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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.
41

Estudo das interações isoflavonas e proteínas da soja: efeitos sobre a digestibilidade e capacidade antioxidante / Study of interactions isoflavones and soy protein: effect on the digestibility and antioxidant capacity

Ana Cristina Lopes Barbosa 08 August 2008 (has links)
Embora a soja em grão seja pouco consumida pela população brasileira, seus derivados protéicos são utilizados como ingredientes em diversos alimentos e a tendência é um aumento significativo do seu uso com a aprovação pela FDA e pela ANVISA da alegação funcional referente ao consumo de proteína de soja. Em paralelo, um número crescente de pesquisas sobre as isoflavonas, fitoestrógenos presentes em quantidades significativas na soja, vem demonstrando diversos efeitos benéficos destes compostos, entre os quais a sua ação antioxidante, anticarcinogênica e hipocolesterolêmica. O objetivo foi estudar as interações entre isoflavonas e proteínas da soja, seu efeito na biodisponibilidade in vitro e in vivo e o status antioxidante das isoflavonas. Os resultados sugerem que a presença da proteína reduz a quantidade e leva a um retardo no tempo de absorção das isoflavonas em relação à administração na forma livre. O efeito sobre a capacidade antioxidante do plasma e sobre a atividade e expressão gênica das enzimas CAT, GPx e SOD divergiu para a suplementação de isoflavonas ou proteínas separadamente ou em associação. / Although soybeans are not commonly consumed by the Brazilian population, soybean products are used as ingredients by the food industry and there is an increased trend in their consumption due to the approval of FDA and ANVISA on the claim regarding the health benefits of soy proteins. Therefore, many studies involving isoflavones, the phytoestrogens found in significant quantities in soybeans, have demonstrated several health benefits of these compounds, such as antioxidant capacity, and anticarcinogenic and hypocholesterolemic effects. The objective of the present study was to evaluate the interaction between isoflavones and soy proteins as well as the effect of this interaction on the in vitro and in vivo bioavailability of isoflavones and on the antioxidant status. The results indicated that the association with protein decreased the rate and proportion of absorption of isoflavones when compared to the free form. The effect of isoflavones on the plasma antioxidant capacity and on the enzymatic activity and gene expression levels of CAT, GPx and SOD was different when isoflavones were combined with soy protein compared to isoflavones alone.
42

Marinação do Biceps femoris com proteína hidrolisada de soja e seu efeito sobre qualidade de carne e estrutura muscular / Marination of Biceps femoris with hydrolyzed soy protein and its effect on beef quality and muscular structure

Alessandra Aparecida Silva 01 October 2009 (has links)
Embora a indústria da carne utilize a marinação em larga escala, o comportamento da penetração da salmoura em bifes massageados de carne bovina é pouco conhecido. O músculo Biceps femoris tem sido considerado pouco macio e suculento e apresentado grande variação de maciez intermuscular. Desta forma, o objetivo deste estudo foi avaliar o efeito da marinação com adição de proteína hidrolisada de soja sobre a estrutura muscular de porções distintas do Biceps femoris e suas implicações sobre a qualidade de carne. No Capítulo 2, 3 e 4, seis músculos bovinos foram submetidos aos tratamentos: CONTROLE (bifes não massageados), CS (bifes massageados com salmoura) e SPHS (bifes massageados com salmoura adicionada de proteína hidrolisada de soja). No capítulo 2, os músculos foram divididos em duas porções: Origem (PO) e Inserção (PI), e os tempos de massageamento foram 30 e 60 min. No capítulo 3 e 4, os músculos foram divididos em três porções: Origem (PO), Inserção 1 (PI1) e Inserção 2 (PI2), e os bifes destas porções foram armazenados por 1 e 12 dias após equalização da salmoura, exceto os bifes CONTROLE que foram armazenados somente por 1 dia. As análises realizadas foram: mensuração da penetração da salmoura, determinação do melhor tempo de massageamento, pH, rendimento (REND), colágeno total (CT), composição centesimal, perdas por gotejamento (PPG), perdas por cocção (PPC), força de cisalhamento (FC), microscopia eletrônica de varredura (MEV), análises microbiológicas e sensoriais. O delineamento experimental utilizado foi em blocos inteiramente casualizados, onde cada músculo representou um bloco. A análise de mensuração da penetração da salmoura demonstrou que os bifes SPHS, massageados por maior tempo (60 min), obtiveram maior absorção e retenção de salmoura ao longo da profundidade dos bifes. A PI2 apresentou menor quantidade de CT em comparação às demais, para o CONTROLE. Já os bifes CS e SPHS da PO e PI1 obtiveram menores quantidades de CT em comparação aos bifes destes mesmos tratamentos da PI2. Os bifes massageados não sofreram efeito de tempo de armazenamento e foram mais macios, suculentos e melhor pontuados para impressão global em comparação ao CONTROLE. O pH dos bifes se elevou com os tratamentos CS e SPHS e pareceu influenciar sobre o REND das porções de forma que, a PO obteve menor pH e maior REND, enquanto a PI resultou em maior pH e menor REND. Menores PPG, PPC e FC foram observados para os bifes CS e SPHS e o período de 12 dias de armazenamento permitiu que as PPC e FC diminuíssem. Respostas similares entre a maciez sensorial e objetiva foram observadas nas porções do músculo de forma que, as PIs foram mais macias do que a PO. A analise MEV demonstrou inchaço das fibras e diminuição dos espaços interfibrilares nos bifes massageados CS e SPHS. / Although meat industry uses marination in large-scale, the brine penetration behavior in tumbled steaks from bovines is little known. The Biceps femoris muscle has been considered little tender and juicy, and presented large range of intramuscular tenderness. Therefore, the objective of this work was to evaluate the effect of marination added of hydrolyzed soy protein on the muscular structure of different portions from the Biceps femoris and its implication on beef quality. In Chapter 2, 3 and 4, steaks from six bovine muscles were submitted to the treatments: CONTROL (no tumbling or addition of brine), WTB (with tumbling and addition of brine), and WTB/HSP (with tumbling and addition of brine plus hydrolyzed soy protein). In Chapter 2, the muscles were divided in two portions: Origin (OP) and Insertion (IP), and the tumbling times were 30 and 60 min. In Chapter 3 and 4, the muscles were divided in three portions: Origin (OP), Insertion 1 (IP1) and Insertion 2 (IP2), and their steaks were stored for 1 and 12 days after equalization of brine, except to the CONTROL steaks that were only stored for 1 day. The analyses performed were: monitoring of brine penetration, pH, yield (YIE), total collagen (TC), proximate composition, drip loss (DL), cooking loss (CL), shear force (SF), scanning electron microscopy (SEM), microbiologic and sensory. The experimental design was completely randomized blocks, where each muscle represented one block. The analysis of monitoring of the brine penetration showed that the WTB/HSP steaks, tumbled for largest time (60 min), had higher absorption and retention of brine along the depth of the steaks. The IP2 presented lower TC amount in relation to other portions, in CONTROL steaks. However, the WTB and WTB/HSP steaks from OP and IP1 had lower TC amount when compared to IP2, in these same treatments. The tumbled steaks were not affected by storing time and were tender, juicier and better scored for overall satisfaction with regard to CONTROL steaks. The pH of the steaks was elevated with the WTB and WTB/HSP treatments and appeared to influence the YIE of the portions, where OP had lower pH and higher YIE, while IP resulted in higher pH and lower YIE. Lower DL, CL and SF were observed for WTB and WTB/HSP steaks and the storing time of 12 days allowed that the CL and SF declined. Similar responses between sensory tenderness and SF were observed in the muscle portions, which IPs were tender than OP. The SEM analysis showed swelling of fibers and decrease of spaces between fibrils in tumbled WTB and WTB/HSP steaks
43

Feasibility of soy protein isolate electrospun nanofibers decorated with metal noble nanoparticles as a possible biodegradable SERS platform

Cindy Carolina Mayorga Perez (9114224) 10 March 2022 (has links)
<p>Detection of pathogens, toxins, hazardous chemicals, and allergens in the food industry with reliable, sensitive, efficient, and rapid results has increased the demand to develop innovative diagnostic tools. Surface-enhanced Raman spectroscopy (SERS) sensors have demonstrated to detect a wide variety of analytes using nanomaterials like metal nanoparticles. Concerns of synthetic materials that can affect the environment with disposal of sensors have opened the possibility of fabricating SERS sensors with biodegradable materials. Fabrication of electrospun nanofibers from natural polymeric materials such as soy protein isolate can be used as a SERS platform. In the first part of this research, the characteristics of SPI solutions blended with NaOH and polyethylene oxide (PEO) such as PEO Mw, zeta potential and viscosity as well operating parameters such as voltage (15, 20, and 27 kV) were studied to evaluate the best solutions for a nanofibrous SERS platform. Characteristics of electrospun nanofibers, such as surface wettability, fiber diameters, and morphology using SEM, helped determine the most feasible fibers for decoration with noble metal nanoparticles. Fibers fabricated with 12 wt% SPI + 5 wt% PEO (0.1 MDa) + 1 wt% NaOH solution showed the smallest fiber diameter and highest water contact angle measurements. Glutaraldehyde (GLA) was added as a crosslinker to partly increase nanofibers hydrophobicity. These nanofibers were decorated with Au-nanostars and Au@Ag-NPs suspended in 90% butanol and in water. Partly hydrophobic nanofibers decorated with Au-nanostars and Au@Ag-NPs in butanol showed the most feasible results for a SERS platform due to smallest fiber diameter and higher water contact angle. In the second part of this research, decorated SPI nanofibers were evaluated to study its feasibility as a SERS platform for detecting bisphenol A (BPA), a toxic chemical present in food packaging materials. However, SERS spectra were difficult to obtain due to CCD overflow (excessive number of photons) at all laser powers on SPI nanofiber mats. Optimizing other Raman spectroscopy parameters such as the exposure time and the number of averages could enhance the SERS measurements. The fabricated SPI nanofibers in this research showed that hydrophilic and partly hydrophobic nanofibers mats could be used for decoration with metal nanoparticles by suspending the nanoparticles in a hydrophobic solvent. Hydrophilic nanofiber mats with nanoparticles in a hydrophobic solvent open a new strategy for developing another type of SERS platform.</p>
44

The effects of dietary soybean saponins on growth and performance, intestinal histology and immune response of first feeding rainbow trout Oncorhynchus mykiss

Penn, Michael H. 14 July 2005 (has links)
No description available.
45

Estudo das condições de processamento para obtenção de isolado protéico de soja com teor aumentado de isoflavonas / Study of conditions the processing to production of isoflavone-rich soy protein isolates

Barbosa, Ana Cristina Lopes 05 February 2004 (has links)
Os isolados protéicos de soja são utilizados como ingredientes em diversos alimentos e sua utilização vêm aumentando juntamente com o aumento das pesquisas sobre os metabólitos secundários da soja, as isoflavonas. Alguns efeitos benéficos vem sendo associados às isoflavonas, entre estes a sua ação antioxidante, a redução ao risco de câncer, doenças cardiovasculares e osteoporose. O objetivo deste estudo foi o de otimizar as condições de extração das isoflavonas e de suas formas conjugadas a partir da farinha desengordurada de soja, visando o preparo de isolado protéico de soja. Os resultados mostraram que a obtenção de isolados protéicos de soja com teor aumentado de isoflavonas depende da utilização de condições brandas de centrifugação para a separação do precipitado isoelétrico, assim como da utilização de água acidificada na sua lavagem. A presença de isoflavonas no isolado resulta de três fatores, o primeiro referindo-se à associação entre isoflavonas e proteínas através de interações hidrofóbicas, eletrostáticas, e pontes de hidrogênio; o segundo à menor solubilidade das isoflavonas presentes na farinha desengordurada de soja no pH isoelétrico; e o último ao processo de carreamento (físico) das isoflavonas pelas proteínas insolubilizadas. / Soy protein isolates are used as ingredients in several food products and their use is increasing together with the increase of the researches on the secondary metabolites of soy, the isoflavones. Some beneficial effects have been associated to the isoflavones, among these their antioxidant action, prevention of cancer, cardiovascular diseases and osteoporosis. The objective of this study was to optimize the extraction conditions of the isoflavones from the defatted soy flour, seeking the preparation of soy protein isolates. The results showed that the obtention of soy protein isolates with increased content of isoflavones depends on the use of mild conditions of centrifugation for the separation of the isoelectric precipitate, as well as on the use of water acidified in the washing step. The presence of isoflavones in the isolates resulted from three factors, the first refers to the association between isoflavones and proteins through hydrophobic; and electrostatic interactions, and hydrogen bonding; the second to the decreased solubility of the isoflavones extracted from the defatted soy flour in the isoelectric pH; and the last to the carrying process (physical) of isoflavones by the precipitating proteins.
46

Efeito da radiação ionizante de feixe de elétrons em propriedades de biopolímeros comestíveis a base de proteína isolada de soja e fécula de mandioca / Effect of ionizing electron beam radiation on properties of edible biopolymers based on isolated soybean protein and cassava starch

Uehara, Vanessa Bernardo 24 May 2017 (has links)
Nas últimas décadas, têm aumentado substancialmente a quantidade de pesquisas focando no desenvolvimento e caracterização de materiais biodegradáveis, particularmente, filmes comestíveis. O uso de polímeros de fontes renováveis, preparados a partir de produtos vegetais, vem ganhando importância nessa abordagem. O concentrado de proteína de soja e amido de mandioca podem ser considerados uma alternativa aos polímeros petroquímicos. O processamento pela radiação ionizante pode ser empregado para a modificação de polímeros e macromoléculas, resultando em novos materiais com grandes perspectivas de utilização industrial. A indústria de alimentos, uma das indústrias tradicionalmente mais inovadoras, exige o desenvolvimento constante de novos produtos. A capacidade de proteínas e polissacarídeos de formar filmes, amplamente conhecida, é um ponto de partida para o desenvolvimento de novos materiais que atendam os variados requerimentos dessa pungente indústria. Neste trabalho elaboraram-se filmes a base de fécula de mandioca e proteína isolada de soja em duas proporções diferentes e posteriormente irradiados e analisados quanto às suas propriedades mecânicas, cor, absorção de água, permeabilidade ao vapor de agua, análise térmica TGA e DSC entre outros. Os filmes tornaram-se aparentemente mais solúveis e menos resistentes a perfuração com o aumento da dose de radiação aplicada. Com relação às propriedades térmicas observou-se que os filmes com maior proporção de proteína são mais resistentes. Os filmes apresentaram-se menos permeáveis na dose de 40 kGy, e, com relação a absorção de água, esta foi reduzida em função da dose de radiação. Filmes com boa resistência ao vapor de água e com reduzida absorção podem ser considerados adequados para embalagens de alimentos. A radiação mostrou ser uma ferramenta conveniente na modificação de materiais poliméricos principalmente para elaboração de filmes solúveis onde esta é uma nova tendência para embalagens bioativas. / In recent decades, there has been a substantial increase in the amount of research focusing on the development and characterization of biodegradable materials, particularly edible films. The use of polymers from renewable sources, prepared from plant products, has gained importance in this approach. Soy protein concentrate and cassava starch may be considered an alternative to petrochemical polymers. Processing by ionizing radiation can be used for the modification of polymers and macromolecules, resulting in new materials with great prospects of industrial use. The food industry, one of the traditionally most innovative industries, requires the constant development of new products. The widely known ability of film forming proteins and polysaccharides is a starting point for the development of new materials that meet the varying requirements of this pungent industry. In this work, films based on manioc starch and isolated soy protein were prepared in two different proportions and later irradiated and analyzed for their mechanical properties, color, water absorption, water vapor permeability, TGA and DSC thermal analysis between others. The films became apparently more soluble and less resistant to drilling with the increased radiation dose applied. Regarding the thermal properties, it was observed that the films with greater protein orientation are more resistant. Properties such as water vapor permeability and water absorption, the films were less permeable at the 40 kGy dose. With regard to water absorption, it was reduced as a function of the radiation dose. Films with good resistance to water vapor and with low absorption are considered efficient for food packaging. Radiation has proven to be a convenient tool in the modification of polymeric materials mainly for the production of soluble films where it is a new trend for bioactive packaging.
47

Efeito da radiação ionizante de feixe de elétrons em propriedades de biopolímeros comestíveis a base de proteína isolada de soja e fécula de mandioca / Effect of ionizing electron beam radiation on properties of edible biopolymers based on isolated soybean protein and cassava starch

Vanessa Bernardo Uehara 24 May 2017 (has links)
Nas últimas décadas, têm aumentado substancialmente a quantidade de pesquisas focando no desenvolvimento e caracterização de materiais biodegradáveis, particularmente, filmes comestíveis. O uso de polímeros de fontes renováveis, preparados a partir de produtos vegetais, vem ganhando importância nessa abordagem. O concentrado de proteína de soja e amido de mandioca podem ser considerados uma alternativa aos polímeros petroquímicos. O processamento pela radiação ionizante pode ser empregado para a modificação de polímeros e macromoléculas, resultando em novos materiais com grandes perspectivas de utilização industrial. A indústria de alimentos, uma das indústrias tradicionalmente mais inovadoras, exige o desenvolvimento constante de novos produtos. A capacidade de proteínas e polissacarídeos de formar filmes, amplamente conhecida, é um ponto de partida para o desenvolvimento de novos materiais que atendam os variados requerimentos dessa pungente indústria. Neste trabalho elaboraram-se filmes a base de fécula de mandioca e proteína isolada de soja em duas proporções diferentes e posteriormente irradiados e analisados quanto às suas propriedades mecânicas, cor, absorção de água, permeabilidade ao vapor de agua, análise térmica TGA e DSC entre outros. Os filmes tornaram-se aparentemente mais solúveis e menos resistentes a perfuração com o aumento da dose de radiação aplicada. Com relação às propriedades térmicas observou-se que os filmes com maior proporção de proteína são mais resistentes. Os filmes apresentaram-se menos permeáveis na dose de 40 kGy, e, com relação a absorção de água, esta foi reduzida em função da dose de radiação. Filmes com boa resistência ao vapor de água e com reduzida absorção podem ser considerados adequados para embalagens de alimentos. A radiação mostrou ser uma ferramenta conveniente na modificação de materiais poliméricos principalmente para elaboração de filmes solúveis onde esta é uma nova tendência para embalagens bioativas. / In recent decades, there has been a substantial increase in the amount of research focusing on the development and characterization of biodegradable materials, particularly edible films. The use of polymers from renewable sources, prepared from plant products, has gained importance in this approach. Soy protein concentrate and cassava starch may be considered an alternative to petrochemical polymers. Processing by ionizing radiation can be used for the modification of polymers and macromolecules, resulting in new materials with great prospects of industrial use. The food industry, one of the traditionally most innovative industries, requires the constant development of new products. The widely known ability of film forming proteins and polysaccharides is a starting point for the development of new materials that meet the varying requirements of this pungent industry. In this work, films based on manioc starch and isolated soy protein were prepared in two different proportions and later irradiated and analyzed for their mechanical properties, color, water absorption, water vapor permeability, TGA and DSC thermal analysis between others. The films became apparently more soluble and less resistant to drilling with the increased radiation dose applied. Regarding the thermal properties, it was observed that the films with greater protein orientation are more resistant. Properties such as water vapor permeability and water absorption, the films were less permeable at the 40 kGy dose. With regard to water absorption, it was reduced as a function of the radiation dose. Films with good resistance to water vapor and with low absorption are considered efficient for food packaging. Radiation has proven to be a convenient tool in the modification of polymeric materials mainly for the production of soluble films where it is a new trend for bioactive packaging.
48

Development and characterization of high performance solvent cast soy protein isolate composite films

Jensen, Alexander Matthew 25 May 2012 (has links)
The application of current soy protein films are limited due to their low mechanical strength and high moisture sensitivity compared to synthetic materials. This research studied several methods to improve the mechanical properties [tensile strength (TS), elongation at break (EAB), Young’s modulus of elasticity (YM)] of solvent cast soy protein isolate (SPI) films. Drying times were significantly reduced through the use of a heated casting surface. Neutral (pH 7) SPI films were prepared but were found to have lower TS, EAB and YM than control films prepared under alkaline conditions. Cellulose was extracted from soybean wastes and transmission electron microscopy (TEM) verified the existence of nano-sized fibres. Composite SPI films were prepared using either extracted cellulose fibres or titanium dioxide (TiO2) nanoparticles and their mechanical and barrier properties (water vapour, and oxygen permeability) were evaluated under different relative humidity (RH) conditions. In general, TS and YM decreased and EAB increased with increasing RH. Films with 5% (w/w) added cellulose exhibited significant (p-value < 0.05) improvements in TS and YM but decreased EAB. TiO2 composites possessed similar TS, YM, and EAB values to control films. Barrier properties were comparable across all samples, and decreased with increasing RH. Samples were characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). Preliminary work investigating synthesis of filler materials using cross-linked sodium alginate particles increased the TS and YM of SPI films to a similar extent as extracted cellulose. A method for electrospinning cellulose using ionic liquids was developed, but requires further process optimization to be used for fibre/filler synthesis. / OMAFRA; Hannam Soy Utilization Fund
49

Advanced cellulose composites, preparation and properties / Advanced cellulose composites; preparation and properties

Abouzeid, Ragab 27 September 2012 (has links)
L'accumulation de déchets agricoles tels que la bagasse et le développement d’alternatives aux polymères issus de la pétrochimie ont reçu une attention croissante au cours des deux dernières décennies, due à l'augmentation de la population et à la préoccupation croissante pour la préservation de l'environnement. Cette étude tente de résoudre ces problèmes à l’aide de deux approches principales.La première est liée à des composites à base de papier et de liant naturel et la seconde est associée à la préparation et à la caractérisation de dérivés cellulosiques présentant des propriétés cristaux liquides. En ce qui concerne les composites à base de papier et de liant naturel, la modification par dénaturation d’isolat de protéines de soja (SPI), l'ajout d'acrylamide et le changement de pH améliorent certaines propriétés et rendent les SPI plus utiles et acceptables dans diverses applications. Des expériences préliminaires ont été menées pour déterminer la concentration optimale de SPI permettant d’obtenir des propriétés mécaniques et physiques maximales. Des concentrations de 0,5%, 2,5%, et 5% ont été utilisées et 2.5% correspond à la concentration optimale. Pour augmenter les propriétés adhésives du SPI, l’acrylamide a été utilisé comme un modificateur supplémentaire dans des proportions 1,5%, 2,5% et 5%. L’addition nucléophile de l'acrylamide aux chaînes de protéines en milieu alcalin améliore les propriétés de solubilité du SPI et augmente ses propriétés adhésives. L'effet supplémentaire de l'acrylamide sur le SPI est prononcé sur les propriétés mécaniques et physiques. Comme la charge nette du SPI peut être modifiée en faisant varier le pH du milieu aqueux, la corrélation entre les propriétés mécaniques et physiques des feuilles de papier et le pH du SPI a été étudiée. Les pH utilisés ont été 3, 5, 7 et 10, où le pH 5 est le point isoélectrique (IEP) du SPI.A ce pH, le nombre de charges positives et négatives est pratiquement identique. La seconde approche a consisté à préparer et caractériser une série de dérivés cellulosiques 4 - alkyoxybenzoyloxypropyl (ABPC-n). Ces dérivés ont été synthétisés par estérification d'hydroxypropylcellulose (HPC) avec un DS 3 par l'acide 4- alkoxybenzoic portant 1, 2, 3, 4, 7, 8, 10, 12 et 14 atomes de carbone dans la chaîne latérale. D'autre part, de la pâte debagasse a été préparée et caractérisée à partir bagasse égyptienne. L’Hydroxypropylation a ensuite été menée sur la cellulose obtenue et de l’HPC partiellement substituée a été obtenue. En outre, l'estérification de ce dernier avec des acides 4-alkyloxybenzoic portant 2, 10 et 12 atomes de carbone dans la chaîne latérale a été réalisée et les dérivés ont été désignés (ABPC-m). La structure moléculaire du HPC partiellement substitué et des deux esters (ABPC-n et-m ABPC) a été confirmée par spectroscopies infrarouge à transformée de Fourier (FT-IR) et 1H RMN. Les phases cristal liquide (LC) et les transitions de phases ont été étudiées par microscopie en lumière polarisée (PLM) et calorimétrie différentielle à balayage (DSC), respectivement. Pour étudier les propriétés lyotropiques, différentes concentrations de ces échantillons ont été dissous dans le diméthylacétamide (DMA) (20, 30, 40, 50 et 60% en poids) et la concentration critique a été déterminée par réfractométrie en mesurant l'indice de réfraction des solutions dans le DMA et en traçant l’évolution des indices de réfraction en fonction des concentrations. Pour ABPC-n, nous avons observé que les températures de transition vitreuse (Tg) et de compensation (Tc) diminuent avec la longueur de la chaîne alkoxy et que la gamme mésomorphique (Tm-Tc) diminue avec la longueur de la chaîne alkoxy. / The present study deals with utilization of Egyptian bagasse in both conventional and non-conventional fields. The conventional application is devoted to papermaking, where bagasse pulp is the most appropriate pulp for this purpose due to the suitability of fiber length and high cellulose and hemicellulose contents. The non-conventional application is dedicated to the preparation of cellulosic derivatives having liquid crystalline properties.The first approach deals with using modified soy protein isolate (SPI) as binder for cellulosic fibers in paper composites. Modification of SPI was carried out through i) denaturation with urea and NaOH. ii) addition of acrylamide to the denatured SPI. iii) changing pH of SPI. These types of modification were used to improve the adhesion properties of SPI. Pronounced mechanical and physical properties of paper sheets filled with 0.5, 2.5 or 5% denatured SPI was obtained upon using 2.5%. The optimum condition of SPI addition was used in ii and iii modifications. The additional effect of acrylamide on SPI was pronounced where the mechanical and physical properties were enhanced. Correlation between the mechanical and physical properties of paper sheets with the pH of SPI was studied. The used pHs were 3, 5, 7 and 10.The results showed that the maximum breaking length was obtainedAbstract - xix -at the isoelectric point of SPI at pH 5 (at the isoelectric point (IEP) the number of positive and negative charges on the polyion is the same, giving a net charge of zero) and it began to decrease when the pH is increased to pH 10. Both the burst index and the tear index showed parallel trends.In the second approach, a series of 4- alkyoxybenzoyloxypropyl cellulose (ABPC-n) samples were synthesized via the esterification of hydroxypropyl cellulose (HPC) with 4-alkoxybenzoic acid bearing alkoxy chain with different lengths. On the other hand, cellulose was isolated in pure form from Egyptian bagasse pulp. Hydroxypropylation was then conducted on the isolated cellulose. 4-alkyoxybenzoyloxypropyl cellulose (ABPC-m) samples were synthesized via the esterification of the latter product with the same acid, bearing 2, 10 and 12 carbon atoms in the side chain and characterized.The molecular structure of both esters (ABPC-n and ABPC-m) was confirmed by Fourier transform infrared (FT-IR) and 1H NMR spectroscopy. The liquid crystalline (LC) phases and transition behaviors were investigated using polarized light microscopy (PLM), and differential scanning calorimetry (DSC), respectively. The lyotropic behavior of the derivatives was investigated in DMA solutions using PLM andAbstract - xx -the critical concentration was firstly determined via refractive index measurements.
50

Concentrado protéico de soja e óleo de soja em rações experimentais para o camarão marinho Litopenaeus vannamei / Soy protein concentrate and soy oil in experimental diets to the marine shrimp Litopenaeus vannamei

Cordeiro Júnior, Evandro Lima January 2011 (has links)
CORDEIRO JÚNIOR, Evandro Lima. Concentrado protéico de soja e óleo de soja em rações experimentais para o camarão marinho Litopenaeus vannamei. 2011. 54 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Engenharia de Pesca, Fortaleza-CE, 2011 / Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-07-13T15:09:42Z No. of bitstreams: 1 2011_dis_elcodeirojúnior.pdf: 916213 bytes, checksum: bd808548b8b802d6b66ada4e3a7fc8e2 (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-07-13T15:10:01Z (GMT) No. of bitstreams: 1 2011_dis_elcodeirojúnior.pdf: 916213 bytes, checksum: bd808548b8b802d6b66ada4e3a7fc8e2 (MD5) / Made available in DSpace on 2016-07-13T15:10:01Z (GMT). No. of bitstreams: 1 2011_dis_elcodeirojúnior.pdf: 916213 bytes, checksum: bd808548b8b802d6b66ada4e3a7fc8e2 (MD5) Previous issue date: 2011 / Currently, there are many studies to replace total or part of fishmeal in the artificial feeds by plant protein sources in order to lower costs and greater predictability of production. The study aimed to evaluate the growth performance of juvenile shrimp Litopenaeus vannamei (1.59 ± 0.46 g) reared in the laboratory under controlled conditions for 72 days. They were stored in 50 polyethylene circular tanks of 500 L at the density of 40 shrimp/tank (70 shrimp/m2). Soybean protein concentrate was the main substitute for fish meal and the soybean oil was the main substitute for fish oil. Eight experimental feeds were formulated combining four levels of inclusion of fish meal and two levels of fish oil (120/20, 120/10, 85/20, 85/10, 50/20, 50/10, 0//20 and 0/10). The first number refers to the inclusion of fishmeal (g kg-1) and the second number refers to the inclusion of fish oil (g kg-1). Differences were significant in weekly growth, weight gain, final weight, total feed intake, FCR, yield and PER based on the percentage of inclusion of fishmeal in diets. Survival and ANPU were not significant. Results showed that it is possible to reduce the level of inclusion of fishmeal in the diet of 120 g kg-1 to 85 g.kg-1 and this doesn’t compromise the shrimp growth only if the diet contains at least 10 g.kg -1 of fish oil. If the level of inclusion of fish oil decreases to 10 g kg-1, the minimum inclusion of fish meal, without prejudice, will be subject to 85 g kg-1. There was a reduction in growth rate of L. vannamei when it was removed completely from the fish meal diet. This fact occurred regardless of inclusion level of tested fish oil (20 or 10 g kg-1). Further work is required to evaluate other levels of inclusion, cheap production techniques, alternative ingredients to fish meal etc / Atualmente, há grande esforço de pesquisa no sentido de se substituir, parcial ou totalmente, a farinha de peixe das rações artificiais por fontes protéicas vegetais, visando menores custos, e maior previsibilidade de produção. O presente trabalhou objetivou avaliar o desempenho zootécnico de juvenis do camarão marinho Litopenaeus vannamei (1,59 ± 0,46 g) cultivados em laboratório sob condições controladas durante 72 dias, sendo estocados em 50 tanques circulares de polietileno de 500 L, na densidade de 40 camarões/tanque (70 camarões/m²). No estudo, o concentrado protéico de soja foi o principal substituto da farinha de peixe, e o óleo de soja o principal substituto do óleo de peixe. Oito rações experimentais foram formuladas combinando quatro níveis de inclusão de farinha de peixe e dois níveis de inclusão de óleo de peixe (120/20, 120/ 10, 85/20, 85/10, 50/20, 50/10, 0/20 e 0/10), o primeiro número se refere à inclusão de farinha de peixe em g kg-1 e o segundo número se refere à inclusão de óleo de peixe em g kg-1. Houve diferença significativa no crescimento semanal, peso final, consumo total de ração, FCA, produtividade e TEP em função do percentual de inclusão de farinha de peixe nas dietas, já para sobrevivência e VPP não houve diferença significativa. Pode ser concluído que é possível diminuir o nível de inclusão de farinha de peixe na dieta de 120 g.kg- 1 para 85 g.kg-1 sem comprometer o crescimento dos camarões somente se a dieta contiver, no mínimo, 10 g.kg-1 de óleo de peixe. Se o nível de inclusão de óleo de peixe cair para 10 g kg-1, a inclusão mínima de farinha de peixe sem prejuízo zootécnico será para 85 g kg-1. Houve perda significativa na taxa de crescimento do L. vannamei quando se retirou por completo a farinha de peixe da dieta, independentemente do nível de inclusão de óleo de peixe testado (20 ou 10 g kg-1). Trabalhos futuros são requeridos para avaliar outros níveis de inclusão, técnicas de produção baratas, ingredientes alternativos à farinha de peixe etc

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