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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.
21

Estudo da capacidade antioxidante, antimicrobiana e anti-hemolítica do gengibre (Zingiber offinale) / Study of antioxidant capacity, antimicrobial activity and anti hemolytic action of ginger (Zingiber officinale)

Jéssica Jamila Dalgê 28 March 2014 (has links)
O presente estudo teve como objetivo determinar a capacidade antioxidante, antimicrobiana e anti-hemolítica do gengibre (Zingiber officinale) utilizando diferentes solventes extratores. Para tal, rasuras secas de gengibre foram trituradas e usadas na proporção 1:50 (p/v) nas quatro diferentes extrações: água, etanol (70%), acetona/ácido acético (70%/2%) ou acetona (70%). Após centrifugação, o extrato foi utilizado pra determinar o conteúdo de compostos fenólicos por Folin-Ciocalteau e ação sobre os radicais ABTS+. e DPPH.. Foi selecionado o melhor solvente extrator pelas propriedades antioxidantes e facilidade de sua remoção da matriz. Este extrato foi submetido à rotaevaporaçao, liofilizaçao e ressuspenção em tampão fosfato salino (PBS) e, então, utilizado nos estudos biológicos de captura de NO, ação antioxidante sobre hemólise induzida e ação sobre o crescimento de S. aureus. Os resultados foram expressos como média e desvio padrão. Para análise estatística empregou o software Minitab® com comparação entre grupos por ANOVA, diferenças significativas por Tukey e P < 0,05. O extrato de gengibre obtido em acetona apresentou maior conteúdo de compostos fenólicos (8,52 ± 1,24 mg equivalente de ácido gálico/g de gengibre). O extrato acetona apresentou menor valor de EC50 e maior ação antioxidante mediantes o ensaio com ABTS+., sendo respectivamente 0,07 ± 0,01 mg de massa seca do extrato/mL de ensaio e 10,93 ± 0,79 mg equivalentes de trolox (ET)/g de gengibre, sem diferença significativa com os valores obtidos nos extratos etanol e acetona/ácido. No ensaio do DPPH., o extrato acetona apresentou menor valor de EC50 (0,15 ± 0,01 mg de massa seca de extrato/mL de ensaio) e maior ação antioxidante (8,35 ± 0,60 mg ET/g de gengibre), sem diferença significativa com relação ao extrato etanólico. Dentre todos os ensaios, a extração em água apresentou resultados menos satisfatórios. A acetona foi selecionada como solvente extrator dos componentes do gengibre para os estudos biológicos. O extrato de gengibre (17,25 mg de massa seca/mL) inibiu 50% da formação de produtos no ensaio de captura de NO, valor similar ao obtido pela presença do antioxidante ácido gálico. Concentrações menores de extrato também agiram sobre o NO, sendo que 1,25 mg/mL refletiu em 33% de inibição. A hemólise foi evitada em 100% pelo extrato de gengibre em concentrações acima de 113 µg de massa seca de extrato/mL, resultado similar ao encontrado no ensaio contendo ácido ascórbico. A lise das hemácias foi evitada em 44% na presença de extrato 57 µg/mL. O extrato de gengibre não apresentou ação antimicrobiana sobre S. aureus. Conclui-se o extrato de gengibre, nas condições deste estudo, apresenta atividade antioxidante sobre ABTS+. e DPPH.; bem como sobre sistemas biológicos modelos como na captura de NO e lise de membrana celular. / The aim of this study was to determinate antioxidant capacity, antimicrobial activity and anti hemolytic action of ginger (Zingiber officinale) extract obtained by different solvents. For this purpose, dried ginger flakes were powdered and used in ratio 1:50 (w/v) in the four different extractions: water, ethanol (70%), acetone/acetic acid (70%/2%) and acetone (70%). The extract was centrifuged and used for phenolic compounds determination by Folin-Ciocalteau and action on ABTS+. and DPPH. radicals. The best extractor solvent was selected by its antioxidant properties and easier elimination from the matrix. The select extract was submitted on evaporation and lyophilization, and subsequent re-suspension on phosphate buffer saline (PBS). Then, this suspension was used in biologic studies as NO scavenging, antioxidant action on induced hemolysis and effect on S. aureus growth. The values were express as mean and standard deviation. Statistical analysis carried out by Minitab® using ANOVA and Tukey to p< 0.05. Acetone ginger extract showed highest value of phenolic content (8.52 ± 1.24 mg galic acid equivalent /g of ginger). The acetone extract showed the lowest EC50 value and higher antioxidant action on ABTS+., 0.07 ± 0.01 mg of dry weight of the extract/mL of assay and 10.93 ± 0.79 mg trolox equivalents (TE)/g of ginger, respectively. These values did not show significant difference in relation to ethanol and acetone/acid extracts. For DPPH. assay, acetone extract showed lower value of EC50 (0.15 ± 0.01 mg dry weight of extract/mL assay) and higher antioxidant action (8.35 ± 0.60 mg TE/g of ginger), without significant difference in relation to ethanolic extract. Among all extracts, aqueous extract showed lesser satisfactory results. Acetone extract was selected for biological assays. Ginger extract (17.25 mg of dry weigth/mL) inhibited 50% of products formation on NO scavenging assay, similarly to galic acid results. Lower extract concentrations as 1.25 mg/mL inhibited 33% of NO. The 100% of hemolysis prevention was obtained by concentrations of ginger extract higher than 113 µg of dry weight of extract/mL of assay. Similar result was observed by presence of ascorbic acid. Erythrocytes lysis was avoided in 44% by 57 µg/mL of ginger extract. Ginger extract did not show antimicrobial action on S. aureus. In conclusion, ginger extract, in present conditions, showed antioxidant action on ABTS+. and DPPH. assays and in biological model systems as in NO scavenging assay and cell membrane lysis.
22

Avaliação in vitro da capacidade antioxidante de grãos de amaranto (Amatanthus Cruentus) / In vitro antioxidant capacity evaluation of amaranth grains (Amaranthus cruentus)

Pazinatto, Caroline 06 April 2008 (has links)
Orientador: Flavia Maria Netto / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-10T19:43:01Z (GMT). No. of bitstreams: 1 Pazinatto_Caroline_M.pdf: 872603 bytes, checksum: 24b721ce9b9486921e2492870c2452f0 (MD5) Previous issue date: 2008 / Resumo: O amaranto se destaca por seu perfil protéico, rico em aminoácidos essenciais e pela presença de outros compostos tais como: fibras, esqualeno, tocoferóis, tocotrienóis e compostos fenólicos, que lhe confere propriedades especiais, incluindo propriedade antioxidante. A fácil adaptação da planta a diferentes condições climáticas, juntamente com as suas qualidades nutricionais e funcionais, aumentam o interesse em introduzir a cultura do amaranto no Brasil. Apesar de bem caracterizado quimicamente e de apresentar compostos com potencial fisiológico, poucos estudos foram realizados para avaliar o potencial do grão de amaranto como alimento funcional. O presente trabalho tem como objetivo avaliar a capacidade antioxidante dos diferentes produtos obtidos a partir do grão integral de amaranto (Amaranthus cruentus). Após a moagem e o desengorduramento dos grãos para a obtenção da farinha desengordurada, diferentes processos, incluindo a hidrólise com Alcalase, foram utilizados na produção dos diversos produtos de amaranto que foram posteriormente digeridos in vitro com as enzimas pepsina e pancreatina. Os efeitos dos processos e da digestão in vitro das frações protéicas, e o efeito dos compostos fenólicos totais na capacidade antioxidante, em extrato aquoso e metanólico, foram avaliados utilizando o ensaio da capacidade seqüestradora de radicais DPPH e o ensaio de ORAC. O teor de fenóis totais apresentou elevada correlação com a capacidade antioxidante quando avaliada no extrato metanólico. Entretanto, a correlação foi menor quando avaliada no extrato aquoso, sugerindo que os compostos hidrossolúveis podem interferir nas avaliações. A hidrólise com Alcalase elevou significativamente o potencial antioxidante das amostras, de 2 a 4 vezes a capacidade seqüestradora de radicais DPPH e de 13 a 15 vezes os valores de ORAC. A digestão in vitro aumentou a capacidade antioxidante medida por ambos os ensaios (até 7 vezes para a capacidade seqüestradora de radicais DPPH e 12 para o valor de ORAC), especialmente para o concentrado protéico e seus hidrolisados. O elevado teor de fenóis totais liberados e o aumento da capacidade antioxidante dos produtos de amaranto após a digestão in vitro sugerem que o mesmo ocorre após a digestão fisiológica. Os resultados sugerem que a inclusão de produtos de amaranto na dieta, especialmente concentrado protéico e seus hidrolisados, pode promover benefícios à saúde / Abstract: Amaranth is well known for its protein profile, rich in essential amino acids and the presence of other compounds such as fiber, squalen, tocols (tocopherols and tocotrienols) and phenolic compounds that are responsible for its special properties, including antioxidant capacity. The easy adaptation of the plant to different climate conditions, together with its nutritional qualities and functional properties, increase the interest to introduce the culture of amaranth in Brazil. Despite being well characterized chemically and exhibiting compounds with physiological potential, few studies have been conducted to evaluate the potential of amaranth grain, as a functional food. This study aims to evaluate the antioxidant capacity of different products obtained from amaranth grain (Amaranthus cruentus). After milling and defatting the grain to obtain deffated amaranth flour, different processes, including Alcalase hydrolysis, were used to produce a variety of products that were digested in vitro with pepsin and pancreatin. The effects of the processes and of the digestion in vitro of the protein fractions, and the effect of the total content of phenolic compounds on the antioxidant capability in aqueous and methanolic extracts were evaluated using scavenging capacity of DPPH radical and ORAC assays. Total phenolic compounds content showed high correlation with the antioxidant capacity, when evaluated in methanolic extract. However, the correlation was lower when using the aqueous extract, suggesting that water soluble compounds may interfere in these evaluations. Hydrolysis with Alcalase increased significantly the antioxidant potencial, from 2 to 5 times the scavenging DPPH capacity and 13 to 15 the ORAC values. In vitro digestion increased the antioxidant capacity measured by both assays (up to 7 times for scavenging DPPH capacity and 12 times for ORAC assays), especially for protein concentrate and its hydrolysates. The high content of phenolic compounds released and the increase in antioxidant capacity after in vitro digestion of the amaranth products suggests that the same occurs after the physiological digestion. These results suggest that the inclusion of these products, especially concentrate and its hydrolysates, in the diet should promote health benefits / Mestrado / Nutrição Experimental e Aplicada à Tecnologia de Alimentos / Mestre em Alimentos e Nutrição
23

Avaliação do estresse oxidativo em humanos e em animais suplementados com ácidos graxos polinsaturados omega-3 / Evaluation of oxidative stress in humans and animals supplemented with Omega-3 polyunsaturated fatty acids

Vania Claudia Barros Monteiro 24 April 2007 (has links)
Ácidos graxos polinsaturados Omega-3 (n-3 PUFA) tais como o ácido eicosapentaenóico (C20:5 n-3, EPA) e docosahexaenóico (C22:6 n-3, DHA) reduzem a concentração plasmática de triacilgliceróis em humanos. Entretanto, uma alta proporção desses ácidos graxos na dieta poderia favorecer a susceptibilidade das células à peroxidação, aumentando o risco de desenvolvimento de doenças cardiovasculares. Embora modelos animais não sejam recomendados para avaliar o efeito de n-3 PUFA nas lipoproteínas plasmáticas, estes têm sido amplamente utilizados como modelo para avaliação de dano oxidativo. Diferenças nos procedimentos metodológicos também têm gerado dificuldade na comparação de resultados. Desta forma, o objetivo deste estudo foi aplicar os mesmos procedimentos metodológicos para comparar o efeito da suplementação de n-3 PUFA nos biomarcadores plasmáticos de estresse oxidativo utilizando um modelo humano e um modelo animal. Indivíduos foram aleatoriamente distribuídos em dois grupos num delineamento paralelo duplo cego e receberam uma suplementação de 460,0 mg/dia de n-3 PUFA (OMEGA) contendo 240,0 mg de EPA + 160,0 mg de DHA + 60,0 mg de outros n-3 PUFAs, ou óleo de soja (PLACEBO) durante 6 semanas. Ratos Wistar também foram distribuídos em dois grupos e receberam uma dieta contendo 192,5 mg/dia de n-3 PUFA (FO) sendo 116,3 mg de EPA + 61,5 mg de DHA + 14,7 mg de outros n-3 PUFAs ou óleo de soja (SO) durante 3 semanas. Indivíduos do grupo OMEGA apresentaram maior concentração de malondialdeído (MDA) no plasma medido por TBARS quando comparado aos respectivos valores no baseline. A suplementação com n-3 PUFA não alterou a concentração plasmática de &#945;-tocoferol e a atividade antioxidante determinada pelo método DPPH. Apesar dos animais terem recebido doses 10 vezes maiores de n-3 PUFA (2,9 mg/kcal) quando comparadas aos humanos (0,3 mg/kcal) não foram observadas alterações entre os grupos FO e SO para as concentrações de MDA no plasma e no homogenato de cérebro. Em resumo, pode-se sugerir que o modelo animal usado neste estudo parece não ser o mais adequado para avaliar o estresse oxidativo após intervenções dietéticas com n-3 PUFAs em função de diferenças no metabolismo e nos mecanismos de proteção antioxidante observados entre os dois modelos. / Omega-3 polyunsaturated fatty acids (n-3 PUFA) such as eicosapentaenoic (C20:5 n-3, EPA) and docosahexaenoic (C22:6 n-3, DHA) reduce plasma triacylglycerol concentration in humans. However, higher proportion of these fatty acids in the diet could raise cells lipoperoxidation susceptibility, increasing the cardiovascular disease risk. Although animal models are not recommended to evaluate the effect of n-3 PUFA in plasma lipoproteins, they have been widely used as model for oxidative damage. Difference in methodological proceedings has also caused difficulties to compare data among assays. Thus, the objective of this study was to apply the same methodology to investigate the effect of n-3 PUFA supplementation on oxidative biomarkers in animal and human model. Individuals were randomly assigned in two groups in a parallel double blind design and received a supplement of 460.0 mg/day n-3 PUFA (OMEGA) containing 240.0 mg EPA + 160.0 mg DHA + 60.0 mg other n-3 PUFAs, or soybean oil (PLACEBO) during 6 weeks. Wistar rats were also assigned in two groups and received a diet containing 192.5 mg/day n-3 PUFA (FO) containing 116.3 mg EPA + 61.5 mg DHA + 14.7 mg other n-3 PUFAs or soybean oil (SO) for 3 weeks. Individuals in OMEGA group showed higher malondialdehyde (MDA) concentration in plasma measured by TBARS when compared to their baseline values. N-3 PUFA supplementation did not change plasma &#945;-tocopherol concentration and antioxidant activity determined by DPPH method. Although animals have received a 10-fold higher dose of n-3 PUFA (2.9 mg/ kcal) than humans (0.3 mg/kcal), no alteration was observed between FO and SO groups for plasma and brain homogenate MDA concentration. In summary, it can be suggested that the model used in this study doesn\'t seem appropriate to evaluate oxidative stress after dietetic interventions with n-3 PUFA due to physiological differences involved in lipid metabolism and antioxidant protection observed between both models.
24

Estudo da composição Química do óleo essencial de Lippia microphylla CHAM em três anos diferentes e atividade antioxidante

Mauro Marcos da Silva 29 March 2014 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O estado de Roraima é dividido em três grandes sistemas ecológicos: floresta, campinas-campinarana e savanas ou cerrados e está localizado no extremo norte da Amazônia brasileira. Apesar da grande variedade de plantas existem poucas informações sobre plantas aromáticas da região. Lippia microphylla Cham., pertence à família Verbenaceae e ao gênero Lippia, e conhecida popularmente em Roraima como salva do campo, sendo encontrada nos lavrados roraimenses. Esta planta pode ser encontrada com facilidade ao longo da BR 174 que liga Boa Vista a Santa Elena de Uairén, na Venezuela. O objetivo desse trabalho foi avaliar a constituição química do óleo essencial de Lippia microphylla Cham. em épocas e horários diferentes e analisar sua atividade antioxidante. As amostras foram coletadas no município de Boa Vista, Roraima, em três horários diferentes (8,12 e 18 horas) nos meses de maio 2009, 2010 e 2011. As folhas extraídas por hidrodestilação com auxílio de um aparelho de clevenger e os óleos foram analisados por cromatografia gasosa com auxílio da espectrometria de massas. Para determinação da atividade antioxidante do óleo essencial foi utilizado o método de capacidade sequestrante do radical livre DPPH. Os maiores rendimentos de óleos foram registrados em maio de 2011, mês que registrou maior precipitação, mas não choveu no dia da coleta. A análise da constituição do óleo revelou que o timol, carvacrol, E-cariofileno, nerolidol e o óxido de cariofileno foram os principais constituintes, sendo o carvacrol majoritário em quase todas as análises. O óleo de melhor capacidade antioxidante foi extraído do material coletado ao meio dia e contem maior concentração de timol (9,22%) e carvacrol (19,80%). Observamos que os óleos coletados nos diferentes anos apresentam diferenças significativas quanto a sua composição química e ao seu rendimento. A chuva do dia da coleta foi mais relevante do que o volume de precipitação no mês. A atividade antioxidante desses óleos pode ser atribuída principalmente à presença dos dois isômeros fenólicos. / The state of Roraima is divided into three major ecological systems: forests, meadow-campinarana and savannas, and are located in the extreme north of the Brazilian Amazon. Despite the wide variety of plants there is little information on herbs of the region. The Lippia microphylla Cham., belongs to the family Verbenaceae and the genus Lippia, popularly known as salva-do-campo being found in the Roraima savannas. This plant is easily found along the margins of the BR 174, the route Boa Vista, Brazil, to the Santa Elena de Uairén, Venezuela. The aim of this study was to evaluate the chemical composition of essential oil of Lippia microphylla Cham. Collected at different times and schedules and analyze their antioxidant activity. The samples were collected in Boa Vista, Roraima, at three different times ( 8, 12 and 18 hours ) in May 2009, 2010 and 2011, for realization of antioxidant activity the samples were collected in the month of March 2011. The leaves were extracted by hydrodistillation with the assistance of a Clevenger apparatus and the oils analyzed by Gas chromatography coupled with mass spectrometry, GC-MS. To determine the antioxidant activity of the essential oil the method of sequestering ability of the free radical DPPH was used. The highest yields of oils were recorded in May 2011, which recorded highest rainfall month, but it did not rain on the day of collection. The analysis of the constitution of the oils revealed that thymol, carvacrol, E-caryophyllene, nerolidol and caryophyllene oxide were the main constituents of which the majority carvacrol was in almost all analyzes. The best antioxidant capacity oil was extracted from material collected at noon containing higher concentration of thymol ( 9.22% ) and carvacrol ( 19.80% ). We observed that the oils collected in different years showed significant differences in their chemical composition and yield. The rain on the day of collection was more important than the volume of rainfall in the month. The antioxidant activity of these oils can be attributed mainly to the presence of two phenolic isomers.
25

Utilização de película de amendoim para produção de pigmento natural em pó: estudo do efeito do processo de atomização na estabilidade, propriedades antioxidante e antimicrobiana do material / Use of peanut skin to produce natural dye powder: study of the effect of the atomization process in the stability, antioxidant and antimicrobial properties of the material

Andressa do Valle Calomeni 08 October 2015 (has links)
A película do amendoim apresenta coloração vermelha intensa e é rica em compostos fenólicos, todavia o extrato líquido é instável e de difícil comercialização. Os objetivos deste trabalho foram extrair os pigmentos da película do amendoim, estudar o processo de secagem por atomização deste extrato, caracterizar os pós obtidos, bem como sua propriedade antioxidante, antimicrobiana e estabilidade durante o armazenamento, sempre comparando com o controle. Quanto a caracterização do extrato líquido foi analisado fenólicos totais, pH, umidade, cinzas, proteínas, lipídeos, açúcares, aflatoxina e acidez. Os extratos foram então misturados com agente carreador nas concentrações de 10, 20 e 30%, estes foram atomizados em spray dryer com temperaturas do ar de entrada de 130, 150 e 170ºC. Para obtenção da amostra controle, parte do extrato foi liofilizado sem a presença de agente carreador. Os pós obtidos foram caracterizados quanto à umidade, atividade de água, higroscopicidade, morfologia, tamanho das partículas, cor, teor de fenólicos totais, solubilidade, estabilidade, propriedade antimicrobiana e antioxidante pelos métodos: ORAC, DPPH e HPLC-ABTS on line. Na caracterização do extrato líquido foram obtidos os seguintes resultados: 0,24% de proteína, 2,31% de açúcares, 0,09% de cinzas, 1,41% de lipídeos, 0,91% de acidez titulável, 42,88 mg de ác. gálico eq./g de extrato (fenólicos totais), pH de 5,30, 90,93% de umidade e 1,81 ng aflatoxina/mL extrato (aflatoxina). Na caracterização dos pós, a umidade foi menor para pós secos a 170ºC e para concentração de 10% de maltodextrina e foi sempre menor que o controle. A higroscopicidade foi menor quanto maior a concentração de maltodextrina, pois esta tem baixa higroscopicidade. Temperaturas mais altas geraram pós mais higroscópicos, pois esses tinham menor umidade. Com relação à solubilidade, os valores variaram de 85,60 a 91,91%, obtendo-se maiores valores para pós com maiores concentrações de maltodextrina, pois esta apresenta elevados valores de solubilidade. O controle apresentou solubilidade mais baixa de 77,62%. Já os parâmetros de cor tiveram influência apenas da concentração de maltodextrina, sendo que as amostras com menor concentração apresentaram cor mais acentuada, o que era de se esperar visto que a maltodextrina apresenta coloração branca. Portanto, o controle sempre apresentou a coloração mais intensa frente aos pós atomizados. A temperatura de 170ºC originou pós de superfícies mais lisas, apresentando assim melhor escoamento. Com o estudo de estabilidade, verificou-se que as amostras atomizadas tiveram menor perda de cor em relação à liofilizada, e as amostras com maior concentração de maltodextrina (30%) preservaram melhor os fenólicos totais, destacando-se a temperatura de 150 ºC. Em relação à atividade antioxidante, o tratamento T5 se destacou frente aos outros, apresentando o melhor valor de atividade antioxidante por todos os métodos estudados. O extrato da película de amendoim em pó também apresentou atividade antimicrobiana contra as bactérias Gram-positivas Staphylococcus aureus e Listeria monocytogenes, apresentando ainda capacidade bactericida para Staphylococcus aureus. Frente a esse estudo, tem-se na película de amendoim um potencial aditivo natural, podendo ser utilizado como pigmento em pó que apresenta excelente estabilidade, baixa higroscopicidade e alta solubilidade; além de apresentar atividades biológicas como capacidade antioxidante e antimicrobiana. / The peanut skin presents intense red color and is rich in phenolic compounds, however the liquid extract is unstable and difficult to commercialize. The aim of this project was to extract the pigments of peanut skin, study the process of spray drying this extract, characterize the powders as well as its antioxidant properties, antimicrobial properties and storage stability, when compared to the control. The extract was characterized measuring the phenolic compounds, pH, moisture, ash, protein, lipids, sugars, aflatoxin and acidity. The extracts were then mixed with the carrier agent at concentrations of 10, 20 and 30%, these were atomized in a spray dryer at inlet air temperatures of 130, 150 and 170 º C. To obtain a control sample, part of the extract was freeze-dried without the presence of maltodextrin. The powders were characterized for moisture, water activity, hygroscopicity, morphology, particle size, color, total phenolic content, solubility, stability, antimicrobial and antioxidant properties by the methods: ORAC, DPPH and ABTS HPLC-online. In the analysis of the liquid extract, the following results were obtained: 0.24% protein, 2.31% sugar, 0.09% ash, 1.41% lipid, 0.91% titratable acidity, 42.88 mg of Galic acid eq. / g extract (phenolic), pH of 5.30, 90.93% moisture and 1.81 ng aflatoxin / mL extract (aflatoxin). In the analysis of the powders, moisture was lower for powders dried at 170ºC and with 10% maltodextrin concentration and was always lower than the control. The hygroscopicity is lower as higher the concentration of maltodextrin, since the last has low hygroscopicity. Higher temperatures generated more hygroscopic powders, because they reduced moisture. In concern to solubility, the values ranged from 85.60 to 91.91%; higher values were obtained for powders with higher concentrations of maltodextrin, since it has high solubility values. The control showed lower solubility of 77.62%. The color parameters were influenced only by the concentration of maltodextrin; the samples with lower concentrations showed more pronounced color, what was to be expected since maltodextrin is white. Therefore, controls have always presented with more intense color than the atomized powders. The temperature of 170 ºC originated powders with smoother surfaces, thus resulting in better flow. In the evaluation of stability, it was found that the atomized sample suffered lower color loss compared to the freeze dried sample, and samples with higher concentrations of maltodextrin (30%) had better preservation of total phenolics, especially at a temperature of 150ºC. In concern to antioxidant activity, the T5 treatment stood out compared to the others, showing the best values of antioxidant activity in all methods studied. The extract of peanut skin in powder also showed antimicrobial activity against Gram-positive bacteria Staphylococcus aureus and Listeria monocytogenes, with bactericidal properties against Staphylococcus aureus. This study clearly showed that peanut skin is a potential natural additive product and may be used as a powdered pigment which has excellent stability, low hygroscopicity and high solubility, besides having biological activities, such as antioxidant and antimicrobial capabilities.
26

Avaliação da capacidade antioxidante de extratos comerciais de alecrim e chá verde e sua influência na estabilidade de hambúrguer de frango durante armazenamento congelado / Antioxidant activity evaluation of commercial extracts of rosemary and green tea and its influence on the stability of chicken burger during frozen storage

Manoela Alves Pires 10 March 2014 (has links)
A atividade antioxidante de dois extratos comerciais de alecrim e chá verde foi comparada com a atividade do sintético BHA para substituição total do sintético em hambúrguer de frango. A quantificação foi determinada pelos métodos Folin-Ciocalteau, FRAP e DPPH. De acordo com as análises de atividade antioxidante, as dosagens dos extratos naturais foram determinadas, utilizando-se como base o limite de dosagem do BHA (0,01% base gordura) e aplicadas em hambúrgueres de frango: T1: Controle; T2: 0,002% BHA; T3: 0,0038% Chá Verde; T4: 0,001% Chá Verde; T5: 0,048% Alecrim; T6: 0,00186% Alecrim. Foram realizadas análises de composição centesimal e pH e análises de estabilidade no armazenamento congelado: rendimento e redução do diâmetro, índice de TBARs, cor objetiva (parâmetros L*, a* e b*) e teste sensorial de aceitação. No método Folin-Ciocalteau, das análises de atividade antioxidante, o BHA não apresentou diferença com o chá verde (p &gt; 0,05), no método FRAP o melhor (p &lt; 0,05) desempenho foi do BHA e no DPPH o chá verde apresentou maior atividade (p &lt; 0,05). Os resultados de TBARS, nos hambúrgueres, mostraram diferença significativa entre as amostras e também interação amostras x tempo do armazenamento (p &lt; 0,05), sendo que após 120 dias o teste com maior dosagem do extrato de alecrim (T5) não diferiu do sintético (T2) (0,423 e 0,369 índice de TBARs, respectivamente). No aspecto sensorial as amostras não diferiram entre si (p&gt;0,05) nem durante todo o período de armazenamento (p &gt; 0,05). Dentro das condições experimentais pode-se afirmar que o extrato comercial de alecrim pode substituir totalmente o antioxidante BHA em hambúrguer de frango, garantindo a mesma estabilidade oxidativa e sem interferir em sua aceitação sensorial. / The antioxidant activity of two commercial extracts, rosemary and green tea, were compared with the activity of the synthetic BHA for total replacement of the synthetic in chicken burger. The spectrometric quantification was determined by UV - VIS methods: Folin - Ciocalteu , FRAP and DPPH . In the Folin-Ciocalteau method the BHA showed no difference with green tea (p &gt; 0.05), in the FRAP method the BHA obtained better (p &lt; 0.05) performance and for DPPH the green tea showed greater activity (p &lt; 0.05). According to the analysis of antioxidant activity, dosages of natural extracts were determined, using as basis the limit dosage of BHA (0.01 % fat base) and applied in chicken burgers: T1: Control, T2: 0.002 % BHA, T3: 0.0038 % Green Tea, T4: 0.001 % Green Tea, T5: 0.048 % Rosemary and T6: 0.00186 % Rosemary. Chemical-physical analysis of chemical composition and pH were made, and also stability analysis: cooking loss and reducing the diameter, TBARs index, objective color (parameters L *, a * and b *) and sensory acceptance test. The results of TBARS showed a significant difference between samples and also samples interaction x storage time (p &lt; 0.05), after 120 days the test with higher dosage of rosemary extract (T5) did not differ from synthetic (T2) (0.423 and 0.369 TBARS index, respectively), thus better performance than the other tests. The sensory evaluation results showed that the samples did not differ during the storage period (p &gt; 0.05). According the experimental conditions can be concluded that the commercial rosemary extract can completely replace the antioxidant BHA.
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Antioxidační aktivita plodů různých kultivarů Sambucus nigra L. / Antioxidant activity of some cultivars of Sambucus nigra L. fruits.

Nehybová, Monika January 2014 (has links)
8. Abstract The fruit of the European elder, Sambucus nigra L., is used in therapy as a drug Sambuci fructus for its diaphoretic, diuretic and laxative effects. Cultivars of European elder are being studied for the use in the food industry and pharmacy. The fruit contains especially large amount of anthocyanins and flavonoids that are known for their antioxidant activity. The aim of this work is to measure the antioxidant activity of the drug Sambuci fructus and of the fruit of the European elder cultivars Samdal, Mammut, Sambo, Sambu, Sampo, Bohatka, Haschberg, Weihenstephan, Allesö, and Samyl. An extract containing anthocyanins was obtained from fruit by a process based on extraction of frozen material with acidified water at high temperature, followed by separation with polymer non-ionogenic polystyrene-divinylbenzene sorbent. The content of anthocyanins in the extracts was determined spectrophotometrically using a modified pH-differential method. The absorbance was measured along the range of 350 - 600 nm. The content of the anthocyanins was quantified in units of mg of cyanidin 3-glucoside in 1 ml of extract. The content ranged from 0.33 - 2.76 mg cyanidin 3-glucoside/ml of extract. The highest content was in the extract from the fruit of the cultivar Samdal and the lowest was of the cultivar Mammut....
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In vitro 5-lipoxygenase and anti-oxidant activities of South African medicinal plants commonly used topically for skin diseases

Frum, Yakov 14 November 2006 (has links)
Faculty of Health Sciences School of Pharmacology 9410866v kermifrum@yahoo.com / ABSTRACT Thirty plant species traditionally used to treat skin pathologies were chosen from the readily available ethnobotanical literature. Four plants (aqueous or methanol extracts) displayed promising 5-lipoxygenase inhibitory activity with IC50 values below 61 ppm. These included Aloe greatheadii, Melianthus comosus, Pentanisia prunelloides and Warburgia solutaris. Essential oils generally displayed superior 5- lipoxygenase inhibitory activity with IC50 values between 22 and 75 ppm. These included the essential oils of Ballota africana, Helichrysum odoratissimum, Heteropyxis natalensis and Lippia javanica. A large proportion of the plants exhibited dose-dependent DPPH anti-oxidant activity with IC50 values between 5 and 94 ppm for the most active. These included Halleria lucida, Croton sylvaticus, Melianthus comosus, Lippia javanica and Pentanisia prunelloides. Aqueous extracts of Melianthus comosus exhibited the most potent anti-inflammatory and anti-oxidant activity. The methanol extract of the leaves of Halleria lucida was subjected to activity guided fractionation and two anti-oxidant molecules were isolated, namely luteolin-5-Oglucoside and verbascoside (acteoside). Isobologram construction resulted in a concentration-dependent additive and antagonistic interaction being recognised between the two isolated compounds. Warburgia salutaris displayed promising 5-lipoxygenase inhibitory activity. Two isolated compounds, mukadiaal and warburganal were found to partially contribute to the anti-inflammatory activity of the plant. The essential oils of Helichrysum odoratissimum, Heteropyxis natalensis and Lippia javanica were subjected to gas chromatography and major compounds contributing to possible anti-inflammatory effects identified. These included β-caryophyllene, 1,8-cineole, limonene and α- humulene. Enantiomers and racemic mixtures of limonene displayed significantly different 5-lipoxygenase inhibitory activity suggesting stereoselectivity of the enzyme-catalysed reaction. The monoterpene 1,8-cineole appeared to cause partial potentiation of the anti-inflammatory activity displayed by limonene. These results provide some in vitro scientific rationale for their traditional use as dermatological agents.
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Use of antioxidant activity and flavonoid levels to assess the quality of commercially available solid dose Sutherlandia frutescens products

Hess, Meggan Sade January 2010 (has links)
The overall aims of this project were to assess the pharmaceutical quality and consistency of commercially available solid dose Sutherlandia frutescens containing products (viz. tablets & capsules) by exploring the use of monitoring the pharmaceutical presentation, flavonoid profile and antioxidant activity levels and to develop/or adapt methods and specifications that may be used for the quality control of such products.Stability tests were conducted on all of the selected SCP. The products were stored under elevated temperatures and environmental humidity conditions and total phenol, antioxidant and chromatographic analysis was conducted on these samples. Samples of each of the SCP were hydrolyzed using HCL and then analyzed using HPLC to test the stability of the flavonoids present in each product. The SCP investigated in this study physically appeared to be of quite good “pharmaceutical” quality, but generally lacked information on the date of manufacture and lacked package inserts, or when these were present they contained insufficient information.Based on the results obtained, it is recommended that, the manufacturers of SCP pay more attention to the information provided on the package inserts and the storage conditions for their products. Further the levels of antioxidant activity, total phenols and flavonoid (sutherlandins A to D) be used as specifications to control the quality of commercially available solid dose Sutherlandia frutescens containing preparations on an individual basis.
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Antioxidant activity of cyclolinopeptides

2013 June 1900 (has links)
Cyclolinopeptides (CLs) are hydrophobic cyclic peptides found in flaxseed. They show immunosuppressive activity, but the biological function of these compounds is largely unknown. This thesis presents the results of studies that were conducted to determine whether CLs could act as antioxidants. In the first study, flaxseed oil was passed over a silica adsorbent column to remove polar compounds. The polar compounds were then eluted from the silica absorbant using a series of increasingly polar solvents. Individual polar fractions were then added back to the silica-treated flaxseed oil and the oxidative stability index of these samples was determined at 100 °C. A polar fraction containing mainly CLA, β/γ- and δ-tocopherol increased the induction time of silica-treated flaxseed oil from 2.3 ± 0.28 h to 3.2 ± 0.41 h. A positive effect of the polar fraction containing a mixture of CLA and CLD-CLG on the oxidative stability of oil was also observed. The antioxidant mechanism of CLs was investigated in several model systems using electron spin resonance spectroscopy. The concentration of radicals in a DMPO (5,5-dimethyl-1-pyrroline-N-oxide) radical-CLs reaction mixture was monitored. All CLs exhibited dose dependent scavenging activities. CLA–CLC reactions with DMPO-OH at a concentration of 5 mM resulted in a 24–30% decrease in electron paramagnetic resonance (EPR) signal intensity. The reaction of CLs and the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH•) revealed a more complex interaction than simple radical scavenging. Peptides (CLG and CLG") that contained both tryptophan and methionine showed stronger radical scavenging activity than did CLs containing methionine or methionine sulfoxide but not tryptophan (CLB and CLC). Irradiation of the reaction mixture of DPPH• and peptide with UV light also affected the radical scavenging behaviour. Scavenging activities of DPPH• by CLB, CLC and CLA were enhanced by light, whereas scavenging of DPPH• by the tryptophan containing peptides CLG and CLG″ was not affected. High-performance liquid chromatography with mass spectrometry (HPLC-MS) analysis of the reaction mixtures after a radical scavenging reaction was used to determine the impact of radical scavenging on the peptides. These reactions revealed new masses that were identified and characterized. It was established that DPPH• reacted with the methionine of CLB and with tryptophan in CLG and CLG, by formation of a new covalently-bonded species. Covalent linkages between these amino acids (alone or in peptides) and DPPH• have not been reported previously.

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