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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

Stimulation of microsomal diacylglycerol acyltransferase activity from microspore-derived cell suspension cultures of oilseed rape

Byers, Susan D., University of Lethbridge. Faculty of Arts and Science January 1999 (has links)
Several factors including an unidentified endogenous substance were found to stimulate microsomal diacylglycerol acyltransferase (DGAT, EC 2.3.1.20) from a microspore-derived cell suspension culture of oilseed rape (Brassica napus L. cv Jet Neuf). Mg2+ salts were found to stimulate microsomal DGAT 14 to 23-fold. ATP and CoA were also found to stimulate the enzyme 2.4 and 12 fold respectively, although the effects were decreased in the presence of high Mg2+ concentrations. While microsomal DGAT activity was only slightly increased by the concentration of exogenous diacylglycerol in the reaction mixture it was increased substantially by the addition of exogenous phosphatidate. Other phospholipids tested were not found to have this stimulatory effect. During attempts to investigate possible covalent modification of the enzyme, the soluble fraction obtained from cell suspension homogenate was found to contain a small metastable organic molecule(s) which stimulated DGAT activity. Stimulation of microsomal DGAT by this factor was concentration dependent but not dependent on preincubation time. / xiii, 95 leaves : ill. ; 28 cm.
22

Molecular strategies for increasing seed oil content in canola

Wiehler, William B., University of Lethbridge. Faculty of Arts and Science January 2001 (has links)
Previous research has shown that microsomal DGAT activity from cultures of Brassica napus was stimulated by human acylation stimulating protein (ASP) and bovine serum albumin (BSA). Genetic constructs were engineered to facilitate the expression of ASP or BSA in developing seeds to test the stimulatory effect of these proteins at the site of TAG formation. As well, genetic constructs were designed to produce a truncation of the BSA polypeptide in an attempt to localize the portion fo the macromolecule responsible for stimulation of DGAT activity. An oleosin promoter was used for seed specific expression and to express the polypeptides at a precisely cooridnated time when oil was accumulating in the developing seeds. Lipid analysis coordinated time when oil was accumlating in the developing seeds. Lipid analysis was performed on the seeds of transgenic plants designed to cytosolically express these mammalian proteins and the seeds of control plants. The first generation data revealed that the total lipid within the mature seeds of ASP and BSA plants was not significantly different from the total lipid of negative control plants using both gravimetric and low resolution-nuclear magnetic resonance methods of analysis. The seeds from ASP 8 and ASP 10 plants, however, did produce significantly more lipid on a per seed basis as compared to negative control plants. The levels of the fatty acid composition for total acyl lipids were measured in these first generation transgenic plants. ASP 3 had significantly lower levels of linoleic acid, ASP 14 had significantly lower levels of a-linolenic acid and BSA 11 had significantly higher levels of both of these fatty acids in comparison to negative control plants. / xix, 245 leaves : ill. ; 28 cm.
23

A molecular genetic approach to reducing the saturated fatty acid content of canola oil

Bondaruk, Mandy, University of Lethbridge. Faculty of Arts and Science January 2003 (has links)
Brassica napus is known to contain an endogenous and soluble stearoyl-acyl carrier protein (^918:0-ACP) desaturase, but does not express a palmitic (16:0)-ACP desaturase. Levels of 16:0 are low in canola oil and are associated with enhanced cholesterol biosynthesis in humans. In an attempt to further reduce the saturated fatty acid (SFA) content of canola oil, B. Napus L. cv Westar was transformed with a cDNA encoding a ^916:0-ACP desaturase from cat's claw (Doxantha unguis-cati L.). Arabidopsis thaliana was also transformed with this cDNA. Transformation of both oilseeds resulted in increased production of palmitoleic acid (^16:1) and many other effects of fatty acid composition. Overall, the SFA content did not decrease in either oilseed and investigation to why this effect occurred was examined using transgenic B. napus. Molecular genetic testing on second generation B. napus also determined the plants contained the cDNA of interest and were transcribing the cDNA. / xxi, 155 leaves : ill. ; 29 cm.
24

Probing the membrane topology of a diacylglycerol acytransferase type I from Brassica Napus

Foroud, Nora Afsaneh, University of Lethbridge. Faculty of Arts and Science January 2005 (has links)
Diacylglycerol acyltransferase (DGAT), an integral membrane protein of the endoplasmic reticulum, catalyses the final step in the sn-glycerol-3-phosphate pathway leading to triacylglycerol. Although DGAT has been cloned from a variety of species, including the major oilseed crop of Canada, canola (Brassica napus), little is known about the structure/function of the enzyme. BnDGAT1 is the major isoform of type I DGAT (DGAT-I) in microspore-derived cell suspension cultures of B. napus L. cv Jet Neuf, with the possible existence of a truncated form of BnDGAT1 known as BnDGAT2. In order to gain some insight into the topology of the enzyme, type I DGAT from B. napus was investigated using two approaches: (1) in vitro translation in the presence of microsomes and (2) immunochemical analyses of microsomes isolated from cell suspension cultures, both in combination with proteolytic mapping. Difficulties were encountered with the in vitro translation approach, possibly due to proper incorporation of the polypeptide into microsomal vesicles. Two cytocolic regions were identified in BnDGAT1, and one cytosolic region in putative BnDGAT2, using the immunochemical approach, thus providing some insight into the topology of B. napus DGAT-I. The results here support and nine and eight membrane-spanning topology for BnDGAT1 and BnGAT2, respectively. / xvii, 194 leaves ; 29 cm.
25

The production of oilseeds in Ethiopia: value chain analysis and the benefit that accrue to the primary producers.

Fanta, Elias Gebreselassie. January 2005 (has links)
<p>Oilseed is the third most important export item in Ethiopian foreign trade. It has registered a high export growth rate over recent years both in terms of volume and value. Besides its growing share in export, it is widely used for the extraction of edible oil and oilcake that is supplied to the domestic market. Although farmers are the primary producers of oilseeds, they are not able to benefit from the growing market share of the product due to the fact that they find themselves at the end of an extended market chain. As a result they only receive a very small proportion of what the final buyers are paying for the oilseed products. In addition, there is not much experience on the part of the farmers to process oilseeds, change it to edible oil and oilcake and retain the value addition in the local economy. This thesis used the value chain approach to investigate the possibilities for the primary producers to increase their income share from the selling of their products either by directly selling to exporters or by processing oilseeds, producing edible oil and oilcake, and retaining the value addition in the local economy.</p>
26

The production of oilseeds in Ethiopia: value chain analysis and the benefit that accrue to the primary producers.

Fanta, Elias Gebreselassie. January 2005 (has links)
<p>Oilseed is the third most important export item in Ethiopian foreign trade. It has registered a high export growth rate over recent years both in terms of volume and value. Besides its growing share in export, it is widely used for the extraction of edible oil and oilcake that is supplied to the domestic market. Although farmers are the primary producers of oilseeds, they are not able to benefit from the growing market share of the product due to the fact that they find themselves at the end of an extended market chain. As a result they only receive a very small proportion of what the final buyers are paying for the oilseed products. In addition, there is not much experience on the part of the farmers to process oilseeds, change it to edible oil and oilcake and retain the value addition in the local economy. This thesis used the value chain approach to investigate the possibilities for the primary producers to increase their income share from the selling of their products either by directly selling to exporters or by processing oilseeds, producing edible oil and oilcake, and retaining the value addition in the local economy.</p>
27

Otimização de protocolos de germinação in vitro de pinhão-manso (Jatropha curcas L.)

Vedovato, Nádia Pita Figueiredo [UNESP] 29 July 2011 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:26:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-07-29Bitstream added on 2014-06-13T20:54:09Z : No. of bitstreams: 1 vedovato_npf_me_jabo.pdf: 472091 bytes, checksum: 2541548e6ff5199c3f8bd4fe048ab8f9 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O pinhão-manso (Jatropha curcas L.) é uma oleaginosa da família Euphorbiaceae, que se destaca pelo seu grande potencial sócio econômico e como uma excelente alternativa para a produção de biodiesel. O presente trabalho teve como objetivo principal a padronização e otimização de protocolos de cultivo in vitro para embriões e sementes com adição dos suplementos complexo vitamínico e ácido giberélico em meio MS, visando a obtenção de plântulas assépticas para a extração de explantes que serão utilizados em outros processos de cultura de tecidos e transformação genética para a produção futura de mudas comerciais padronizadas. No primeiro experimento com embriões, em meio MS com sacarose e ágar foram acrescidas várias dosagens de um complexo vitamínico (0,0; 0,5; 1,0; 2,0; 3,0 e 4,0 ml.L-1) e após duas semanas do estabelecimento, dez variáveis foram analisadas. Foi utilizado o delineamento inteiramente casualizado com quatro repetições. Os dados foram submetidos à análise de variância, e as variáveis significativas tiveram suas médias comparadas pelo teste Tukey (5%) e algumas pela regressão polinomial. Os resultados indicaram que a adição de vitaminas ao meio de cultura não é essencial para a germinação e crescimento inicial. No entanto, para a formação de raízes, a presença do complexo vitamínico forneceu incrementos nos resultados. A presença de folhas também respondeu positivamente com o aumento da dosagem de vitaminas. No segundo experimento com as sementes, várias dosagens de ácido giberélico GA3 (0,0; 1,0; 2,0; 4,0; 6,0 e 8,0 mg.L-1) foram acrescentadas em meio MS com sacarose e ágar e após duas semanas dez variáveis foram analisadas. Foi utilizado o delineamento inteiramente casualizado com quatro repetições. Os dados foram submetidos à análise de variância... / The phisic nut (Jatropha curcas L.) is an oil family Euphorbiaceae, which is distinguished by its great potential economic partner and as an excellent alternative to produce biodiesel. The present work had as main objective the standardization and optimization of protocols for in vitro embryos and seeds with the addition of multivitamin supplements and gibberellic acid on MS medium, in order to obtain seedlings for the extraction of aseptic explants to be used in other processes of tissue culture and genetic transformation for the future production of standard commercial seedlings. In the first experiment with embryos in MS medium with sucrose and agar were added various doses of a vitamin complex (0.0, 0.5, 1.0, 2.0, 3.0 and 4.0 ml.l-1) and after two weeks of the establishment, ten variables were analyzed. We used a completely randomized design with four replications. Data were subjected to analysis of variance, and the significant variables had their means compared by Tukey test (5%) and some by polynomial regression. The results indicated that the addition of vitamins to the culture medium is not essential for germination and early growth. However, for root formation, the presence of vitamin complex increments provided in the results. The presence of leaves also responded positively by increasing the dosage of vitamins. In the second experiment with the seeds, various doses of gibberellic acid GA3 (0.0, 1.0, 2.0, 4.0, 6.0 and 8.0 mg.L-1) were added in MS medium with sucrose and agar, and after two weeks ten variables were analyzed. We used a completely randomized design with four replications. Data were subjected to analysis of variance, and the significant variables had their means compared by Tukey test (5%) and some by polynomial regression, as in the first experiment. The results indicated that the... (Complete abstract click electronic access below)
28

Otimização de protocolos de germinação in vitro de pinhão-manso (Jatropha curcas L.) /

Vedovato, Nádia Pita Figueiredo. January 2011 (has links)
Resumo: O pinhão-manso (Jatropha curcas L.) é uma oleaginosa da família Euphorbiaceae, que se destaca pelo seu grande potencial sócio econômico e como uma excelente alternativa para a produção de biodiesel. O presente trabalho teve como objetivo principal a padronização e otimização de protocolos de cultivo in vitro para embriões e sementes com adição dos suplementos complexo vitamínico e ácido giberélico em meio MS, visando a obtenção de plântulas assépticas para a extração de explantes que serão utilizados em outros processos de cultura de tecidos e transformação genética para a produção futura de mudas comerciais padronizadas. No primeiro experimento com embriões, em meio MS com sacarose e ágar foram acrescidas várias dosagens de um complexo vitamínico (0,0; 0,5; 1,0; 2,0; 3,0 e 4,0 ml.L-1) e após duas semanas do estabelecimento, dez variáveis foram analisadas. Foi utilizado o delineamento inteiramente casualizado com quatro repetições. Os dados foram submetidos à análise de variância, e as variáveis significativas tiveram suas médias comparadas pelo teste Tukey (5%) e algumas pela regressão polinomial. Os resultados indicaram que a adição de vitaminas ao meio de cultura não é essencial para a germinação e crescimento inicial. No entanto, para a formação de raízes, a presença do complexo vitamínico forneceu incrementos nos resultados. A presença de folhas também respondeu positivamente com o aumento da dosagem de vitaminas. No segundo experimento com as sementes, várias dosagens de ácido giberélico GA3 (0,0; 1,0; 2,0; 4,0; 6,0 e 8,0 mg.L-1) foram acrescentadas em meio MS com sacarose e ágar e após duas semanas dez variáveis foram analisadas. Foi utilizado o delineamento inteiramente casualizado com quatro repetições. Os dados foram submetidos à análise de variância... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The phisic nut (Jatropha curcas L.) is an oil family Euphorbiaceae, which is distinguished by its great potential economic partner and as an excellent alternative to produce biodiesel. The present work had as main objective the standardization and optimization of protocols for in vitro embryos and seeds with the addition of multivitamin supplements and gibberellic acid on MS medium, in order to obtain seedlings for the extraction of aseptic explants to be used in other processes of tissue culture and genetic transformation for the future production of standard commercial seedlings. In the first experiment with embryos in MS medium with sucrose and agar were added various doses of a vitamin complex (0.0, 0.5, 1.0, 2.0, 3.0 and 4.0 ml.l-1) and after two weeks of the establishment, ten variables were analyzed. We used a completely randomized design with four replications. Data were subjected to analysis of variance, and the significant variables had their means compared by Tukey test (5%) and some by polynomial regression. The results indicated that the addition of vitamins to the culture medium is not essential for germination and early growth. However, for root formation, the presence of vitamin complex increments provided in the results. The presence of leaves also responded positively by increasing the dosage of vitamins. In the second experiment with the seeds, various doses of gibberellic acid GA3 (0.0, 1.0, 2.0, 4.0, 6.0 and 8.0 mg.L-1) were added in MS medium with sucrose and agar, and after two weeks ten variables were analyzed. We used a completely randomized design with four replications. Data were subjected to analysis of variance, and the significant variables had their means compared by Tukey test (5%) and some by polynomial regression, as in the first experiment. The results indicated that the... (Complete abstract click electronic access below) / Orientador: Antônio Orlando Di Mauro / Coorientador: Sandra Helena Unêda-Trevisoli / Banca: Bianca Waléria Bertoni / Banca: Jesus Aparecido Ferro / Mestre
29

Obtenção de extrato de matriz oleaginosa de origem amazonica via tecnologia supercritica : determinação das isotermas de rendimento global, dos parametros de processo e caracterização quimica dos extratos / Obtaining of extract from amazon oil matrix via supercritical technology : determination of the global yield isotherms, kinetic parameters and chemical characterization of the extracts

Cavalcanti, Rodrigo Nunes 13 August 2018 (has links)
Orientador: Maria Angela de Almeida Meireles / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-13T04:16:44Z (GMT). No. of bitstreams: 1 Cavalcanti_RodrigoNunes_M.pdf: 38161190 bytes, checksum: 52a9f06bfcd237167fdac55c212e06f5 (MD5) Previous issue date: 2009 / Resumo: O Brasil constitui um grande produtor de plantas e frutas tropicais, cujo emprego pelas indústrias farmacêutica, alimentícia e de cosméticos vem aumentando a cada ano. Com a finalidade de aproveitar efetivamente o seu potencial, o país necessita desenvolver e/ou adaptar tecnologias que sejam economicamente viáveis e ecologicamente corretas como, por exemplo, os processos de extração com solventes GRAS (Generally Recognized as Safe). Dentro desse âmbito, o processo de extração supercrítica caracteriza-se pela obtenção de produtos de elevada qualidade com a minimização dos resíduos de solventes e da alteração das propriedades do extrato em comparação aos processos de extração convencionais. Apesar dessa tecnologia já estar sendo estudada há muitos anos no Brasil e da vasta disponibilidade de matéria-prima de alta qualidade e baixo custo no país, ainda não existe na América Latina nenhuma planta industrial. A produção de oleaginosas tem mostrado um notável aumento nas últimas décadas. Esta evolução deve-se ao crescente consumo de gorduras comestíveis, como óleos vegetais e seus produtos, devido à substituição gradual da gordura animal pela de origem vegetal. A mudança está relacionada com a noção de estilo de vida saudável e a necessidade de comer alimentos com uma influência positiva na saúde, aumentando o uso de alimentos ricos em compostos com comprovado benefício. Sendo assim, estudos visando o conhecimento sobre as possibilidades de comercialização de matrizes oleaginosas são necessários para proporcionar o beneficiamento social, econômico e ambiental através da valorização e/ou do aproveitamento de seus produtos e subprodutos, o que implica em uma maior competitividade, e conseqüente, expansão comercial, uma vez que se observa uma tendência generalizada do mercado em relação à busca por produtos que não agridam o meio ambiente, gerem vantagens econômicas e possibilitem o desenvolvimento social. Este trabalho pretende avaliar o processo de extração supercrítica de matriz vegetal oleaginosa de origem Amazônica, através da determinação e caracterização dos parâmetros de processo e composição química dos extratos obtidos. Este estudo divide-se em três etapas. Na etapa de caracterização química e física foram determinados a composição, o tamanho e a densidade das partículas da matriz vegetal oleaginosa. Na etapa de extração, foi realizada a determinação dos parâmetros de processo, bem como a caracterização dos extratos com relação ao teor de tocoferóis, tocotrienóis, composição em ácidos graxos, fenóis, flavonóides e atividade antioxidante. Na última etapa, foi realizada a análise de viabilidade econômica, visando a determinação da condição de extração que possibilite a melhor relação custo-benefício. A otimização das condições de separação da mistura de extrato e solvente constitui uma etapa importante do processo de extração de produtos naturais utilizando fluidos supercríticos, uma vez que permitirá uma melhor recuperação e/ou fracionamento do extrato / Abstract: Brazil is a great producing of plants and tropical fruits whose utilization by the pharmaceutical, nutrition and cosmetics industries has been increasing every year. With the purpose of taking advantage his/her potential indeed it is necessary to develop and/or to adapt technologies economically viable and ecologically correct as, for instance, the extraction processes with GRAS solvents (Generally Recognized as Safe). Inside of that extent the process of supercritical fluid extraction is characterized by the obtaining of products with high quality, the minimization of the residues of solvents and of the alteration of the properties of the extract in comparison with the conventional extraction processes. In spite of that technology has been studied many decades in Brazil and of the vast readiness of raw material of high quality and low cost in the country, it still doesn't exist in Latin America any industrial plant. Besides that, the production of oleaginous has been showing a notable increase in the last decades. This evolution is due to the crescent consumption of eatable fats, as vegetable oils and their products, due to the gradual substitution of the animal fat for the of vegetable origin. The change is related with the notion of healthy lifestyle and the need of eating foods with a positive influence in health, increasing the use of foods rich in elements with proven health benefit. Therefore, studies seeking the knowledge about the possibilities of commercialization of oil matrices are necessary to provide the improvement social, economical and environmental through the valorization and/or of the use of their products and sub-products what implicates in a larger competitiveness, and consequently, commercial expansion, once a widespread tendency of the market is observed in relation to the search by products that don't attack the environment, generate economical advantages and make possible the social development. This work intends to evaluate the process of supercritical fluid extraction of oil matrices from Amazonian origin, through the determination and characterization of the process parameters and chemical composition of the obtained extracts. This study becomes separated in three stages. In the stage of chemical and physical characterization it was obtained the chemical composition, size and density of the particles of the oil matrices. In the extraction stage the determination of the process parameters was accomplished, as well as the characterization of the extracts regarding the composition of: tocopherols, tocotrienols, fatty acids, phenols, flavonoids and antioxidant activity. In the last stage the analysis of economical viability was accomplished seeking the determination of the extraction condition to make possible the best relationship cost-benefit. The optimization of the conditions of separation of the extract mixture and solvent constitutes an important stage of the process of extraction of natural products using supercritical fluids, once it allow a better recovery and/or separation of the extract. / Mestrado / Mestre em Engenharia de Alimentos
30

Atividade antioxidante de extratos liofilizados de plantas brasileiras / Antioxidant activity of extracts of freeze-dried Brazilian plants

Barrera Arellano, Daniel, 1953- 18 October 1985 (has links)
Orientador : Walter Esteves / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos e Agricola / Made available in DSpace on 2018-07-14T03:11:36Z (GMT). No. of bitstreams: 1 Barrera-Arellano_Daniel_D.pdf: 6777737 bytes, checksum: 08147ff920ced079d398611e26a80aa0 (MD5) Previous issue date: 1985 / Resumo: A atividade antioxidante de 140 extratos liofilizados, de diversas partes de 45 plantas brasileiras, foi avaliada em um sistema modelo aquoso de B-caroteno-ácido linoleico. Os extratos que apresentaram um efeito protetor mais destacado, em número de 42, foram testados em.um sistema lipídlco (61eo de soja). Diversas técnicas cromatográficas (papel, camada de1gr da, coluna, líquida de alta eficiência e gasosa) foram empregadas na separação dos compostos presentes em 4 dos extratos mais ativos nos dois sistemas. Frações obtidas de extratos de Piptadenia maeroearpa (folhas), Mikania smiZaeina (folhas), SoZanum viarum (folhas" e galhos} e CoehZosprmum insigne (raiz) mostraram atividade antioxidante similar ou maior que o BHT (2,6 di-ter-butil p-cresol) no sistema lipídico. A identificação destas frações não foi por tratar-se de misturas com vários componentes. conseguida Usando Espectroscopia U1travio1eta (UV) , Ressonância Magnética Nuclear de Pr6tons (RMN'H) e Espectrometria de Massa (EM) foi identificada a presença do f1avon6ide di-hidrokampferol (3,4',"5, 7-tetra-hidroxi di-hidro f1avono1) no extrato de raiz de Coeh-Zos-permumi"nsigne. Esta substância não tem sido citada na família Coch10spermaceae.O di-hidrokampferol, embora presente num extrato com alto poder antioxidantenão mostrou atividade em 61eo de soja,quando adicionado numa concentração de 0,1% / Abstract: Antioxidant aetivity of liophilized extraets of Brasilian plants, The antioxidante aetivities of 140 lyophilized extraets of different parts of 4S Brasilian plants were evaluated in amodel aqueous system eontaining B-earotene and linolei aeid. The exttaets that presented a marked proteetive effeet were subsequen-.tly tested in a lipid system (soybean oil). Different ehromatographie teehniques (paper, thinlayer, 'high performanee liquid and gas-liquid) were used to separa te toe eompounds present in four extraets whieh were most aetive in the two systems. Fraetions of extraets of Piptadenia macrocarpa (leaves}, Mikania smiZacina (leaves), SoZanum viarum (leavesand branehesl and. Coch Zospermum insigne (roots) showed antioxidant., aetivi"' ty similar to or greater than that shown by BHT (2,6 di-ter -butil p~eresol) in the lipidie system. It was not possible to identify these fraetions since each was a mixture of various components. Using ultraviolet speetroseopy (UV), proton magnetic resonanee (.PMR) and mass spectrometry (MS) , the presence of the flavonoid dihydrokaempferol (.3, 4 I, S, 7-tetrahydroxydihydroflavo-noll was deteeted in the e.xtraet of the roót of CochZospermum in-si'gne. This substanee had not been previously reported in the Íamily Coehlospermaeeae.Dihydrokaempferol, although present in an extract.with a oigh antioxidant activity, showed no aetivity in soybean oilwhen added at a eoneentration / Doutorado / Ciência de Alimentos / Doutor em Ciência de Alimentos

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