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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.
411

Otimização de obtenção de um extrato aquoso de milho roxo (Zea mays L.) rico em antocianinas e perfil de degradação / Optimization of obtaining an aqueous extract of purple corn (Zea mays L.) rich in anthocyanins and degradation profile.

Stanquevis, Regina 23 October 2013 (has links)
O milho roxo (Zea mays L.), cultura tradicional da região Andina, é conhecido por apresentar alto conteúdo de antocianinas. As antocianinas apresentam diversas propriedades biológicas demonstradas em estudos in vitro e in vivo; entre elas, alto poder antioxidante, atividade anti-inflamatória e quimiopreventiva; entretanto são compostos que se degradam facilmente. Assim, o objetivo deste trabalho foi obter um extrato aquoso rico em antocianinas, a partir do milho roxo, e estudar a estabilidade química das antocianinas presentes frente ao pH e temperatura. Inicialmente o milho roxo comercial, utilizado como matéria prima, foi caracterizado por CLAE-DAD-ESI-MS/MS por apresentar cinco derivados de cianidina, três derivados de peonidina, três derivados de pelargonidina, dois derivados de quercetina e dois derivados de isoramnetina, com presença de acilação nas antocianinas. O teor de antocianinas totais foi de 4,61 mg/g, sendo 3,16 mg cianidina 3-glucosídeo eq./g, 0,63 mg pelargonidina/g e 0,81 mg peonidina/g, além de 1,19 mg quercetina/g e 1,06 mg ácido protocatecúico/g. Para a otimização da obtenção do extrato aquoso e estudo de degradação térmica das antocianinas, foi realizado o delineamento experimental para análise de superfície de resposta. Um delineamento fatorial 33 (15 ensaios com 3 repetições do ponto central) foi aplicado para avaliar o efeito de três fatores,em três níveis, para a obtenção do extrato aquoso. Os fatores incluídos foram temperatura (70ºC, 95ºC e 120ºC), tempo de extração (10, 50 e 90 min) e pH da solução (3,0, 5,0 e 7,0). Foram avaliadas três respostas: teor de antocianinas monoméricas, teor de ácido protocatecúico e capacidade antioxidante, os quais foram encontrados: (a) para antocianinas monoméricas, a melhor condição de extração foi obtida no menor valor de pH (3,0) e tempo (10 min), com temperatura intermediária (95ºC); (b) para o ácido protocatecúico, a melhor concentração foi obtida em condições de maior valor de pH (7,0) e tempo (90 min), ou seja, oposto à condição anterior, com temperatura intermediária (95ºC); (c) para a capacidade antioxidante, a melhor condição foi obtida quando preparou-se o extrato no ponto central dos níveis (pH 5,0), tempo 50 min e temperatura (95ºC). Os modelos referentes às respostas de teor antocianinas monoméricas e teor de ácido protocatecúico foram validados, apresentando valores 40,30 mg cianidina 3-glucosídeo eq./L e 0,57 mg/100 mL, respectivamente. Os flavonoides identificados no extrato aquoso de milho roxo foram semelhantes à composição do milho roxo comercial, entretanto, com considerável degradação de derivados de cianidina e peonidina, principalmente aciladas, a ácido protocatecúico e ácido vanílico, respectivamente. Assim, os resultados sugerem que um extrato aquoso de milho roxo rico em antocianinas é obtido em condições de extração de menor valor de pH, onde as antocianinas estão em sua forma mais estável. Porém, quando esse extrato aquoso é exposto a maiores valores de pH e/ou alta temperatura, pode ocorrer degradação das antocianinas presentes aos seus respectivos ácidos fenólicos. / Purple corn (Zea mays L.), traditional culture of the Andean region, is known for its high content of anthocyanins. Anthocyanins exhibit several biological properties demonstrated in in vitro and in vivo, among them, high antioxidant, anti-inflammatory and chemopreventive activities, however they are unstable. The objective of this study was to obtain an aqueous extract rich in anthocyanins from purple corn and study the chemical stability of anthocyanins. Initially commercial purple corn, used as raw material, was characterized by HPLC-DAD-ESI-MS/MS by presenting five cyanidin derivatives, three peonidin derivatives, three pelargonidin derivatives, two quercetin derivatives and two isorhamnetin derivatives, with acylation in some anthocyanins. The anthocyanin content was 4.61 mg/g, which 3.16 mg cyanidin 3-glucoside eq./g, 0.63 mg pelargonidin/g and 0.81 mg peonidin/g, in addition 1.19 mg quercetin/g and 1.06 mg protocatechuic acid/g. To optimize the aqueous extract and study thermal degradation of anthocyanins, an experimental design was performed for response surface analysis. A 33 factorial design (15 trials with 3 replicates of the center point) was applied to evaluate the effect of three factors at three levels, to obtain the aqueous extract. The factors included were temperature (70°C, 95°C and 120°C), extraction times (10, 50 and 90 min) and pH solution (3.0, 5.0 and 7.0). Three variables were evaluated: monomeric anthocyanin content, protocatechuic acid content and antioxidant capacity, which were found: (a) for monomeric anthocyanins content, the best extraction condition was obtained at lower pH (3.0) and time (10 min), and intermediate temperature (95°C); (b) for protocatechuic acid content, the optimal concentration was obtained under higher pH (7.0) and time (90 min), opposite to the previous condition, with intermediate temperature (95°C); (c) for antioxidante capacity, the best condition was obtained when the extract was prepared at the midpoint of levels pH 5.0, time 50 min and 95°C. The mathematicals models concerting monomeric anthocyanins content and protocatechuic acid content has been validated, with values of 40.30 mg cyanidin 3-glucoside eq./L and 0.57 mg/100 mL, respectively. The flavonoids profile in the aqueous extract of purple corn were similar to the composition of commercial purple corn, however, with considerable degradation of cyanidin and peonidin derivatives, mainly acylated form, to protocatechuic acid and vanillic acid, respectively. Therefore, the results suggests that an aqueous extract of purple corn rich in anthocyanins can be obtained at lower pH, where the anthocyanins are in their most stable form. However, when the aqueous extract is exposed to higher pH and/or high temperature, anthocyanins degradation may occur to their respective phenolic acids.
412

Efeito de extratos orgânicos de variedades de cebola sobre o quorum sensing bacteriano / Effect of organic extracts of onion varieties on bacterial quorum sensing

Quecan, Beatriz Ximena Valencia 13 June 2018 (has links)
Muitos genes bacterianos são regulados pelo mecanismo de comunicação denominado quorum sensing (QS). Neste sistema, moléculas sinalizadoras ativam um comportamento de grupo, conforme a densidade celular, permitindo o controle da expressão gênica. Estudos sugerem o potencial de compostos extraídos de plantas sobre o QS, a exemplo da quercetina, um flavonol presente em concentrações elevadas em algumas frutas e hortaliças. Este composto é o flavonoide majoritário presente em cebola (Allium cepa), mas não existem estudos que mostrem a atividade anti-QS de extratos orgânicos deste vegetal. Este trabalho avaliou o potencial antimicrobiano e anti-QS de extratos orgânicos de cebola branca e cebola roxa, assim como de alguns de seus componentes majoritários identificados, em fenótipos regulados pelo QS como a produção de violaceína em Chrormobacterium violaceum ATCC 12472, a motilidade tipo swarming e a formação de biofilmes em Pseudomonas aeruginosa PAO1 e Serratia marcescens MG1. Extratos de cebola branca e roxa foram obtidos por extração em fase sólida utilizando coluna de poliamida e seus compostos identificados e quantificados pelas técnicas de Cromatografia líquida- ionização por elétron spray-espectrometria de massas e cromatografia líquida de alta eficiência acoplada a detector de arranjo de diodo. A atividade antimicrobiana foi avaliada pelas curvas de multiplicação de cada micro-organismo. O efeito dos compostos quercetina aglicona (inibidor do QS já relatado na literatura e encontrado no extrato de cebola roxa) e quercetina-3-β-D-glicosideo (um dos compostos majoritários encontrados em ambos extratos) sobre os micro-organismos utilizados neste estudo foi também avaliado. Foram obtidos três extratos: cebola branca em metanol (CB-MeOH), cebola branca em metanol amônia (CBMeOH/ NH4) e cebola roxa em metanol (CR-MeOH). Os compostos quercetina 3,4\'- diglicosídeio, quercetina-4-glicosídeo, quercetina-3-β-D-glicosideo e quercetina aglicona foram os predominantes nos extratos das duas variedades de cebola. Cianidina-3-O-glicosideo também foi identificada no extrato de cebola roxa. A concentração inibitória mínima (MIC) dos extratos foi igual ou superior a 125 µg/ml (p/v) de extrato seco. Não foi observada inibição significativa da produção de violaceína em C. violaceum pelos extratos orgânicos de cebola e nem pela quercetina-3-β-D-glicosideo, nas concentrações sub-inibitórias avaliadas. No entanto, a quercetina aglicona inibiu significativamente a produção de violaceína em todas as concentrações. A glicosilação da quercetina pode ter afetado sua atividade sobre a inibição da produção de violaceina, já que estudos mostram menor atividade biológica deste composto quando glicosilado. Para a motilidade tipo swarming em P. aeruginosa PAO1 houve inibição significativa pelo extrato de cebola roxa, em todas as concentrações estudadas. Os demais extratos não apresentaram inibição contra este micro-organismo. Para S. marcescens MG1, foi observada inibição da motilidade swarming somente na concentração de 125 µg/ml de CBMeOH/ NH4. As análises de comparação entre os dois tipos de quercetina revelaram que, embora para as duas bactérias testadas os dois compostos apresentaram atividade inibitória sobre a motilidade tipo swarming, a quercetina-3-β-D-glicosideo foi menos eficiente que a quercetina aglicona na concentração de 125 µg/ml. A formação de biofilmes não foi influenciada pelos extratos e, inesperadamente, não se detectou inibição da formação de biofilmes por ambos tipos de quercetina avaliados. De forma geral, os extratos orgânicos de cebola mostraram pouco efeito sobre os fenótipos controlados pelo quorum sensing e a glicosilação da quercetina provavelmente explica a baixa atividade antimicrobiana e anti-QS dos extratos. / Many bacterial genes are regulated by a communication mechanism called quorum sensing (QS). In this system, signaling molecules activate a group behavior according to cell density, allowing the control of gene expression. Studies suggest the inhibitory potential of compounds extracted from plants on the QS system, like quercetin, a flavonol present in high concentrations in some fruits and vegetables. This compound is the main flavonoid found in onion (Allium cepa); however, there are no studies showing the anti-QS activity of organic extracts of this plant. The objective of this work was to evaluate the antimicrobial and anti-QS potential of organic extracts of white and red onions, and their major components studied in QS-regulated phenotypes such as violacein production in Chromobacterium violaceum, swarming motility and biofilm formation in Pseudomonas aeruginosa PAO1 and Serratia marcescens MG1.White and red onion extracts were obtained by solid phase extraction using a polyamide column and its compounds were identified and quantified by Liquid Chromatography - Electron Spray-Mass Spectrometry and high performance liquid chromatography coupled to diode array detector. O The antimicrobial activity was evaluated by growth curves of each microorganism. The effect of non-glycosylated quercetin (a QS inhibitor already reported in the literature and found in red onion extract) and quercetin-3-β-D-glycoside (one of the major compounds found in both extracts) on the microorganisms used in this study was also evaluated. Three extracts were obtained: white onion in methanol (CB-MeOH), white onion in methanol ammonia (CB-MeOH / NH4) and red onion in methanol (CR-MeOH). Our results showed that quercetin 3,4\'- diglycoside, quercetin-4-glycoside, quercetin-3-β-D-glycoside and non-glycosylated quercetin were predominant in the extracts of the two onion varieties. Cyanidin-3-O-glycoside has also been identified in the purple onion extract. The minimum inhibitory concentration (MIC) of extracts was equal or greater than 125 µg / ml (w / v) of dry extract. There was no significant inhibition of violacein production in C. violaceum by organic onion extracts or by quercetin-3-β- D-glycoside at the sub-inhibitory concentrations evaluated. However, non-glycosylated quercetin showed a significant inhibition of violacein production in all tested concentrations. The glycosylation of Quercetin could have altered its inhibition activity towards violacein production, and in fact, some studies have shown less biological activity of some phenolic compounds when they have been glycosylated. For swarming motility in P. aeruginosa PAO1 there was significant inhibition by red onion extract, in all studied concentrations. The other extracts did not present inhibition against this microorganism. For S. marcescens MG1, inhibition of swarming motility was observed only at the concentration of 125 µg / ml of CB-MeOH / NH4. Comparative analyses between the two types of quercetin showed that, although for the two bacteria tested the two compounds showed inhibitory activity on swarming motility, quercetin-3-β-D-glycoside was less efficient than non-glycosylated quercetin in the concentration of 125 µg / ml. Biofilm formation was not influenced by the extracts and unexpectedly, both types of quercetin evaluated did not show inhibition towards biofilm formation. In general, organic onion extracts showed little effect on quorum sensing controlled phenotypes and glycosylation of quercetin probably explains the low antimicrobial and anti-QS activity of the extracts.
413

Propostas metodologicas para componentes em matrizes alimenticias, alimentos enriquecidos e contaminantes utilizando eletroforese capilar acoplada a espectrometria de massas e detecção UV/VIS / Methodological proposals for food matrix components, enriched foods and contaminants using capillary electrophoresis coupled to mass spectrometry and UV/Vis detection

Fukuji, Tatiana Shizue 20 December 2011 (has links)
O trabalho envolve o desenvolvimento de métodos para análise de alimentos visando a determinação de ácidos fenólicos em frutas, ácido fólico em farinhas enriquecidas e corantes Sudan em produtos de pimenta utilizando eletroforese capilar nos modos de detecção UV e MS. A separação de dez ácidos fenólicos (ácidos clorogênico, siríngico, p-cumárico, benzóico, p-hidroxibenzóico, ferúlico, vanílico, cafeico, gálico e protocatecuico) foi obtida por eletroforese capilar de zona (CZE). Um eletrólito composto de 50 mmol L-1 de tetraborato e 7,5% metanol (v/v) permitiu a separação em linha de base dos dez ácidos fenólicos em menos de 15 minutos. A fim de promover o \"clean-up\", pré-concentração e liberação dos ácidos fenólicos esterificados, um procedimento de extração líquido-líquido seguido pela hidrólise alcalina foi realizado. O método foi validado obtendo-se limites de detecção de 1,63-3,80 &#181g mL-1 e limites de quantificação de 4,95-11,39 &#181g mL-1. O método otimizado foi aplicado para análise de frutas como a abiu-roxo (Chrysophyllum caimito), amora silvestre (Morus nigra L.) e tomate de árvore (Cyphomandra betacea), identificando os ácidos fenólicos na fração livre e hidrolisada. Este trabalho também otimizou o processo de extração e caracterizou a composição de ácidos fenólicos na forma livre e hidrolisada presentes no açaí Juçara (Euterpe precatória Mart.), açaí do Pará (Euterpe oleracea) e em produtos comercias de açaí como polpa congelada e \"açaí na tigela\". Para a determinação do ácido fólico, estudos de pré-concentração online foram realizados. A focalização do ácido fólico foi obtida por CZE e MEKC, devido a fenômenos de isotacoforese transiente. Um método de extração simples baseado na dissolução da farinha em solução de Na2HPO4 seguida de ultrassom e adição de HCl concentrado foi adotado. Entretanto, a detecção do ácido fólico no extrato foi obtida por MEKC com injeção de grande volume de amostra em condições eletroforéticas de 40 mmol L-1 TBS e 30 mmol L-1 SDS, 15 kV a 310 nm. Os limites de detecção e de quantificação atingidos foram de 0,047 e 0,14 µg mL-1, sendo adequados para quantificação do ácido fólico em farinhas de trigo. Um método para determinação de corantes Sudan (I, II, III e IV) em alimentos foi desenvolvido por cromatografia eletrocinética micelar (MEKC) com preenchimento parcial do capilar. A separação dos quatro corantes foi obtida utilizando-se um preenchimento de 25% do capilar (volume total) com eletrólito composto por 40 mmol L-1 NH4HCO3, 25 mmol L-1 SDS e 32,5% ACN (v/v). O restante do capilar foi preenchido com um tampão composto de 40 mmol L-1 NH4HCO3 e 32,5% (v/v) de ACN. Após otimização do método por CE-UV o método foi aplicado para o acoplamento ao CE-MS. Para detecção dos compostos no MS os parâmetros de ionização foram otimizados. A separação em linha de base dos quatro compostos foi obtida em menos de 10 min com limites de detecção de 0,57 a 0,75 µg mL-1 para detecção no UV-Vis e 0,05 a 0,2 µg mL-1 para detecção no MS. O método foi eficaz para a determinação destes corantes adicionados a amostras de molho de tomate e pimenta e chilli em pó / The present work involves the development of methods for food analysis in order to determinate phenolic acids in fruits, folic acid in enriched flour and Sudan dye in chilli products by capillary electrophoresis with UV/Vis and MS detection. The separation of ten phenolic acids (benzoic, caffeic, chlorogenic, p-coumaric, ferulic, gallic, p-hydroxybenzoic, protocatechuic, syringic, and vanillic acid) was obtained by capillary zone electrophoresis (CZE). An electrolyte composed by 50 mmol L-1 of tetraborate and 7,5% methanol (v/v) allowed the baseline resolution of all phenolic acids under investigation in less than 15 min. In order to promote sample clean up, to preconcentrate the phenolic fraction and to release esterified phenolic acids from the fruit matrix, elaborate liquid-liquid extraction procedures followed by alkaline hydrolysis were performed. The proposed method was validated with limits of detection of 1.63-3.80 µg mL-1 and limits of quantification of 4.95-11.39 µg mL-1. The optimized method was applied to evaluation of phenolic contents of abiu-roxo (Chrysophyllum caimito), wild mulberry (Morus nigra L.) and tree tomato (Cyphomandra betacea). This work also optimized the extraction process and characterized the free and hydrolysed forms of phenolic acids in Juçara açaí (Euterpe precatória Mart.), Pará´s açaí (Euterpe oleracea) and commercial products such as frozen pulp and açaí desserts. For the determination of folic acid, on-line preconcentration studies were performed. The focalization of folic acid was obtained by CZE and MEKC by transient isotacophoresis. A simple method of extraction based on dissolution of flour in a Na2HPO4 solution followed by ultrasonication and the addition of concentrated HCl was adopted. However, the detection of folic acid in flour extract was obtained by MEKC with the large volume sample injection with eletrophoretic conditions of 40 mmol L-1 TBS and 30 mmol L-1 SDS, 15 kV and 310 nm. The limits of detection and quantification reached were 0.047 and 0.14 µg mL-1, which are suitable limits to quantify folic acid in enriched wheat flours. A method of Sudan dyes (I, II, III and IV) was developed by micellar electrokinetic chromatography (MEKC) with partial filling technique. Filling 25 % of the capillary with a MEKC solution containing 40 mmol L-1 NH4HCO3, 25 mmol L-1 SDS and 32.5 % ACN (v/v), a baseline separation of the four azo-dyes was obtained. The rest of capillary was filled with 40 mmol L-1 NH4HCO3 and 32.5 % ACN (v/v). After the optimization by CE-UV the method was applied to CE-MS coupling. To detect the compounds in MS the ionization parameters were optimized. The baseline separation of four compounds was obtained in less than 10 min with limit of detection within 0.57 to 0.75 µg mL-1 to UV-Vis detection and 0.05 to 0.2 µg mL-1 to MS detection. The method was efficient in the determination of these dyes spiked in tomato chilli sauces and chilli powder.
414

Caracterização química, avaliação da atividade antioxidante in vitro e in vivo, e identificação dos compostos fenólicos presentes no Pequi (Caryocar brasiliense, Camb.) / Chemical characterization, in vitro and in vivo antioxidant activity evaluation, and identification of the phenolic compounds present in the pequi fruit (Caryocar brasiliense, Camb.)

Lima, Alessandro de 23 April 2008 (has links)
O estresse oxidativo produzido no organismo relaciona-se com o aparecimento e/ou desenvolvimento de uma série de doenças crônico-não transmissíveis. Os compostos fenólicos, presentes nos vegetais, são capazes de neutralizar as estruturas radicalares; diminuindo, portanto, o risco de surgimento de patologias a elas associadas. O objetivo do presente trabalho foi avaliar a atividade antioxidante do fruto e da amêndoa do pequi e a participação desta atividade na prevenção do processo oxidativo em ratos. Foram obtidos, de forma seqüencial, os extratos etéreo, alcoólico e aquoso, bem como as frações de ácidos fenólicos livres (AFL), esterificadas solúveis (AFS) e insolúveis (AFI) da polpa e da amêndoa do pequi. Todos os extratos e frações foram avaliados quanto à atividade antioxidante in vitro pelos ensaios de co-oxidação do β-caroteno/ácido linoléico, DPPH (radical 1,1-diphenil-2-picrilhydrazil), ABTS (radical 2,2\'azinobis-(3-ethylbenzthiazoline-6-sulfonic acid), ORAC (Capacidade de Absorção de Radicais Oxigênio) e Rancimat; e apresentaram expressiva atividade antioxidante. Entre os extratos, o aquoso da polpa apresentou maior atividade; entre as frações, a AFL da polpa se destacou nos ensaios β-caroteno/ácido linoléico, DPPH e ABTS. Os extratos e frações foram também avaliados quanto à composição em ácidos fenólicos, por HPLC. Encontraram-se os ácidos elágico, gálico, 4-OH benzóico, p-cumárico e procianidina B2. O ácido elágico esteve presente em todos os extratos e/ou frações, sempre em maior concentração; a procianidina B2, apenas no extrato aquoso da amêndoa. Na avaliação da atividade antioxidante in vivo, em ratos normais, foi administrado, por gavagem, extrato aquoso (100 e 300 mg/kg v.o.) e AFL (40 e 100 mg/kg v.o.) obtidos da polpa do pequi. Evidenciaram-se redução da lipoperoxidação e elevação da atividade das enzimas antioxidantes catalase (CAT), superóxido dismutase (SOD), glutationa peroxidase (GPx) e glutationa redutase (GR) no cérebro e no fígado dos animais que receberam o extrato aquoso a 300 mg/kg e a fração AFL a 100 mg/kg. Isso demonstra que o pequi possui propriedades antioxidantes tanto in vitro como in vivo. / The oxidative stress produced in live organisms is related to the appearance and/or development of a series of non-transmissible chronic diseases. Phenolic compounds present in vegetables are able to neutralize these substances, thus reducing the risk of development of free radicals associated to pathologies. The aim of this work was to evaluate the antioxidant activity in the pulp and almond of the pequi fruit and its effects in preventing the oxidative process in rats. Extracts were obtained by means of sequential extraction in which solvents with different polarities (ether, ethanol and water) were used, as well as free phenolic acid fraction (and) soluble esters and insolublebound compounds from the pulp and almond of the pequi. The total antioxidant capacity was estimated through the following methods: β-carotene bleaching, DPPH (1,1- diphenyl-2-picrylhydrazyl radical), ABTS (2,2\'azinobis-(3-ethylbenzthiazoline-6-sulfonic acid), oxygen radical absorbance capacity (ORAC), and Rancimat assays. All extracts and fractions of phenolic acids showed a significant antioxidant activity. Among the extracts, the pulp aqueous extract showed higher activities than the others. Free phenolic acids fraction from the pulp of the pequi was better compared to other fractions in β-carotene bleaching, DPPH and ABTS assays. Phenolic acids composition was identified by HPLC. It was found ellagic, gallic, 4-Hydroxybenzoic, p-coumaric and procyanidin B2 acid being ellagic acid presents at larger amounts in all extracts and fractions, whereas procyanidin B2 was found only in the aqueous extract of the almond from pequi. For evaluating the antioxidant activity in vivo, aqueous extract (100 and 300 mg/kg b.w.) and free phenolic acids (40 and 100 mg/kg b.w.) obtained from pequi pulp were administered in rats by oral gavage. It was observed a decrease in the levels of lipid peroxidation and an increased activity of antioxidant enzymes catalase (CAT), superoxide dismutade (SOD), glutathione peroxidase (GSHPx), and glutathione reductase (GSSGr) in the brain and liver of animals that received aqueous extract at 300 mg/kg b.w. and free phenolic acids fraction at 100 mg/kg, which demonstrate that pequi fruit has both in vitro and in vivo antioxidative properties.
415

Obtenção, caracterização, encapsulação e aplicação do extrato de vitex (Vitex agnus castus L.) / Obtention, characterization, encapsulation and application of chasteberry extract (Vitex agnus castus L.)

Echalar Barrientos, Mariana Alejandra 25 April 2017 (has links)
O fruto de vitex (Vitex agnus castus L.) é muito aromático, picante e amargo pelo alto teor de compostos fenólicos. É utilizado como pimenta na gastronomia e seu extrato como medicamento fitoterápico para combater os sintomas da tensão pré-menstrual (TPM), síndrome que acomete cerca de 80% das mulheres na idade reprodutiva. Assim, para a aplicação do extrato, com vistas à obtenção de um chocolate funcional para o público feminino, foi proposta sua encapsulação por spray drying visando mascarar ou atenuar o seu sabor desagradável e proteger os compostos fenólicos da oxidação. Portanto, o objetivo deste projeto foi à obtenção em condições otimizadas, caracterização, encapsulação por spray drying e aplicação em chocolate meio amargo do extrato concentrado dos frutos secos e maduros de vitex. O extrato foi obtido por maceração com solução 60 % etanol, a 60 °C e 12 h. Após a concentração do extrato, este foi encapsulado por spray dryer com 4 concentrações de carreador goma arábica e 2 temperaturas de ar de entrada diferentes. Os pós foram caracterizados fisicamente e em relação ao teor dos compostos bioativos. O tratamento com melhores propriedades (T6) foi aplicado em chocolate meio amargo e foi realizada a caracterização do produto. (I) Foi possível obter um extrato rico em compostos fenólicos, com alta atividade antioxidante. (II) A encapsulação foi possível, protegeu os compostos fenólicos da degradação, porém não foi eficiente para mascarar o sabor do extrato. Contudo, (III) a aplicação desse extrato, na forma livre e encapsulada, em chocolate meio amargo foi bem sucedida, pois os produtos obtidos tiveram uma boa aceitação sensorial e a casticina, um dos compostos bioativos responsáveis pela ação terapêutica do extrato, (IV) manteve-se estável durante o período de estocagem. Neste contexto, este trabalho representou uma (V) inovação na área de alimentos funcionais com apelo à manutenção da qualidade de vida de mulheres em período reprodutivo. Ainda, destaca-se a relevância deste trabalho devido à escassez de trabalhos acadêmicos que abordam a encapsulação e aplicação deste extrato em alimentos. / Chasteberry (Vitex agnus castus L.) is very aromatic, spicy and bitter by the content of phenolic compounds. It is used as pepper in gastronomy and its extract as an herbal medicine to combat the symptoms of premenstrual syndrome (PMS), syndrome that affects 80% of women in reproductive age. Thus, for an application of the extract, with goal to obtain a functional chocolate for the female public, its encapsulation was proposed by spray-drying in order to mask or attenuate its unpleasant taste and to protect the phenolic compounds from oxidation. Therefore, the aim of this project was to obtain an extract of chasteberry in optimized conditions, its characterization, encapsulation by spray drying and application in semisweet chocolate. The extract was obtained by maceration with a 60% ethanol solution, at 60 ° C for 12 h. After the extract concentration, it was encapsulated by spray drier with 4 different concentrations of gum arabic charcoal and 2 different inlet air temperatures. The powder was characterized physically and in relation to the content of the bioactive compounds. The treatment with better properties (T6) was applied to the semisweet chocolate and a characterization of the product was carried out. (I) It was possible to obtain an extract rich in phenolic compounds, with high antioxidant activity. (II) Encapsulation was possible, it protected the phenolic compounds from degradation, but was not efficient to mask the flavor of the extract. However, (III) the application of the extract in the free and encapsulated form in semisweet chocolate was successful, the products obtained had a good sensory acceptance and casticina, one of the bioactive compounds responsible for the therapeutic action of the extract, (IV) remained stable during the storage period. In this context, this work represents an (V) innovation in the area of functional foods with maintenance in the quality of life of women in the reproductive period. Still, a relevance of this work is highlighted due to the lack of academic papers that approach the encapsulation or application of chasteberry extract in foods.
416

Downstream Processing of Recombinant Proteins from Transgenic Plant Systems: Phenolic Compounds Removal from Monoclonal Antibody Expressing Lemna minor and Purification of Recombinant Bovine Lysozyme from Sugarcane

Barros, Georgia 2012 May 1900 (has links)
Transgenic plant systems have been proposed as bioreactors in the production of pharmaceutical and industrial proteins. The economic benefits of inexpensive plant production systems could be erased if the downstream processing ends up being expensive. To avoid monoclonal antibody (mAb) modification or fouling of chromatography resins, removal of phenolics from plant extracts is desirable. Removal of major phenolics in Lemna extracts was evaluated by adsorption to PVPP, XAD-4, IRA-402 and Q-Sepharose resins. Analysis of phenolics adsorption to XAD-4, IRA-402 and Q-Sepharose showed superior dynamic binding capacities at pH 4.5 than at 7.5. The economic analysis using SuperPro Designer 7.0 indicated that addition of a phenolics adsorption step would increase mAb production cost only 20% by using IRA-402 compared to 35% for XAD-4 resin. The overall mAb processing cost can be reduced by implementing a phenolics removal step. To understand phenolics-resin interactions, adsorption isotherms of phenolic compounds (chlorogenic acid, ferulic acid, rutin, syringic acid and vitexin-2-O-rhamnoside) from different phenolic classes on three resins (IRA-402, PVPP, XAD-4) at pH 4.5 and 7.5 were determined. Differences in adsorption with the type of phenolics were observed, and PVPP was not efficient for phenolics removal. Screening of sugarcane lines for bovine lysozyme (BvLz) accumulation indicated that expression levels are still inadequate for commercial development. To maximize BvLz extraction, pH and ionic strength were evaluated; five conditions resulted in equivalent BvLz/TSP ratio. Membrane filtration process using BvLz extracts attained partial removal of native proteins by the 100 kDa membrane step, but also BvLz loss (21-29%). Regardless of the extraction condition, at least 47% of the starting BvLz was lost during the membrane processing. None of the evaluated extraction conditions caused a substantial recovery of BvLz in the concentrate. Alternative purification options for the IEX+HIC process, which achieved 95% BvLz purity, were tested. Direct loading of sugarcane extract concentrate on HIC and XAD-4 pretreatment of juice did not recovered BvLz as effectively as the IEX chromatography. Pure BvLz was obtained by the XAD+HIC process, but higher purification fold and HIC yield were achieved by the IEX+HIC process, due to the complete separation of BvLz and 18-kDa protein.
417

Ultrasound Assisted And Supercritical Carbon Dioxide Extraction Of Antioxidants From Roasted Wheat Germ

Gelmez, Nilufer 01 February 2008 (has links) (PDF)
This study covers the extraction of antioxidants from wheat germ / which is the byproduct of the flour-milling industry and a rich source of antioxidants / with Ultrasound Assisted (UAE) and Supercritical Carbon Dioxide (SC-CO2) extractions. Extraction conditions were ultrasonication time (1&ndash / 11 min), temperature (20&ndash / 60&deg / C) and ethanol level (5&ndash / 95%) for UAE, and pressure (148&ndash / 602 bar), temperature (40&ndash / 60&deg / C) and time (10&ndash / 60 min) for SC-CO2 extraction. The extraction conditions were optimized based on yield (%), total phenolic contents (TPC, mg GAE/g extract) and antioxidant activities (AA, mg scavenged DPPH&amp / #729 / /g extract) of the extracts, using Central Composite Rotatable Design. Total tocopherol contents (TTC) of the extracts were determined, as well. UAE (at 60&deg / C) with low ethanol level (~5-30%) and short times (1-3 min) provided protein rich extracts with high yield, medium TPC and AA. On the other hand, with high ethanol level (~90%) and long times (6-11 min), waxy structured extracts with low yield but high TPC and AA were obtained. SC-CO2 extraction at 442 bar, 40&ordm / C and 48 min. enabled almost 100% recovery of wheat germ oil (9% yield) but TPC and AA of the extracts were low. On the contrary, the extracts obtained at lower pressures (~150bar) and shorter times (~10 min) at 50-60&ordm / C had high TPC and AA since the oil yield was low. However, TPC and AA of these extracts were only half of those extracted by UAE. Maximum tocopherol (7.142 mg tocopherol/g extract) extraction was achieved at 240 bar, 56&ordm / C for 20 min. Both of the methods extracted high amounts of tocopherols from roasted wheat germ (SC-CO2 extraction / 0.31 mg tocopherol/g germ, UAE / 0.33 mg tocopherol/g germ) but TTC of the extracts obtained by SC-CO2 extraction was superior compared to 1.170 mg tocopherol/g extract obtained by UAE at 9 min, 58&ordm / C and 95% ethanol level. All these extracts with different characteristics have potential uses in cosmetic and food industry depending on the targeted specific application.
418

Phenolic resin/polyhedral oligomeric silsesquioxane (POSS) hybrid nanocomposites and advanced composites for use as anode materials in lithium ion batteries

Lee, Sang Ho, January 2007 (has links)
Thesis (M.S.)--Mississippi State University. Department of Chemistry. / Title from title screen. Includes bibliographical references.
419

Characterisation of chemical components in manually isolated aleurone and associated layers from maize, wheat and barley kernels

Ndolo, Victoria Uchizi January 2015 (has links)
Health benefits related to consumption of whole grains have been attributed in part to phytochemical and micronutrient composition. Understanding the composition, structure and distribution of these components in different cereal grains is of potential importance in aiding the selection of whole grains and their processed fractions for inclusion in the diet, and as ingredients in development of new food products. The aim of this research was to characterise the chemical components in the botanical fractions of yellow corn, barley, wheat. Manual separation, a tedious and laborious technique that yields pure fractions, suitable for compositional analysis, was used to separate whole grains into pericarp, aleurone layer, germ and endosperm fractions. Component identification and quantification of tissue components was accomplished by several techniques. The study also explored the possibility of using spectral characteristics fluorescence intensity values to provide rapid estimates of the concentrations and distribution of ferulic acid (FA), a major phenolic compound in cereal grains. While composition of phenolic acids and carotenoids was similar, the distribution was significantly different (P < 0.05) among cereal types and grain fractions. Phenolic acids were concentrated in pericarp and aleurone fractions, followed by the germ and the endosperm had the lowest levels. Yellow corn exhibited the highest values. Carotenoids, lutein and zeaxanthin were concentrated in the germ and aleurone layer of wheat and barley while in yellow corn it was in the endosperm and aleurone layer. This is the first study to report on carotenoid composition of aleurone fractions. Mineral elements, thiamine and niacin were higher in wheat aleurone than in purple barley and yellow corn aleurone layers. These findings suggest that yellow corn aleurone layers have potential as a functional food ingredient despite the low micronutrient content. A positive, significant correlation (r= 0.421, p < 0.0001) was found between fluorescence intensity values and ferulic acid concentration. Thus, fluorescence intensity profiles are a promising approach for rapid assessment of FA concentration in grain in-situ. This work has provided information that would act as a database for selection of cereal fractions and guide the miller to obtain grain fractions with enriched levels of phytochemicals and micronutrients. / February 2016
420

Studies about Fusarium infection of emmer and naked barley during grain ripening and the post-harvest period

Trümper, Christina 04 February 2014 (has links)
No description available.

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