• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 122
  • 111
  • 36
  • 32
  • 9
  • 9
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 4
  • 2
  • 2
  • Tagged with
  • 384
  • 384
  • 104
  • 47
  • 44
  • 38
  • 34
  • 30
  • 25
  • 21
  • 20
  • 19
  • 17
  • 17
  • 17
  • 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.
341

Estabelecimento da vida útil de hortaliças minimamente processadas sob atmosfera modificada e refrigeração. / Establishing the shelf life of minimally processed vegetables by modified atmosphere and refrigeration.

Lucimeire Pilon 28 August 2003 (has links)
As perdas pós-colheita de alimentos hortícolas justificam a adoção de técnicas de conservação. Uma vez beneficiados, esses produtos permitem agregar valor à produção primária e se tornam de conveniência ao consumidor. Essa pesquisa teve como objetivo definir as metodologias do processamento mínimo de cenoura, pimentão e salada mista (batata e vagem), quanto ao tipo e intensidade de adoção das técnicas de barreiras e monitorar o processamento, via controle microbiológico, sensorial, físico-químico e nutricional. As hortaliças foram lavadas em água corrente, descascadas e cortadas com facas afiadas de aço inoxidável. Para a sanificação, foram imersas por 15 min em água refrigerada (± 7ºC) com 100 mg L-1 de cloro livre a pH ajustado para 7,0; a seguir foram centrifugadas a 550-900 G, por 5 min. As hortaliças foram acondicionadas, manualmente, em sacos plásticos de filme multicamada laminado, do tipo BOPP/PEBD (polipropileno biorientado/polietileno de baixa densidade). As embalagens foram fechadas em seladora modelo AP-500, marca Tec Maq, sob ar atmosférico, vácuo e atmosfera modificada (2% de O2, 10% CO2 e 88% de N2) e a seguir foram armazenados sob refrigeração a 1ºC ± 1ºC. A vitamina C não foi afetada em nenhum dos tratamentos nos três produtos. Os teores de b-caroteno mantiveram-se praticamente constantes em cenoura e salada mista; no pimentão, após a primeira semana de armazenamento, sofreram um decréscimo, permanecendo praticamente inalterados ao longo do armazenamento. Quanto à análise sensorial, os resultados para a cenoura e salada mista, foram satisfatórios até 21 dias de armazenamento para todos os tratamentos; exceto para o pimentão. Os três produtos obtiveram em todos os tratamentos, contagens para psicrotróficos variando de 10 2 a 10 5 UFC/g, 10 1 a 10 3 UFC/g e 10 3 a 10 6 UFC/g, respectivamente. Anaeróbios mesófilos e coliformes totais, foram constatados em pimentões minimamente processados. Porém, as baixas contagens obtidas, em todos os tratamentos, mostraram que a vida útil destes prolongou-se até o 14º dia de armazenamento. Para a cenoura e salada mista minimamente processadas, não foram constatados coliformes totais e fecais, anaeróbios mesófilos e Salmonella em nenhum dos tratamentos. / The postharvest losses of horticultural products justify the adoption of preservation techniques. Once these products are processed, they add value to the primary products and they become convenient to the consumer. This research had the purpose of defining the methodologies for minimal processing of carrot, green pepper and mixed salad of potato and string bean in relation to the type and intensity of adoption of the barrier techniques. In addition, it was our objective to monitor the processing, through by microbiological, sensory, physical-chemical and nutritional evaluation. The vegetables were washed in running water, peeled and cut with sharp stainless steel knives. For the sanitization they were submerged, for 15 min, in cold water (± 7ºC) with 100 mg L -1 of free chlorine at pH 7,0; next, they were centrifuged at 550-900 G, for 5 min. The product was hand packed in plastic bags BOPP/LDPE (biorientated polypropylene/low-density polyethylene). The packages were sealed under air, vacuum and modified atmosphere (2% O2, 10% CO2 and 88% N2) and stored under refrigeration at 1ºC±1ºC. The vitamin C content was not affected in any of the treatments. The values for b-carotene remained stable for carrot and mixed salad. For the green pepper, the values decreased after the first week of storage. In relation to the sensory analysis, carrot and mixed salad were considered satisfactory until 21 days of storage for all treatments; but for green pepper. In all treatments, counts for the three products ranged psychrotrophic ranging from 10 2 to 10 5 UFC g -1 , 10 1 to 10 3 UFC g -1 , 10 3 to 10 6 UFC g -1 , respectively. Anaerobic mesophiles and total coliforms were observed in minimally processed green peppers. However, the low count obtained in all treatments indicated a shelf life of 14 days. For the minimally processed carrot and mixed salad, no total or fecal coliforms, anaerobic mesophiles and Salmonella were observed in any of the treatments.
342

Estudo da congestão venosa após amputação subtotal de membro de ratos: efeito protetor do alopurinol, vitamina c, tirofiban ou heparina na isquemia secundária / Study of venous congestion after partial limb amputantion in rats: protective effects of Allopurinol, Vitamin C, Tirofiban or Heparin in secondary ischemia

Jose Carlos Faes da Silva 17 March 2014 (has links)
A trombose venosa é a principal complicação da microcirurgia vascular e a intervenção precoce é necessária para o salvamento dos retalhos, com índices de sucesso de apenas 50% das revisões cirúrgicas; trombose da microcirculação, produção de radicais livres de oxigênio (RLO) e edema são os elementos principais da lesão de isquemia/reperfusão (I/R), e o planejamento das terapias protetoras tem como objetivo amenizar estas alterações. Os fármacos antioxidantes, antiagregantes plaquetários e anticoagulantes são utilizados no controle da lesão de I/R em diferentes órgãos. Neste estudo, em modelo de amputação subtotal de membro posterior de rato submetido a isquemia global primária, foi testado o efeito protetor dos fármacos alopurinol, heparina, tirofiban ou vitamina C durante a isquemia secundaria pós congestão venosa. Foram operados 100 ratos, que apos isquemia global de 90 minutos, foram divididos em cinco grupos de 20 animais recebendo uma das respectivas drogas na veia femoral contra-lateral: 1ml de solução fisiológica 0,9% no grupo controle (GC), 1ml de alopurinol 45mg/kg no grupo experimental 1 (G1), 1ml de heparina 200UI/kg no grupo experimental 2 (G2), 1ml de tirofiban 50 ug /ml no grupo experimental 3 (G3) e 1 ml de vitamina C 100mg/kg no grupo experimental 4 (G4); o clampe foi então retirado do feixe vascular e se iniciou a reperfusão de 60 minutos; a colocação do clampe vascular apenas na veia femoral direita iniciou a congestão venosa (isquemia secundária) do membro por 90 minutos seguido de outra reperfusão de 60 minutos; O músculo gastrocnêmio foi dissecado e retirado para analise histológica e os animais sacrificados por injeção letal. Foram estudados a porcentagem de viabilidade celular muscular, o edema e o extravasamento de hemácias. A porcentagem de lesão celular do músculo do grupo controle foi 54,6% (±10,6), do G1 31,5% (±13,6), do G2 24,7% (±11,7), do G3 24,6% (±8,6) e do G4 21,3% (±8,6). Os grupos foram comparados por modelo de comparação múltiplas one way-ANOVA e post-hoc Tukey com significância de p < 0,05. A porcentagem de lesão celular foi menor para os grupos G1, G2, G3 e G4 quando comparados ao GC (p < 0,001), e quando comparados os grupos experimentais entre si, apenas o G4 (vitamina C) foi menor estatisticamente que G1(alopurinol) (p < 0,029). A utilização individual dos fármacos alopurinol, heparina ,tirofiban e vitamina C mostraram efeito protetor na congestão venosa secundaria a isquemia global primária, e a vitamina C foi mais efetiva nesta ação que o alopurinol quando comparados os antioxidantes entre si. Quando avaliado o edema, apenas os antioxidantes tiveram índices menores estatisticamente que o GC, enquanto que todos os fármacos diminuíram o extravasamento de hemácias comparados com o grupo controle (p < 0,001) / Venous thrombosis is the main complication of vascular microsurgery an early intervention is mandatory to rescue the flap, with a success rate of only 50% of surgical revisions; microcirculation thrombosis, oxygen free radicals production and edema are the main elements of ischemia/reperfusion (I/R) injury, and protective therapies aim to mitigate these changes. Antioxidants, antiplatelets and anticoagulants are used in different organs to control this injury. In this study, in a partial hind limb amputation model submitted to global ischemia, it was tested the protective effect of Allopurinol, Heparin, Tirofiban or Vitamin C during secondary ischemia after venous congestion. A hundred rats divided in five groups of 20 animals each were operated; after global ischemia of 90 minutes each group was injected into the contra lateral femoral vein one of the following solutions: 1 ml of saline solution NaCl 0,9% - control group (CG); 1ml of Allopurinol 45mg/kg - experimental group 1 (G1); 1ml of Heparin 200 UI/kg - experimental group 2 (G2); 1ml of Tirofiban 50 ug /ml - experimental group 3 (G3); 1ml of Vitamin C 100mg/kg - experimental group 4 (G4). Sixty minutes of limb reperfusion was performed, and a secondary period of limb ischemia started with the clamping of the femoral vein only (limb congestion) which lasted for 90 minutes (secondary ischemia). After that, the vein clamp was removed and a 60 minute reperfusion period was observed; at the end of the second reperfusion period, the right gastrocnemius muscle was removed and fixed in 10% formaldehyde, animals were euthanized with a lethal dose of Pentobarbital. Muscle fibers were scored as uninjured or injured based on the morphology of individual fibers; interstitial edema and bleeding were graded on a four-point scale. The control group had more damaged muscle cells 54.6±10.6% when compared to allopurinol 31.5±13,6%, heparin 24.7±11.7%, tirofiban 24.6±8.6% and Vitamin C 21.3±8.6% all reached statistical significance (p < 0.00 0.029). These comparisons were analysed using ANOVA and post-hoc Tukey. The single use of Allopurinol, Heparin, Tirofiban or Vitamin C showed a protective effect on venous congestion after global ischemia, and Vitamin C was more effective than Allopurinol when compared both antioxidants. When evaluating the edema, only the antioxidants had statistically lower rates than the CG, whilst all drugs reduced the extravasation of red blood cells compared with the control group (p < 0.001)
343

Educação nutricional de pré-escolares: consumo de alimentos ricos em ferro e vitamina C / Nutrition education of preschool: consumption foods rich in iron and vitamin C

Brasil, Renata 30 July 2013 (has links)
Submitted by Aline Batista (alinehb.ufpel@gmail.com) on 2015-03-24T16:47:40Z No. of bitstreams: 2 Educação nutricional de pré-escolares consumo de alimentos ricos em ferro e vitamina C.pdf: 1628355 bytes, checksum: bef0095c87d8d1342a37506289a64614 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2015-03-24T18:02:32Z (GMT) No. of bitstreams: 2 Educação nutricional de pré-escolares consumo de alimentos ricos em ferro e vitamina C.pdf: 1628355 bytes, checksum: bef0095c87d8d1342a37506289a64614 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2015-03-24T18:04:03Z (GMT) No. of bitstreams: 2 Educação nutricional de pré-escolares consumo de alimentos ricos em ferro e vitamina C.pdf: 1628355 bytes, checksum: bef0095c87d8d1342a37506289a64614 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-03-24T18:04:03Z (GMT). No. of bitstreams: 2 Educação nutricional de pré-escolares consumo de alimentos ricos em ferro e vitamina C.pdf: 1628355 bytes, checksum: bef0095c87d8d1342a37506289a64614 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013-07-30 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Objetivo Realizar intervenção de educação nutricional com pré-escolares, estimulando o consumo de alimentos que aumentam o aporte de ferro para o organismo e também para o consumo de alimentos fontes de vitamina C, que é um facilitador da absorção desse mineral. Métodos A intervenção foi realizada com 42 crianças, de quatro a seis anos de idade, que estudavam no turno da manhã de uma Escola Municipal de Educação Infantil, da cidade de Capão do Leão, RS. Foram coletados dados socioeconômicos, de saúde da criança e antropométricos. Como estratégia de educação nutricional foram utilizados métodos lúdicos visando o incentivo ao consumo de preparações alimentares ricas em ferro e vitamina C. As crianças foram avaliadas em relação a aprendizagem sobre o tema e a aceitação das preparações oferecidas. Palestras com informações de nutrição e saúde foram repassadas aos pais e/ou responsáveis, professores e merendeiras visando consolidar as práticas de nutrição no ambiente familiar das crianças. Resultados O perfil antropométrico demonstra alta prevalência de risco de sobrepeso (27,3%) para crianças menores de cinco anos de idade e de sobrepeso (31,6%) naqueles com cinco anos ou mais. Foi verificado aumento do conhecimento das crianças em relação aos alimentos que visam prevenir a anemia e aumento no consumo das preparações ricas em ferro e vitamina C inseridas na alimentação escolar. Conclusão A estratégia de educação nutricional de caráter lúdico produziu resultados positivos junto aos pré-escolares quanto à adesão ao consumo de alimentos fontes de ferro e vitamina C para prevenção da anemia, e pode ser usado como modelo para estímulo ao consumo de outros alimentos e o combate a outras deficiências nutricionais. / Objective To conduct nutrition education intervention for preschool children, encouraging the consumption of foods capable of increasing iron level in the body, as well as food sources of vitamin C, since it is an absorption facilitator of that mineral. Methods The intervention was conducted with 42 children aged four to six years old, studying in the morning shift of a Municipal School of Early Childhood Education in the city of Capão do Leão, Rio Grande do Sul, Brazil. Socioeconomic, anthropometric and child health data were collected. Playing methods were used as the nutrition education strategy in order to encourage consumption of meals rich in iron and vitamin C. Children’s learning about the topic and acceptance of the offered meals were assessed. Lectures on nutrition and health information were given to parents and/or guardians, teachers and cooks to consolidate the nutrition practices in the children’s family environment. Results The anthropometric profile shows a high prevalence for risk of overweight (27.3%) in children under five years old and for overweight (31.6%) in those aged five years or more. Increases were noticed in children's knowledge on food items that help preventing anemia and in the consumption of food preparations rich in iron and vitamin C inserted in school meals. Conclusion The nutrition education strategy of playfulness rendered positive results among the preschoolers concerning the adherence to the consumption of foods source of iron and rich in vitamin C to prevent anemia, therefore it can be used as a model for encouraging the consumption of other foods and combat other nutritional deficiencies.
344

Detecção amperométrica, com microeletrodos, de espécies reativas de oxigênio e nitrogênio em células isoladas estimuladas por substâncias biologicamente ativas / Amperometric detection, with microelectrodes, of reactive oxygen and nitrogen species in isolated cells stimulated by biologically active substances

Ferreira, Danielle Cristhina Melo 02 May 2008 (has links)
The production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) is a metabolic situation, observed in different physiological conditions. When their production is exacerbated, there is an efficient antioxidant system able to control and re-install the homeostasis. Oxidative stress results from an acute and chronic imbalance between the production of ROS and antioxidant capacities of living cells and organisms. In the present case, the release of bursts of ROS and RNS by individual macrophages RAW 264.7 was investigated, in real time, in absence and presence of quinones (alpha- and beta-lapachones) and ascorbic acid. A selective electrochemical detection of each ROS or RNS was conducted at platinized carbon fiber microelectrodes positioned at micrometric distances from single cells, always compared to controls. The results show that the presence of beta-lapachone with 0.1 to 100 µM, within one hour of incubation, leads to a decrease of RONS release by macrophages. Conversely, when the incubation time increases (4 hours and more), for concentrations of 1 µM of ortho-quinone, the quantity of the released species increases. Finally, the increasing of the concentration up to 10 µM with four hours of incubation and more is associated to cell death. The exact nature of the released electroactive species was characterized and the original flux could be reconstructed in terms of O2• and NO•. In the first hour, with 10 µM, the decrease of the oxidative burst concerns mainly the RNS species. The amount of ROS, quantified in terms of H2O2 was shown to be higher than in control. At concentration of 1 µM and after longer time incubation, i. e., 4 hours, the amount of ROS, quantified in terms of H2O2 and O2• and NO2- was shown to be higher than in control. It was observed which ONOO- was decreased in both situations. On the other hand, alpha-lapachone was unable to significantly increase ROS and RNS production in macrophage cells, even after 24 hours of incubation. The cytotoxic concentration observed for alpha-lapachone was ten times higher when compared with beta-lapachone. To overcome solubility and bioavailability problems with beta-lapachone, beta-cyclodextrin was used. UV/vis spectroscopy has been used to monitor the inclusion phenomena of beta-lapachone within the cavity of beta-cyclodextrin, together with studies concerning the competitive effects of ethanol concentration on this behavior. A value of 15 ± 5 M-1 was found for the association constant between beta-lapachone and beta-cyclodextrin in phosphate buffer. This clearly indicates that the equilibrium between the free and the complexed substrate is decreased in the presence of EtOH. Amperometry at platinized carbon fiber ultramicroelectrodes allowed quantitative and kinetic investigations of the overall effect of ascorbic acid on oxidative stress responses produced by single cells pertaining to two different cell lines derived from immune cells: macrophages RAW 264.7 and phagocytes PLB-985. These fine and minute amperometric measurements performed on single cells confirmed that in contradiction with its alleged universal anti-oxidant properties, ascorbic acid may affect positively or negatively the RNS content of oxidative bursts produced by each cell type, through affecting the primary production of NO• by the cells. So, vitamin C acts exclusively as an anti-oxidant (viz., reduced the primary NO• flux) onto PMA-treated PLB 985 cells, thus decreasing the quantity of RNS released by these granulocyte-type cells. Conversely, it gives rise to a prooxidant activity (viz., increased the primary NO• flux) onto RAW267.4 macrophage cells, increasing their production of RNS species. These studies demonstrate the advantage of electrochemical methods for analyzing in real-time and quantitatively the effect of pharmacologically active compounds in cells, in case of oxidative burst. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Conselho Nacional de Desenvolvimento Científico e Tecnológico / A produção de espécies reativas de oxigênio (ERO), de nitrogênio (ERN), entre outras espécies reativas, é parte integrante do metabolismo e é observada em diversas condições fisiológicas. Quando sua produção é exacerbada, o organismo dispõe de um eficiente sistema antioxidante que consegue controlar e restabelecer o equilíbrio. O estresse oxidativo resulta do desequilíbrio entre o sistema pró e antioxidante, com predomínio dos oxidantes. A liberação de ERO e ERN em macrófagos individuais da linhagem RAW 264.7 foi estudada em tempo real, em ausência e presença de quinonas (alfa- e beta-lapachonas) e de ácido ascórbico. A detecção eletroquímica seletiva de ERO e ERN, em conjunto e individualmente foi conduzida, utilizando-se microeletrodos de fibra de carbono platinizada, posicionados a distâncias micrométricas de uma célula, sempre em relação a controles. Os resultados do tratamento com beta-lapachona (0,1 a 100 µM), com 1 hora de incubação, mostram que ocorre a diminuição de ERON liberados pelos macrófagos. Contrariamente, quando o tempo de tratamento aumenta (4 e 6 horas) para a concentração de 1 µM, ocorre o aumento da quantidade de espécies reativas liberadas. Em concentração de 10 µM e com tempo de tratamento acima de 4 horas ocorre morte celular. A natureza exata das espécies eletroativas liberadas foi caracterizada e o fluxo original foi determinado em termo de O2• e NO•. No tratamento de 1 hora com 10 µM de beta-lapachona, houve diminuição do surto oxidativo relacionado principalmente às ERNs. A quantidade de ERO, em termos de H2O2 foi muito maior do que o controle. Em diferentes condições, com 1 µM com 4 horas de tratamento, a quantidade de ERO, em termos de H2O2, O2• e NO2-, foi maior que o controle. Nas duas condições, obteve-se a diminuição acentuada de ONOO-. Por outro lado, a incubação com alfa-lapachona não foi capaz de alterar significantemente a liberação de ERON pelos macrófagos, mesmo após 24 horas de tratamento. A concentração citotóxica observada para a alfa-lapachona foi dez vezes maior quando comparada com a beta-lapachona. Para contornar problemas relacionados à solubilidade e biodisponibilidade da beta-lapachona, fez-se uso da ciclodextrina. A espectroscopia no UV/Vis foi utilizada para monitorar o fenômeno de inclusão de beta-lapachona na cavidade da beta-ciclodextrina, com análise do efeito competitivo do etanol. O valor da constante de associação entre a beta-lapachona e a beta-ciclodextrina, em tampão fosfato, foi de 15 ± 5 M-1, mostrando que a presença de etanol afeta a formação do complexo. A amperometria utilizando ultramicroeletrodos de fibra de carbono platinizada permitiu investigar quantitativa e cineticamente o efeito total do ácido ascórbico no surto oxidativo produzido por células individuais pertencentes a duas diferentes linhagens derivadas de células imunes: macrófagos (RAW 264.7) e fagócitos PLB-985. Medidas amperométricas finas realizadas em células individuais confirmaram que o ácido ascórbico pode estimular ou atenuar o surto oxidativo produzido por cada linhagem celular, afetando a produção primária de NO• das células. Assim, a vitamina C reduz o fluxo primário de NO• nas células PLB-985 pré-tratadas com PMA, enquanto aumenta o fluxo primário de NO• em macrófagos RAW 264.7. Esses estudos demonstram a vantagem dos métodos eletroquímicos para analisar em tempo real e quantitativamente o efeito farmacológico de compostos ativos em células, no caso de surto oxidativo.
345

Analýza vybraných nutričních parametrů v nových odrůdách angreštů / Analysis of selected nutritional parameters in the new varieties of gooseberries

Nováková, Jana January 2013 (has links)
Diploma thesis deals with the new varieties of gooseberries. The theoretical part characterizes gooseberry from a biological point of view, what is the content of healthful nutrients and states food technology aspects. Furthermore, the theoretical part deals with the main parameters examined nutrition: vitamin C, anthokyanům and antioxidant activity. In the experimental part was measured both weight solids content and soluble solids. Vitamin C was measured by HPLC, anthocyanins using a pH differential method and for antioxidant activity determination was selected method by Kanedy known also as DPPH.
346

Charakterizace plodů aronie (Aronia melanocarpa) a muchovníku (Amelanchier alnifolia) / Characterisation of chokeberry and saskatoon berry fruits

Burdějová, Lenka January 2014 (has links)
Diploma thesis deals with the characterization of chokeberry (Aronia melanocarpa) and saskatoon berry (Amelanchier alnifolia) fruits. The theoretical part focuses on the botanical classification, chemical composition, curative effects and the use of chokeberry and saskatoon berry in the food industry. Further, the attention is also devoted to a review of methods for the determination of important antioxidants, specialized on the determination of polyphenols, anthocyanins, ascorbic acid and total antioxidant activity. The experimental part of the work deals with the determination of selected parameters in different varieties of chokeberry and serviceberry, harvested in 2012 and 2013 using spectroscopic and chromatographic techniques with an emphasis on effect of solvent (50% ethanol, destilled water, DMSO). Specifically total content of polyphenols and anthocyanins, color characteristics using the CIE L*a*b* system and the ability of the sample to reduce the iron are determined using the UV-VIS-NIR spectroscopy. Further ascorbic acid concentration in individual extracts is quantified by High performance liquid chromatography coupled with a diode array detector and the total antioxidant activity is characterized by electron paramagnetic resonance involving •DPPH and ABTS•+ assays.
347

Možnosti přípravy kombinovaných nápojů z vybraných druhů ovoce / Possibilities of preparation combined drinks from selected fruits

Zábranská, Miroslava January 2016 (has links)
This thesis deals with the preparation of the combined alcoholic beverages based on wine and fruit juices. The fruit juices were obtained from the selected fruits as honeysuckle, mulberry, dogwood, rose hips, elderberry, buckthorn and aronia. Some chemical properties e. g. total fenolics, total anthocyanins, vitamin C and sacharides were determined for characterization of the mentioned juices. As well as chemical parameter of juices, the same chemical parameters were determined on wine. There were prepared three sets of combined beverages from wine and juices. The two best evaluated beverages were chosen on the basis of their sensory evaluation. In the end, the same chemical properties were determined in both particular juices and resulting beverages.
348

Stanovení vybraných chemických parametrů plodů moderních odrůd angreštů / Determination of selected chemical parameters of fruits of modern gooseberry varieties

Javorská, Kateřina January 2014 (has links)
Diploma thesis deals with determination of individual chemical parameters contained in modern varietes of gooseberries (Grossularia uva-crispa). The theoretical part is focused on the botanical characteristics of the plant, a description of selected varietes, chemical composition and food utilization fruits. The second half of the theoretical part is devoted to the characterization of selected nutritional parameters and methods for determination of total anthocyanins, phenolic compounds, vitamin C and antioxidant activity. Total of 17 varietes of gooseberries, which come from growers Vondráček and the Research and Breeding Institute of Pomology Holovousy Ltd. were analyzed in the experimental part. pH differential method was used to determination total monomeric anthocyanins. Total content of polyphenols were determined by using the Folin-Ciocalteu reagent. Next was determined content of vitamin C in all varieties by HPLC and was evaluated the total antioxidant aktivity using radical DPPH. In conclusion, individual varieties of gooseberries were compared by the contents of the determined chemical parameters.
349

Oxidative Lipid Fragmentation; New Mechanisms, Synthesis and Reactions of Putative Intermediates

Gu, Xiaodong January 2010 (has links)
No description available.
350

Потенциометрия в определении антиоксидантной емкости соединений разной гидрофильности с использованием ПАВ и смесей растворителей : магистерская диссертация / Potentiometry in determining the antioxidant capacity of compounds of different hydrophilicity using surfactants and solvent mixtures

Старчеусова, В. А., Starcheusova, V. A. January 2023 (has links)
Объектами исследования являются антиоксиданты аскорбиновая кислота, α-токоферол их смеси, специи, орехи и семена растений. Цель работы - разработка способа определения АОЕ соединений разной гидрофильности при их совместном присутствии на примере витаминов С и Е потенциометрическим методом. В работе представлены причины возникновения окислительного стресса, классификация антиоксидантов, эффект синергизма, проявляемый антиоксидантами в организме человека, описаны методы определения антиоксидантных свойств. В процессе работы были подобраны оптимальные условия для проведения анализа; определена антиоксидантная емкость индивидуальных антиоксидантов, модельных смесей и реальных объектов потенциометрическим методом; проведено сравнение результатов с методом Фолина-Чокальтеу. В результате исследования был разработан способ совместного определения антиоксидантной емкости соединений разной гидрофильности потенциометрическим методом. / The objects of research are antioxidants ascorbic acid, α-tocopherol mixtures thereof, spices, nuts, and plant seeds. The aim of the work is to develop a method for determining AOE compounds of different hydrophilicity in their joint presence using the example of vitamins C and E by the potentiometric method. The paper presents the causes of oxidative stress, the classification of antioxidants, the synergistic effect manifested by antioxidants in the human body, describes methods for determining antioxidant properties. In the course of the work, optimal conditions were selected for the analysis; the antioxidant capacity of individual antioxidants, model mixtures and real objects was determined by the potentiometric method; the results were compared with the Folin-Chocalteu method. As a result of the study, a method was developed for the joint determination of the antioxidant capacity of compounds of different hydrophilicity by the potentiometric method.

Page generated in 0.0721 seconds