Afin de protéger durablement les écosystèmes face aux rejets planifiés ou accidentels de radionucléides dans l’environnement, il est essentiel d’évaluer l’impact de l’exposition des organismes aux radiations ionisantes sur le long terme, à l’échelle de plusieurs générations. Dans ce contexte, ce travail de doctorat vise à améliorer la caractérisation des processus moléculaires et la prédiction des effets transgénérationnels lors d’une exposition aux radiations gamma. Une approche expérimentale concerne l’étude des modifications épigénétiques radio-induites, c’est-à-dire des modifications des mécanismes régulant l’activité des gènes sans modification de la séquence d’ADN elle-même et de leur transmission au fil des générations. Cette étude a permis de mettre en évidence que certaines modifications de la méthylation de l’ADN, l’un des mécanismes épigénétiques les plus étudiés, peuvent être transmises par la lignée germinale aux les générations non-exposées (génération F3) suite à une exposition parentale (génération F0) externe aux radiations gamma (6,5 µGy.h-1 et 41,3 mGy.h-1) pendant 25 jours. Dans une seconde approche, un modèle mécaniste DEBtox (Budget Energétique Dynamique appliqué à la toxicologie) est modifié pour permettre l’analyse des effets des radiations gamma sur la croissance et la reproduction de D. magna à l’échelle de plusieurs générations. Pour ce faire, on utilise des compartiments de dommage, dont le niveau peut être hérité d’une génération à la suivante. Le modèle est ajusté aux données avec des méthodes d’inférence bayésienne afin d’estimer les paramètres tout en tenant compte des incertitudes qui leur sont associées. / In order to durably protect ecosystems facing planned or accidental releases of radionuclides, the long-term impact of organism exposure to ionizing radiation must be studied on a multigenerational scale. The aim of this PhD is to improve the characterization of molecular processes and the prediction of transgenerational effects during a gamma irradiation. First, an experimental approach investigated on radio-induced modifications of epigenetic processes, i.e. changes in mechanisms that regulate gene expression without changing DNA sequence itself and on the transmission of these modifications to subsequent generations. Significant changes in DNA methylation, a well-studied epigenetic mechanism, detected in generation F3 clearly showed that epigenetic modifications could be transmitted to unexposed generations, in response to the exposure of a parental generation (F0) to external gamma radiation (6.5 µGy.h-1 et 41.3 mGy.h-1) for 25 days. Second, a mechanistic modelling approach used a modified version of the DEBtox model (Dynamic Energy Budget model applied to toxicology) in order to analyze effects of gamma radiation on D. magna growth and reproduction over several generations. To that end, damage compartments, with damage levels that were transmitted from one generation to the next, were included. The model was fitted to data using Bayesian inference methods, in order to estimate the parameters while considering their associated uncertainty.

A fécula de açafrão (Curcuma longa L.) apresenta grande potencial para a indústria de alimentos, pois está presente em abundância nos rizomas do açafrão, podendo assim, ser considerada uma fonte alternativa aos amidos já comercializados. Muitos amidos tem passado por modificações físicas, como a aplicação da irradiação gama, para que este adquira novas características e aumente sua aplicabilidade. O objetivo desta pesquisa foi estudar a influência de diferentes doses de radiação sobre a fécula de açafrão (Curcuma longa L.) e avaliar sua aplicação tecnológica em bolo de cenoura. A composição centesimal não foi influenciada significativamente pelas doses de radiação. No entanto, a textura dos géis foi afetada, bem como as soluções gelatinizadas. A solução não gelatinizada apresentou comportamento dilatante e a gelatinizada foi caracterizada como pseudoplástica. Em relação a substituição parcial da farinha de trigo pela fécula de açafrão sob todas as doses estudadas, o resultado se mostrou viável na elaboração do bolo de cenoura, indicando que esta fécula pode ser aplicada em diversos alimentos, sem provocar a rejeição do produto final. / The saffron starch (Curcuma longa L.) presents great potential for the food industry, as it is present in abundance in the saffron rhizomes, and can therefore be considered an alternative source to already commercialized starches. Many starches have undergone physical modifications, such as the application of gamma irradiation, so that it acquires new characteristics and increases its applicability. The objective of this research was to study the influence of different doses of radiation on safflower starch (Curcuma longa L.) and to evaluate its technological application in carrot cake. The centesimal composition was not significantly influenced by radiation doses. However, the texture of the gels was affected, as well as the gelatinized solutions. The non-gelatinized solution presented dilating behavior and the gelatinized solution was characterized as pseudoplastic. Regarding the partial substitution of wheat flour for saffron starch under all doses studied, the result was viable in the preparation of the carrot cake, indicating that this starch can be applied in several foods without causing the rejection of the final product.

An environmental friendly and simple approach to synthesis of Platinum (Pt), Palladium (Pd), Rhodium (Rh) and Osmium (Os) nanoparticles via gamma radiolysis is demonstrated. Herein, we report on the effect of gamma rays radiation on Platinum (Pt), Osmium (Os), Rhodium (Rh) and Palladium (Pd) salts solutions for synthesis of nanoparticles. Pt, Os, Rh and Pd salts solutions of different concentrations were exposed to intense gamma rays irradiation with doses varying from 70 to 120 kGy. The metal ion salt solutions were easily converted into metal nanoparticles (MNP) using radiolysis method. The radiolytic conversion effect produced MNP suspended in the solution. For Pt, Pd and Rh a metal coating on the edges of the polypropylene tube used as a container, was unexpectedly observed but not for the Os solution. Physical/chemical properties of γ-ray produced nanoparticles were reported. UV-Vis spectroscopy, X-ray diffraction (XRD) and High resolution transmission electron microscopy (HRTEM) analyses confirmed that both the coating and the MNP correspond to the pure metal coming from the reduction of the initial salt. HRTEM analysis shows the particles size and particle distribution of the produced nanoparticles. Quantitative analysis of the XRD patterns shows information about the size and stress of the converted metals. The functional groups in the solvent are analysed by Fourier Transform Infrared spectroscopy (FTIR). The production of a metal coating on polypropylene plastic tubes by gamma-rays irradiation is presenting an interesting alternative to conventional techniques of metal deposition especially for coating the inner part of a tube. / Physics / D. Lit. et Phil. (Physics)

Recent studies have demonstrated that peanut and grape processing by-products may be richer sources of bioactive compounds as compared to their original raw material and feedstock; however, before their application as a source of nutraceuticals or in the prevention of lipid oxidation in food systems, certain technological challenges have to be addressed. This study discusses recent advances in the application of plant food processing by-products as sources of phenolic compounds with special emphasis on the profiling and screening of phenolics using high-performance liquid chromatography-mass spectrometry, their potential health benefits, and microbiologial safety. The major findings are summarized in chapters 2, 3, and 4. The first chapter deals with phenolics from grape by-products. In general, insoluble-bound phenolics were more effective in inhibiting copper-induced human LDL-cholesterol oxidation in vitro than free and esterified phenolics. Phenolic extracts from all fractions inhibited peroxyl radical-induced DNA strand breakage. The third chapter brings about the effects of gamma-irradiation on the microbial growth, phenolic composition, and antioxidant properties of peanut skin. Gamma-irradiation at 5.0 kGy decreased the microbiological count of the product. Total phenolic and proanthocyanidin contents, ABTS radical cation, DPPH radical, hydrogen peroxide, and hydroxyl radical scavenging capacities as well as the reducing power of the sample were increased upon gamma-irradiation in both the free and insoluble-bound phenolic fractions. The bioactivity of the free phenolics against in vitro human LDL-cholesterol oxidation and copper induced DNA strand breakage was improved upon gamma-irradiation. Phenolic compounds were positively or tentatively identified and their distribution was in the decreasing order of free > esterified > insoluble-bound forms. Procyanidin dimer A was increased in all phenolic fractions, whereas procyanidin dimer B decreased. Gamma-irradiation induced changes may be explained by molecular conversion, depolymerization, and cross-linking. In the fourth chapter, the ability of selected enzymes in improving the extraction of insoluble-bound phenolics from the starting material (experiment I) or the residues containing insoluble-bound phenolics (experiment II) were evaluated. Pronase and Viscozyme improved the extraction of insoluble-bound phenolics. Viscozyme released higher amounts of gallic acid, catechin, and prodelphinidin dimer A compared to Pronase treatment. Furthermore, p-coumaric and caffeic acids, as well as procyanidin dimer B, were extracted with Viscozyme but not with Pronase treatment. Solubility plays an important role in the bioavailability of phenolic compounds, hence this study may assist in better exploitation of phenolics from winemaking by-products as functional food ingredients or supplements. / Estudos recentes têm demonstrado que subprodutos da indústria processadora de amendoim e uva podem ser mais ricos em compostos bioativos em comparação às suas matérias-primas. No entanto, alguns desafios tecnológicos precisam ser enfrentados antes da sua aplicação como fonte de compostos nutracêuticos ou na prevenção da oxidação lipídica em sistemas alimentares. Este estudo discute os recentes avanços na aplicação de subprodutos da indústria processadora de amendoim e uva como fontes de compostos fenólicos. Especial ênfase foi dada a sua caracterização por cromatografia líquida acoplada à espectrometria de massas, aos potenciais benefícios à saúde e à segurança microbiológica. As principais conclusões estão apresentadas nos capítulos 2, 3 e 4. O primeiro capítulo trata de compostos bioativos de subprodutos da indústria de suco de uva e da produção vinícola. A fração da qual foram extraídos os compostos fenólicos ligados à parede celular foi predominante. Em geral, esta fração também foi a mais eficaz na inibição da oxidação do LDL - colesterol in vitro quando comparada à fração que continha os fenólicos livres e os esterificados. Os compostos fenólicos de todas as frações inibiram o dano oxidativo ao DNA induzido por radicais peroxila. O terceiro capítulo fala sobre os efeitos da irradiação gama sobre a carga microbiana, a composição fenólica e as propriedades antioxidantes da película de amendoim. A irradiação gama (5,0 kGy) diminuiu a contagem microbiana do produto. Os compostos fenólicos totais, o teor de proantocianidinas e a capacidade dos extratos em neutralizar radicais como o ABTS, DPPH e espécies reativas de oxigênio como o peróxido de hidrogênio e radicais hidroxila, assim como o poder redutor da amostra, aumentaram devido à irradiação gama em ambas as frações (contendo fenólicos livres e ligados à parede celular). A bioatividade dos compostos fenólicos livres contra a oxidação do LDL-colesterol in vitro e contra os danos oxidativos ao DNA aumentou com a irradiação gama. Os compostos fenólicos foram positivamente ou tentativamente identificados, distribuindo-se entre: fenólicos livres > esterificados > ligados. Houve aumento na concentração de dímeros de procianidina A em todas as frações, enquanto a concentração de dímeros de procianidina B diminuiu. Essas alterações podem ser explicadas pela conversão molecular, despolimerização e formação de ligações cruzadas. No quarto e último capítulo, enzimas selecionadas foram aplicadas à matéria-prima inicial (experimento I) ou nos resíduos contendo apenas compostos fenólicos insolúveis (experimento II). Pronase e Viscozyme aumentaram a extração de compostos fenólicos insolúveis (ligados à parede celular). Viscozyme liberou maiores quantidades de ácido gálico, catequina e dímero de prodelfinidina A em comparação ao tratamento com Pronase. Além disso, os ácidos p-cumárico e ácido caféico, bem como o dímero de procianidina B, foram extraídos com Viscozyme, mas não com Pronase. A solubilidade desempenha um papel importante na biodisponibilidade de compostos fenólicos. Desta forma, o terceiro estudo oferece uma alternativa para a exploração de compostos fenólicos de subprodutos da indústria vinícola como ingredientes alimentares com propriedades funcionais ou suplementos alimentares.

This PhD project studied the caesium and strontium removal capacities of six nanoporous materials. Indeed, it was linked in with the SIXEP plant present at Sellafield site, UK, which is currently using natural clinoptilolite, originally mined from the Mojave Desert, to remove radioactive caesium and strontium ions from wastewater effluents. At the moment the feeds entering the SIXEP plant correspond to the best working conditions for clinoptilolite. As the feeds are moving toward more acidic pH and complex solutions and as clinoptilolite works at neutral pH, new nanoporous materials are required. This project had been divided into sub-projects, which all had the same purpose of finding the best material for caesium and strontium removal under complex solutions. The first part of the PhD focused on the synthesis of CST, SNT, ETS-4 and ETS-10 materials following literature reviews. The two last materials studied were provided by Fortum Power and Heat Oy for CsTreat material and by Sellafield Ltd for clinoptilolite material. The second part of the PhD consisted in studying the exchange capacities for caesium and strontium ions for each material studied under batch conditions using several water compositions relevant to Sellafield Ltd. Each water composition had different competing ions or pH and were used to classify the materials between them. From that it was found that Clinoptilolite stays the best materials for caesium and strontium removal. The third part of the project was the gamma irradiation of the materials. This irradiation had an aim to check the stability of the structure of the studied materials under gamma irradiation. The materials were exposed to four different gamma doses which were 0.5; 1; 3 and 6 MGy, the last one corresponding to the maximum dose were structural changes could happen. This revealed that all the materials, except ETS-4 material, were stable under gamma irradiation and that no structural changes were observable. The fourth part of the project was an extension of the third part in which the materials were Cs exchanged before being gamma irradiated to a dose of 6 MGy. This showed that the caesium exchange process is not affected by radiation. Finally, the unexchanged materials were alpha irradiated using a 15 MeV He2+ beam at the Dalton Cumbria Facility. Two irradiations were performed on CsTreat, CST, ETS-4, ETS-10 and clinoptilolite material. It was found that all the materials were damaged by alpha irradiation and displayed amorphous framework To resume, it appeared that clinoptilolite still stays one of the best materials for the removal of caesium and strontium ions in a wide range of wastewater composition. Additionally, it was discovered that ETS-10 material could be a good alternative to clinoptilolite material as its structure is stable under gamma irradiation and it displayed good exchange capacities when competing ions were present in the feeds. CST could also be a substitute as it shows good ion exchange properties under a broad range of pH. SNT material was great for strontium removal while CsTreat was working well for caesium removal. Even though ETS- 4 revealed good ion exchange capacities they were lower than clinoptilolite, ETS- 10 or CST materials.

This thesis presents results from a two part, prospective study using honey collected from Guelph and surrounding area in southwestern Ontario. The first part determined the antibacterial of honey by collecting 26 samples of honey over two summers (2011-2012) and conducting microbroth and agar dilution assays and comparing the results to those of the criterion standard, Medihoney™ (100% manuka honey paste). Some honey samples from southwestern Ontario had antibacterial activity that was not significantly different from that of Medihoney™. The second part evaluated the effects of storage and gamma irradiation on the antibacterial activity of highly antibacterial honeys. It was found that storage for 8 months at 4°C and -20°C reduced the antibacterial activity of honey. The antibacterial activity of honey was not altered after gamma irradiation. / Pet Trust Fund

Orientador: Rogério Lopes Vieites / Banca: Giuseppina Pace P. Lima / Banca: Josalba Vidigal de Castro / Resumo: O presente trabalho teve por objetivo verificar os efeitos do ácido ascórbico e da radiação gama na conservação pós-colheita de maçã Royal Gala minimamente processada, submetida à refrigeração, visando estender a sua vida útil, retardando seu amadurecimento e reduzindo a incidência de patógenos, sem prejuízo das suas características físicas, químicas e organolépticas. Foram realizados 4 experimentos: Experimento 1 - os frutos processados em cubos de 2 x 2 cm; Experimento 2 - os frutos processados em rodelas de 1 cm; Experimento 3 - os frutos cortados em 4 partes. Para os experimentos 1, 2 e 3, após o processamento nos diferentes cortes, os frutos foram acondicionadas em bandejas de isopor envolvidas em filme plástico e submetidas a diferentes concentrações de ácido ascórbico (0%, 1%, 2%, 3% e 4%); Experimento 4 - os frutos processados em cubos de 2 x 2 cm, imersos em solução de 3% de ácido ascórbico, acondicionados em bandejas de isopor envolvidas em filme plástico e irradiadas com diferentes doses de radiação gama (T1 - Testemunha (0,0kGy), T2 - 0,1kGy, T3 - 0,2kGy, T4 - 0,3kGy, T5 - 0,4kGy, T6 - 0,5kGy). As frutas foram irradiadas na EMBRARAD, localizada em Cotia - SP. Foram utilizadas nessa pesquisa maçãs Royal Gala, provenientes da Empresa Agroban (Vacaria - RS). Os frutos foram transportados ao Laboratório de Frutas e Hortaliças, pertencente ao Departamento de Gestão e Tecnologia Agroindustrial, da Faculdade de Ciências Agronômicas - UNESP - Câmpus de Botucatu, SP. Para cada experimento, os frutos após receberem cada tratamento, foram armazenados em câmara fria a 5l1ºC e 85 - 90% de umidade relativa. As avaliações foram realizadas a cada dois dias, durante 10 dias de armazenamento. As alterações na qualidade pós-colheita foram detectadas por meio das análises de perda de massa fresca... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The present work had as objective to verify the effects of the ascorbic acid and the gamma radiation in the postharvest conservation of the minimally processed apple 'Royal Gala' minimally processed, submitted to the refrigeration aiming to extend its useful life, delaying its ripening and reducing the microorganisms incidence, without damage of its physical, chemistries and sensorial characteristics. Four experiments were accomplished: Experiment 1 - the fruits processed in cubes of 2 x 2 cm; Experiment 2 - the fruits processed in slices of 1 cm; Experiment 3 - the fruits cut in 4 parts. For the experiments 1, 2 and 3, after the processing in the different cuts, the fruits were conditioned in isopor trays involved in plastic film and submitted to different concentrations of ascorbic acid (0%, 1%, 2%, 3% and 4%); Experiment 4 - the fruits processed in cubes of 2 x 2 cm, immersed in solution of 3% of ascorbic acid, conditioned in isopor trays involved in plastic film and irradiated with different gamma radiation doses (T1 - control (0,0kGy), T2 - 0,1kGy, T3 - 0,2kGy, T4 - 0,3kGy, T5 - 0,4kGy, T6 - 0,5kGy). The fruits were irradiated in EMBRARAD, located in Cotia - SP. Apples ' Royal Gala' were used in this research, coming from the Company Agroban (Vacaria - RS). The fruits were transported to the Laboratory of Fruits and Vegetables, belonging to the 'Departamento de Gestão e Tecnologia Agroindustrial', of 'Faculdade de Ciências Agronômicas - UNESP - Campus of Botucatu, SP'. Each fruit after receiving treatment, was stored for each experiment in a cold camera to 5l1ºC and 85 - 90% of relative humidity. The evaluations were accomplished every other day, for 10 days of storage. The alterations in the quality postharvest were detected through the analyses of loss of fresh mass... (Complete abstract, click electronic access below) / Mestre

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-05-16T13:12:17Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação - Tiago Lopes de Araújo - VERSÃO FINAL.pdf: 5049016 bytes, checksum: 19afff51e97123d7092ffd5fd7abcdca (MD5) / Made available in DSpace on 2017-05-16T13:12:17Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação - Tiago Lopes de Araújo - VERSÃO FINAL.pdf: 5049016 bytes, checksum: 19afff51e97123d7092ffd5fd7abcdca (MD5) Previous issue date: 2016-02-29 / CNPQ / O poli(cloreto de vinila) (PVC) é empregado na fabricação de embalagens para alimentos e alguns produtos para saúde. Em geral, esses produtos precisam ser esterilizados antes de serem consumidos. Um dos métodos utilizados para esse fim é a irradiação gama. Todavia, esse tipo de radiação ionizante promove alterações na estrutura das cadeias poliméricas, afetando as propriedades do PVC em maior ou menor grau. Dessa forma, é necessário adicionar determinadas substâncias à resina para estabilizar o material contra a irradiação. O objetivo deste trabalho foi investigar o efeito da radiação gama em filmes de PVC e filmes de PVC contendo 1, 3 e 5 % (m/m) de pentóxido de nióbio (Nb2O5), que é um composto inerte, atóxico e biocompatível. Os filmes foram preparados pela técnica de solution casting, utilizando tetraidrofurano como solvente, e os corpos de prova foram irradiados nas doses de 25 e 50 kGy em temperatura ambiente. Foram utilizadas uma resina de PVC comercial obtida pelo processo de polimerização em suspensão, com massa molar média viscosimétrica igual a 201 kg/mol, e uma amostra de Nb2O5 cujas partículas apresentavam formato irregular, diâmetro volumétrico médio igual a 77 µm e estrutura cristalina monoclínica. Os efeitos da radiação gama e/ou do óxido na matriz polimérica foram avaliados através de viscosimetria de soluções diluídas, colorimetria, ensaio mecânico de tração, análise termogravimétrica (TGA) e espectroscopia no infravermelho médio por transformada de Fourier (FT-MIR). Os resultados da viscosimetria de soluções diluídas mostraram que o percentual de 5 % (m/m) de Nb2O5 conferiu proteção radiolítica ao polímero, diminuindo os eventos de cisão das cadeias principais em relação à matriz de PVC. De acordo com os ensaios colorimétricos, os filmes se tornaram mais escuros e mais amarelados, tanto em função do aumento do percentual de óxido quanto do aumento da dose de radiação. Para o mesmo material, a exposição à radiação gama não causou mudanças significativas nas propriedades mecânicas avaliadas pelo ensaio mecânico de tração (tensão na força máxima, módulo de Young e alongamento percentual na força máxima). Por outro lado, a presença do Nb2O5 nos sistemas contribuiu para diminuir o valor dessas propriedades. Os resultados da TGA mostraram que a radiação gama reduziu a estabilidade térmica dos materiais preparados, enquanto que o óxido não a alterou significativamente. A exposição dos filmes à radiação gama contribuiu para reduzir a energia de ativação do processo de desidrocloração e aumentar a energia de ativação do processo de quebra das sequências de polienos, embora o óxido não tenha catalisado nenhum dos dois processos. Algumas modificações químicas provocadas pela irradiação dos filmes foram detectadas pela espectroscopia FT-MIR, empregando a reflectância total atenuada para a aquisição dos espectros. Também foi constatado que o Nb2O5 não apresentou atividade antibacteriana frente à Escherichia coli, avaliada pelo ensaio de macrodiluição em caldo com agitação. / Poly(vinyl chloride) (PVC) is used in the manufacture of food packaging and some health products. In general, these products need to be sterilized before being consumed. One method for this purpose is gamma irradiation. However, this type of ionizing radiation promotes changes in the structure of polymeric chains affecting PVC properties a greater or lesser extent. Thus, it is necessary to add certain substances to the resin to stabilize the material against the irradiation. The objective of this study was to investigate the effect of gamma radiation on PVC films and PVC films containing 1, 3 and 5 wt% of niobium pentoxide (Nb2O5), which is an inert, non-toxic and biocompatible compound. The films were prepared by solution casting technique using tetrahydrofuran as a solvent and the proof bodies was irradiated at doses of 25 and 50 kGy at room temperature. A commercial PVC resin obtained by suspension polymerization process with viscosimetric average molar mass equal to 201 kg/mol and a Nb2O5 sample whose particles had irregular shape, volume mean diameter of 77 μm and a monoclinic crystalline structure have been used. The effects of gamma radiation and/or oxide in polymer matrix were evaluated using dilute solution viscometry, colorimetry, mechanical tensile test, thermogravimetric analysis (TGA) and Fourier transform middle infrared (FT-MIR) spectroscopy. The results of dilute solution viscometry showed that the percentage of 5 wt% of Nb2O5 conferred radiolytic protection to the polymer, reducing main chain scission events in relation to PVC matrix. According to colorimetric test, the films became darker and yellowish, both due to the increase in oxide percentage as the increase of radiation dose. For the same material, exposure to gamma radiation did not cause significant changes in the mechanical properties evaluated by the mechanical tensile test (tensile strength, Young's modulus and percent elongation). Moreover, the presence of Nb2O5 in systems contributed to reduce the value of these properties. The results of TGA showed that gamma radiation reduced the thermal stability of prepared materials, while the oxide did not change it significantly. Exposure of the films to gamma radiation contributed to reduce the activation energy for the dehydrochlorination process and increase the activation energy for the breakdown process of polyenes sequences, although the oxide has not catalyzed neither processes. Some chemical changes caused by irradiation of the films were not detected by FT-MIR spectroscopy, using attenuated total reflectance to the spectra acquisition. It was also found that Nb2O5 did not presented antibacterial activity against Escherichia coli, evaluated by broth macrodilution test with agitation.

La connaissance du comportement sous irradiation γ et en présence d'eau des Résines Echangeuses d'Ions est nécessaire pour prévoir leur impact sur l'environnement pendant la phase d'entreposage et dans un éventuel stockage en profondeur géologique. Les REI étudiées sont la résine MB400 en lit mélangé ainsi que ses composants anionique et cationique « purs ». La stratégie expérimentale suivie a été basée sur l'utilisation d'outils chimiométriques qui ont permis d'étudier l'effet du milieu d'irradiation, du débit de dose, de la dose et de la température de lixiviation. Les produits de radiolyse gazeux et hydrosolubles ont été analysés par Spectrométrie de Masse gaz et Chromatographie Ionique. Les REI génèrent principalement du H2g, du CO2g et des amines dont les quantités dépendent de la nature de la résine et des conditions d'irradiation. L'analyse des résines solides irradiées a été effectuée par spectroscopie Infrarouge à Transformée de Fourrier et par Résonance Magnétique Nucléaire. Ces techniques révèlent des modifications structurales différentes suivant les conditions d'irradiation. Le comportement sous eau des REI a été étudié sur une période de 143 jours en caractérisant la matière organique relarguée après lixiviation post-irradiation. Les études cinétiques montrent qu'au premier contact avec l'eau, toutes les espèces hydrosolubles sont relarguées. La quantité de Carbone Organique Total dépend, selon la nature de la résine, soit de la dose, soit du milieu d'irradiation. Le débit de dose n'a pas d'effet sur la dégradation et la lixiviation de la résine MB400 qui, néanmoins se comporte d'une façon différente de ses composants pris séparément. / The knowledge of the behavior under irradiation and in presence of water of Ion Exchange Resins (IER) is very necessary to predict their impact on the environment during the storage phase and in a possible deep geological disposal. The IER studied are the MB400 mixed bed resin and its « pure » anionic and cationic components. The experimental strategy used in this work was based on the use of chemometric tools permitting to estimate the effect of the irradiation atmosphere, the dose rate, the absorbed dose and the leaching temperature. The gaseous and water-soluble radiolysis products were analyzed by gas Mass Spectrometry (MS) and Ion Chromatography (IC). The IER generated principally H2g, CO2g and amines for which quantities depended of the resin nature and the irradiation conditions. The analysis of solid irradiated resins was investigated by Fourier Transformed Infrared (FTIR) and Nuclear Magnetic Resonance (13C NMR) techniques. The last ones revealed structural modifications of the IER solid matrix in function of the experimental conditions. Their behavior in presence of water was studied during 143 days by characterization of the organic matter released after their post-irradiation leaching. The kinetics showed that all the water-soluble components were releasing at the first contact with water. The Total Organic Carbon (TOC) quantity released depends, according to the resin nature, either on the dose, either on the irradiation atmosphere. The dose rate has no effect on the degradation and the leaching of the MB400 resin, which behaved differently than its pure components.

Orientador: Flavia Maria Netto / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-07T16:15:22Z (GMT). No. of bitstreams: 1 Souza_AparecidaSoniade_D.pdf: 1116607 bytes, checksum: 498527d5fa8ce5e4faecf37aa8409d46 (MD5) Previous issue date: 2006 / Resumo: O presente trabalho teve como objetivo estudar os efeitos da irradiação e do tempo de armazenamento na composição química de grãos de soja e funcionais de seus isolados protéicos. Os grãos de soja foram divididos em quatro lotes, sendo que dois foram irradiados em fonte de 60Cobalto, com doses de 2,0 ou 5,0 kGy, um lote foi irradiado em acelerador de elétrons com dose de 2,0 kGy e um lote foi utilizado como controle (não irradiado). Os lotes foram armazenados por um período de 12 meses. A cada quatro meses, uma porção de cada lote foi retirada para produção laboratorial de farinhas desengorduradas (FDSs) e isolados protéicos (IPSs). A composição centesimal nos grãos, FDSs e IPSs foi determinada. Nos grãos foram analisados a atividade de água, teor de isoflavonas e atividade antioxidante (IA) e nas FDSs, os teores de fitato e inibidores de tripsina (IT). O teor de acidez foi avaliado nos óleos obtidos do desengorduramento das farinhas. As características estruturais das proteínas dos IPSs obtidos foram avaliadas por análises de eletroforese em gel de poliacrilamida na presença de dodecil sulfato de sódio (SDS-PAGE) em condições não redutoras, das proteínas solúveis em diferentes sistemas, calorimetria diferencial de varredura (CDV), grupos sulfidrila livres (SH), fluorescência intrínseca (FI), cromatografia liqüida de alta eficiência de fase reversa (CLAE-FR) e cromatografia liqüida de alta eficiência de exclusão molecular (CLAE-EM). As propriedades funcionais avaliadas foram: solubilidade, gelificação, capacidade de retenção de água (CRA), capacidade emulsificante (CE), índice de atividade emulsificante (IAE) e estabilidade de emulsão (EE). O teor das isoflavonas totais e o índice de antioxidação, analisados nos grãos, não diferiu significativamente (p>0,05) e permaneceu estável ao longo do armazenamento, independente do tipo ou dose de radiação. No entanto, houve aumento das concentrações relativas dos b-glicosídeos e diminuição dos malonil glicosídeos ao longo do armazenamento. O teor de acidez aumentou em até 81,6% no óleo de grãos irradiados com dose de 5 kGy e armazenados por doze meses. As FDSs de grãos irradiados apresentaram os menores valores dos inibidores de tripsina e fitato. As análises de calorimetria diferencial de varredura, fluorescência intrínseca e cromatografia liqüida de alta eficiência de exclusão molecular indicaram não ter ocorrido alterações estruturais importantes nos isolados protéicos devido à irradiação ou ao armazenamento. Entretanto, os grupos sulfidrila livres aumentaram nos IPSs de grãos irradiados, mas sofreram pouca alteração ao longo dos 12 meses de armazenamento. Houve aumento da proporção relativa de frações hidrofóbicas observadas por CLAE-FR em todos os isolados após quatro meses de armazenamento dos grãos. Os IPSs de grãos irradiados apresentaram maior solubilidade protéica e capacidade emulsificante, enquanto que a estabilidade de emulsão e o índice de atividade emulsificante não diferiram significativamente (p>0,05). Os valores de dureza e capacidade de retenção de água dos géis dos IPSs não diferiram significativamente (p>0,05) em função do tratamento empregado. No entanto, os géis dos IPSs de grãos armazenados tiveram maiores valores de dureza. Os valores coesividade e elasticidade dos géis dos isolados, independente da dose e tipo de radiação, não diferiram significativamente (p>0,05). Nas condições estudadas, as radiações gama com doses de até 5 kGy e de feixe de elétrons com dose de 2 kGy podem ser utilizadas sem prejuízo as propriedades químicas de grãos e funcionais de seus isolados protéicos, durante o armazenamento / Abstract: The aim of this work was to study the effects of both irradiation and storage on the chemical composition of soybean grains and on the physicochemical and functional properties of their protein isolates. The soy grains were divided into four lots, two of them were irradiated with of 60Cobalt source in doses of 2.0 or 5.0 kGy, a third one was irradiated with an electron beam at 2.0 kGy and another was used as control (non-irradiated). All the lots were stored for a maximum of 12 months. Every four months, a portion of each lot was removed to produce deffated soy flour (DFS) and soy protein isolate (SPI). The proximal compositions of the grains, FDSs and SPIs were determined. In the grains, the water activity, total isoflavone content and antioxidant index (AI) were measured and in DFSs, the phytate content and trypsin inhibitor activity (TIA). The acidity content was measured in the oil obtained from the whole flours. The structural characteristics of SPIs were evaluated by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate (SDSPAGE) under non reducing conditions of the soluble proteins using different systems. Additionally, differential scanning calorimetry (DSC), free sulfhydryl groups (SH), intrinsic fluorescence (IF), reversed-phase high performance liquid chromatography (RP-HPLC) and of size exclusion high performance liquid chromatography (SE-HPLC) were also used to evaluate the effects. The analyses of the functional properties in SPIs were: solubility, gelation, water holding capacity (WHC), emulsifying capacity (EC), emulsifying activity index (EAI) and emulsifying stability (ES). The total isoflavone content and antioxidant index analyzed in the grains did not differ significantly (p>0.05) and remained stable throughout storage, as a function of the dose or type of irradiation. However, there was an increase in the b-glycosides and decrease in the mean percentage of malonyl glycosides. The acidity content increased in the percentage of 81.6% in the oil grains irradiated with 5 kGy and stored for 12 months. DFSs of irradiated grains exhibited smaller values of the trypsin inhibitor and phytate. The analyses of differential scanning calorimetry, intrinsic fluorescence and size exclusion high performance liquid chromatography showed that no important structural alterations occurred in the protein isolates due irradiation or storage. However, the free sulfhydryl groups increased in SPIs of irradiated grains, without further significant changes along the storage. There was an increase of the proportion of the hydrophobic fractions, showed by reversed-phase high performance liquid chromatography profile, for all the isolated after four months of storage of the grains. SPIs of irradiated grains presented high solubility, emulsifying capacity while emulsifying stability and emulsifying activity index did not differ significantly (p>0.05). The values of hardness and water holding capacity of the SPIs gels did not differ significantly (p>0.05) for all treatment. However, SPIs gels of stored grains had high values of hardness. The values cohesiveness and elasticity of the SPIs gels did not differ significantly (p>0.05), independent of the dose and type of irradiation. Under the studied conditions, gamma irradiation at doses of 5 kGy and of electron beam of 2 kGy can be used without damage to the grain composition or storage property or to the physicochemical properties of the protein isolates / Doutorado / Nutrição Experimental e Aplicada à Tecnologia de Alimentos / Doutor em Alimentos e Nutrição