Made available in DSpace on 2017-07-21T18:53:02Z (GMT). No. of bitstreams: 1 Christiane Schamne.pdf: 2521926 bytes, checksum: b4f1eed111a019961433a0be8ece30f3 (MD5) Previous issue date: 2007-09-25 / Fundação Araucária de Apoio ao Desenvolvimento Científico e Tecnológico do Paraná / The celiac disease is associated to food ingestion containing gluten, a protein that is found in some vegetable raw materials, as wheat, rye, barley and oats, damaging the surface of the intestine mucosa, making difficult nutrients absorption by the organism. The celiac disease has been object of frequent technological and clinical research on food alternatives to persons having the disease. The objective of this study was to develop the gluten free baked products, having a good sensorial acceptance, using cassava starch with the addition of soybeans derived products . From the rice cream, the cassava starch and the maize starch used in the formulation, the experimental design for Simplex-Centróide mixtures was carried through, and after that the software called Statistica 7.0 was used, inserting the maximum limit restriction of 50% of cassava starch, resulting in the experimental design for mixtures, giving then seven samples. Using these seven samples, sensorial and instrumental analysis composed of specific volume, elasticity and firmness analysis was carried through. For the sensorial analysis, the optimized formulation of mixture was 50% of rice cream and 50% of cassava starch, and for the instrumental analysis, the optimal simultaneous point for the three conducted analyses was 20% of rice cream, 50% of maize starch and 30% of cassava starch. From these two optimal points, a second sensorial analysis was realized, and the optimal formulation obtained from instrumental analyses was significantly preferred (hedonic scale average=6,96±1,71, using scale of 1 to 9) comparing to the first sensorial analysis (hedonic scale average=5,77±1,83, using scale of 1 to 9). From these samples, it was realized the comparative analysis of specific volume, elasticity, firmness and triangular test between baked bread and pre-baked and freeze bread. The baked sample and the pre-baked and freeze sample showed differences only in product elasticity, having not showed sensorial difference between the samples analyzed. For the muffin, a sensorial analysis was conducted, that resulted on hedonic scale average 7,76±1,07, using scale of 1 to 9. It was realized instrumental analysis of specific volume, elasticity and firmness, and comparative analysis between baked muffin and pre-baked and freeze muffin, adopting the same procedure used for bread analysis. The baked muffin and pre-baked and freeze muffin differed on specific volume and elasticity, however they didn´t have any sensorial difference when the triangular test was applied. For both, the bread and muffin, it was realized the physic-chemistry, nutritional and microbiological analysis, and both were according to the current law. It was realized cost analyses of the developed products, and the conclusion was that they are economically according with similar products. / A doença celíaca está relacionada à ingestão de alimentos que contêm glúten, proteína presente em algumas matérias-primas vegetais, como trigo, centeio, cevada e aveia, danificando a superfície da mucosa do intestino, dificultando a absorção de nutrientes pelo organismo. A doença celíaca tem sido objeto freqüente de estudos clínicos e tecnológicos em busca de alternativas alimentares para indivíduos que sofrem da enfermidade. O objetivo desse trabalho foi desenvolver produtos panificados isentos de glúten, de boa aceitação sensorial, utilizando amido de mandioca e adicionados de derivados de soja. A partir do amido de mandioca, creme de arroz e amido de milho utilizados na formulação, foi realizado o delineamento experimental para misturas Simplex-Centróide, e posteriormente os dados foram lançados no software Statistica 7.0, inserindo-se a restrição do limite máximo de 50 % de amido de mandioca, que resultou no delineamento para misturas originando sete amostras. A partir dessas sete amostras, foram realizadas análises sensorial e instrumentais de volume específico, elasticidade e firmeza. Para a análise sensorial, a formulação ótima de mistura encontrada foi 50% de creme de arroz e 50% de amido de mandioca, e para a análise instrumental, o ponto ótimo simultâneo das três análises realizadas foi 20% de creme de arroz, 30% de amido de mandioca e 50% de amido de milho. A partir dos dois pontos ótimos obtidos, foi realizada uma segunda análise sensorial, na qual a formulação ótima obtida a partir das análises instrumentais realizadas foi significativamente preferida (média escala hedônica=6,96±1,71, numa escala de 1 a 9) em relação à formulação ótima obtida na primeira análise sensorial (média escala hedônica 5,77±1,83, numa escala de 1 a 9). A partir dessa amostra, foram realizadas análises comparativas de volume específico, elasticidade e firmeza, e teste triangular entre o pão assado e o pão pré-assado e congelado. A amostra assada e a amostra pré-assada e congelada do pão diferiram apenas com relação à elasticidade do produto, não sendo percebida nenhuma diferença sensorial entre as amostras analisadas.Para o muffin foi realizada análise sensorial, a qual apresentou média de escala hedônica de 7,76±1,07, numa escala de 1 a 9. Foram realizadas análises sensorial e instrumentais de volume específico, elasticidade e firmeza comparativas entre a amostra assada e a amostra pré-assada e congelada, adotando o mesmo procedimento aplicado ao pão. O muffin assado e o muffin pré-assado e congelado diferiram com relação ao volume específico e elasticidade, porém não apresentaram diferença sensorial significativa aplicando-se o teste triangular. Para ambos os produtos foram realizadas análises físico-químicas, nutricionais e microbiológicas, as quais mostram estar de acordo com a legislação vigente. Foram realizadas levantamento de custo dos produtos desenvolvidos, os quais mostram estar economicamente de acordo com produtos similares encontrados no mercado.

A silagem de milho é um dos principais alimentos suplementares utilizados na alimentação de gado leiteiro, no entanto, seu elevado custo de produção tem levado técnicos e produtores a buscarem outras alternativas como fonte de volumoso. O farelo de glúten de milho pode ser utilizado como fonte energética, protéica e fibrosa, substituindo parte da silagem de milho em rações para ruminantes. O presente ensaio teve por objetivo estudar o efeito da substituição de 0, 8 e 16% da MS da silagem de milho por FGM-21 em rações de vacas holandesas em lactação na produção de leite, composição do leite, parâmetros sanguíneos metabólicos, variação de peso, escore de condição corporal e a viabilidade econômica. O trabalho foi conduzido no confinamento “free-stall” do Departamento de Zootecnia da Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo, localizada no município de Piracicaba. As rações foram formuladas de forma que fossem isoprotéicas e isoenergéticas. Foi feita avaliação de produção de leite, composição do leite, variação de peso, escore de condição corporal e a viabilidade econômica, utilizando-se 30 vacas Holandesas com produções de leite ao redor de 25 a 30kg/vaca/dia, com média de peso de 654kg e média de escore corporal 2,8. A inclusão do FGM-21 nos dois níveis 8 e 16% aumentou a produção de leite bem como a produção de leite corrigida para 3,5% de gordura. Foi feita avaliação de parâmetros metabólicos, utilizando-se 15 vacas Holandesas pertencentes ao grupo. Os resultados para os teores de N-Uréico plasmático e de glicose plasmática não diferiram entre os tratamentos. A análise de viabilidade econômica mostrou aumento na lucratividade nos tratamentos com inclusão de FGM-21 nas rações considerando-se os preços dos alimentos na época do estudo. / Corn silage is one of the major feedstuffs used in dairy farms but its high cost has encouraged farmers to look after alternative feeds. Corn gluten feed has been used as a source of energy, protein and effective fiber in dairy rations. This study was carried out at the Departamento de Zootecnia, Escola Superior de Agricultura “Luiz de Queiroz”, in a free-stall facility, with 30 mid-lactation Holsteins multiparous cows, averaging 25 to 30 kg milk/day and 654 kg body weight. The objectives of this study were to evaluate the effects of replacing 0, 8 and 16% corn silage dry matter with dried corn gluten feed. Experimental diets were formulated by the NRC, 2001 and were isonitrogenous and isoenergetic. Cows fed both corn gluten feed supplemented diets produced more milk and 3.5% FCM than control animals. Milk composition and plasma urea and glucose were the same among treatments. Under the conditions of this trial, corn gluten feed was an effective replacement for corn silage, both from the nutritional and economical stand point.

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / A produÃÃo mundial de farinha de peixe e derivados estagnou ao longo dos Ãltimos anos. Em contrapartida, a aquicultura à o setor de produÃÃo de alimento que mais cresce anualmente. Atualmente o cultivo de organismos aquÃticos marinho depende da farinha de peixe e seus derivados. Ingredientes vegetais tÃm sido testados como fontes alternativas e viÃveis de proteÃna para alimentaÃÃo destes organismos. O glÃten de milho surge como um ingrediente promissor, apresentando 60% de proteÃna bruta (PB). Este trabalho avaliou a substituiÃÃo da proteÃna da farinha de peixe pela proteÃna do glÃten de milho em dietas prÃticas para camarÃes marinhos cultivados em tanques experimentais. Juvenis do camarÃo branco, Litopenaeus vannamei, foram estocados em tanques em sistema de recirculaÃÃo de Ãgua (RAS) na densidade de 70 camarÃes m-2 durante um perÃodo de 72 dias. Cinco dietas foram formuladas, quatro experimentais e uma controle, com 37,5-38,3% PB e 17,5-18,0% EB (energia bruta). As dietas experimentais foram formuladas a partir de uma dieta basal (12% farinha de peixe salmÃo (importada) + 2,4% farinha de resÃduo de peixes marinhos (nacional), pela substituiÃÃo (15, 30, 45 e 60%) da proteÃna da farinha de peixe pela proteÃna do glÃten de milho, com suplementaÃÃo de aminoÃcidos essenciais: lisina, metionina e triptofano (dieta basal: 2,75% lisina, 1,09% metionina e 0,75% triptofano). Ao final do experimento observou-se que houve diferenÃa significativa (P<0,05) para variÃveis de desempenho zootÃcnico, peso corporal final (g) e ganho em peso semanal (g), entre a dieta controle GM0 (17,50  1,15 g e 1,70  0,11 g, respectivamente) e a dieta com 60% de substituiÃÃo GM60 (15,65  1,01 g e 1,52  0,10 g, respectivamente). As demais variÃveis de desempenho zootÃcnico: sobrevivÃncia (94,4  1,88 %), produtividade (956,08  28,11 g m-2), consumo alimentar aparente (34,8  0,58 g camarÃo-1) e FCA (2,3  0,04) nÃo apresentaram diferenÃa estatisticamente significativa (P&#8805;0,05) entre as dietas. O glÃten de milho pode substituir a farinha de peixe em atà 50 g kg-1 nas dietas, sem prejuÃzo zootÃcnico aos camarÃes, reduzindo a participaÃÃo em 30% do ingrediente animal como fonte proteica na raÃÃo. Uma substituiÃÃo mais drÃstica com inclusÃo de 78 g kg-1 de glÃten de milho pode causar uma queda moderada no desempenho zootÃcnico dos camarÃes. Entretanto, a reduÃÃo de 45% na participaÃÃo da farinha de peixe serà provavelmente vantajosa do ponto de vista econÃmico (melhor relaÃÃo custo: benefÃcio). / Global production of fish meal and derivatives has stalled in the last few years. On the other hand, aquaculture has grown rapidly representing today the fastest food production sector. However, farm-reared fish and shellfish still relies heavily on fish meal and derivates as a dietary protein source. Plant ingredients have been tested as alternative and viable sources of protein.Corn gluten is a promising ingredient, as it contains 60% crude protein (CP). This study has evaluated the replacement of fish meal protein by protein from corn gluten meal in practical diets for marine shrimp farmed in experimental tanks. Juvenile white shrimp, Litopenaeus vannamei, were stocked in tanks under a recirculating water system (RAS) at a density of 70 shrimp m-2 for a period of 72 days. Five diets were formulated, four experimental and one control, with 37.5 to 38.3% CP and 17.5 to 18.0% GE (gross energy). Experimental diets were formulated based on a basal diet by replacing 5, 30, 45 and 60% of the fish meal CP by corn gluten protein and supplementing them with the essential amino acids lysine, methionine and tryptophan. At the end of the experimental period, it was observed that there was significant difference (P<0.05) in the growth performance variables, final body weight (g) and weekly weight gain (g) between the control diet GM0 (17.50  1 15 g and 1.70  0.11 g, respectively) and the diet with 60% replacement GM60 (15.65  1.01 and 1.52  0.10 g, respectively). The other production performance variables, i.e., survival (94.4  1.88%), productivity (956.08  28.11 g m-2), feed consumption (34.8  0.58 g shrimp-1) and FCR (2.3  0.04), showed no statistically significant difference (P &#8805; 0.05) among dietary treatments. Gluten meal could replace fish meal up to 50 g kg-1 in diets without losses to shrimp performance, reducing 30% in the inclusion of animal ingredients as protein sources in the diet. A more drastic replacement of fish meal with an inclusion of 78 g kg-1 of corn gluten caused a moderate decrease in shrimp growth performance. However a 45%-reduction in the use of fish meal is likely to be advantageous from an economic standpoint (cost: benefit ratio).

<p>Prema najnovijim istraživanjima modifikovanim skrobovima može se pripisati jo&scaron; jedna uloga &ndash; aditivi u pekarstvu, s obzirom da utiču na pobolj&scaron;anje kvaliteta hleba i<br />usporavaju proces starenja. Međutim, prema saznanjima autora ove disertacije, ne<br />postoje istraživanja na temu uticaja emulgujućih skrobova (skrob-natrijum<br />oktenilsukcinata, OSA skrobova) na kvalitet testa i hleba od p&scaron;eničnog bra&scaron;na.<br />Uzimajući u obzir činjenicu da druge vrste modifikovanih skrobova ispoljavaju dobre<br />osobine u smislu pobolj&scaron;anja kvaliteta hleba i da je OSA skrob nutritivno vredna<br />sirovina, s obzirom da se u organiznu pona&scaron;a kao prehrambeno vlakno, od velike je<br />važnosti ispitati ulogu OSA skroba kao aditiva u pekarstvu.<br />Međutim, usled kompleksne prirode testa kao sistema, bilo je te&scaron;ko odrediti relativni<br />uticaj pojedinačnih komponenti (proteina, p&scaron;eničnog skroba, OSA skroba) i njihovih<br />međusobnih interakcija na osobine testa. Stoga je, u cilju rasvetljavanja uticaja različitih OSA skrobova na viskoelastične osobine testa i retrogradaciju skrobne komponente (fenomen povezan sa starenjem hleba), p&scaron;enično bra&scaron;no frakcionisano na gluten i skrob, i vr&scaron;ena su ispitivanja strukturnih, reolo&scaron;kih i termičkih osobina hidratisanog glutena i skrobnih gelova sa dodatkom OSA skroba. Takođe su pripremani i model sistemi testa.<br />Ispitivanja na realnim sistemima (testo i hleb) izvođena su zamenom 2,5; 5 i 10%<br />p&scaron;eničnog bra&scaron;na, jednim od tri vrste OSA skroba: skrob-natrijum oktenilsukcinatom<br />(OSA-ST), preželatiniziranim skrob-natrijum oktenilsukcinatom (Pregel OSA-ST) i<br />hidrolizovanim su&scaron;enim u spreju skrob-natrijum oktenilsukcinatom (Hydrol OSA-ST).<br />Cilj je bio da se ispita uticaj dodatka OSA skrobova na strukturu testa (SEM), empirijske (miksolab, alveograf i reofermentometar) i fundamentalne (oscilatorna merenja i testovi puzanja i deformacije) reolo&scaron;ke osobine, kao i parametre kvaliteta hleba (specifična zapremina, boja kore i sredine hleba, vlaga sredine hleba, parametri raspodele veličine pora i tekstura sredine). Pored pomenutog, praćena je i promena kvaliteta hleba tokom skladi&scaron;tenja, kako bi se dobio uvid u kinetiku starenja hleba.<br />Rezultati dobijeni u ovoj disertaciji ukazali su da reolo&scaron;ko pona&scaron;anje testa sa dodatkom OSA skrobova zavisi od strukture skrobnih granula, tj. od stepena dezintegracije i depolimerizacije granule tokom procesa modifikacije. Stoga je dodatak OSA-ST doveo do ojačavanja glutenske mreže &scaron;to se odrazilo na porast modula elastičnosti i testa i glutena. Nasuprot tome, Pregel and Hydrol OSA-ST uticali su na kontinualnost glutenske mreže koja je u njihovom prisustvu bila poroznija, a time su i dobijena testa bila mek&scaron;a i rastegljivija. Istraživanja na realnim i model sistemima (p&scaron;enični skrob sa dodatkom OSA skroba) ukazala su da sva tri OSA skroba usporavaju retrogradaciju p&scaron;eničnog skroba. Takođe je dokazano da svi ispitivani emulgujući skrobovi povećavaju specifičnu zapreminu hleba u poređenju sa kontrolnim, pri čemu je Pregel OSA ispoljio najjači efekat. To se odrazilo i na strukturne osobine sredine hleba, a posledično i na mehaničke osobine sredine, čija promena je praćena u cilju određivanja kinetike starenja hleba. Prema dobijenim rezultatima, vrednosti čvrstoće sredine hleba koji je sadržao OSA-ST i Pregel OSA-ST su i nakon 24 h bile slične ili značajno niže od vrednosti čvrstoće kontrolnog uzorka određene 2 h nakon pečenja.</p> / <p>Recent studies have demonstrated that modified starches can be used as novel additives in breadmaking since they improve bread quality and retard stalling. However, up to the author&#39;s knowledge, there are no investigations concerning the influence of emulsifying starches (starch sodium octenyl succinates - OSA starches) on wheat flour dough and bread quality. Taking into account the fact that other modified starches have exhibited significant bread improving properties and that OSA starch has special nutritional value since it can act as functional fibre, it is of a great importance to investigate the feasibility of OSA starch as bread improver.<br />However, due to the complex nature of dough, it was difficult to determine the relative contributions of protein, native and modified starch components and their interactions on dough properties. Therefore, in order to resolve the influence of different OSA starches on dough viscoelastic properties and starch retrogradation (the phenomenon related to bread stalling), wheat flour was fractionated into gluten and starch; and the structural, rheological and thermal behaviour of the hydrated gluten samples and starch gels supplemented with emulsifying starches was also studied. Dough model systems were also prepared.<br />Experiments on real systems (dough and bread) were performed by incorporating<br />starch sodium octenyl succinate (OSA-ST), pregelatinized OSA starch (Pregel OSA-ST) and hydrolysed spray-dried OSA starch (Hydrol OSA-ST) at 2.5, 5 and 10 % into wheat flour. The aim was to investigate the effect of incorporating OSA starches on dough structural (SEM imaging), empirical (Mixolab, Alveograph, Rheofermentometre) and fundamental (oscillatory and creep measurements) rheological properties as well as bread quality parameters (specific loaf volume, crust and crumb colour, crumb moisture, crumb grain features, crumb texture). In addition, the bread quality attributes during storage were also monitored in order to get insight into bread stalling kinetics.<br />The results obtained in this thesis revealed that the rheological behaviour of OSA starch supplemented dough depended on the OSA starch granule rigidity, i.e. extent of OSA starch granule disintegration and polysaccharide degradation during modification. OSA-ST starch caused a reinforcement of the gluten network, as shown by the increase in storage modulus of doughs and gluten. On contrary, Pregel and Hydrol OSA-ST affected the continuity of gluten network which became porous and thus produced softer and stickier doughs in comparison to control. Investigations on real dough and model systems containing wheat and OSA starches revealed that all three types of OSA starches reduced starch retrogradation.<br />In general, all the examined emulsifying starches increased bread loaf volume in comparison to control bread with no added polymers, while Pregel OSA starch has expressed the greatest impact. It also reflected on bread crumb structural features and consequently on the crumb mechanical properties which were used for bread stalling monitoring. Firmness values of OSA-ST and Pregel OSA-ST starch supplemented bread crumbs, after 24 h of storage, were similar to or significantly lower than those of control determined 2 h after baking.</p>

Les protéines alimentaires se trouvent principalement dans des aliments traditionnels d'origine animale et végétale. L'évaluation de la qualité nutritionnelle de différents sources de protéines alimentaires consiste à mettre en relation les caractéristiques de l'apport alimentaire et les caractéristiques de la demande métabolique concept relatif à l'état de l'individu. La recommandation de base WHO/UNU est de 0,8g /kg /j de protéine de bonne qualité pour l'homme adulte. L'objet de ce travail est d'évaluer les conséquences d'une adaptation à un régime hyperprotéique sur des modifications fonctionnelles et morphologique chez le rat en croissance. Plus particulièrement, on a analysé les effets d'un régime à 50% en protéines sur l'évolution du poids corporel, le poids de certains organes ainsi que sur la structure intestinale du rat. Dans ce but, 96 rats mâles de souche wistar pesant entre 175 et 185g (180±2,27g), sont répartis en 5 groupes : le 1er groupe (n=30) reçoit un régime normoprotéique à base de protéine totale de lait (14%) et constitue le groupe témoin, le 2ème groupe (n=30) reçoit un régime hyperprotéique (50%) à base de protéine totale de lait, le 3ème groupe (n=12) reçoit un régime normoprotéique (14,5%) à base de protéine végétale onab , le 4ème groupe (n=12) reçoit un régime hyperprotéique (50%) à base de protéine de soja, le 5ème groupe (n=12) reçoit un régime hyperprotéique (50%) à base de gluten. Tous ces régimes sont administrés pendant 60 jours, durée de l'expérimentation. Les résultats montrent qu'une surconsommation de protéines s'accompagne d'une diminution significative du poids corporel et d'une modification de la structure histologique de l'épithélium intestinal qui se traduit par une atrophie villositaire et par une augmentation des lymphocytes intra-épithéliaux. Ces modifications seraient la manifestation de phénomènes induits par l'exposition chronique de l'épithélium intestinal à des teneurs élevés en protéines. Nous avons conclu qu'une surconsommation de protéines n'est pas sans conséquence sur la composition corporelle et la fonction intestinale. Il convient donc d'observer une certaine prudence dans l'utilisation à long terme de formules diététiques enrichies en protéines chez l'homme.

Soixante-dix-sept lots de matières premières (MP) (10 de blé, 10 de triticale, 5 de seigle, 5 d'orge, 7 de maïs, 6 de sorgho, 3 de farine basse de blé, 4 de remoulage de blé, 3 de son de blé, 7 de corn gluten feed, 4 de tourteau de colza, 4 de tourteau de tournesol et 9 de tourteau de soja) ont fait l'objet d'une caractérisation analytique et d'une mesure de digestibilité iléale des acides aminés (AA) sur des porcs, mâles castrés, pesant entre 35 et 100 kg, et préparés en anastomose iléo-rectale termino-terminale. La digestibilité iléale vraie (DIV) de l'azote (N) et des AA de chaque lot de MP a été calculée en corrigeant la digestibilité iléale apparente de l'excrétion endogène basale. Cette dernière a été mesurée au moyen d'un aliment protéiprive. La digestibilité iléale réelle (DIR) des AA des lots de céréales, de tourteau de colza et de tourteau de soja a été calculée après détermination de l'excrétion endogène totale d'AA par régression linéaire multiple.<br />L'excrétion endogène basale d'azote est en moyenne de 1.14 g/kg MSI. L'animal en est le principal facteur de variation.<br />En moyenne, la DIV de l'N des céréales se situe entre 77% pour le seigle et 87-89% pour le blé, le triticale, et le maïs. Celle des issues de meunerie passe de 94% pour les farines basses à 70% pour les sons. Celle du corn gluten feed varie de 62 à 75%, selon le lot. Elle est de 74% pour le tourteau de colza, 81 % pour le tourteau de tournesol et 88% pour le tourteau de soja. La DIV des AA des issues de meunerie, du corn gluten feed et du tourteau de soja peut être prédite à partir de leurs teneurs en fibres insolubles et/ou du pourcentage d'azote lié au résidu NDF (NNDF).<br />En moyenne, l'excrétion endogène spécifique d'N se situe entre 1.1 et 2.1 g/kg MS pour les céréales. Elle est de 3.6 et 7.9 g/kg MS pour, respectivement, le tourteau de soja et le tourteau de colza. Pour la plupart des matières premières, l'excrétion endogène spécifique d'N augmente significativement avec la teneur en fibres insolubles. Toutefois, plus l'animal est léger, plus il semble sensible à une augmentation de la teneur en fibres insolubles, et en particulier en ligno-cellulose, du régime. Par ailleurs, la fibre de type blé serait plus stimulante que la fibre de type orge. Des équations de prédiction de l'excrétion endogène spécifique d'N en fonction de la teneur en ADF (Acid Detergent Fibre) du lot de matière première et du poids de l'animal sont proposées.<br />En moyenne, la DIR de l'azote est supérieure à 95% pour le blé, le triticale et le maïs, elle est de 94% pour le tourteau de soja, 91 % pour le sorgho, 88% pour l'orge, 84% pour le seigle et 86% pour le tourteau de colza.

LES REGIMES HYPERPROTEIQUES INDUISENT UNE DEPRESSION DE LA PRISE ENERGETIQUE CHEZ LE RAT. LES MECANISMES SOUS-TENDANT CETTE DEPRESSION SONT MAL CONNUS. L'OBJET DE CETTE THESE EST D'ANALYSER LES ROLES RESPECTIFS DE LA PALATABILITE, DE LA SATIETE, ET DE L'AVERSION GUSTATIVE CONDITIONNEE DANS CE PHENOMENE. LAPPLICATION DE LA METHODE DENREGISTREMENT DE LA PRISE ALIMENTAIRE ET DE VIDEO ANALYSE A DES RATS, LORS DE LA TRANSITION DUN REGIME NORMOPROTEIQUE (14%) VERS UN REGIME HYPERPROTEIQUE (>50%), MONTRE DES MODIFICATIONS TRANSITOIRES DU COMPORTEMENT DE LANIMAL LORS DU PREMIER JOUR : REDUCTION DE LA TAILLE DU REPAS, DIMINUTION DE LA VITESSE DINGESTION ET MODIFICATION DE LA SEQUENCE COMPORTEMENTALE DE SATIETE. APRES ADAPTATION AU REGIME HYPERPROTEIQUE, LA QUANTITE DENERGIE INGEREE AVEC LE REGIME HYPERPROTEIQUE RESTE NEANMOINS EN DEÇA DE CELLE INGEREE EN REGIME NORMOPROTEIQUE ET LE POIDS DES ANIMAUX RECEVANT UN REGIME HYPERPROTEIQUE EST PLUS FAIBLE. DES LE SECOND OU TROISIEME JOUR, SELON LA PROTEINE ALIMENTAIRE UTILISEE, LA SEQUENCE COMPORTEMENTALE DE SATIETE N'EST PLUS DIFFERENTE DE CELLE INDUITE PAR UN REPAS NORMOPROTEIQUE. L'ABSENCE D'AVERSION GUSTATIVE CONDITIONNEE ET LA PRESENCE D'UN EFFET SATIETOGENE DES PROTEINES A ETE CONFIRMEE QUAND LES RATS, ELEVES SUR UN REGIME NORMOPROTEIQUE, ET RECEVANT TROIS REPAS PAR JOUR, INGERENT UN EN-CAS PROTEINE. LES PROTEINES DEPRIMENT PLUS LA PRISE ALIMENTAIRE LORS DU REPAS SUIVANT QUE LES GLUCIDES. LANALYSE DE LA SEQUENCE ALIMENTAIRE MONTRE QUE LA DIMINUTION DE LA TAILLE DU REPAS INDUITE PAR LES CHARGES PROTEIQUES 35% ET 50% EST DU A UN EFFET SATIETOGENE ET NON A UNE AVERSION GUSTATIVE CONDITIONNEE. NOTRE ETUDE A AUSSI MONTRE QUE PLUSIEURS PARAMETRES BIOCHIMIQUES (AMINOACIDEMIE TOTALE, ACIDES AMINES BRANCHES ) OU HORMONAUX (LEPTINEMIE) SONT SUSCEPTIBLES DETRE A LA BASE DES SIGNAUX ENVOYES AU CERVEAU POUR INITIER LA BAISSE DE PRISE ALIMENTAIRE. EN RESUME, LES RATS NE DEVELOPPENT PAS UNE AVERSION GUSTATIVE CONDITIONNEE VIS A VIS DU REGIME HYPERPROTEIQUE. LES MODIFICATIONS DE LA PRISE ALIMENTAIRE ET DU COMPORTEMENT, CORRESPONDENT PLUS A UN EFFET SUR-SATIETOGENE DU REGIME HYPERPROTEIQUE COMBINE A SA FAIBLE PALATABILITE ET A UNE NECESSAIRE ADAPTATION METABOLIQUE DE L'ANIMAL A CE REGIME. NOS RESULTATS, QUE CE SOIT DANS LE CADRE DE L'INGESTION D'UN REGIME HYPERPROTEIQUE OU, PLUS SIMPLEMENT LORS D'UN REPAS, MONTRE QUE L'INGESTION DE PROTEINES S'ACCOMPAGNE D'UN EFFET SATIETOGENE QUI RESTE A EXPLIQUER

Les pâtes surgelées sont relativement stables et peuvent être fabriquées à l'échelle industrielle, distribuées et cuites à la demande au moment de la vente ou de la consommation (point chaud). La congélation des pâtes sucrées induit une baisse de volume et une augmentation du temps de fermentation, ces conséquences sont dues à deux facteurs : la baisse de la production de CO2 (viabilité des levures) et la faible capacité de rétention de gaz du réseau gluténique. La perte de la qualité des pâtes congelées est accélérée durant le stockage. Cette thèse porte sur l'étude de l'effet de la congélation et de la conservation sur les levures et les propriétés techno-fonctionnelles des pâtes sucrées type Kougelhopf. Ce travail vise à l'étude de l'impact de la vitesse de congélation sur les propriétés microbiologiques, rhéologiques, structurales et sensorielles de ces pâtes. Elles ont été congelées à différentes températures (-20 °C, -30 °C, -40 °C et une immersion dans l'azote liquide) puis conservées à -40 °C pendant 9 semaines. Les principaux résultats de cette étude ont permis de mettre en évidence le rôle de la vitesse de congélation et de la durée de conservation sur les propriétés intrinsèques des pâtes sucrées surgelées. Il en découle que l'activité fermentaire et l'intégrité du réseau du gluten sont tributaire de la vitesse de congélation. En effet, cette dernière contrôle la taille et la localisation des cristaux de glace d'où la recherche d'un compromis entre une vitesse de congélation ni trop rapide pour diminuer la viabilité des levures ni trop lente pour former de gros cristaux pouvant perforer le réseau de gluten de la pâte. Ce travail a démontré que le surdosage de levure reste valable uniquement pour les pâtes sucrées surgelées destinées à être conservées au-delà de 4 semaines. Ce surdosage améliore ainsi la qualité globale du Kougelhopf en compensant la perte de l'activité des levures pendant la congélation et le stockage.

Chitosan, Whey Protein Isolate (WPI) and vital wheat gluten (WG) are three biomaterials that have quite promising properties for packaging purposes. They have good film forming properties and good gas barrier properties in dry conditions. Moreover, because they are produced from industrial waste of food processing, they offer an ecological advantage over polymers made from petroleum. However, their physicochemical characteristics still must be improved for them to be of commercial interest for the food packaging industry. The purpose of this work was to study different strategies aiming to improve the water resistance and aging properties of these polymers, which are some of the key disadvantages of these materials. The produced solution cast chitosan and WPI films were characterised with scanning electron microscopy (SEM), density measurements and thermogravimetry. The water vapour transmission rate was determined at a relative humidity of 11%. In the first part, mechanical properties of solid films and seals were assessed by tensile testing. WG film’s tensile properties and oxygen and water vapour permeabilities were measured as a function of aging time. The changes in the protein structure were determined by infrared spectroscopy and size-exclusion high-performance liquid chromatography and the film structure was revealed by optical and scanning electron microscopy. Gluten-clay nanocomposites were characterised by tensile testing, X-ray diffraction and transmission electron microscopy. The incorporation of a hydrophobic biodegradable polymer, poly ( ε-caprolactone), PCL, in both chitosan and whey protein, yielded a significant decrease in water vapour transmission rate. It was observed that a certain amount of the PCL particles were ellipsoidal in chitosan and fibrous in WPI. The obtained data also indicated that the particle shape had an important influence in the water vapour transmission rate. In the second part, the aging properties of WG films, plasticized with glycerol and cast from water/ethanol solutions with pH=4 or pH=11 were investigated. WG films made from alkaline solutions were mechanically more time-stable than the acidic ones, the latter being initially very ductile but turning brittle towards the end of the aging period. The protein solubility measurements indicated that the protein structure of the acidic films was initially significantly less aggregated than the in basic films. During aging the acidic films lost more mass than the basic films through slow evaporation of volatiles (water/ethanol) and through migration of glycerol to the paper support. The oxygen permeability was also lower for the basic films. In the last part, the properties of new and aged glycerol-plasticized WG films at acidic and basic conditions containing ≤4.5 wt% natural or quaternary-ammonium-salt-modified montmorillonite were studied. Films of WG with montmorillonite were possible to produce by solution casting. The aging rate of acidic and basic films was unaffected by the incorporation of clay. However, the large reduction in water vapour permeability for most systems suggested that the clay sheets were evenly distributed within the films. The film prepared from basic solution and containing natural clay was almost completely exfoliated as revealed by transmission electron microscopy and X-ray diffraction. The best water vapour barrier properties were obtained by using modified clay. / QC 20101013

Background Sweden has experienced a unique epidemic of celiac disease (CD) in children younger than 2 years of age. The epidemic was partly explained by changes over time in infant feeding and indicated a multifactorial aetiology. In CD, a strict lifelong gluten-free diet (GFD) is crucial for health but noncompliance is often reported among adolescents. Knowledge is limited regarding their own perspectives and experiences of managing the disease and adhering to GFD. Objectives To analyse the incidence of CD in epidemic and post epidemic birth cohorts, and explore and understand how adolescents with CD perceive and manage their everyday lives in relation to the GFD. Methods A population-based incidence register of CD in children covering the entire nation from 1998 to 2003, and part of the country back to 1973. ESPGHAN diagnostic criteria for CD and NUTS classification of regions were used. Incidence rates for each year of diagnosis, age group, gender and region, and cumulative incidence by age for each birth cohort were calculated. Ten focus groups were conducted with 47 CD adolescents aged 15-18 years. Transcribed interviews were analysed to illustrate and explain adolescents’ own perspectives concerning life with a GFD, and to search for recurrent stigma-related themes across the groups. Results A considerable gap in the cumulative incidence of CD at comparable ages was demonstrated between birth cohorts of the epidemic and post-epidemic periods. The gap persisted during pre-school years, although it decreased somewhat with age. During the final years of follow-up there was again a gradual increase in incidence rate among children younger than 2 years of age. The childhood populations in ‘West Sweden’ and ‘Småland and the islands’ had a significantly higher incidence rate compared to ‘North Middle Sweden’ and ‘Stockholm’. CD adolescents described an awareness of being different from others produced by meal appearance and the poor availability of gluten-free (GF) food. Eating in public had the effect of making an invisible condition visible and thereby creating a context for felt or enacted stigma. Maintaining invisibility avoided the negative consequences of stigma. The probability of compliance with the GFD was compromised by insufficient knowledge of significant others, problems with the availability and sensory acceptance of GF food, insufficient social support and their perceived dietary deviance. Three different approaches to the GFD emerged: compliers, occasional non-compliers, and non-compliers. Conclusions The difference in CD risk between birth cohorts at comparable ages may suggest an opportunity for primary prevention. Based on post-epidemic incidence trends, the Swedish epidemic might not have been as unique as previously thought, even though its magnitude was striking. The regional variation in CD risk supports multifactorial aetiology. Continued efforts are warranted to define factors besides gluten exposure that modulate CD risk. CD adolescents experience various dilemmas related to the GFD. It can produce stigma experiences in adolescence, and dietary compliance (or lack of) can be understood in terms of dealing with GFD concealment and disclosure. The increase in CD prevalence over time and unmet needs in young celiacs require resources to attain adequate levels of dietetic provision, regulated subsidies for covering additional costs for GF food, evidence-based practice, and increased general CD awareness for optimum clinical outcomes.