genes were identified as differentially expressed between lines of oysters selected for resistance or susceptibility to summer mortalities. Some studies suggest that the susceptibility to oxidative stress may represent a cost of reproduction taking part to the process of senescence. In this context, we analyzed the antioxidant capacity of oysters according to their reproductive investment. For this, the technique of RNA interference was used to manipulate the reproductive effort of oysters. The expression of the main antioxidant enzymes (transcript levels and enzyme activities) and the dosage of oxidative damages were then measured in different tissues and cells of the organism (gills, gonad, hemocytes and gametes). The results obtained in this thesis suggest that the antioxidant capacity of C. gigas is particularly effective and that reproduction alone is not sufficient to induce oxidative stress. This antioxidant capacity appears to be tissue-specific even cell-specific and glutathione metabolism would to play a major role in this protection. This resistance to oxidative stress would make C. gigas be a species particularly adapted to life in stressful environments.
92

Recherche des capacités antibactériennes et antioxydantes de Ludwigia spp., invasives de Sud de France / Research antibacterial and antioxidant capacities of Ludwigia spp invasive hydrophytes southern France

Smida, Imen 05 May 2014 (has links)
Introduite depuis l'Amérique du sud au début du XIXème siècle à Montpellier, les Ludwigia, hydrophytes amphibies, ont depuis envahi toute la France. L'objectif de nos recherches a été la possibilité de valoriser leurs tonnes annuelles de biomasse polluante. Ainsi, notre étude s'est centrée sur la mise en évidence des capacités antibactériennes et antioxydantes de L. grandiflora (durant deux cycles de développement) et de L. peploides (durant une période de floraison). Les extraits bruts de leurs différents organes se sont montré actifs contre 14 souches de bactéries Gram + ou Gram-, potentiellement pathogènes. Ainsi, les meilleurs résultats ont été obtenus avec les extraits des organes des plantes en période de floraison. Les capacités antibactériennes de L. grandiflora sont apparues supérieures à celles de L. peploides. De même, les extraits des fleurs et des feuilles ont été les plus inhibiteurs. Certains d'entre eux se sont montrés plus actifs que six antibiotiques communs. L'activité antioxydante totale a également été mise en évidence et suivie durant le cycle de développement des deux Ludwigia. Les EC50 sont même très basses, et parfois concurrentielles de celle obtenue avec le Trolox, le témoin utilisé. Les fractionnements bioguidés effectués ont permis d'isoler des fractions plus actives que l'extrait brut. Toutefois, les analyses par spectrométrie de masse (SM) et de spectroscopie (RMN 1D, IR) n'ont pas permis de pouvoir à ce stade en déterminer les molécules actives. Nos travaux, novateurs, ouvrent cependant des perspectives de valorisation dans les domaines de la Pharmaceutique, de la Cosmétique et de l'alimentation, et, également en écologie. / Introduced from South America in the early nineteenth century in Montpellier, Ludwigia, amphibious hydrophytes have since invaded the whole of France. The objective of our research was to study the possibilities to enhance the annual tons of biomass clean their beds. Thus, our study focused on the identification of antibacterial and antioxidant capacitiesof L. grandiflora (for two development cycles) and of L. peploides (during a period of flowering) in herbarium southern France. It was found that crude extracts of their different organs are shown active against 14 strains Gram+ and Gram- potentially pathogenic bacteria. The best results were obtained with extracts of plant organs during flowering. In general, the antibacterial capacity of L. grandiflora appeared superior to those of L. peploides. Similarly, extracts of flowers and leaves were the most inhibitors. Some of them were more active than six common antibiotics, some very powerful, against 14 strains tested. The total antioxidant activity was also highlighted and followed during the development cycle of both Ludwigia. The EC50 is even very low, and sometimes competing that obtained with Trolox, the control used. The guided bio splits made during this preliminary study led to the isolation of the most active fractions as the crude extract. However, analysis by mass spectrometry (MS) and spectroscopy (1DNMR, IR) did not allow this time to be able to determine the active molecules. Our innovative study, yet provide opportunities for enhancement in the areas of Pharmaceutical, Cosmetics and alimentation, and also for research in phytochemistry and ecology.
93

Determinação de isoflavonas e capacidade antioxidante de alimentos industrializados à base de soja e/ou produtos derivados consumidos no Brasil / Determination of isoflavones content and antioxidant capacity of industrialized foods containing soy and soy products consumed in Brazil

Alezandro, Marcela Roquim 18 May 2009 (has links)
A soja contém alto conteúdo protéico e de lipídeos poliinsaturados e representa a principal fonte de isoflavonas. Por este grão não fazer parte da dieta brasileira, produtos contendo soja surgiram no mercado como fontes de isoflavonas, adaptados ao paladar da nossa população. Os condimentos também têm sido incorporados aos ditos \"alimentos funcionais\" pela sua relação com efeitos benéficos à saúde. Este trabalho objetivou determinar o teor de isoflavonas dos produtos contendo soja e/ou derivados, o teor de flavonóides de diferentes condimentos e marcas, e a capacidade antioxidante destas amostras. Os resultados mostram que o quibe vegetariano destaca-se como fonte de isoflavonas, e o chocolate pela capacidade antioxidante. Entre os condimentos, houve diferença significativa entre tipos e marcas. O orégano destacou-se quanto à capacidade antioxidante e a salsa quanto ao teor de flavonóides. Alimentos contendo soja ou derivados e os condimentos podem representar fontes de compostos bioativos para a população brasileira. / Soy contains high protein and polyunsaturated lipids content and represents the main source of isoflavones. This grain is not part of the Brazilian diet, so some products containing soy emerged as sources of isoflavones, adapted to the taste of our population. Spices have also been incorporated into \"functional foods\" by their relation to health benefits. This study aimed to determine the isoflavone content of products containing soy and/or derivatives, flavonoids content in different brands and condiments, and antioxidant capacity of these samples. The results showed that vegetarian \"quibe\" is a good source of isoflavones, and chocolate had the highest antioxidant capacity. Among spices, there were significant differences between the types and brands. Oregano had the highest antioxidant capacity and parsley had the highest flavonoids content. Foods containing soy or derivatives and condiments may represent sources of bioactive compounds for Brazilian population.
94

Teor de isoflavonas e capacidade antioxidante de bebidas à base de soja / Isoflavone contents and antioxidant capacity of soy beverages

Callou, Kátia Rau de Almeida 21 May 2009 (has links)
A soja é a principal fonte de isoflavonas, tendo sido associada a efeitos benéficos à saúde humana, incluindo a redução do risco de câncer, de doenças cardiovasculares, osteoporose e melhora dos sintomas da menopausa. A população brasileira não consome soja tão habitualmente quanto os países asiáticos e, nesse contexto, as bebidas de soja poderiam ser uma forma de incluir essas substâncias bioativas na dieta ocidental. Contudo, trabalhos que avaliem o teor de isoflavonas desses produtos são escassos na literatura, o que justifica o presente trabalho. Amostras de doze marcas comercialmente disponíveis de bebidas de soja (n = 65), incluindo os produtos elaborados com isolado protéico de soja ou extrato de soja e acrescidos de sucos de fruta e/ou ingredientes aromatizantes, foram analisadas quanto ao teor e perfil de isoflavonas, utilizando-se a cromatografia líquida de alta eficiência. A capacidade antioxidante foi mensurada pelo método de sequestro de radicais livres do DPPH e o teor de fenólicos totais pelo método do Folin-Ciocalteau. Os valores da concentração total de isoflavonas e o teor de fenólicos totais mostraram uma grande variação entre as diversas marcas de bebidas de soja, variando de 0,7 a 4,9 mg isoflavonas/200 mL e de 6 a 146 mg equivalentes de catequina/200 mL para as bebidas contendo sucos de fruta. Bebidas de soja de sabor original ou chocolate apresentaram variação do teor de isoflavona de 4 a 13 mg/200 mL e fenólicos totais variando de 38 a 155 mg equivalentes de catequina/200 mL. O teor protéico variou de 0,8 a 6 g/200 mL e mostrou-se positivamente correlacionado ao teor de isoflavonas das amostras. As formas predominantes de isoflavonas, nos produtos analisados, foram os β- glicosídeos. Os resultados mostraram que o teor e perfil de isoflavonas, assim como os valores de fenólicos totais das bebidas de soja dependem das condições de processamento e que a atividade antioxidante variou significantemente entre os produtos. Os resultados obtidos mostram que o consumo de uma porção de 300 mL de bebida de soja sabor natural poderia resultar em uma ingestão de 20 mg de isoflavonas, o equivalente a ingestão diária Koreana, indicando que as bebidas de soja poderiam representar fontes importantes de isoflavonas para a nossa dieta. Além disso, o teor de isoflavonas solúveis das bebidas de soja diminui com o decorrer do armazenamento associado à redução da solubilidade da proteína de soja. O perfil de isoflavonas e a capacidade antioxidante das bebidas também são alterados. / Soybean is the most important source of isoflavones, which have been associated with beneficial effects in humans, including prevention of cancer, cardiovascular diseases, osteoporosis and relief of menopausal symptoms. Soybean consumption in Brazil is not as significant as in Asian countries and in this context, soy beverages could be a way to include these bioactive substances in ocidental diet. However, studies about isoflavone content in these products are scarce, which accounts for the present work. Samples of 12 different brands of commercially available soy milk drinks (n = 65), including products made from isolated soy protein and soymilk mixed with fruit juices and/or containing flavoring ingredients were analysed for their isoflavone content and profile using highperformance liquid chromatography. The antioxidant activity was measured using 2.2- diphenil-1-picryl-hydrazil (DPPH) free radical method and the total phenolics was determined by Folin-Ciocalteau method. There was a large variation in total isoflavone concentration and total phenolics content among the different brands of soy milks ranging from 0.7 to 4.9 mg isoflavones/200 mL and 6 to 146 mg equivalents of catechin/200 mL of soymilk mixed with fruit juice. For natural or chocolate soy beverages, the isoflavone content varied from 4 to13 mg/200 mL and the total phenolics ranged from 38 to155 mg equivalent of catequina/200 mL. Levels of protein ranged from 0.8 to 6.0 g/200 mL, these values were associated positively with isoflavone content from samples. The β-glycosides were the predominant form of the isoflavones in the products analyzed. The results showed that total isoflavone, phenolic contents and isoflavone profile of soy beverages depends on processing conditions. Also the antioxidant activity varied significantly among products. The results obtained show that the consumption of 300 mL of soy beverage natural flavor would result in an intake of around 20 mg isoflavone, very similar to the Korean daily intake, indicating that soy beverages could represent important sources of isoflavones in our diet. Furthermore, the soluble isoflavone content of soy beverage decreases with the storage time associated with a reduction of the solubility of soy protein. The profile of isoflavones and antioxidant capacity of beverages are also altered.
95

Extratos de Arrabidaea chica (Humb. & Bonpl.) verlot obtidos por processos biotecnológicos: otimização da extração e avaliação farmacológica. / Arrabidaea chica (Humb. & Bonpl.) Verlot extracts obtained by biotechnological processes: extraction optimization and pharmacological evaluation.

Taffarello, Denise 30 January 2009 (has links)
Arrabidaea chica Verlot (Bignoniaceae), conhecida como crajiru, fornece pigmentos vermelhos utilizados pelos índios no Brasil como corante e agente cicatrizante. Este estudo visou otimizar a extração de compostos fenólicos de A. chica e avaliar sua atividade farmacológica. Extratos de A. chica foram obtidos através de tratamento com xilanases de Bacillus pumilus previamente à extração. Os ensaios foram monitorados por CLAE e ESI-MS. O tratamento enzimático forneceu extratos enriquecidos em antocianidinas. Extratos sem tratamento enzimático apresentaram maior teor de antocianosídeos. O estudo farmacológico demonstrou que as atividades anticâncer e antioxidante in vitro estão diretamente relacionadas ao maior teor de agliconas. O ensaio in vitro de indução de crescimento de fibroblastos indicou que o maior teor da aglicona carajurina é inversamente proporcional à ação cicatrizante. Portanto, foi desenvolvida uma metodologia inovadora, através de processos biotecnológicos, para extração de antocianidinas que apresentam propriedades corantes e terapêuticas. / Arrabidaea chica Verlot (Bignoniaceae), known as crajiru, produces red pigments used by Brazilian indians as dye and as healing agent. This study has aimed the optimization of phenolic compounds extraction from A. chica and to evaluate its pharmacological activities. Extracts from A. chica were obtained through treatment with xylanases from Bacillus pumilus before the extraction. The assays were monitored by HPLC and ESI/MS-MS. The enzymatic treatment has produced more concentrated in anthocyanidins extracts. Those obtained without enzymatic treatment have presented higher glycosilated anthocyanins content. The pharmacologic study has demonstrated that the antitumoral and the antioxydant in vitro properties for A. chica are directly related to the higher contents of aglycones. In vitro assay for fibroblasts growth induction has demonstrated that a higher content of carajurin is inversely proportional to the healing action. In conclusion, a novel approach has been developed, through biotechnological process, aiming the extraction of anthocyanidins presenting dye and therapeutic properties.
96

Características químicas e nutricionais de arroz-preto, vermelho e selvagem e comparação por análise estatística multivariada / Chemical and nutritional characterization of black, red and wild rice and comparison by multivariate analysis

Massaretto, Isabel Louro 17 December 2013 (has links)
O arroz (Oryza sativa L.) é consumido predominantemente na forma polida, porém há uma tendência na procura por grãos integrais não pigmentados e pigmentados, como o preto e o vermelho, e também pelo arroz selvagem, que pertence ao gênero Zizania. Além da composição nutricional e propriedades sensoriais distintas, os tipos pigmentados possuem compostos bioativos, que atribuem cor aos grãos e que têm sido relacionados a efeitos benéficos à saúde. Contudo, uma comparação em termos nutricionais e de bioativos entre esses grãos ainda inexiste. Este projeto visou comparar a composição química, incluindo os compostos fenólicos totais (CFT), os polifenóis majoritários e a capacidade antioxidante de três amostras de arroz-preto produzido no Estado de São Paulo, duas de arroz-preto produzido no Estado do Rio Grande do Sul e 11 de arroz-preto produzido no Estado de Santa Catarina, 9 de arroz-vermelho, produzido nos estados mencionados e, 6 amostras de arroz selvagem, importadas do Canadá e comercializadas em São Paulo; todas as amostras foram produzidas e/ou comercializadas no período de 2009 a 2011. A comparação das variáveis foi feita pelo uso de análise estatística uni- e multivariada. Fez parte do escopo do projeto avaliar o efeito do cozimento sobre a estabilidade dos CFT e a atividade antioxidante. Também foi conduzida uma comparação preliminar dos teores de fitoquímicos lipossolúveis, γ-orizanol, tocoferóis e tocotrienóis, entre 7 amostras de arroz-preto e 4 de arroz-vermelho, todas da safra de 2013. Com base nas análises químicas e na análise estatística multivariada, foi possível agrupar os vários tipos de arroz em quatro grupos, significativamente diferentes entre si: arroz selvagem, arroz-preto de grãos longos, arroz-preto de grãos médios e arroz-vermelho. O grupo que mais se diferenciou dos demais foi o arroz selvagem, por apresentar os maiores teores proteicos (12,9 g/100g) e de ácido α-linolênico (0,12 g/100g) e os menores teores de lipídeos (0,9 g/100g), de compostos fenólicos e atividade antioxidante, entre os grupos estudados. Outro grupo com características distintas foi o arroz-preto de grãos longos que se destacou principalmente pelo elevado teor de compostos fenólicos, representados pelas antocianinas, e elevada atividade antioxidante. A cianidina-3-O-glicosídeo foi identificada por CLAE-DAD-MS/MS, como sendo a antocianina majoritária. Os teores de proteínas e de lipídeos, da ordem de 9,8 e 3,6 g/100g, respectivamente, foram maiores do que dos outros dois grupos estudados. O arroz-preto de grãos médios e o vermelho foram similares em termos de composição de nutrientes e CFT. Os teores proteicos em ambos os grupos foi, em média, de 8,8 g/100g. Porém, enquanto no arroz-preto predominam antocianinas, a coloração do arroz-vermelho é conferida por proantocianidinas, com diferenças na sua atividade antioxidante. O arroz-preto de grãos médios apresentou atividade antioxidante mais do que o dobro do arroz-vermelho, no entanto próxima ao do arroz-preto de grãos longos. Este resultado indica que o elevado teor de antocianinas, independente do formato do grão, é responsável pela alta capacidade antioxidante no arroz-preto. A análise multivariada demonstrou que o formato do grão é determinante na diferenciação dos dois grupos de arroz-preto em termos de composição de nutrientes, como proteínas e lipídeos, mas não de fitoquímicos e de atividade antioxidante. O método ORAC foi mais apropriado para avaliar a atividade antioxidante do arroz-preto, por ser mais sensível à presença de antocianinas do que o método de DPPH·. Nos outros dois grupos, vermelho e selvagem o método de DPPH· também pode ser utilizado. O cozimento do arroz provocou perda significativa nos teores de CFT e na atividade antioxidante do arroz-preto e vermelho. No arroz-preto, a perda de CFT foi de 26%, em média, enquanto a perda das antocianinas foi de 50%. A explicação pode ser que durante o cozimento uma parte das antocianinas seja convertida em ácido protocatecóico, que é dosado como CFT. No arroz-vermelho, a redução de CFT foi de 60%, possivelmente devido a uma insolubilização de parte das proantocianidinas. No arroz selvagem, o cozimento não causou perdas significativas. A capacidade antioxidante dos vários grupos de arroz após o cozimento depende do método empregado, sendo fortemente correlacionada com os teores de CFT remanescentes. Assim, o arroz-preto, mesmo depois de cozido, apresentou a maior capacidade antioxidante, seguido do arroz-vermelho e do selvagem. Numa avaliação inicial, os teores dos fitoquímicos lipossolúveis, γ-orizanol e homólogos da vitamina E, foram semelhantes em arroz-preto e vermelho, indicando que independem da coloração do pericarpo. / Rice (Oryza sativa L.) is mostly consumed in its milled form; however there is an increasing demand for whole non-pigmented and pigmented rice, such as black, red, and wild rice, which the latter belongs to the genus Zizania. Pigmented rice has particular nutritional composition and sensory characteristics, and in addition high amounts of phenolic compounds, which not only confer color but also has been linked to beneficial effects on human health. To date, little is known about the nutritional and bioactive contents of these grains. The aim of this study was to compare the chemical composition, including the total phenolic compounds (TPC), the majoritarian polyphenols and the antioxidant radical efficiency of the following accessions: three black rice from the state of São Paulo, two black rice from the state of Rio Grande do Sul, eleven black rice genotypes from Santa Catarina state, nine red rice from those states and six wild rice, imported from Canada and marketed in São Paulo. All samples were cultivated and/or marketed from 2009 to 2011. Data were evaluated by uni- and multivariate statistical analysis. The effect of cooking on the stability of TPC and antioxidant capacity was also evaluated. In addition, a preliminary comparison of γ- oryzanol, tocopherols and tocotrienols was carried out between two groups: seven black rice and four red rice samples, all of them cultivated in 2013. Based on chemical results and multivariate statistical analysis it was possible to cluster the various types of rice in four groups, significantly different among themselves: wild rice, black long grain rice, black medium grain rice, and red rice. Wild rice was the most dissimilar group due to its highest contents of protein (12.9 g/100g) and α-linolenic acid (0.12 g/100g), and the lowest amounts of lipids (0.9 g/100g), TPC, and antioxidant capacity. Black long grain rice was characterized mainly by its high contents of TPC, especially anthocyanins and by its elevated antioxidant capacity. Cyanidin-3-O-glycoside was identified by HPLC-DAD-MS/MS as being the main anthocyanin. The protein and lipid mean contents in these groups were respectively, 9.8 and 3.6 g/100g and were higher than the amounts in the other next two types of rice. The black medium grain rice and red rice were similar in terms of nutrient composition and TPC. The average amount of protein in both groups was about 8.8 g/100g. However, in black rice prevails anthocyanins, while in red rice coloration is provided by proanthocyanidins, which results in differences in antioxidant activity. Medium and long black grain rice showed a 2-fold higher antioxidant activity than red rice. These findings indicate that the high content of anthocyanins, independent of the grain shape, is responsible for the high antioxidant capacity in black rice. The multivariate analysis demonstrated that the grain shape is fundamental to differentiate black rice in terms of nutrient composition, like protein and lipids, but not in relation to amounts of phytochemicals and antioxidant capacity. ORAC was more suitable than DPPH· methodology to evaluate the antioxidant activity of black rice, due to its high correlation to anthocyanin contents. Conversely, DPPH· can be a consistent method to evaluate antioxidant capacity of red and wild rice. Cooking resulted in significant loss on TPC contents and on the antioxidant capacity of black and red rice. In black rice, 26% of TPC was reduced on average, while the loss of anthocyanins was 50%. The reason may be that during cooking, part of the anthocyanins is converted into protocatechuic acid, which is quantified as TPC. The reduction in TPC in red rice was 60%, possibly due to a partial insolubilization of proanthocyanidins. In wild rice, cooking caused no significant loss of TPC. The antioxidant capacity of different types of cooked rice was dependent on the method used, being strongly correlated with the remaining levels of TPC. Thus, black rice even after cooking showed the highest antioxidant capacity, followed by red and wild rice. From a preliminary evaluation, the contents of lipophilic phytochemicals, &#947-orizanol and vitamin E homologues were similar in black and red rice, which indicates that the contents of these compounds are not dependent of the pericarp color.
97

Production and spray drying of probiotic beverage made from the fermentation of cashew apple juice / ElaboraÃÃo e secagem em spray dryer de bebida probiÃtica formulada a partir da fermentaÃÃo do suco de caju

Ana Lucia Fernandes Pereira 07 February 2013 (has links)
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.
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Desidrata??o osm?tica de banana utilizando solu??es de fruto-oligossacar?deos e xarope de milho em diferentes temperaturas / Study banana osmotic dehydration using solutions containing fructo-oligosaccharides and corn syrup at different temperatures

LANDIM, Ana Paula Miguel 02 June 2016 (has links)
Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-05-09T17:18:58Z No. of bitstreams: 1 2016 - Ana Paula Miguel Landim.pdf: 1756748 bytes, checksum: edb655700eacaf99a7fa2c3d482f3283 (MD5) / Made available in DSpace on 2017-05-09T17:18:58Z (GMT). No. of bitstreams: 1 2016 - Ana Paula Miguel Landim.pdf: 1756748 bytes, checksum: edb655700eacaf99a7fa2c3d482f3283 (MD5) Previous issue date: 2016-06-02 / CAPES / Banana is a perishable fruit, as it ripens fast and cannot be adequately preserved by the cold, resulting in large post-harvest losses. The application of preservation techniques, such as osmotic dehydration, reduces losses of the commodity in post-harvest stage, extend its shelf-life, while not severely affecting its nutritional values, and functional and sensorial properties, which makes it at processing alternative for the fruit. The aim of this study is to evaluate the kinetics of osmotic dehydration, as well as the quality of the osmotically dehydrated samples in terms of color, texture, and antioxidant capacity, using fructo-oligosaccharide, corn syrup and the mixture of both, under different temperatures. To determine the kinetics, the fruit, cut in cubes, was dehydrated in different solutions, under temperatures of 40, 50 and 60 ? C. The kinetics of water loss (WL) and solid gain (SG) were evalueted at 30, 60, 90, 120, 180, 240, 360, 720 to 1440 minutes. The analysis of variance was used to verify the effect of each solution and temperature on kinetics. The kinetic parameters were modeled based on the equations of Peleg, Page modified and Barbosa Junior et al. using non-linear regression. The time to reduce the dehydration rate or penetration to one third of its initial values (t(1/3)) and the process average time (t(average)) were obtained on the Barbosa Junior et al. model The quality of the samples was accessed at these two times, in different solutions under different temperatures. For such, the variation of the instrumental parameters of color, antioxidant capacity (FRAP, DPPH and total phenolic content), and texture (axial compression tests) of samples, in nature as well as processed, were verified. The WL was not affected significantly by the type of solute used, however, the temperature presented significant influence over these parameters (p < 0.05). The experimental data for the WL was adequately adjusted to the Peleg and Page modified models with coefficients of determination (R?) superior than 0.98, mean relative error (E) inferior than 6.5% in all treatments. The water loss content values varied from 15.75 to 28.79% at time t(1/3), while for the time t(averege) 15.75 to 30.27% between treatments. The process of osmotic dehydration had affect on the quality of the final product, showing significant differences between the fruits in natura and processed state, in terms of color, antioxidant capacity and texture of the samples. / A banana ? um fruto perec?vel, pois sofre r?pido amadurecimento, n?o pode ser devidamente conservado pelo frio, sendo acometido por grandes perdas p?s-colheita. A utiliza??o de t?cnicas de conserva??o, como a desidrata??o osm?tica, reduz as perdas p?s-colheita, estende a validade comercial, n?o acarreta em severas altera??es nas caracter?sticas nutricionais, funcionais e sensoriais e mostra-se como uma alternativa de processamento para este fruto. O objetivo desde trabalho foi avaliar a cin?tica da desidrata??o osm?tica, bem como, a qualidade das amostras desidratadas osmoticamente em termos de cor, textura e capacidade antioxidante, utilizando fruto-oligossacar?deo, xarope de milho e a mistura de ambos, em diferentes temperaturas. Para determina??o da cin?tica, a banana, cortada em cubos foi desidratada nas diferentes solu??es, sob as temperaturas de 40, 50 e 60 ?C. As Cin?ticas de Perda de ?gua (PA) e ganho de s?lidos (GS) foram avaliadas nos tempos 30, 60, 90, 120, 180, 240, 360, 720 e 1440 minutos. A an?lise de vari?ncia foi usada, a fim de verificar o efeito do tipo de soluto e da temperatura na cin?tica. Os par?metros cin?ticos foram modelados de acordo com a equa??o Peleg, Page modificado e Barbosa J?nior et al. utilizando regress?o n?o-linear. A partir do modelo de Barbosa J?nior et al., obteve-se o tempo para reduzir a taxa de desidrata??o ou impregan??o a um ter?o de seus valores iniciais (t(1/3)) e o tempo m?dio de processo (t(m?dio)). A qualidade das amostras foi avaliada nestes dois tempos, nos diferentes solutos e temperaturas. Para tal, foram verificadas a varia??o dos par?metros instrumentais de cor, a capacidade antioxidante (FRAP, DPPH e teor de fen?licos totais) e a textura (ensaios de compress?o axial) das amostras in natura e processadas. A PA n?o foi afetada significamente pelo tipo de soluto empregado, no entanto, a temperatura apresentou influ?ncia significativa neste par?metro (p < 0,05). Os dados experimentais para a PA se ajustaram adequadamente ao modelo de Peleg e Page modificado e obtiveram-se coeficientes de determina??o (R?) maiores do que 0,98, desvio relativos m?dios (E) inferiores a 6,5% em todos os tratamentos. O modelo do tempo de n-redu??o da taxa de desidrata??o se mostrou uma boa alternativa na defini??o do tempo de processamento das amostras submetidas ? desidrata??o osm?tica. Os valores de perda de ?gua variaram de 15,70 a 28,79% no tempo t(1/3), enquanto que para o tempo de t(m?dio) de 15,75 a 30,27% entre os tratamentos. O processo de desidrata??o osm?tica influenciou na qualidade final dos produtos, apresentando diferen?as significativas entre a fruta in natura e a processada para varia??o dos par?metros de cor, a capacidade antioxidante e a textura das amostras in natura e processadas.
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Evaluación del efecto de la incorporación de Camellia sinensis L. (té verde) sobre el contenido de flavonoides, capacidad antioxidante y aceptación sensorial de un yogurt probiótico / Evaluation of the effect of the incorporation of Camellia sinensis L. (green tea) on the flavonoid content, antioxidant capacity and sensory acceptance of a probiotic yogurt

Canale Vásquez, Alessandra, Michilot Soto, Tamara 24 July 2019 (has links)
Objetivo: Evaluar el efecto de la incorporación de Camellia sinensis L. (2%, 4% y 6% de extracto de té verde) sobre el contenido de compuesto fenólicos, capacidad antioxidante y aceptación sensorial de un yogurt probiótico. Material y métodos: Estudio experimental de laboratorio dónde se elaboró un yogurt probiótico con té verde añadido en distintas concentraciones de 2%, 4% y 6%. Además, se evaluó la aceptabilidad sensorial y se analizó las características físicoquímicas de cada muestra. Asimismo, para determinar el contenido de polifenoles se utilizó el método de Folin-Ciocalteau y, el método de DPPH (2,2-difenil-1-1-picrilhidrazilo) para determinar la capacidad antioxidante. Resultados: Se encontró que en el yogurt probiótico con 6% de té verde añadido había 1.64 mg/mL de contenido de polifenoles, casi el triple del contenido de polifenoles que en el yogurt probiótico con 2% de té verde añadido. Además, se encontró que el yogurt con mayor porcentaje de té verde añadido (6%) obtuvo 61% de decoloración del reactivo de DPPH, lo que nos indica mayor capacidad antioxidante a comparación de las muestras con menor porcentaje de té verde añadido. Conclusión: A mayor contenido de compuestos fenólicos, mayor es la capacidad antioxidante de un yogurt probiótico con té verde añadido, además de ser el que mayor aceptabilidad sensorial alcanzó, siendo su olor y sabor los atributos más apreciados por los panelistas no entrenados quienes le otorgaron un puntaje de 4 en una escala hedónica de 5 puntos, lo que equivale a un “le gusta moderadamente”. / Objective: To evaluate the effect of Camellia sinensis L. (2%, 4% and 6% of green tea extract) incorporation on the content of phenolic compounds, antioxidant capacity and sensory acceptance of a probiotic yogurt. Material and methods: In this experimental laboratory study, probiotic yogurt with added green tea was elaborated using three concentrations of green tea extract (2%, 4% and 6%), and the sensory acceptability and the physical-chemical characteristics were determined for each concentration. Likewise, to determine the content of polyphenols, the Folin-Ciocalteau method was used, and the DPPH method (2,2-diphenyl-1-1-picrylhydrazyl) was used to determine the antioxidant capacity. Results: It was found that in the probiotic yogurt with 6% green tea extract added there was 1.64 mg / mL of polyphenol content, almost triple the polyphenol content than in the probiotic yogurt with 2% green tea added. In addition, it was found that the yogurt with the highest percentage of green tea added (6%) obtained 61% discoloration of the DPPH reagent, which indicates greater antioxidant capacity compared to samples with a lower percentage of green tea added. Conclusion: The higher the content of phenolic compounds, the greater the antioxidant capacity of a probiotic yogurt with green tea added, besides being the one with the highest sensory acceptability, its smell and taste were the attributes most appreciated by the untrained panelists who gave it a score of 4 on a hedonic scale of 5 points, which is equivalent to a "moderately like". / Tesis
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Measurement and Evaluation of Antioxidant Status and Relation to Oxidative Stress in Humans

Nälsén, Cecilia January 2006 (has links)
<p>Numerous diseases are associated with reduced antioxidant defence and oxidative stress. The antioxidant defence includes dietary and endogenous antioxidants and involves complex interactions between them. The effects of dietary factors on antioxidant status and oxidative stress of healthy humans were investigated in the studies described in this thesis. Assays of plasma antioxidant capacity encompass interactions between various antioxidants. Although uric acid has an unclear function as an antioxidant, it is a major determinant of antioxidant capacity. We measured antioxidant capacity in the presence and absence of uric acid to provide more information on the application of measures of antioxidant capacity. Individuals with high dietary intakes of various antioxidants and antioxidant rich foods, especially when combined, had higher plasma antioxidant capacities than those with lower antioxidant intakes. However, there were no associations between dietary intake of antioxidants or antioxidant rich foods and the plasma concentration of F<sub>2</sub>-isoprostanes, which is considered a reliable biomarker for oxidative stress. Intakes of various doses of a mixture of bilberry juice and black tea, rich in flavonoids for four weeks, increased antioxidant capacity in some groups, but urine levels of F<sub>2</sub>-isoprostanes were not affected. There were substantial individual variations in responses to the drinks related to baseline antioxidant capacity. Supplementation with eicosapentaenoic acid and docosahexaenoic acid decreased the plasma levels of F<sub>2</sub>-isoprostanes, but not prostaglandin F<sub>2α</sub> formation or antioxidant capacity. </p><p>It was concluded that a high intake of foods rich in antioxidants is related to improved antioxidant status. After intake of foods rich in antioxidants, the antioxidant status may increase, but with considerable individual variation in the responses, which warrants further investigation. Lipid peroxidation <i>in vivo</i> is not easily affected by dietary antioxidants in healthy humans. Although n-3 fatty acids are highly unsaturated, they reduce nonenzymatic free radical-catalyzed lipid peroxidation, but not enzymatic lipid peroxidation.</p>

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