• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 202
  • 89
  • 8
  • 8
  • 4
  • 3
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 351
  • 351
  • 205
  • 198
  • 51
  • 48
  • 44
  • 43
  • 40
  • 40
  • 40
  • 39
  • 37
  • 35
  • 32
  • 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.
171

Doce em massa convencional e light de goiabas (Psidium Guajava L.): estabilidade de compostos bioativos, qualidade sensorial e microbiológica / Sweet Conventional mass and light of guava (Psidium guajava l.): stability of bioactive compounds, microbiological and sensory quality

Freda, Suzan Almeida 21 February 2014 (has links)
Submitted by Aline Batista (alinehb.ufpel@gmail.com) on 2015-03-24T17:06:47Z No. of bitstreams: 2 Doce em massa convencional e light de goiabas (Psidium Guajava L.) estabilidade de compostos bioativos, qualidade sensorial e microbiológica.pdf: 1618992 bytes, checksum: adca4d452f1badee8320583cbe5be422 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2015-03-24T18:02:56Z (GMT) No. of bitstreams: 2 Doce em massa convencional e light de goiabas (Psidium Guajava L.) estabilidade de compostos bioativos, qualidade sensorial e microbiológica.pdf: 1618992 bytes, checksum: adca4d452f1badee8320583cbe5be422 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2015-03-24T18:04:22Z (GMT) No. of bitstreams: 2 Doce em massa convencional e light de goiabas (Psidium Guajava L.) estabilidade de compostos bioativos, qualidade sensorial e microbiológica.pdf: 1618992 bytes, checksum: adca4d452f1badee8320583cbe5be422 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-03-24T18:04:22Z (GMT). No. of bitstreams: 2 Doce em massa convencional e light de goiabas (Psidium Guajava L.) estabilidade de compostos bioativos, qualidade sensorial e microbiológica.pdf: 1618992 bytes, checksum: adca4d452f1badee8320583cbe5be422 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-02-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Atualmente, o consumo de frutas vem aumentando principalmente em decorrência do seu valor nutritivo e de seus potenciais efeitos benéficos à saúde. Estes alimentos contêm compostos oriundos do metabolismo secundário das plantas, destacando-se os compostos bioativos como os carotenoides, compostos fenólicos e ácido L-ascórbico. A goiaba (Psidium guajava L.) pertence à família Myrtaceae, é um fruto do tipo baga, com casca fina, lisa e verde, com polpa vermelha ou branca, de acordo com a variedade. Estes frutos são consumidos principalmente na forma in natura ou em forma de doces, sucos, compotas e geleias. O doce em massa convencional de goiaba (goiabada) é uma das principais formas de consumir a goiaba, além do consumo em sua forma in natura. Com base nestes aspectos surgiu a proposta deste estudo de realizar determinações dos principais compostos bioativos em goiabas e avaliar a estabilidade destes compostos durante o processamento e estocagem de doce em massa convencional e light produzidas com goiabas da variedade vermelha. As goiabas da variedade Paluma (vermelha) e Kumagai (branca), foram adquiridas na EMBRAPA Clima Temperado localizada na cidade de Pelotas. Os frutos foram sanitizados, e posteriormente ocorreu o preparo da polpa e dos doces, que foram armazenados por um período de 12 meses em temperatura ambiente e ao abrigo de luz. Foram realizadas análises de compostos bioativos (carotenoides, compostos fenólicos e ácido L-ascórbico), cor e microbiológicas nos doces a cada 3 meses. As polpas e os doces logo após processados foram analisados quanto à composição proximal e os principais parâmetros físico químicos. Os doces em massa logo após processados também foram submetidos a análises sensoriais através do teste triangular, aceitação e intenção de compra. As composições proximais das polpas de goiabas branca e vermelha, e dos doces apresentaram-se diferentes, assim como os parâmetros físico químicos avaliados. As polpas de goiaba vermelha e branca, e os doces em massa, apresentaram altos teores de compostos fenólicos, e o licopeno foi o principal carotenoide identificado nas polpas de goiaba vermelha e nos doces. O teor de ácido L-ascórbico apresentou-se elevado nas polpas e nos doces estocados pelo período de até 6 meses. Sensorialmente, no teste triangular os julgadores conseguiram diferenciar os doces em massa light e convencional, e no teste de aceitação apenas o doce em massa convencional alcançou o valor necessário para ser considerado aceito. Microbiologicamente, exceto aos 12 meses de estocagem, os doces apresentaram-se dentro dos padrões exigidos por legislação. Pelos resultados pode-se constatar que tanto as polpas quanto os doces apresentaram quantidades significativas de compostos com alto potencial antioxidante. / Currently, fruit consumption is increasing mainly due to its nutritional value and its potential health benefits. These foods contain compounds derived from secondary plant metabolism, especially the bioactive compounds such as carotenoids, phenolic compounds and L-ascorbic acid. Guava (Psidium guajava L.) belongs to the Myrtaceae family, is a fruit of the berry type, with thin, smooth and green with red or white pulp shell, according to the variety. These fruits are mainly consumed in the form in nature or in the form of sweets, juices, jams and jellies. The conventional sweet mass of guava (goiabada) is one of the main ways to consume guava, beyond consumption in their fresh form. Based on these aspects this study proposed to perform determinations of the major bioactive compounds in guava and evaluate the stability of these compounds during processing and storage of conventional and light sweet mass produced with red guavas variety. The variety of Paluma guava (red) and Kumagai (white), were purchased from EMBRAPA located in the city of Pelotas. The fruits were sanitized, and subsequently it was prepared the pulp and sweets, which were stored for a period of 12 months at room temperature and under light protection. The bioactive compounds (carotenoids, phenolic compounds and Lascorbic acid), color and microbiological analysis were performed every 3 months. Squashes and sweet mass soon after processed were analyzed for proximate composition and the main physical and chemical parameters. The sweet mass soon after processed were also subjected to sensory analysis through the triangular test, acceptance and purchase intent. Proximal composition of white and red pulp guavas, and sweet mass were different, as well the physical-chemical parameters evaluated. The pulps of red and white guava, and sweet mass, showed high levels of phenolic compounds, and the lycopene was the main carotenoid identified in red guava pulp and sweet mass. The content of L-ascorbic acid showed up high in the pulps and sweets mass stored for up to 6 months. The judges were able to differentiate between light and conventional sweet mass by the triangular test, and by the acceptance testing only the conventional sweet mass obtained the score to be considered accepted. Microbiologically, except for 12 months of storage, the sweets were within the standards requirements by legislation. By the results it can be seen that both the pulps as sweet mass showed significant amounts of compounds with antioxidant potential.
172

Consumo de feijão e efeitos do processamento na cocção sobre compostos fenólicos, capacidade antioxidante e atributos sensoriais / Consumption of beans and the processing effects on cooking over phenolic compounds, antioxidant capacity and sensory attributes

Botelho, Fabiana Torma 13 February 2014 (has links)
Submitted by Gabriela Lopes (gmachadolopesufpel@gmail.com) on 2016-09-26T14:08:40Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese-versao final_31_03.pdf: 1465705 bytes, checksum: 6bdab3574c99a765714c6fe1098adb64 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2016-09-26T18:32:52Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese-versao final_31_03.pdf: 1465705 bytes, checksum: 6bdab3574c99a765714c6fe1098adb64 (MD5) / Made available in DSpace on 2016-09-26T18:32:52Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese-versao final_31_03.pdf: 1465705 bytes, checksum: 6bdab3574c99a765714c6fe1098adb64 (MD5) Previous issue date: 2014-02-13 / Sem bolsa / O feijão é um alimento de excelente qualidade nutricional e fonte de compostos bioativos que auxiliam na prevenção de doenças. No Brasil, o consumo de feijão deve ser mantido por fazer parte da tradição culinária brasileira, porém estudos demonstram crescente redução no seu consumo em decorrência de alimentos prontos e refeições fora do lar. Ademais, não existe um consenso sobre efeitos de diferentes processamentos na cocção de feijão sobre compostos bioativos e atributos sensoriais de feijão. Diante disso, o objetivo desse estudo foi avaliar hábitos de consumo de feijão em restaurante e em casa, relacionando características sócio demográficas com motivos que influenciam no consumo de feijão, além de avaliar o efeito de diferentes processamentos na cocção de feijão sobre o conteúdo de compostos fenólicos, antocianinas, capacidade antioxidante e atributos sensoriais. Os resultados mostraram que: (1) o consumo de feijão em casa ainda é um hábito nas refeições e que os motivos nutricionais, sensoriais e culturais influenciam na escolha em consumir feijão; (2) a forma de processamento para a cocção está diretamente relacionada com a capacidade antioxidante e afeta a disponibilidade de compostos fenólicos, antocianinas e interfere nos atributos sensoriais do feijão. / Beans are food with excellent nutritional quality and source of bioactive compounds which help preventing diseases. In Brazil, beans consumption must be maintained because they are part of Brazilian culinary tradition. However, studies demonstrate the increasing reduction in beans consumption due to ready-to-eat food and meals eaten outside the household. Moreover, there is no consensus on the different processing effects of cooking over bioactive compounds and sensory attributes of beans. Therefore, the objective of this study was to evaluate consumption habits for beans in restaurants and households, relating socio-demographic characteristics to reasons that influence consumption of beans, besides evaluating the effect different processes have on beans cooking in relation to phenolic compounds content, anthocyanins, antioxidant capacity and sensory attributes. The results showed that: (1) consumption of beans at home is still a habit for meals and that nutritional, sensory and cultural reasons influence the choice to consume beans; (2) the kind of processing for cooking is directly related to the antioxidant capacity and affects the availability of phenolic compounds, anthocyanins and interferes in the sensory attributes of beans.
173

Evaluation of biologically active compounds in Coleonema album

Liebenberg, Lindy 12 June 2008 (has links)
The undeniable efficacy of medicinal plants and wide range of biological activities attributed to plant secondary metabolites are an indication that plants can serve as an excellent pool of bioactive compounds with useful therapeutic properties. The South African flora is recognised as one of the richest centres of plant diversity in the world. From this enormous biodiversity a large number of species has the potential to yield pharmacologically active compounds. C. album is an indigenous plant belonging to the Cape fynbos biome with potentially useful bioactivities. The aim of this study was to evaluate the bioactivity of C. album by screening plant extracts for antibacterial, anti-mycobacterial, antifungal, antioxidant and anti-HIV activity. For rapid and effective screening for the presence of bioactive compounds, a bioassay-guided fractionation methodology was followed. Extracts from plant material obtained from two different geographic regions, the Cape and Highveld, were prepared by liquid extraction in a ratio of 150g fresh plant material per litre solvent, either acetone or ethanol. Qualitative analysis of the crude extracts by TLC and RP-HPLC documented the multi-component plant constituents as a fingerprint, revealing a highly complex, but similar profile of extracted components in both plant groups. Preliminary identification and structural information of the bioactive components present in the active C. album extracts was obtained by a combination of preparative TLC and LC/MS. The development of resistance to all available classes of antibiotic agents, their decreased effectiveness and the re-emergence of previously uncommon infections has necessitated the search for antimicrobial substances with novel antimicrobial mechanisms. The antimicrobial activity, including the antibacterial (Gram-positive and Gram-negative), anti-mycobacterial and antifungal activity of the crude extracts were evaluated. The TLC-bioautographic method used to screen the plant extracts for antimicrobial activity, as well as the localisation of compounds with antibacterial and antifungal activity, indicated the presence of a number of inhibitory compounds with activity against all the microorganisms tested. Evaluation of the inhibitory strength of each extract by the serial microdilution assay indicated that the C. album extracts effectively inhibited all the microorganisms, with the minimum inhibitory concentrations in the low mg/ml range. The significant antimicrobial activity exhibited against all the microorganisms, especially against the Gram-negative bacteria, Mycobacterium tuberculosis and Candida albicans, could suggest the potential use of the extracts or their active constituents as therapeutic agents for the treatment of infectious diseases. The need for natural antioxidants in the health care sector and food industry, due to the role that free radicals play in the pathology of a variety of human diseases and radical-induced deterioration of food products, supported the evaluation of the free radical scavenging activity of C. album extracts against relevant free radical species. The antioxidant activity of the extracts measured using the TLC-DPPH method, revealed the presence of a number of compounds with antioxidant activity. Quantification of the radical scavenging activity by the DPPHspectrophotometric assay revealed that the acetone extracts had a higher radical scavenging activity compared to the ethanol extracts, a pattern that was also found with the fluorescencemicroplate based oxygen radical absorbance assay (ORAC), specific for peroxyl radicals. The observed antioxidant activity were correlated with the total polyphenol content of the crude extracts, determined by the Folin-Ciocalteau procedure, but not with the reducing capacity evaluated by a Fe3 + - Fe2 + reduction method. HIV/AIDS has gained significant interest due to the high mortality rate and the rapid spread of the disease. The appearance of HIV strains resistant to certain antiretroviral drugs, in addition to the high cost, severe metabolic side effects and therapeutic failure of currently available antiretroviral agents, served as motivation for evaluation of C. album for anti-HIV properties and to evaluate potential cytotoxicity of plant extracts in mammalian cell cultures. The effects of the crude extracts on the in vitro HIV-1 subtype C (the predominant HIV-1 form in South Africa) replication and cytopathic effect on CEMnkrCCR5 lymphoid cells were determined. Viability assays using tetrazolium salts and viability dyes allowed the assessment of the host cell responses in the cytotoxicity and anti-HIV screening. Assays were performed at the maximum non-toxic concentration of 50 μg/ml. Some of the plant extracts exhibited significant reduction of the virusinduced cytopathic effect and induced a significant increase in cellular viability. The effect of the extracts on HIV activity was also investigated by determining the viral p24 core protein level, an indication of the replication fitness of the virus; and a significant decrease in p24 antigen level, was found. An attempt to clarify the main active compounds and the structural elements conferring the bioactivity in the analysed systems, revealed the presence of phenolic compounds, primarily coumarins and flavonoids, which are thought to be responsible for the observed antibacterial and antioxidant activities. The results of this study indicate that C. album possess strong bioactivity that warrants further investigation. / Prof. I.A. Dubery Dr. D. Meyer
174

Isolation of bioactive metabolites with activity against HIV-1 target proteins from extracts of Sutherlandia frutescens and Lobostemon trigonus

Dambuza, Ntokozo Shirley January 2007 (has links)
Acquired Immunodeficiency Syndrome (AIDS) is a human disease caused by the human immunodeficiency virus type 1 (HIV-1) and it is one of the biggest social, economic and health challenges in the world. The Joint United Nations Programme on HIV/AIDS (UNAIDS) and World Health Organization (WHO) estimated that between 33.4 to 46.0 million people around the world were living with HIV/AIDS in December 2005 and the highest estimates are in the Sub-Saharan Africa (around 25 million). In more developed countries a combined antiretroviral therapy called highly active antiretroviral therapy (HAART) is used, which results in reduced progression to AIDS in most patients. Despite the beneficial effects of HAART, significant side effects are experienced by treated patients. In addition, most infected people live in countries where the treatment is very expensive or, in many cases, not available at all. These people therefore rely on medicinal plants for health care. In this study, aqueous extracts from Sutherlandia frutescens and Lobostemon trigonus were screened for potential anti-HIV activities in a series of in vitro enzymatic assays, including reverse transcriptase, HIV-1 protease and glycohydrolases. Two extracts of Sutherlandia leaves (SFL-1 and SFL-2) were prepared that inhibited HIV reverse transcriptase and a Lobostemon leaf extract (LTL) was shown to also inhibit this enzyme. All extracts were assayed at 1.25mg/ml. Tannin content was determined for all active extracts using a tannic acid assay. SFL-1 and SFL-2 were found to contain about 6 percent and 7 percent tannins, respectively, and LTL contained 31% tannins by weight. Tannins were removed using polyamide columns and three fractions were collected for each. The extracts were also fractionated with Sephadex G-25, Amberlite IR 120 and Dowex 1-X8 as size exclusion, cation exchange and anion exchange, respectively. Extracts were also fractionated by preparative thin layer chromatography where two compounds were separated from S. frutescens extract with high activity against reverse transcriptase while showing insignificant inhibition towards other enzymes tested. SFL-BFW-10 and SFL-WEF-7 inhibited reverse transcriptase by almost 100 percent and the IC50 values calculated for these compounds were 0.34 and 0.23mg/ml, respectively. Cytotoxicity of these compounds was evaluated on Chang liver cells and peripheral blood mononuclear cells (PBMCs). None of these compounds showed any significant inhibition of cell proliferation. The purity of these compounds could not be confirmed because there was insufficient material to use in the techniques required to show purity and identification. Therefore, TLC was used to determine the nature of these compounds. SFL-BFW-10 was identified as an organic acid and SFL-WEF-7 was identified as flavonoid.
175

In vitro testing to investigate the anticoagulant/antithrombotic and antidiabetic biological activity of Leonotis Leonurus

Mnonopi, Nandipha Olivia January 2007 (has links)
The rising costs of prescription drugs in the maintenance of personal health and wellbeing have increased the interest in medicinal plants. The World Health Organization estimates that 65 percent-80 percent of the world’s population use traditional medicine as their primary form of health care. In this project the focus has been on the use of Leonotis leonurus extracts as a traditional medicine. The major chemical constituent of this plant is marrubiin, which is a diterpenoid labdane lactone formed from a precursor called premarrubiin. Aqueous and acetone extract (AL and OL extract, respectively) of this plant has been found to have an antithrombotic effect, with IC50 values of 3mg/ml and 6mg/ml, respectively. The extracts also have an effect on fibrinolysis, where the lysis time was decreased by more than 50 percent by the organic extract and standard marrubiin. In whole blood ADP-induced platelet aggregation, the organic extract inhibited aggregation by 68 percent at a final concentration of 138μg/ml (equivalent to 7.2μg/ml marrubiin). Marrubiin has also been screened for antithrombotic/anticoagulant activity; no antithrombotic activity has been observed but it increased the rate of fibrinolysis, by decreasing lysis time by 64 percent and also decreasing fibrin formation. From these findings it can be concluded that marrubiin has a fibrinolytic effect and antiplatelet aggregation effect. In the diabetic studies, in hyperglycemic condition, the OL (10μg/ml) extract and standard marrubiin significantly increased insulin secretion by 200 percent (2-fold) and 400 percent (4-fold), respectively, with respect to the control. The OL extract and standard marrubiin stimulated the release of insulin, the stimulatory index was significantly increased by 450 percent (4.5-fold) and 500 percent (5-fold), respectively, with respect to the control. In the apoptotic studies, in the normoglycemic and hyperglycemic conditions, the OL extract decreased the occurrence of apoptosis, in a dose-dependent manner, with the lower concentrations inducing apoptosis significantly higher than the relevant controls. Standard marrubiin did not have an effect on apoptosis in hyperglycemic condition, but it decreased the occurrence of apoptosis by 200 percent (2-fold) under normoglycemic conditions. The OL extract increased proliferation by 148 percent (1.48- fold) and 155 percent (1.55-fold) in normoglycemic and hyperglycemic conditions, respectively. The same effect was observed for standard marrubiin, where, proliferation was increased by 180 percent (1.8-fold) and 200 percent (2.0-fold) in normoglycemic and hyperglycemic conditions, respectively. RT-PCR displayed that standard marrubiin inhibited the expression of insulin by 50 percent under normoglycemic conditions.
176

Chemical transformations and phytochemical studies of bioactive components from extracts of Rosmarinus officinalis L

Okoh, Omobola Oluranti January 2010 (has links)
Variations in the yield, chemical composition, antibacterial, and antioxidant properties of the essential oils of Rosmarinus officinalis L. cultivated in Alice, Eastern Cape of South Africa over a period of 12 months using the solvent-free microwave extraction and traditional hydrodistillation methods were evaluated. The GC-MS analyses of the essential oils revealed the presence of 33 compounds with 1,8-cineole, a-pinene, camphor, verbenone, bornyl acetate and camphene constituting about 80 percent of the oils throughout the period of investigation, with the solvent-free microwave extraction method generally yielding more of the major components than the hydrodistillation method. Each of the major components of the oils varied in quantity and quality of yield at different periods of the year. The method of extraction and time of harvest are of importance to the quantity and quality of essential oil of Rosmarinus officinalis. Higher amounts of oxygenated monoterpenes such as borneol, camphor, terpene- 4-ol, linalool, a-terpeneol were present in the oil of SFME in comparison with HD. However, HD oil contained more monoterpene hydrocarbons such as a-pinene, camphene, β-pinene, myrcene, a-phellanderene, 1,8-cineole, trans- β-ocimene, γ-teprinene, and cis-sabinene hydrate than SFME extracted oil. Accumulation of monoterpene alcohols and ketones was observed during maturation process of Rosmarinus leaves. Quantitative evaluation of antibacterial activity, minimum inhibitory concentration values were determined using a serial microplate dilution method. The essential oils obtained using both methods of extraction were active against all the bacteria tested at a concentration of 10 mg mL-1. The minimum inhibitory concentrations for the SFME extracted oils ranged between 0.23 and 1.88 mg mL-1, while those of the HD extracted oils varied between 0.94 and 7.5 mg mL-1, thus suggesting that the oil obtained by solvent free microwave extraction was more active against bacteria than the oil obtained through hydrodistillation. The antioxidant and free radical scavenging activity of the obtained oils were tested by means of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH+) assay and β- carotene bleaching test. In the DPPH+ assay, while the free radical scavenging activity of the oil obtained by SFME method showed percentage inhibitions of between 48.8 percent and 67 percent, the HD derived oil showed inhibitions of between 52.2 percent and 65.30 percent at concentrations of 0.33, 0.50 and 1.0 mg mL-1, respectively. In the β-carotene bleaching assay, the percentage inhibition increased with increasing concentration of both oils with a higher antioxidant activity of the oil obtained through the SFME than the HD method. Thin layer chromatography (TLC) was used to analyze the chemical composition of the extracts using three eluent solvent systems of varying polarities i. e. CEF, BEA and EMW and sprayed with vanillin-sulfuric acid. The chemical composition of the different extracts was similar with the exception of methanol and water extracts which had only one or two visible compounds after treating with vanillin-spray reagent. To evaluate the number of antibacterial compounds present in the fractions, bioautography was used against two most important nosocomial microorganisms. S. aureus (Gram positive) and E. coli (Gram negative). Nearly all the crude serial extraction fractions contained compounds that inhibited the growth of E. coli. The hexane extract had the most lines of inhibition followed by ethyl acetate. Bioassay-guided fractionation against E. coli was used to isolate antibacterial compounds. The largest number of antibacterial compounds occurred in the hexane fraction. Furthermore we tried to complete the characterization by extracting and studying other biologically important plant metabolites such as phenolic compounds to evaluate the antioxidant capacity of Rosmarinus extracts.
177

Valorisation de coproduits de la viticulture, les sarments de vigne, comme source de polyphénols à activité fongicide / Viticultural bioproducts valorization, grapes canes, as fungicidal polyphenol bioresource

Houillé, Benjamin 14 December 2015 (has links)
Ce travail porte sur la valorisation de sarments de vigne comme source de polyphénols bioactifs. Après purification d’oligomères du resvératrol et hémi synthèse d’analogues du resvératrol, l’activité antifongique de ces molécules a été testée. Le 3,5-diméthoxyresvératrol a montré des activités intéressantes sur douze espèces du genre Candida. Pendant le stockage des sarments, une forte augmentation en E-resvératrol et E-picéatannol a lieu de façon thermo dépendante et l’expression des gènes PAL, C4H et STS participent à la biosynthèse de novo du E-resvératrol. Une infection par le mildiou au vignoble pendant la période de croissance modifie à la fois la composition et la répartition spatiale des stilbénoïdes dans les sarments. L’analyse métabolomique ciblée par UPLC-MS couplée à une analyse PLS-DA permet de discriminer les sarments selon leur génotype et de déterminer des métabotypes. La distance biochimique observée correspond à la distance génétique inter cépage. Ces résultats démontrent le potentiel antifongique des stilbènoïdes et permettent d’identifier quelques facteurs clés influençant la composition phytochimique des sarments de vigne. / This work aims at grape cane valorization as a source of bioactive polyphenols. After purifying E-resveratrol oligomers and obtaining E-resveratrol analogues through semi-synthesis, the antifungal activity of the compounds was evaluated. The 3,5-dimethoxyresveratrol exhibited interesting activity against twelves Candida species. During post-pruned grape cane storage, a strong and temperature dependent increase in E-resveratrol and E-piceatannol was observed and the expression of PAL, C4H, 4CL and STS genes contributed to a de novo biosynthesis of E-resveratrol. Downy mildew infection in vineyard during the growing season modified both the composition and the spatial distribution of stilbenoids in grape canes. UPLC-MS-based targeted metabolomics coupled to multivariate statistical analysis discriminates grape canes according to their genotypic origin and determines metabotypes. The observed biochemical distances between genotypes corresponded to genetic distances. Finally, results highlight the antifungal potential of stilbenoids and several key factors affecting the phytochemical composition of grape canes
178

Efeito dos sistemas de produção orgânico e convencional na qualidade nutricional de alface dos grupos lisa, crespa e americana

Souza, André Luiz Gomes de 27 February 2012 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The nutritional quality of vegetables is related to the management practices adopted in production systems. According to theory Trofobiose conventional production systems may affect the development of plants providing higher levels of free amino acids and soluble sugars making vegetables more vulnerable to attack by pests and disease manifestations by facilitating the availability of nutrients. The objective of this study was to evaluate the effects of production systems on conventional and organic compound levels of primary and secondary metabolism of lettuce groups Lisa Crespa and Americana. Groups of lettuce produced in organic and conventional farms were collected in the wild region of Sergipe in two production cycles. For each production system and cycle were collected 10 heads of lettuce Lisa Crespa and Americana. The data were analyzed levels of chlorophyll, carotenoids, total phenols, total organic acids, ascorbic acid, protein, nitrate, ash, fiber and soluble solids, determining the activity of polyphenol oxidase and phenylalanine ammonia-lyase. The analyzes were performed with five repetitions of each system and the production cycle. It was found in all groups lettuce than the conventional system can reduce the levels of bioactive compounds, and antioxidants, to the time which can provide increased levels of soluble solids. Lettuce American group showed the greatest effects related to production systems having a more severe nutritional quality and thus can be regarded as less suitable conventional production systems compromise by providing a greater degree of vitamins and provitamins. The organic production system contributed to the nutritional potential of lettuce groups Lisa, and American Crespa favoring the levels of bioactive compounds and antioxidants compared to those grown in conventional production system. / A qualidade nutricional de produtos hortícolas está relacionada com as práticas de manejo adotadas nos sistemas de produção. Segundo Teoria da Trofobiose os sistemas de produção convencional podem afetar o desenvolvimento dos vegetais proporcionando maiores teores de aminoácidos e açúcares solúveis livres tornando os produtos hortícolas mais vulneráveis ao ataque de pragas e manifestações de doenças por facilitar a disponibilização de nutrientes. Assim, o objetivo do presente trabalho foi avaliar os efeitos dos sistemas de produção orgânico e convencional sobre os teores de compostos dos metabolismos primário e secundário de alfaces dos grupos Lisa, Crespa e Americana. Os grupos de alface produzidos em sistema orgânico e convencional foram coletados em propriedades rurais da região do agreste sergipano em dois ciclos de produção. Para cada sistema de produção e ciclo foram coletadas 10 cabeças de alface Lisa, Crespa e Americana. As análises realizadas foram os teores de clorofila, carotenoides, fenóis totais, ácidos orgânicos totais, ácido ascórbico, proteínas, nitrato, cinzas, fibras e sólidos solúveis totais, determinação da atividade de polifenol oxidase e fenilalanina amônia-liase. As análises foram realizadas com 5 repetições de cada sistema e ciclo de produção. Verificou-se em todos os grupos de alface que o sistema convencional pode reduzir os teores de compostos bioativos e antioxidantes, ao tempo em que pode proporcionar aumento dos teores de sólidos solúveis totais. A alface do grupo Americana apresentou os maiores efeitos relacionados aos sistemas de produção apresentando um maior comprometimento da qualidade nutricional, sendo assim pode ser considerada como a menos indicada aos sistemas de produção convencional por comprometer em maior grau o fornecimento de vitaminas e pró-vitaminas. O sistema de produção orgânico contribuiu com a potencialidade nutricional dos grupos de alface Lisa, Crespa e Americana favorecendo os teores de compostos bioativos e antioxidantes quando comparadas àquelas cultivadas em sistema de produção convencional.
179

Avaliação da atividade antioxidante e da presença de oligossacarídeos na polpa de araticum (Annona crassiflora Mart.) / Evaluation of antioxidant activity and the presence of oligosaccharides in araticum pulp (Annona crassiflora Mart.)

Arruda, Henrique Silvano, 1991- 27 August 2018 (has links)
Orientador: Glaucia Maria Pastore / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-27T06:59:39Z (GMT). No. of bitstreams: 1 Arruda_HenriqueSilvano_M.pdf: 2437126 bytes, checksum: 9776995b146a9a85c66a8622faee620c (MD5) Previous issue date: 2015 / Resumo: Por apresentar basicamente fórmulas, o Resumo, na íntegra, poderá ser visualizado no texto completo da tese digital / Abstract: The complete Abstract is available with the full electronic document / Mestrado / Ciência de Alimentos / Mestre em Ciência de Alimentos
180

Avaliação do potencial antioxidante in vitro de azeites de oliva identificados como extra virgem produzidos no Brasil / Evaluation of in vitro antioxidant potential of olive oils identified as extra virgin produced in Brazil

Baroni, Naiara Aparecida Franco, 1987- 27 August 2018 (has links)
Orientador: Juliana Alves Macedo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-27T12:01:55Z (GMT). No. of bitstreams: 1 Baroni_NaiaraAparecidaFranco_M.pdf: 1466937 bytes, checksum: 5a517dbdb43e197ac98d726b669f3c2d (MD5) Previous issue date: 2015 / Resumo: O azeite de oliva virgem extra é considerado um alimento funcional com importantes propriedades biológicas relacionadas à elevada concentração de ácido graxo monoinsaturado. Estudos recentes indicam que os componentes minoritários na composição do azeite têm sido muito associados com benefícios à saúde, muito além do conteúdo de ácido oleico, destacando-se os compostos fenólicos, principalmente hidroxitirosol e tirosol. A região na qual as oliveiras são cultivadas pode ter influência direta na composição do azeite, principalmente no que se refere aos compostos minoritários. O objetivo deste trabalho foi avaliar se o potencial antioxidante dos azeites de oliva produzidos no Brasil (ArbequinaRS, ArbequinaMG e Maria da Fé) se assemelha ao dos azeites europeus (ArbequinaMed e Gallo®) tradicionais no mercado brasileiro. O perfil de ácidos graxos mostrou que a amostra Maria da Fé assemelha-se à amostra referência Gallo®, apresentando as maiores concentrações de ácido oleico. O teor de tocoferóis foi maior nas amostras ArbequinaRS e Maria da Fé. Quanto à determinação de fenólicos totais, pelo método de Folin-Ciocalteu, destacaram-se a ArbequinaRS e ArbequinaMed. Esta também apresentou maior concentração de hidroxitirosol, enquanto que, a referência Gallo® apresentou maior teor de tirosol. A capacidade antioxidante foi avaliada por métodos de sequestro de radicais, ORAC e DPPH, este permitiu identificar diferença estatística entre as amostras testadas. Dentre as amostras de variedade Arbequina, destaca-se o azeite produzido na região Sul do Brasil, equiparando-se estatisticamente ao comercial de origem mediterrânea; foi observada uma correlação positiva entre conteúdo de fenólicos totais e a capacidade antioxidante pelo método de sequestro de radical DPPH. O método ORAC não mostrou diferença estatística significativa entre as amostras. A atividade biológica foi avaliada através da mensuração da atividade de enzimas endógenas, catalase e superóxido dismutase, do arsenal antioxidante de hepatócitos humanos. Após o ensaio MTT de viabilidade celular foram definidas duas concentrações de estudo para os testes enzimáticos: 0,5 e 2mg/mL. De forma geral, nos ensaios de ativação do sistema celular endógeno antioxidante de hepatócitos, dentre os azeites testados os de maior potencial biológico foram os brasileiros, com importante destaque para a variedade Arbequina produzida no Rio Grande do Sul, ArbequinaRS / Abstract: The extra virgin olive oil is considered a functional food with important biological properties related to the high concentration of monounsaturated fatty acid. Recent studies indicate that minor components in olive oil composition have been very associated with health benefits, far beyond the content of oleic acid, highlighting the phenolic compounds, especially hydroxytyrosol and tyrosol. The region where the olive trees are grown may have direct influence on oil composition, especially with regard to minority compounds. The objective of this study was to evaluate the antioxidant potential of olive oils produced in Brazil (ArbequinaRS, ArbequinaMG and Maria da Fé) is similar to European oil (ArbequinaMed and Gallo®) traditional in the Brazilian market. The fatty acid profile showed that the sample Maria da Fé resembles the reference sample Gallo®, with the highest concentrations of oleic acid. The tocopherols content was higher in ArbequinaRS and Maria da Fé samples. The determination of total phenolic by the Folin-Ciocalteu method, the highlights were the ArbequinaRS and ArbequinaMed. This also showed a higher concentration of hydroxytyrosol, while the Gallo® reference showed greater tyrosol content. The antioxidant capacity was evaluated by sequestration methods of radicals, ORAC and DPPH, this allowed us to identify significant differences between the samples tested. Among the samples of Arbequina variety, stand out from the oil produced in southern Brazil, equating statistically the trade of Mediterranean origin; was observed a positive correlation between total phenolic content and antioxidant activity by DPPH radical sequestration method. The ORAC method was not significantly different between the samples. The biological activity was evaluated by measuring the activity of endogenous enzymes of the antioxidant arsenal of human hepatocytes: superoxide dismutase and catalase. After the MTT assay cell viability was defined two concentrations to study enzyme tests 0,5 and 2 mg/mL. In general, the antioxidant endogenous cellular system hepatocyte activation assays, among the oils tested the highest biological potential were Brazilians, with major emphasis on the Arbequina variety produced in Rio Grande do Sul, ArbequinaRS / Mestrado / Nutrição Experimental e Aplicada à Tecnologia de Alimentos / Mestra em Alimentos e Nutrição

Page generated in 0.0902 seconds