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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.
141

INFLUÊNCIA DE DIFERENTES PARÂMETROS EM MÉTODOS DE EXTRAÇÃO DE COMPOSTOS BIOATIVOS DE MIRTILO (Vaccinium ashei Reade) E ATIVIDADE ANTIOXIDANTE E ANTIMICROBIANA / INFLUENCE OF DIFFERENT PARAMETERS IN BLUEBERRY BIOACTIVE COMPOUNDS EXTRACTION METHODS (Vaccinium ashei Reade) AND ANTIOXIDANT AND ANTIMICROBIAL ACTIVITY

Piovesan, Natiéli 29 August 2016 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study aimed to investigate the influence of different parameters (concentration of solvent, time, temperature and power) in extraction methods (focused microwave, conventional and ultrasound) bioactive compounds in blueberries, seeking higher yield of compounds biativos, antioxidant and antimicrobial activity of the extracts.The extracts were characterized regarding the phenolic compounds, flavonoid and anthocyanins content. The in vitro antioxidant activity was quantified by the methods of DPPH, ABTS, FRAP, and β-carotene, was calculed the IC50 and evaluated the antimicrobial activity.The results for focused microwave extraction generally indicated that the antioxidant activity (FRAP, ABTS and DPPH), total phenolics and total anthocyanins showed a positive linear trend in relation to the extraction temperature, with no significant difference between the solvent concentrations (60 and 80%). The IC50 and β-carotene showed the greatest inhibition at 60°C at solvent concentrations of 60% and 80%, respectively. The flavonoids showed no significant difference in terms of the extraction temperature or the concentration of solvent that was used. No antimicrobial activity was detected in the extracts in relation to the tested microorganisms. In the conventional method of extracting the best extraction conditions for phenolic compounds, flavonoids and anthocyanin employed 60% solvent, 60 minutes at 40ºC; however, the anthocyanins did not suffer any influence from time and temperature. The best results for the antioxidant activity using the DPPH and FRAP methods were obtained with 60% solvent, 30 minutes at 30ºC, and the DPPH was not influenced by temperature. Regarding ABTS+ the best results were reached with 60% solvent, 120 minutes, at 40ºC, while the β-carotene required 80% solvent at 40ºC, regardless of the time. The different extracts tested did not show antimicrobial activity. Ultrasound provided better phenolic extraction conditions, flavonoids and anthocyanins using 60% solvent, 20 minutes and 80 watts of power, and phenolic compounds not influenced by the power and flavonoids were not affected by the solvent. The antioxidant activity by DPPH and IC50 showed the best results com 60% solvent, 60 minutes and 80 W of power, the same conditions were found for β-carotene, but with 20 minutes of extraction. FRAP methodology is presented more efficient solvent 60%, 60 minutes and 220W power, whereas for the ABTS assay was 80% solvent and 80 W of power, independent of the extraction time. The extracts obtained through different methods of extraction showed no antimicrobial activity. However, the study confirms the antioxidant capacity of blueberries, which can be used as a functional ingredient or as a natural antioxidant in the preparation of food products. / Este trabalho teve como objetivo investigar a influência de diferentes parâmetros (concentração de solvente, tempo, temperatura e potência) nos métodos de extração (assistida por micro-ondas focalizada, convencional e por ultrassom) de compostos bioativos de mirtilo, visando maior rendimento dos compostos biativos, atividade antioxidante e antimicrobiana dos extratos. Os extratos foram caracterizados quanto o teor de fenólicos totais, flavonoides totais e antocianinas totais. As atividades antioxidante in vitro foram quantificadas pelos métodos de DPPH, ABTS, FRAP e β-caroteno, foi calculado o IC50 e avaliada a atividade antimicrobiana. Os resultados encontrados para a extração através das micro-ondas focalizadas apontam que as atividades antioxidantes medidas por FRAP, ABTS+ e DPPH, compostos fenólicos totais e antocianinas totais apresentaram uma tendência linear positiva em relação à temperatura de extração, sem diferença significativa entre as concentrações dos solventes (60 e 80%). O IC50 e o β-caroteno apresentaram maior inibição na temperatura de 60°C, porém estes somente nas condições de solvente 60% e 80%, respectivamente. Os flavonóides não tiveram diferenças significativas na temperatura de extração e nem no solvente utilizado. No método convencional de extração as melhores condições de extração para os compostos fenólicos, flavonóides e antocianinas foi utilizando 60% de solvente, 60 minutos e à 40ºC, porém as antocianinas, não sofreram influencia do tempo e da temperatura. O melhores resultados para as atividades antioxidantes, pelos métodos DPPH e FRAP, foram obtidos com solvente 60%, 30 minutos e à 30ºC, sendo que o DPPH não foi influenciado pela temperatura. Para o ABTS+ os melhores rendimentos foram com 60% solvente, 120 minutos e à 40ºC, enquanto que para o β-caroteno, 80% de solvente a 40ºC, independentemente do tempo. O ultrassom proporcionou melhores condições de extração de fenólicos, flavonóides e antocianinas utilizando 60% de solvente, 20 minutos e 80 W de potência, sendo que os compostos fenólicos não sofreram influência da potência e os flavonoides não foram influenciados pelo solvente. A atividade antioxidante pelo método DPPH e o IC50 apresentaram os melhores resultados com 60% de solvente, 60 minutos e 80 W de potência, as mesmas condições foram encontradas para o β-caroteno, porém com 20 minutos de extração. A metodologia de FRAP apresentou-se mais eficiente com solvente 60%, 60 minutos e 220W de potência, enquanto que para o método ABTS+ foi com 80% de solvente e 80 W de potência, independente do tempo de extração. Os extratos obtidos através das diferentes metodologias de extração não apresentaram atividade antimicrobiana. Contudo, o estudo confirma a capacidade antioxidante do mirtilo, podendo este ser utilizado como ingrediente funcional ou como antioxidante natural na elaboração de produtos alimentícios.
142

AVALIAÇÃO DA ATIVIDADE ANTIOXIDANTE DE EXTRATO DE INFLORESCÊNCIA DE BANANEIRA (Musa cavendishii) E SUA APLICAÇÃO EM HAMBÚRGUER DE CARNE SUÍNA / EVALUATION OF ANTIOXIDANT ACTIVITY OF EXTRACT OF BANANA INFLORESCENCE (Musa cavendishii) AND ITS APPLICATION IN PORK BURGERS

Schmidt, Michele Mantelli 08 May 2014 (has links)
This study aimed to evaluate the functionality of extracts from banana inflorescence (Musa cavendishii) obtained under different extraction conditions, and to analyze the effect in pork burgers. The extracts were obtained by conventional stirring and ultrasound, varying the ethanol concentration (50, 70 and 90%), time (30, 45 and 60 minutes) and temperature (20, 40 and 60 °C). The levels of phenolic compounds, total flavonoids and antioxidant activity were quantified by the DPPH and FRAP methods. The best results were found for extraction using stirring and without the use of ultrasound at 60 ºC for 30 minutes with an ethanol concentration of 50%, which resulted 1690.0 mg EAG/100g of total phenolic compounds and IC50 of 0.31 μg/mL; this extract was then applied in the products. The pork burgers were prepared with different concentrations of the extract of banana inflorescence (0, 1.0 and 2.0%) and sodium erythorbate (0.100, 0.150 and 0.200%), synthetic antioxidant commonly employed in meat products, and stored for 120 days at -12 º C. Microbiological and chemical composition analyses were performed, and every 30 days pH, color and TBARS values (substances reactive to 2-thiobarbituric acid), were evaluated. Also sensory evaluation was performed on days 10 and 60. There was no significant difference (p > 0.05) in the chemical composition of the different burgers developed. All the treatments showed a reduction in pH during storage, which was not affected by the addition of the extract. During storage, all the treatments showed a decrease in the intensity of red coloring, and the burgers without the addition of extract were yellower in color. TBARS values increased linearly during storage; at 120 days all the treatments with added extract of banana inflorescence had significantly (p< 0,005) lower TBARS values than the other treatments. The treatment with 0.200 % of added sodium erythorbate and 2.0% extract was most effective in delaying lipid oxidation. The sensory evaluation showed that the treatments maintained their sensory characteristics, with good tasters acceptability. The banana inflorescence was shown to be a potential source of antioxidant compounds and its extract showed satisfactory results to ensure the shelf life of pork burgers in relation to lipid oxidation, without causing damage to the physicochemical and sensory characteristics of the product. / O presente estudo teve por objetivo avaliar a funcionalidade do extrato da inflorescência de bananeira da espécie Musa cavendishii obtido em diferentes condições de extração, e analisar os efeitos em hambúrgueres de carne suína. Os extratos foram obtidos por agitação convencional e ultrassom, variando a concentração de etanol (50, 70 e 90%), tempo (30, 45 e 60 minutos) e temperatura (20, 40 e 60 ºC). Foram quantificados os teores de compostos fenólicos e flavonoides totais e atividade antioxidante pelos métodos de DPPH e FRAP. Os melhores resultados foram encontrados para a extração sob agitação sem emprego do ultrassom à 60 ºC por 30 minutos com concentração de etanol de 50%, que resultou 1690,0 mg EAG/100g de compostos fenólicos totais e IC50 de 0,31 μg/mL, sendo este extrato posteriormente aplicado no produto. Os hambúrgueres de carne suína foram elaborados com diferentes concentrações do extrato da inflorescência de bananeira (0, 1,0 e 2,0%) e eritorbato de sódio (0,100, 0,150 e 0,200%), antioxidante sintético comumente empregado em produtos cárneos, e armazenados durante 120 dias a -12 ºC. Foi realizada a avaliação microbiológica e composição centesimal e a cada 30 dias foram avaliados pH, cor e índice de TBARS (substâncias reativas ao ácido 2-tiobarbitúrico). Também foi realizada a avaliação sensorial nos dias 10 e 60. Não houve diferença significativa (p> 0,05) na composição centesimal dos diferentes hambúrgueres desenvolvidos. Todos os tratamentos apresentaram uma redução do pH durante o armazenamento, que não foi afetada pela adição de extrato. Durante o armazenamento todos os tratamentos apresentaram uma diminuição na intensidade da coloração vermelha, e os hambúrgueres sem adição de extrato apresentaram maior amarelamento. Os valores de TBARS aumentaram de maneira linear durante o armazenamento e aos 120 dias todos os tratamentos acrescidos de extrato de inflorescência de bananeira apresentaram valores de TBARS significativamente (p< 0,005) inferiores aos demais. O tratamento adicionado de 0,200% de eritorbato de sódio e 2,0% de extrato foi o mais eficiente em retardar a oxidação lipídica. A avaliação sensorial mostrou que os tratamentos mantiveram suas características sensoriais, apresentando boa aceitabilidade pelos provadores. A inflorescência de bananeira se mostrou uma fonte potencial de compostos antioxidantes, e seu extrato apresentou resultados satisfatórios em garantir a vida útil de hambúrgueres de carne suína frente à oxidação lipídica, sem causar prejuízos às características físico-químicas e sensoriais do produto.
143

Fracionamento químico biomonitorado da fração aquosa do extrato etanólico das folhas de Cissampelos sympodialis eichl (milona)

Gomes , Ayala Nara Pereira 25 May 2015 (has links)
Submitted by Cristhiane Guerra (cristhiane.guerra@gmail.com) on 2017-01-27T12:30:48Z No. of bitstreams: 1 arquivototal.pdf: 2494704 bytes, checksum: 2c859301d10b48690a8411328b499ae8 (MD5) / Made available in DSpace on 2017-01-27T12:30:48Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2494704 bytes, checksum: 2c859301d10b48690a8411328b499ae8 (MD5) Previous issue date: 2015-05-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The use of natural products as a therapeutic resource is both ancient and ubiquotous. The species Cissampelos sympodialis (Menispermaceae) is popularly known as milona, jarrinha, abuteira and orelha-de-onça and the aqueous fraction of the ethanol extract of its leaves (FAEEF) has shown promising pharmacological actions. The Menispermaceae family is known by the presence of alkaloids and studies with C. sympodialis have shown that in addition to alkaloids, there is a significant amount of phenolic compounds. Although all pharmacological studies have been conducted with the FAEEF, chemical studies have focused so far in the ethanol extract of leaves and roots. Thus, the aim of this work was to conduct a bioassay-guided fractionation of FAEEF. The aqueous fraction was prepared using ultrasound-assisted extraction and then submitted to solid phase extraction (using reverse phase C18 cartridges). The cartridges were eluted using a gradient of MeOH:H2O yielding four fractions. The content of phenolics and total flavonoids in the fractions was determined using the Folin-Ciocalteau and Aluminium chloride methods respectively. The antioxidant potential of the fractions was determined using the iDPPH and ABTS radical methods.. All fractions were then submitted to immunopharmacological assays to evaluate the toxicity of the fractions to peritoneal murine macrophages (using the MTT viability assay), nitric oxide production (through nitrite quantification), and secretion of cytokines TNF-α and IL-1β using ELISA. The more polar fractions (eluted with 25% and 50% MeOH) had a hogher content of total phenolics (11.51 ± 1.73 and 14.50 ± 5.25 mg GAE/ 100 mg respectively) and also a higher antioxidante activity with the 25% fraction showing a EC50 of 13.54 ± 0.13 μg/mL using the ABTS method and 15.09 ± 0.14 μg/mL using the DPPH method. The fractions studied (at concentrations of 3 and 50 μg/mL did not presente toxicity tom urine macrophages and the 75% fraction was the only one that was able to significantly reduce the levels of NO, TNF-α and IL-1β, and thus is the fraction showing the most promising anti-inflammatory action. This study confirms the anti-inflammatory action of the species, besides demonstrating its antioxidant potential, and points to the role of polar substances, possibly as phenolic compounds responsible for these activities. / A utilização dos produtos naturais para o tratamento das enfermidades é uma prática antiga e comum mundialmente. A espécie Cissampelos sympodialis (Menispermaceae) é conhecida popularmente como milona, jarrinha, abuteira e orelha-de-onça, e sua fração aquosa do extrato etanólico das folhas (FAEEF) apresenta comprovadas ações farmacológicas. A família é caracterizada pela presença de alcaloides, e estudos com a C. sympodialis demonstram que além destes, há uma quantidade relevante de compostos fenólicos. Embora os estudos farmacológicos tenham sido realizados com a FAEEF os estudos químicos se concentram até o momento no extrato etanólico das folhas e raízes. Assim, o objetivo deste trabalho foi realizar um fracionamento químico biomonitorado da FAEEF de C. sympodialis. Uma partição do extrato em água foi feita com o auxílio de ultrassom, para obtenção da FAEEF e esta foi submetida a uma extração em fase sólida (com cartuchos de sílica de fase reversa C-18) com eluição com MeOH:H20 em ordem decrescente de polaridade e forneceu quatro subfrações. O teor de compostos fenólicos e flavonóis totais foi determinado respectivamente pelo método de Folin–Ciocalteau e Cloreto de alumínio e a atividade antioxidante através dos métodos indiretos com os radicais DPPH e ABTS. As subfrações também foram submetidas a ensaios imunofarmacológicos, onde foi avaliada a viabilidade celular em macrófagos peritoneais murinos pelo método de MTT, dosagem de óxido nítrico, através da determinação indireta do nitrito e quantificação das citocinas TNF-α e IL-1β através de ELISA. Observou-se que as frações mais polares (eluídas com 25 % e 50% de metanol) apresentaram uma maior quantidade de compostos fenólicos (11,51 ± 1,73 e 14,50 ± 5,25 mg EAG/ 100 mg respectivamente) além de uma maior atividade antioxidante, chegando a fração de 25 % a uma CE50 de 13,54 ± 0,13 μg/mL pelo método ABTS e 15,09 ± 0,14 μg/mL pelo método DPPH. As subfrações estudadas (3 e 50 μg/mL) não apresentaram toxicidade às células e a fração eluída com 75% de Metanol foi a única que reduziu de forma significativa os níveis de NO, TNF-α e IL-1β, sendo considerada como a fração com melhor ação anti-inflamatória. O presente trabalho confirma a ação anti-inflamatória da espécie, além de demonstrar seu potencial antioxidante, e aponta para o papel de substâncias polares, possivelmente compostos fenólicos como responsáveis por estas atividades.
144

Employment of emerging technologies on orange juice processing added of prebiotic fructo-oligosaccharide and orange juice produced via enzymatic synthesis / Emprego de tecnologias emergentes no processamento de suco de laranja adicionado de fruto-oligossacarÃdeos e suco de laranja produzido via sÃntese enzimÃtica

Francisca Diva Lima Almeida 30 October 2015 (has links)
CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / The aim of this research was to use emerging technologies on the processing of the prebiotic orange juice added of fructo-oligosaccharides (FOS) and in prebiotic orange juice produced by enzymatic synthesis. The first stage of the study was evaluated the effect of atmospheric pressure cold plasma (ACP) and high pressure processing (HPP) on the prebiotic orange juice added 7% commercial FOS. The orange juice was directly and indirectly exposed to plasma discharge at 70 kV with processing times of 15, 30, 45 and 60 seconds. For high pressure processing, the juice containing the same concentration of FOS was treated at 450 bars for 5 minutes. After the treatments, the fructo-oligosaccharides were qualified and quantified by Thin Layer Chromatography (TLC), using densitometer. The organic acids, color analysis and pH values were also evaluated. Both processes did not degrade the FOS. The organic acids and the color of the treated samples were also preserved. On the second stage of the study, the effect of plasma and ozone treatments on prebiotic orange juice produced by enzymatic synthesis were evaluated. The orange juice was directly and indirectly exposed to plasma discharge at 70 kV with processing times of 15, 30, 45 and 60 seconds. For ozone processing, different loads (0.057, 0.128 and 0.230 mg/ O3.mL of juice) were evaluated. After the treatments, the oligosaccharides were quantified by HPLC. The juice pH, color, total phenolic content and total antioxidant activity were also determined. Both processes promoted a partial degradation of the oligosaccharides in the juice. However, the juice maintained an enough amount of oligosaccharides to be classified as a prebiotic food. The other parameters analyzed were preserved. Thus, atmospheric cold plasma and ozone are suitable non-thermal alternatives for prebiotic orange juice treatment. / O objetivo desta pesquisa foi empregar tecnologias emergentes no processamento de suco prebiÃtico de laranja adicionado de fruto-oligossacarÃdeos (FOS) e em suco prebiÃtico de laranja produzido via sÃntese enzimÃtica. A primeira etapa da pesquisa consistiu em avaliar o efeito da aplicaÃÃo das tecnologias de plasma e de alta pressÃo, como mÃtodos de conservaÃÃo, em suco de laranja adicionado de 7% de FOS comercial. O suco foi exposto direta e indiretamente ao processamento por plasma em diferentes tempos: 15 30, 45 e 60 s. Para o processamento com alta pressÃo, o suco foi tratado a uma pressÃo de 450 bars por 5 minutos. ApÃs os tratamentos, a concentraÃÃo de fruto-oligossacarÃdeos foi quantificada pela tÃcnica de cromatografia em camada delgada (CCD), utilizando o equipamento densitÃmetro. DeterminaÃÃes de cor, pH e concentraÃÃo de Ãcidos orgÃnicos foram tambÃm realizadas. Ambos os processos nÃo degradaram os FOS presentes no suco. Ãcidos orgÃnicos e a cor das amostras tratadas tambÃm foram preservados. Na segunda etapa da pesquisa, foi avaliado o efeito da aplicaÃÃo dos tratamentos de plasma e ozÃnio em suco prebiÃtico de laranja produzido via sÃntese enzimÃtica. O suco foi exposto direta e indiretamente ao processamento por plasma, a 70 kV, em diferentes tempos: 15 30, 45 e 60 s. Para o processamento com ozÃnio, diferentes cargas (0,057, 0,128 e 0,230 mg/ O3.mL de suco) foram avaliadas. ApÃs os tratamentos, a concentraÃÃo de oligossacarÃdeos foi determinada pela tÃcnica de HPLC. Os valores de pH, cor, conteÃdo de fenÃlicos totais e atividade antioxidante total tambÃm foram determinados. Ambos os processos promoveram uma degradaÃÃo parcial dos oligossacarÃdeos no suco. Contudo, o suco manteve uma quantidade suficiente de oligossacarÃdeos para ser classificado como um alimento prebiÃtico. Os demais parÃmetros analisados foram preservados. Diante disso, sugere-se que os tratamentos de plasma, alta pressÃo e ozÃnio sÃo alternativas nÃo tÃrmicas adequadas para o tratamento de suco de laranja prebiÃtico.
145

Potencial antioxidante de extratos de resíduos de acerolas (Malpighia Emarginata D.C.) em diferentes sistemas modelos e na estabilidade oxidativa do óleo de soja

CAETANO, Ana Carla da Silva 26 February 2009 (has links)
Submitted by (edna.saturno@ufrpe.br) on 2016-07-26T11:49:42Z No. of bitstreams: 1 Ana Carla da Silva Caetano.pdf: 782522 bytes, checksum: f2c222ad97acdbff5efc95970a75c528 (MD5) / Made available in DSpace on 2016-07-26T11:49:42Z (GMT). No. of bitstreams: 1 Ana Carla da Silva Caetano.pdf: 782522 bytes, checksum: f2c222ad97acdbff5efc95970a75c528 (MD5) Previous issue date: 2009-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The observation that the plants have biologically active substances, mainly polyphenols, that provide benefits to health, has driven studies on the antioxidant property. Thus, considering that the agri-industrial waste from acerola also contains phenolic compounds, this study was carried out to determine the procedure for extraction of polyphenols and the antioxidant activity of their extracts. Hyidroacetone, hydroethanolic, hydromethanolic and aqueous extracts, obtained by sequential extraction procedure, combining three extraction cycles (20 minutes each one) and two temperatures (25 ± 2ºC and 50 ± 2ºC), were submitted to the determination of total phenolic and screened for their free DPPH• (1,1-diphenyl-2-picrilhidrazil) and ABTS•+ (2,2 '-azino-bis-(3-etilbenzotiazolina 6-sulfonic acid) scavenging activity and their effect on the linoleic acid peroxidation by the ferric thiocyanate method.Soybean oil with the addition of the extracts (200ppm) were submitted to anaccelerated storage test in an oven at 60°C for 28 days, where sample were taken at time intervals and analyzed for peroxide value and conjugated dienes. The extracts showed high content of total polyphenols; however, the hydroacetone extract exhibited the highest total phenolic content (5,954.2 μg catechin equivalent. mL-1). Hydroethanolic and hydromethanolic extracts exhibited good DPPH• scavenging activity (low value of EC50 and TEC50, high value of EA), good ABTS•+ scavenging capacity (1.445,1 e 1.145,5μMol TEAC/g, respectively), high percentage of inhibition of peroxidation of linoleic acid (96.12% and 91.84%, respectively). These extracts showed the ability to retard the formation of peroxides and conjugated dienes in soybean oil. The procedure involves aqueous-organic solvents, three cycles of extraction and temperature of 25°C is effective in the extraction of phenolic compounds. Although, the hydroacetone extract has exhibited the highest total phenolic content, the antioxidant action of this extract was less than shown by hydroethanolic and hydromethanolic extracts that, under the experimental conditions, exhibited the best antioxidant activity, both in model system and in soybean oil. Therefore, the agri-industrial waste from acerola can be considered as a source of natural antioxidants and can be useful in food applications in replace or in association with synthetic antioxidants. / A constatação de que os vegetais possuem substâncias biologicamente ativas, principalmente polifenóis, que trazem benefícios à saúde, tem impulsionado estudos sobre sua propriedade antioxidante. Assim, considerando que os resíduos gerados pela agroindústria de polpa de frutas, ainda, contém significante teores de compostos fenólicos, este trabalho teve como objetivo determinar o solvente e a temperatura mais eficiente para a extração destes fitoquímicos a partir de resíduos de acerola e avaliar o potencial antioxidante de seus extratos. Desta forma, extratos hidroacetônico,hidroetanólico, hidrometanólico e aquoso, obtidos por processo de extração seqüencial, em duas temperaturas (25 ± 2ºC e 50 ± 2ºC), foram avaliados quanto ao teor de compostos fenólicos, e a sua ação antioxidante em sistemas modelos, por meio do método da capacidade de seqüestro do radical DPPH• (1,1-difenil-2-picrilhidrazil), do radical ABTS•+ (2,2’-azino-bis- (3-etilbenzotiazolina-6-ácido sulfônico) e da inibição da peroxidação do ácido linoléico pelo método Tiocianato Férrico, bem como, em óleo de soja por meio do teste acelerado em estufa. Quanto ao teor de fenólicos, independente da temperatura usada no processo de extração, destacou-se o hidroacetônico por ter apresentado o mais elevado teor (5.954,2 μg em equivalente de catequina. mL-1). Os extratos hidroetanólicos e hidrometanólico exibiram forte capacidade de seqüestro do radical DPPH• (baixo valor de EC50 e de TEC50, alto valor de EA), elevada capacidade de seqüestro do radical ABTS•+ (1.445,1 e 1.145,5μMol TEAC/g, respectivamente), e forte proteção do ácido linoléico contra a peroxidação (96,12% e 91,84% respectivamente). Estes extratos, também, apresentaram boa capacidade em retardar formação de peróxidos e de dienos conjugados em óleo de soja. Os resultados obtidos permitem evidenciar que o procedimento envolvendo solventes orgânico-aquosos, três ciclos de extração e a temperatura de 25°C se mostrou eficaz na extração de fenólicos totais. O solvente hidroacetônico embora tenha propiciadoa extração de uma maior quantidade de fenólicos totais, a ação antioxidante deste extrato foi inferior a exibida pelos extratos hidroetanólico e hidrometanólico que, nas condições experimentais, exibiram a melhor ação antioxidante, tanto em sistema modelo como no teste acelerado em estufa. Desta forma, o resíduo agroindustrial de acerola apresenta-se como fonte de antioxidante natural, permitindo vislumbrar a sua utilização em alimentos em substituição ou em associação aos antioxidantes sintéticos.
146

Compostos bioativos, atividade antioxidante e antimicrobiana na casca de cebola roxa (Allium cepa L.) submetidos a diferentes métodos de extração / Bioactive compounds, antioxidant activity and antimicrobial activity in red onion skin (Allium cepa L.) submitted to different extraction methods

Viera, Vanessa Bordin 11 July 2016 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / This study evaluated the use of different methods (focused microwave, ultrasound and conventional agitation) and varying parameters (concentration of solvent, time, temperature, power and pulse) in the extraction of bioactive compounds from red onion skin to obtain an extract with a high content of phenolic compounds, as well as high antioxidant capacity and antibacterial and antifungal activity. The total phenolic content, total flavonoids, anthocyanins, antibacterial capacity and antifungal activity, as well as the in vitro antioxidant capacity, of the extracts were determined by four different methods. The extracts obtained by conventional extraction using agitation had a higher content of total phenolics, flavonoids and total anthocyanins when they were extracted using a higher solvent concentration (80%). With regard to time, it was found that the lowest extraction time of (30 minutes) favored the extraction of compounds with higher antioxidant activity by the DPPH methods and low IC50, and the longest time of (240 minutes) obtained extracts with the highest antioxidant activities using the β-carotene and ABTS methods. The results for focused microwave extraction generally indicated that the highest solvent concentrations (60 to 80%) were more effective in extracting bioactive compounds and, consequently, to obtain extracts with higher antioxidant capacity. Regarding the extraction temperature, it was found that the extracts with highest content of flavonoids and phenolic compounds were obtained at 70 °C. However, the content of total anthocyanins and the DPPH and FRAP methods antioxidant activity of the extracts were not influenced by the extraction temperature. The use of ultrasound to extract bioactive compounds from red onion skin indicated that the extraction of total flavonoids, total anthocyanins and antioxidant activity (FRAP and β-carotene) were efficient at 130 W, with pulsed mode and 60% solvent concentration. The DPPH methods antioxidant activity was only successful at 60% solvent concentration, and the ABTS methods values were highest with 80% solvent, pulsed mode and 130 W power. For the highest inhibiting power of 50% of the DPPH radical (IC50), the best conditions were 130 W, pulsed mode and 40% solvent. The extracts that were obtained through different extraction methods showed no antifungal or antibacterial activity in relation to the different tested microorganisms. However, it can be inferred that red onion skin is a good source of bioactive compounds with antioxidant action and that it can be used as a potential ingredient in the preparation of food products to inhibit lipid oxidation, as well as contributing to reducing agro-industrial waste. / Este trabalho teve como objetivo avaliar o emprego de diferentes métodos (micro-ondas focalizada, ultrassom e convencional por agitação) variando parâmetros como concentração de solvente, tempo, temperatura, potência e pulsos na extração de compostos bioativos da casca de cebola roxa a fim de obter um extrato com alto teor de fenólicos totais, elevada capacidade antioxidante, atividade antibacteriana e antifúngica. Foi determinado o teor de fenólicos totais, flavonoides totais e antocianinas totais dos extratos obtidos, além da capacidade antioxidante in vitro por quatro métodos distintos e atividade antibacteriana. Os extratos obtidos através da extração convencional por agitação apresentaram maior teor de fenólicos totais, flavonoides e antocianinas totais quando extraídos com concentração maior do solvente (80%). Com relação ao tempo, verificou-se que o menor tempo de extração, (30 minutos) favoreceu a extração de compostos com maior atividade antioxidante pelo método DPPH e menor concentração inibinitória (IC50) e com o maior tempo (240 minutos) obteve-se extratos com maiores atividades antioxidantes pelo método β-caroteno e ABTS. Os resultados encontrados para a extração através das micro-ondas focalizadas, de modo geral, indicaram que as maiores concentrações de solvente (60 e 80%) foram mais eficazes na extração de compostos bioativos e consequentemente para obtenção de extratos com maior capacidade antioxidante. Em relação à temperatura de extração, verificou-se que os extratos com maiores teores de compostos fenólicos totais e flavonoides foram obtidos a 70°C. No entanto, o teor de antocianinas totais, atividades antioxidante pelos métodos DPPH e FRAP dos extratos não foram influenciadas pela temperatura de extração. A utilização do ultrassom na extração de compostos bioativos da casca de cebola roxa apontou que a extração de flavonoides totais, antocianinas totais, atividade antioxidante (FRAP e β-caroteno) foram eficientes em potência 130 W, modo pulsado e solvente 60%. A atividade antioxidante pelo método DPPH sofreu influência somente do solvente 60% e os valores pelo método ABTS foram maiores com solvente 80%, modo pulsado e 130 W. Para maior poder de inibição de 50% do radical DPPH (IC50) as condições necessárias são 130 W, modo pulsado e 40% de solvente. Os extratos obtidos através das diferentes metodologias de extração não apresentaram atividade antibacteriana para os diferentes micro-organismos testados. Contudo, pode-se inferir que a casca de cebola roxa é boa fonte de compostos bioativos com ação antioxidante, podendo ser ingrediente em potencial na elaboração de produtos alimentícios inibindo a oxidação lipídica, além de contribuir na redução de resíduos agro-industriais.
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Recherche des déterminants biochimiques de la durabilité naturelle du bois de teck (Tectona grandis) / Search for biohemical attributes of natural durability of teak (Tectona grandis)

Niamké, Florence Bobolé 22 July 2010 (has links)
La durabilité du bois de teck (Tectona grandis) est une propriété pouvant varier selon le génotype et les facteurs environnementaux. Chez le teck, le degré d'implication des extractibles dans la durabilité naturelle est controversé. A partir d'une approche quantitative incluant les aspects biologiques et technologiques conduites sur des échantillons de bois séchés à l'air ambiant, cette thèse s'est attachée à rechercher les déterminants chimiques de nature phénolique de la durabilité naturelle. Nous avons tout d'abord mis en évidence que les formes osidiques stockées dans l'aubier sont transformées en extractibles de nature quinonique. Nous avons ainsi caractérisé deux composés, l'un dans l'aubier le forsythoside B, un trisaccharide de l'acide caféique et l'autre dans le duramen, le 4',5'-dihydroxy-épiisocatalponol qui ont été identifiés pour la première fois dans le bois de teck. Nous avons mis en évidence que le second composé inhibe la croissance de Trametes versicolor indiquant son rôle directe dans la propriété de durabilité naturelle du bois de teck. Ainsi, les composés du métabolisme des naphthoquinones sont les plus impliqués dans la durabilité naturelle du bois de teck à l'égard de Trametes versicolor et de Poria placenta. Les mécanismes de transformation des sucres pourraient indiquer le niveau de durabilité naturelle des espèces. Ces nouvelles données contribueront aussi à l'amélioration de la qualité du bois qui par ailleurs assure la pérennité des arbres. / Teak (Tectona grandis) wood natural durability is a property which can vary with genotype and environmental factors. The implication of quinonic extractives in the property of natural durability is controversial. Using a quantitative approach including biological and technological conducted on air-dried wood samples, this thesis aimed to search chemical attributes of natural durability. We first demonstrated that osidic forms stored in the sapwood were transformed into quinone derivative. We have characterized two compounds the forsythoside B, a trisaccharide of cafeic acid in the sapwood and in the heartwood, the 4',5'-dihydroxy(epi)isocatalponol that were identified for the first time in teakwood. The latter compound exhibited strong fungicidal activity against Trametes versicolor indicating that its direct implication in decay resistance of teak wood. We have shown that compounds from naphthoquinones metabolism were involved in decay resistance of teak wood against Trametes versicolor and Poria placenta. The mechanisms of sugars transformation may indicate the natural durability level of sustainable species. There these new data will contribute to improve the wood quality that ensures the perennity of trees.
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Uticaj tehnoloških faktora u proizvodnji crvenih vina na sadržaj i stabilnost katehina i njihovih oligomera / Influence of technological factors in the production of red wine on the content and stability of catechins and their oligomers

Puškaš Vladimir 13 July 2010 (has links)
<p>Fenolna jedinjenja su zaslužna za<br />osnovna senzorna svojstva srvenih vina,<br />pre svega boju i trpkost. Superoksid (O2<sup>&bull;-</sup>) i hidroksil radikali (<sup>&bull;</sup>OH) izazivaju<br />ozbiljna o&scaron;tećenja tkiva degradaciju<br />proteina, nerastvornih lipida, ugljenih<br />hidrata i nukleinskih kiselina. U ovom<br />radu ispitan je uticaj tehničkotehnolo&scaron;kih<br />uslova proizvodnje i odnosa<br />čvrste i tečne faze u kljuku, na boju vina,<br />sadržaj fenolnih jedinjenja i<br />antioksidativni potencijal. Izmena odnosa<br />čvrste i tečne faze u kljuku vr&scaron;ena je<br />vraćanjem jednog dela ili celokupne<br />količine &scaron;epurine i povećavanjem<br />sadržaja semenki dodavanjem 100, 200 i<br />300 % semenki u odnosu na prirodni<br />sadržaj. Stabilnost boje, sadržaja fenolnih<br />jedinjenja i antioksidativnog potencijala<br />ispitivana je pre i nakon tretmana vina sa<br />dva organska i dva neorganska sredstva<br />za bistrenje i stabilizaciju. Utvrđeno je da<br />povećanje sadržaja semenki u kljuku<br />pojačava antioksidatovno delovanje vina.<br />U vinu Cabernet sauvignon utvrđena je<br />vi&scaron;a vrednost antiradikalske aktivnosti<br />prema DPPH radikalima (AA<sub>(DPPH&bull;)</sub>),<br />koja se nije promenila pod delovanjem<br />sredstava za bistrenje i stabilizaciju vina.<br />Vino Merlot ispoljilo je veću<br />antiradikalsku aktivnost na hidroksil<br />radikale (AA<sub>(&bull;OH)</sub>).</p> / <p>Phenolic compounds are responsible for<br />basic sensory properties of red wines,<br />primarily color and astrigency.<br />Superoxide (O2<sup>&bull;-</sup>) and hydroxyl radicals<br />(<sup>&bull;</sup>OH) causes serious damage to the tissue<br />degradation of proteins, ansolubility<br />lipids, carbohydrates and nucleic acids.<br />The paper examined the impact of<br />technical and technological conditions of<br />production and relations of liquid and<br />solid phases in pomase on the color of<br />wine, phenolic compounds content and<br />antioxidant potential. Changing relations<br />between solid and liquid phases in<br />pomase carried out the return of a part, or<br />the whole amount of stem and increasing<br />seeds content adding +100, +200 and<br />+300 % of seeds. Color stability,<br />phenolic compounds content and<br />antioxidative potential was examined<br />before and after treatment of wine with<br />two organic and two inorganic agens for<br />fining and stabilization. It was found that<br />increasing the seeds content in pomase<br />increases antioxidative action of wines.<br />In the wine Cabernet Sauvignon was<br />found higher value antiradical activity to<br />DPPH radicals (AA<sub>(DPPH&bull;)</sub>), which are not<br />changed under the fining action and<br />stabilization of wine. Merlot wine<br />exhibited a higher antioxidant potential<br />of the hydroxyl radicals (AA<sub>(&bull;OH)</sub>).</p>
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Chemical composition of indiginous of watermelon (Citrullus lanatus Tthunb) Matsum. and Nakai)) landrace seeds from the Sekhukhune and Capricorn District in the Limpopo Province

Mogotlane, Emmanuel Alpheus January 2015 (has links)
Thesis (M. Sc. (Botany)) -- University of Limpopo, 2015 / The aim of this study was to investigate the chemical composition of indigenous watermelon landraces (Citrullus lanatus) seeds grown in two districts in the Limpopo Province. Watermelon seeds are the most undermined oilseeds. The seeds have nutritional values that compare favourably with those of soybean, sunflower and ground nuts. Many cucurbit seeds such as watermelon seeds are rich in protein and oil, although none of these products have been used on an industrial scale. Nine indigenous watermelon landraces seeds (four from the Sekhukhune district and five from the Capricorn district) were examined. The landrace 06CDGM was found to have the highest mass per one hundred seeds (10.95 g per 100 seeds) with 07CDGM having the lowest mass (8.05 g per 100 seeds). The landrace 10CDGM was found to have the highest oil (41.5%), protein (20.39%) and fibre content (23.98%) with 01SDPW having the lowest oil yield (30.00%), 02SDPW was found to have the highest saponification value (184.57 mg KOH/g oil) and 09CDGM had the highest iodine value (138.575 g I2/100 g oil). The landrace 01SDPW had the highest total sugar content. All landraces were found to have the essential amino acid leucine. Antioxidant activity (66.95%) and total flavonoids (0.295 mg/g as catechin equivalents) were found to be highest in the 09CDGM landrace, and total phenolic content (0.91 mg/g gallic acid equivalent) was found to be highest in 05SDPW. The landrace 06CDGM was found to have the highest copper content (0.088 mg/g); 02SDPW was found to have the highest iron content (0.194 mg/g); 10CDGM had the highest zinc (0.312 mg/g) and sulphate content (0.129 mg/g); while both 10CDGM and 03SDPW had the highest content of calcium (9.13 mg/g). The landraces were found to differ slightly in the content and quality of components tested. Each of the landraces was found to have some qualities that render them superior to the other landraces. The qualities and content of the landraces compare favourably with those of commercial oil seeds such as the sunflower and soybean. Overall, the landraces from the Capricorn district were observed to have superior qualities than those from the Sekhukhune district. The findings indicated that the landraces from Capricorn district had more mean oil, mean protein, crude fibre content, total phenolics and total flavonoid content than those from the Sekhukhune district. The landraces from Sekhukhune district had high carbohydrate, ash content and high content of the minerals iron and calcium. The landrace 10CDGM was found to have overall high vi values with regard to most analyses, thus making the landrace superior to the others. The results indicate that landraces from both districts have complementary qualities to each other; however the landraces from the Capricorn are more superior in most aspects. The watermelon seeds have the potential to be used as a cost-effective and easily accessible source of nutrients and oil to meet nutritional challenges in developing countries. KEY CONCEPTS Citrullus lanatus; Landrace; Sekhukhune district; Capricorn district; Indigenous watermelon; Oil seeds; Essential amino acids; Antioxidant activity; Total phenolics; Total flavonoids; Mineral content; Total sugars; Crude fibre; Oil content; Saponification value; Iodine value.
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Obsah antioxidačních látek ve vybraných druzích ovocných a bylinných čajů / Antioxidative substances in selected fruit and herbal teas

Tomková, Martina January 2008 (has links)
This diploma project deals with antioxidant and antimutagenic properties of selected herbal and fruit teas commonly used in Czech population. Influence of different tea packaging (bag teas and loose leaf teas) on bioactive compound content was compared. Further, effect of long-term storage in common household conditions was studied. Antioxidant properties of teas were characterized using some group parameters - total antioxidant activity ("Randox Total Antioxidant Status Kit"), total phenolics and total flavonoids - as well as some individual representatives of low molecular weight antioxidants. Higher antixidant content was found in herbal teas than in fruit teas. Comparing bag teas with loose leaf teas higher antioxidant activity was shown in loose leaf teas. Individual antioxidants were analyzed using HPLC method with spectrophotometric detection and verified by on-line LC/MS. IN all tea samples catechins - catechin, epicatechin, epicatechin gallate and other flavonoids - rutin, morin, quercetin, kaempferol, myricetin and luteolin were determined. In most of teas high level of catechin and rutin was detected. The highest level of flavonoids was determined in herbal poured teas. Ascorbic acid content was also determined by HPLC method. Higher vitamine C level was found in most of fruit teas and in rose hip tea. Antimutagenicity of tea extracts was tested by in vitro test using Saccharomyces cerevisiae D7 yeast. High antimutagenic activity showed mainly nettle tea, tutsan tea and most of fruit teas. During long-term storage (1 year, 20°C, darkness) a significant decrease of all analyzed antioxidant parameters was followed. Higher lost of antioxidants was found in fruit teas when compared with the herbal ones.

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