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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.
181

Effect of compaction on strength and arching of cohesive material in storage bins

Guan, Wei 09 April 2010 (has links)
An experimental study was carried out to determine the effect of compaction on arching of wheat flour in storage. A model bin 475 mm in height and 600 mm × 375 mm in cross-section was used to conduct tests and wheat flour at moisture contents (MC) of 8.6% and 14.2% was tested. Direct shear tests were performed to determine the angle of internal friction and cohesion of wheat flour subjected to various compaction pressures. It was observed that the internal friction angles were about the same for the wheat flour at two moisture contents (37.1 vs. 37.5), but cohesion for 14.2% MC was 32% higher than that for 8.6% MC. The flowability of wheat flour decreased with increasing compaction pressure sharply at the initial stage of compaction. Compaction led to a 64% increase in required hopper opening for arching-free flow for flour at 8.6% MC, and 49% at 14.2% MC. However, compaction pressure had little effect on arch formation after it reached above 5 kPa.
182

Desoxinivalenol em farinha de trigo: otimização de método analítico, validação e ocorrência

Pereira, Lara Tschopoko Pedroso [UNESP] 27 August 2014 (has links) (PDF)
Made available in DSpace on 2015-03-03T11:52:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-08-27Bitstream added on 2015-03-03T12:06:56Z : No. of bitstreams: 1 000806708_20151231.pdf: 795208 bytes, checksum: 2ad1b7f4489aeed9a2757b25a536b2dd (MD5) Bitstreams deleted on 2016-01-04T10:26:44Z: 000806708_20151231.pdf,. Added 1 bitstream(s) on 2016-01-04T10:28:35Z : No. of bitstreams: 1 000806708.pdf: 1652255 bytes, checksum: 30f1ec1eea04ae1fad0ee3f652522b10 (MD5) / O trigo é um dos mais nobres alimentos e responde atualmente por cerca de 30% da produção mundial de grãos. Desoxinivalenol (DON) é uma micotoxina produzida principalmente por Fusarium graminearum e é conhecida como vomitoxina, possui vários efeitos dentre os quais: redução de consumo alimentar, irritação na pele, diarréia, hemorragias múltiplas e os efeitos imunossupressores. Pertencem ao grupo dos Tricotecenos. Os objetivos do presente estudo foram otimizar e validar o método analítico QUECHERS para a determinação de desoxinivalenol em farinha de trigo e avaliar a ocorrência da micotoxina em amostras de farinha do trigo produzido em algumas regiões brasileiras. A partir dos delineamentos de Palckett & Burman e Composto Central Rotacional foi possível obter um novo método analítico para a determinação de desoxinivalenol em farinha de trigo. QUECHERS é método analítico de fácil execução, economicamente viável, rápido e com menor geração de resíduos orgânicos. Os parâmetros de desempenho do método analítico avaliado indicaram seletividade para a micotoxina desoxinivalenol, linearidade, efeito de matriz significativo, exatidão e precisão, com limite de detecção de 50 ?g.kg-1 e limite de quantificação de 100 ?g.kg-1. O método apresentou porcentagens de recuperação de 86 a 96%. Verificou-se que das amostras provenientes do Rio Grande do Sul, 15% (3) apresentaram contaminações que variaram de 1700 a 3689 ?g. kg-1, com média de 2753 ?g. kg-1, portanto em desacordo com as legislações brasileira (1750 ?g.kg-1). Das amostras provenientes do estado do Paraná, 1 (10%) apresentou contaminação de 877 ?g. kg-1 e nenhuma amostra mineira apresentou contaminação detectável, indicando a qualidade destas amostras para estes parâmentros. Do total das amostras brasileiras avaliadas, 14% apresentaram contaminações que variaram de 147 a 3688 ?g. kg-1 e 6% apresentaram média de 2753 ?g. kg-1, ... / Wheat is a noble grain and corresponds for about 30% of world grain production. Deoxynivalenol (DON) is a mycotoxin produced mainly by Fusarium graminearum and is known as vomitoxin, has several effects among which are: reduction of food intake, skin irritation, diarrhea, hemorrhages and multiple immunosuppressive effects. Belong to the group of Trichothecenes. The aims of this study was to optimize a analytical method QuEChERS for determination of the deoxynivalenol in wheat flour, as well validate the method and then evaluate the occurrence of deoxynivalenol in samples of wheat flour grown in some Brazilian regions. From Palckett & Burman and Rotational Central Composite designs was obtained a analythical method for determination of the deoxynivalenol in wheat flour. An easy, cheap and fast method, wich employs a minimum amount of organic solvents. The analytical method performance parameters showed selectivity for the mycotoxin deoxynivalenol, linearity, significant matrix effect, accuracy and precision, with detection limit of 50 ?g.kg-1 and limit of quantification of 100 ?g.kg-1. The method recovery evaluated was percentages of 86-96%. The contamination by deoxynivalenol was observed in approximately 14% of the 50 samples analyzed. Among total of twenty samples analyzed from the Rio Grande do Sul, 15% (3) showed contamination ranging 1700-3689 mg. kg-1, with mean level of 2753 mg. kg-1. Among total of ten samples analyzed form Paraná state one (10%) of samples were contaminated by deoxynivalenol showed contamination of 877 mg. kg-1 and no detectable contamination in the samples from Minas Gerais. Of total Brazilian samples evaluated, 14% showed contamination ranging 147-3688 mg. kg-1 and 6% had average 2753 mg. kg-1, exceeding the limits allowed by Brazilian legislation. Because the natural contaminant of wheat, DON exerts great impact on human and animal health, so the occurrence of mycotoxin demonstrates the importance of ...
183

Desenvolvimento de um produto tipo "hambúrguer" à base de carne de frango (Gallus gallus) e resíduo de soja, fermentado com Lactobacillus acidophilus CRL 1014 /

Bomdespacho, Laura de Queiroz. January 2010 (has links)
Orientador: Elizeu Antonio Rossi / Banca: Daniela Cardoso Umbelino Cavallini / Banca: Raquel Bedani / Resumo: Okara é o resíduo do processo de produção do extrato hidrossolúvel de soja ou "leite de soja", cujo valor nutricional tem sido considerado por apresentar proteínas, lipídeos e fibras em quantidades significativas, além de compostos bioativos como as isoflavonas. As grandes quantidades de okara produzidas anualmente no Brasil e demais países geram um problema de eliminação e têm servido apenas para a alimentação de animais. Tal situação pode ser modificada por meio de estudos que demonstrem a viabilidade de sua utilização na alimentação humana. Nesse sentido, a proposta desse trabalho foi desenvolver um "hambúrguer" fermentado com cultivo probiótico, a base de carne de frango e que empregue em sua formulação a farinha de okara. A primeira etapa do projeto teve como objetivo testar a viabilidade da incorporação da farinha de okara. Foram processadas 5 formulações de "hambúrgueres" de frango variando as concentrações de farinha de okara entre 10-50%. Os resultados demonstraram que foi possível a elaboração de "hambúrguer" de frango, fermentado com Lactobacillus acidophilus CRL 1014, adicionado de 10% de farinha de okara, apresentando características tecnológicas e sensoriais adequadas. O cultivo probiótico de Lactobacillus acidophilus CRL 1014 foi capaz de se desenvolver satisfatoriamente no produto cárneo em estudo, na ausência de sais de cura. A segunda etapa do projeto teve como objetivo verificar o efeito da fermentação com Lactobacillus acidophilus CRL 1014 nas características físico-químicas... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Okara is the residue of the soy milk production process, whose nutritional value has been considered for presenting proteins, lipids and fiber in significant quantity, and bioactive compounds such as isoflavones. Despite of these qualities, the large quantities of okara produced annually in Brazil, as well as in other countries, create a disposal problem and have served only to feed animals. This situation can be changed by studies demonstrating the feasibility of its use in food for humans. For that reason, the purpose of this study is to develop a "burger" fermented with probiotic culture, having as a basis of its formulation chicken meat and okara flour. The first stage of the project aimed at testing the feasibility of incorporating the okara flour. There were 5 processed formulations of chicken "burgers", varying the concentration of okara flour between 10-50%. The results showed that it was possible to prepare chicken "burger", fermented with Lactobacillus acidophilus CRL 1014, added with 10% okara flour, which presented adequate technological and sensory characteristics. The cultivation of probiotic Lactobacillus acidophilus CRL 1014 was able to grow satisfactorily in the meat product in the absence of curing salts. The second stage of the project aimed to investigate the effect of fermentation with Lactobacillus acidophilus CRL 1014 in the physico-chemical, microbiological and sensory characteristics of a product like "hamburger" made of chicken meat and okara, with reduced use of curing salts. Three treatments were processed: ...(Complete abstract click electronic access below) / Mestre
184

Efeitos da radiacao gama do cobalto-60 nas fases do ciclo evolutivo de tribolium castaneum (Herbst.,1797) (Coleoptera-Tenebrionidae)

FONTES, LUCIA da S. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:37:41Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:00:15Z (GMT). No. of bitstreams: 1 05344.pdf: 2112095 bytes, checksum: b5b5473c9436a1e4d97ff7f054328796 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
185

Efeito da radiação ionizante em diferentes tipos de farinhas utilizadas em tecnologia de panificação / Ionizing radiation efect on different types of flours used in bakery technology

TEIXEIRA, CHRISTIAN A.H.M. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:33:15Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:16Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
186

Investigation of the emusifying properties of bambara groundnut flour and starch

Gabriel, Ebunoluwa Grace January 2013 (has links)
Thesis submitted in fulfillment of the requirements for the degree Master of Technology: Chemical Engineering In the Faculty of Engineering At the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY 2013 / A number of foods, pharmaceutical and industrial products are formulated as emulsions. The immiscibility of oil and water makes emulsions thermodynamically unstable, thus requiring emulsifiers. Natural and synthetic substances have been used as emulsifiers with preference for the former for safety, cost and availability purposes. Bambara groundnut (BGN) is an important source of nutrient in many African communities. Similar to soybean, flaxseed, and other leguminous products, the important blend of high protein and carbohydrate composition of BGN makes it a potential candidate as an emulsifier where, it can serve additional nutritional role in such emulsions. No literature evidence exists to support any earlier study on the potential emulsifying property of BGN. It is therefore of interest to investigate the potential of BGN flour (BGNF) and starch (BGNS) in stabilizing oil-in-water emulsions. The current study aimed to investigate the emulsifying properties of Bambara groundnut flour and starch. A batch of BGN was milled to produce the BGNF. BGNS was extracted from the BGNF. Emulsions were prepared using a wide range of flour-oil-water and starch-oil-water composition as generated through computational modelling. Emulsions were physically observed for stability, and then subjected to various stability studies using the Turbiscan® (which gives kinetic information on the process leading to phase separation; and allows for the detection of two kinds of destabilisation phenomena (particle migration): creaming and sedimentation) and optical microscope (which helps to detect particle size variation or aggregation in order to measure coalescence and/or flocculation). The most stable emulsions (one BGNF-stabilized and the other BGNS-stabilzed) were determined and subjected to same stability studies in the presence of varying physicochemical and physic-mechanical environmental conditions: effects of homogenization speed (9,000 – 21,000 rpm), pH (2 - 10), the presence of salt (2 – 10% w/v NaCl) and vinegar (2 – 10% v/v). Results were expressed in terms of relative stability (using creaming/sedimentation rate) and absolute oil droplet growth (coalescence and flocculation). The emulsifier-oil compositions (emulsifier and water make 100 mL gelatinized mixture before the addition of oil) that gave the most stable emulsions were 9 g BGNF-39 g oil and 5 g BGNS-30 g oil. The two emulsions had only 15% and 30% growth in oil droplet diameter respectively by day 5, compared to over 3000% in the unstable ones. The emulsions were generally observed physically to be stable till day 5 with minimal creaming. Emulsions prepared with BGNS were physically observed to have increasing viscosity with time. There was microbial growth on the emulsions after 3 days. This might have been encouraged because of the rich nutritional composition of BGN. The stability of the emulsions increased significantly (p < 0.05) with the speed of homogenization (up to 15, 000 rpm beyond which the difference in stability was not significant). Compared to control (pH 7), emulsion stability decreased significantly (p < 0.05) with decreasing (up to 16% instability by Day-5 at pH 2) and increasing pH (10% instability at pH 10) with corresponding increase in droplet size. Emulsion stability increased significantly (p < 0.05) with increasing NaCl concentration (35% instability at 2% NaCl compared to 18% instability at 10% NaCl). Stability however decreased sharply with increasing concentration of vinegar (55% instability at 10% vinegar compared to 19% instability at 2% vinegar). The BGNF-stabilized emulsions were more stable (ordinarily and in the presence of the additives) than the BGNS-stabilized ones. Instability values in the BGNS emulsions, in most cases, double those for BGNF. Emulsions were successfully stabilized with BGNF and BGNS. The emulsions were optimal when prepared at a homogenization speed of 15,000 rpm and at neutral pH. The higher the concentration of salt, the more stable the emulsions. Increasing concentration of vinegar however, destabilized the emulsions.
187

Desenvolvimento e caracterização de filmes nanocompósitos de farinha de amaranto - montmorillonita / Development and characterization of nanocomposite films based on amaranth flour and montmorillonite

Villamán Diéguez, María Cristina 02 April 2011 (has links)
Orientadores: Florencia Cecília Menegalli, Paulo José do Amaral Sobral / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-17T09:34:33Z (GMT). No. of bitstreams: 1 VillamanDieguez_MariaCristina_M.pdf: 3299521 bytes, checksum: b5bf8aa7ece9693c382d364d2a207cb4 (MD5) Previous issue date: 2011 / Resumo: A aplicação da nanotecnologia na elaboração de filmes nanocompósitos, tem sido muito utilizada nos últimos anos na área de desenvolvimento de materiais biodegradáveis. Os nanocompósitos são misturas de polímeros orgânicos e partículas nanométricas, entre as mais estudadas para esta aplicação está a montmorillonita (MMT), uma argila mineral composta por capas de aluminatos e silicatos hidratados. Neste projeto foram elaborados filmes nanocompósitos (F.NC) baseados em farinha de amaranto (FA) e MMT, utilizandose o método de intercalação por solução. Foram realizados estudos preliminares para escolher o processo mais indicado para a inclusão da MMT na solução filmogênica (SF). Experimentaram-se quatro processos, que compreenderam diferentes tipos e velocidades de agitação e distintos tempos onde era adicionada a MMT (antes ou depois do processo térmico). As análises de microscopia óptica revelaram que o processo em que se utilizou uma agitação forte (7.000 rpm) e que a gelatinização do amido ocorreu na presença da MMT, foi o único que conseguiu obter uma matriz filmogênica homogênea. Por meio deste processo elaboraram-se filmes e analisaram-se por microscopia eletrônica de varredura (MEV), onde se confirmou a formação de uma matriz homogênea, na superfície e na secção transversal dos filmes. Para o desenho experimental foi utilizado um delineamento composto central rotacional DCCR 22, para se estudar o efeito da concentração da argila [CMMT] e da temperatura do processo (TP), nas propriedades dos filmes. Trabalhou-se numa faixa de [CMMT] entre 0% a 9,4% (m/m), com uma concentração fixa de glicerol de 25%, na qual os filmes obtidos eram facilmente manipuláveis. Como resultado observouse que o aumento simultâneo da [CMMT] (m/m) e da TP, produz um aumento na tensão e, conseqüentemente uma diminuição da elongação destes filmes. A propriedade de solubilidade também foi afetada por ambos os fatores. Realizaram-se análises estatísticas para maximizar o valor de tensão e minimizar a solubilidade destes filmes. Encontraramse que as condições ótimas para conseguir esse propósito foram: [CMMT] = 9,4% e TP = 83°C. Nessa T P, quando a CMMT foi aumentada de 0 a 9,4% a tensão aumentou de 1.20 MPa para 1.61 MPa e a solubilidade diminuiu de 48.2% a 44.98%. Interessante foi o resultado obtido para a permeabilidade ao vapor de água (PVA), que decresceu em 96% ao ser adicionada a MMT / Abstract: The application of nanotechnology in the development of nanocomposite films has been the most widely used in recent years in the development of biodegradable materials. Nanocomposites are mixtures of organic polymers and nano-sized particles, among the most studied for this application, is montmorillonite (MMT), a mineral clay composed of layers of hydrated silicates and aluminates. Were carried out preliminary studies to determine what would be the most appropriate process for the production of amaranth flour films (FA) and montmorillonite (MMT) by the method of intercalation by solution. We compared different types of agitation and the differences in the addition of the nanoclay before or after the heat treatment. Optical microscopy analysis revealed that process with vigorous shaking (7.000 rpm) and where gelatinization of the starch occurred in the presence of montmorillonite, was the only one forming a homogeneous matrix. Using Scanning Electron Microscopy (SEM) we were able to corroborate the production of a homogeneous matrix in both, the surface and cross sections. Then the study of the effect of clay content [CMMT] and process temperature (TP) on the production of amaranth flour/clay nanocomposite films was investigated. Since easily manageable films were obtained at concentrations ranging from 0% to 9,4 % (w/w) of MMT and 25% glycerol, these conditions were chosen in the DCCR 22 experimental design. The simultaneous rise on [CMMT] (w/w) and TP, resulted on increased tensile strength and, consequently, decreased elongation at break values. Solubility was also affected by both factors. Statistical analysis was performed to maximize the tensile strength and to minimize the solubility of these films. A concentration of 9,4% at a temperature of 83°C was found to be optimal for this purpose. At that TP, when CMMT was increased from 0 to 9,4% the tensile strength was increased from 1.20 MPa to 1.61 MPa and the solubility (%) was decreased from 48.2% to 44.98%. Interestingly, the water vapor permeability (WVP) values were decreased by 96% upon addition of MMT / Mestrado / Mestre em Engenharia de Alimentos
188

Efeito da extrusão termoplastica sobre propriedades funcionais e nutricionais de farinhas a base de milho, caseina e derivados de levedura / Effect of thermoplastic extrusion on nutritional and functional properties of the base of maize meal, casein and derived from yeast

Alvim, Izabela Dutra 28 July 2018 (has links)
Orientador : Valdemiro Carlos Sgarbieri / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-07-28T09:34:31Z (GMT). No. of bitstreams: 1 Alvim_IzabelaDutra_M.pdf: 3995270 bytes, checksum: ecbf8bdf5b5c8afa389c74f68a05c07d (MD5) Previous issue date: 2001 / Resumo: O principal objetivo desse trabalho foi mostrar a possibilidade de aplicações de derivados de levedura na produção de uma base para sopa constituida de farinha de milho adicionada de produtos de levedura e caseína e submetida ao processo de extrusão / Abstract: The main objective of this study was to show the possibility of applications, from yeast to produce a base for soup made from maize flour added products of yeast and casein and subjected to the extrusion process / Mestrado / Mestre em Ciência de Alimentos
189

Efeitos da radiacao gama do cobalto-60 nas fases do ciclo evolutivo de tribolium castaneum (Herbst.,1797) (Coleoptera-Tenebrionidae)

FONTES, LUCIA da S. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:37:41Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:00:15Z (GMT). No. of bitstreams: 1 05344.pdf: 2112095 bytes, checksum: b5b5473c9436a1e4d97ff7f054328796 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
190

Efeito da radiação ionizante em diferentes tipos de farinhas utilizadas em tecnologia de panificação / Ionizing radiation efect on different types of flours used in bakery technology

TEIXEIRA, CHRISTIAN A.H.M. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:33:15Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:16Z (GMT). No. of bitstreams: 0 / O presente trabalho teve como objetivo avaliar as alterações causadas pela radiação ionizante em diferentes tipos e quantidades de produtos ricos em amido (farinhas de trigo, de mandioca, centeio, trigo integral, polpa de banana verde e milho) nas características reológicas, tecnológicas, físicas e de textura. As amostras foram irradiadas em fonte de 60Co, com doses de 1, 3 e 9kGy, e taxa de dose 2kGy/h. Foram estudadas a energia de deformação e a extensibilidade, para farinhas de trigo forte e fraca e observou-se o comportamento das características reológicas um, cinco e trinta dias após a irradiação. A característica tecnológica estudada, por até 1 mês após irradiação, foi a atividade enzimática das farinhas de trigo forte e fraca irradiadas. As características físicas: altura, peso e perda de umidade e textura de fatias de pães confeccionadas com a substituição parcial (30%) da farinha de trigo por diferentes farinhas irradiadas foram estabelecidas. Os resultados mostraram que com o aumento da dose de radiação houve uma diminuição no valor da atividade enzimática, principalmente a 9kGy, desta forma não haveria necessidade do acréscimo de melhoradores enzimáticos na elaboração de pães. A altura, o peso, e a perda de umidade dos pães apresentaram diversos comportamentos dependendo do tipo de produto utilizado na sua formulação em substituição à farinha de trigo. Com o aumento da dose de radiação aplicada, houve um aumento na altura dos pães, bem como, diminuição da perda de umidade para a farinha de trigo e farinha de trigo contendo 30% de farinha de banana verde. Do ponto de vista tecnológico, a atividade enzimática não foi negativamente afetada pela radiação. Considerando as características estudadas, a aplicação da dose de 9kGy seria recomendável visando a produção de pães de forma. Embora o processo de irradiação seja geralmente aplicado na preservação da qualidade higiênica de produtos alimentícios, a irradiação de farinhas induz algumas características tecnológicas benéficas para seu uso na produção de pães. / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

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