Un développement racinaire optimal est essentiel pour favoriser la croissance des plantes et leur permettre d’accéder à de meilleurs rendements. La plupart de nos connaissances concernant le contrôle moléculaire du développement racinaire a été acquise grâce à l’étude de la plante modèle dicotylédone Arabidopsis thaliana. Les racines de riz, plante modèle des monocotylédones, présentent une anatomie semblable à celle d’A.thaliana. Ces deux systèmes racinaires sont caractérisés par une organisation concentrique des tissus autour de la stèle. Entre l’endoderme et l’épiderme, le riz présente deux couches plus externes, appelées le sclérenchyme et l’exoderme, ainsi que plusieurs couches de cortex dans la zone centrale. Chacun de ces tissus possèdent des spécificités anatomiques et moléculaires qui leur confèrent des rôles divers dans le développement et la croissance de la racine. Le nombre de couches variable de cortex dépend du type de racines, du stade de développement de la plante et des conditions environnementales. Le tissu cortical a un rôle structurel, fonctionnel et adaptatif essentiel pour les racines de riz. La différenciation du cortex et de l’endoderme a été longuement étudiée chez A.thaliana durant la dernière décennie. Le gène SHORT-ROOT (SHR) a été identifié comme un gène clé dans leur formation. Un modèle moléculaire a été développé, où SHR est transcrit dans la stèle, et la protéine migre jusque l’endoderme où elle active la transcription du gène SCARECROW (SCR). Ensemble SHR et SCR induisent la division périclinale asymétrique d’une cellule initiale, permettant la formation des deux couches de tissus internes que sont l’endoderme et le cortex. Chez le riz, il existe des orthologues de SHR et SCR, qui sont apparus suite à des duplications, appelés OsSHR1 & OsSHR2 et OsSCR1 & OsSCR2. Au sein de cette thèse nous avons tenté d’identifier le rôle des gènes OsSHR1&2 dans la mise en place des différentes couches de cortex chez le riz. / Optimal root development is central for plants to reach maximum growth and yield. Most of our knowledge regarding genes involved in root development has been accumulated in the dicotyledon model plant Arabidopsis thaliana. Roots of rice, the monocotyledon model, present several extra ground tissue layers compared to A. thaliana. Between epidermis and endodermis, rice possesses two outer cell layers, exodermis and schlerenchyma, and a multilayered cortex. All these tissues have specific cell identity, anatomical and molecular adaptations related to their diverse roles in root growth and function. Variation in the number of cortex cell layers depends on the rice root type and cortex is one of the key tissues for rice adaptation to submergence and tolerance to other environmental stresses. Cortex and endodermis differentiation in A. thaliana has been extensively studied during the last 10 years. Thereby, SHORTROOT (SHR) gene in Arabidopsis thaliana has been identified as a key gene required for their formations. An elegant model was developed, where SHR is transcribed in stele tissue and its protein moves to the endodermis where it activates SCARECROW (SCR) transcription. Together, SHR and SCR induce periclinal division of the ground tissue initial separating cortex and endodermis cell layers. Cortex formation in rice represents an intriguing contrast to A. thaliana. Variations in the number of cortex cell layers can be observed between the root types and during rice development. There should be a control mechanism for the number of cortical cell layers, and SCR and SHR rice orthologs represent good candidates. Two duplications in rice led to apparition ortholog genes of AtSHR (OsSHR1 and OsSHR2) and we have addressed the question of their respective function in cortex formation in rice root.

The purpose of this study was to evaluate physical properties of eight staple rice cultivars grown and consumed in Kyrgyzstan. The objective was to record and discuss values of several analysis in sub-sections of basic physical characteristics, textural characteristics, mechanical characteristics and cooking properties. The physical properties investigated seed dimensions, equivalent diameter, surface area of the grain, sphericity, aspect ratio, volume of the grain, bulk and solid density, porosity, thousand kernel weight, hardness of the grain, colour characteristic, optimum cooking time and water uptake ratio. Those analysis were performed in the laboratory of Czech University of Life Sciences and given methodology was strictly followed.

Cette thèse s'inscrit dans le cadre de l'analyse statistique en grande dimension. Plus précisé- ment, l'objet de cette thèse est d'étudier la possible application d'outils issus de la théorie des processus Gaussiens afin de redémontrer certaines propriétés des matrices à entrées Gaussiennes et d'étendre certaines procédures de test du modèle linéaire Gaussien standard. Dans la première partie, nous nous concentrons sur les matrices Gaussiennes. Notre objectif est de démontrer, via des formules du type Kac-Rice, qu'une telle matrice satisfait, avec très grande probabilité, la Null Space Property (NSP) et la Propriété d'Isométrie Restreinte (RIP). De plus, nous déduisons des transitions de phases dépendant des paramètres classiques de la régression parcimonieuse, à savoir le nombre d'observations, le nombre de prédicteurs et le degré de sparsité. Dans la seconde partie, nous traitons le cas du test de nullité globale des paramètres pour le modèle linéaire Gaussien, afin de l'appliquer au cas de la sélection de modèle. Dans ces travaux, qui s'inscrivent dans la continuité de Taylor, Loftus et Tibshirani, nous proposons un test non conditionnel pour l'hypothèse de nullité globale dans le cadre du lasso et discutons autour de sa puissance. De plus, nous généralisons ces résultats aux processus Gaussiens, pour inclure, par exemple, la cas de la super-résolution. Dans une troisième partie, nous présentons quelques applications de la formule de Rice visantà calculer la fonction de répartition du maximum d'un processus Gaussien afin d'en déduire une version numériquement implémentable. Dans un deuxième temps, nous discutons de l'efficacité ou non de certaines approximations classiques pour la fonction de répartition du maximum. Enfin, nous étudions le comportement asymptotique du nombre de franchissements d'un niveau donné u sur un intervalle de temps [0,T] pour un processus Gaussien dérivable. / This thesis fallin within the context of high-dimensional data analysis. More specificaly, the purpose is to study the possible application of some Gaussian tools to prove classical results on matrices with Gaussian entries and to extend existing test procedures for Gaussian linear models. In a first part, we focus on Gaussian matrices. Our aim is to prove, using a Kac-Rice formula on Gaussian processes, that such a matrice satisfies, with overwhelming probability, the Null Space Property (NSP) and the Restricted Isometry Property (RIP). Moreover, we derive phase transition graphs depending on the classical parameters of sparse regression, namely the number of observations, the number of predictors and the level of sparsity. In a second part, we deal with global null testing for Gaussian linear models, with application to Compressed Sensing. Following recent works of Taylor, Loftus and Tibshirani, we purpose a test for global null hypothesis in the lasso case and discuss about its power. Furthermore, we generalize these method to Gaussian processes, to include, for instance, the super-resolution case. In a third part, we present some applications of Rice formula to compute the cumulative distribution function of the maximum of a Gaussian process and derive corresponding numerical routines to investigate the efficiency of classical approximations. Finaly, we consider the asymp- totical comportement of the number of crossings of a differentiable Gaussian process for a given level u and time interval [0,T].

Made available in DSpace on 2015-08-20T17:10:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-03-30. Added 1 bitstream(s) on 2015-08-20T17:27:02Z : No. of bitstreams: 1 000843759.pdf: 1198801 bytes, checksum: a7d728ac692d7c1e17e88074d6859d76 (MD5) / O complexo de manchas da bainha do arroz engloba três doenças causadas por diferentes espécies de Rhizoctonia: a queima-da-bainha (causada R. solani AG-1 IA), a mancha agregada da bainha (R. oryzae-sativae) e a mancha da bainha (R. oryzae). Distinguir os agentes causais é um passo crítico para manejá-los eficazmente. Em levantamento recente efetuado em cinco áreas de cultivo de arroz no Vale do Paraíba, Brasil, e nos Llanos na Colômbia, R. oryzae-sativae, o patógeno da mancha agregada da bainha, foi a espécie predominante em ambos os países. Neste estudo, nosso principal objetivo foi determinar a estrutura genética das populações de R. oryzae- sativae do arroz no agroecossistema da região do Vale do Paraíba e nos Llanos Colombianos. Inferiu-se sobre o fluxo gênico entre populações do patógeno, dentro e entre os países, e sobre o modo reprodutivo predominante. Nosso segundo objetivo foi determinar o potencial de duas populações brasileiras de R. oryzae-sativae em adaptar-se a espécies forrageiras do gênero Urochloa. Uma vez que essas espécies de forrageiras são cultivadas em áreas adjacentes ou em rotação com arroz, podem estar exercendo elevada pressão de seleção sobre as populações de R. oryzae- sativae. Análises da estrutura genética de populações foram baseadas na genotipagem de isolados de quatro populações do patógeno usando cinco marcadores microssatélites. Populações próximas e distantes apresentaram indícios de fluxo gênico. Evidências de reprodução sexuada nas populações do patógeno e a baixa fração clonal, indicaram a predominância de um sistema reprodutivo recombinante. É provável que basidiósporos desempenhem papel mais importante no ciclo da doença do que se supunha anteriormente. Isolados das duas populações brasileiras de R. oryzae-sativae foram patogênicos e apresentaram variação na agressividade à Urochloa spp., porém com baixos índices de herdabilidade,... / The rice sheath-blight complex comprises three diseases caused by different Rhizoctonia species: sheath blight (caused by R. solani AG-1 IA), aggregated sheath spot (R. oryzae-sativae), and sheath spots (R. oryzae). To be able to distinguish among the causal agents is a critical step in order to manage them effectively. In a recent survey in five rice cropping areas from the Paraíba Valley region, Brazil, and from the Llanos in Colombia, R. oryzae-sativae (the aggregated sheath spot pathogen) was the predominant species on both countries. In this study, our primary objective was to determine the genetic structure of populations of R. oryzae-sativae from rice paddy fields sampled from the Paraiba Valley and the Colombian Llanos. We inferred about gene flow among populations within and between countries and the pathogen's main reproductive mode. The second objective was to infer the potential of the two brazilian populations of R. oryzae-sativae to adapt and become pathogen of forage pastures of the genus Urochloa. Once these forage species are intensively cropped in adjacent areas or under rotation with rice, they might be exerting strong selection pressure on R. oryzae-sativae populations. Population structure analyses were based on genotyping fungal isolates from four populations of the pathogen using five microsatellites markers. Gene flow was detected among geographically close and distant populations. Evidences of sexual reproduction and low clonal fraction found in the populations, indicated the predominance of a mixed reproductive system. It is plausible that basidiospores play a more important role on the disease cycle than previously thought. Isolates from the two brazilian populations of R. oryzae-sativae were pathogenic and varied on aggressiveness to Urochloa spp. However, low levels of heritability for aggressiveness were detected, indicating a yet limited adaptation to Urochloa spp

Manipulation de la recombinaison chez une plante cultivée, le riz.L’accroissement prévisible de la population mondiale ainsi que les conséquences du changement climatique obligent les sélectionneurs à créer de nouvelles variétés plus productives et plus résilientes. Les nouvelles combinaisons d’allèles favorables sont issues de la recombinaison génétique entre chromosomes homologues dont le siège est la prophase de première division de méiose. De récentes avancées chez la plante modèle Arabidopsis ont montré que l'inactivation de certains gènes permet de manipuler la méiose pour abolir ou au contraire augmenter très significativement la recombinaison. Les mécanismes de la méiose étant relativement bien conservés chez les eucaryotes, l’objectif de cette thèse était de transposer ces avancées chez une plante cultivée importante, le riz. Abolir la recombinaison méiotique permettrait de propager de façon clonale par grain des formules variétales hybrides F1 dont le rendement est de 20% supérieur à celui des lignées pures chez le riz mais dont les semences restent peu utilisées par les riziculteurs de subsistance. Les travaux réalisés dans une première partie de la thèse ont montré que le cumul de trois mutations Ososd1, pair1 et Osrec8, permettait d’obtenir des gamètes clonaux diploïdes mâles et femelles. Le phénotype apoméiotique obtenu, appelé MiMe (Mitosis instead of meiosis) chez Arabidopsis, peut être utilisé pour tester différentes stratégies d’induction de la parthénogenèse afin de produire des grains formant des plantes diploïdes clonales apomictiques. Une optimisation du mécanisme permettrait d'envisager l'utilisation de l'apomixie pour fixer l'hétérosis dans les semences hybrides F1. Par ailleurs, une augmentation globale ou locale de la recombinaison méiotique est recherchée car elle permettrait de diminuer la taille des populations de sélection et de réduire la taille des segments chromosomiques introduits dans les variétés élite de riz. Nous avons montré dans une seconde partie, que la mutation du gène OsRECQl4 codant pour une hélicase permet d'augmenter le taux de recombinaison d'un facteur de 3,3 fois faisant passer la taille de la carte génétique de 1670 cM à 5538 cM sans affecter la fertilité de la plante ni le déroulement de la méiose. Chez les plantes affectées dans la fonction d’une autre hélicase, OsFANCM, le taux de recombinaison a été également augmenté mais dans une moindre mesure (x 2,2). L’augmentation de la recombinaison s’opère sur l'ensemble des bras chromosomiques sauf au niveau des centromères. Ces résultats confirment ceux obtenus chez A. thaliana qui ont montré le rôle de régulateur négatif des crossing-overs (CO) des protéines RECQ4 et FANCM. La combinaison en cours de ces mutations entre elles ou avec celle affectant l’AAA-ATPase FIGL1 permet d’espérer une augmentation de la recombinaison encore supérieure. Ces résultats ouvrent la voie à l'utilisation des gènes anti-COs pour augmenter de façon globale le nombre de recombinants dans les croisements chez le riz et sans doute chez les autres céréales. Pour offrir une possibilité concrète aux sélectionneurs d'utiliser les gènes anti-CO, nous avons montré que la technologie CRISPR/cas9 permet d'éteindre l'expression de OsFANCM OsRECQl4 et OsFIGL1. / Manipulation of recombination in a crop, rice.The forecasted increase of world population as well as the consequences of global climate change oblige plant breeders to develop new varieties that are both more productive and resilient. Novel combinations of favourable alleles are generated through genetic recombination between homologous chromosomes, which occurs during the prophase of the first division of meiosis. Recent advances in the model plant Arabidopsis have demonstrated that the inactivation of some genes allows meiosis manipulation resulting in either an abolishment or in contrast, a significant enhancement of meiotic recombination. The meiosis mechanisms being relatively conserved across eucaryotes, the overall objective of this thesis was to transfer these advances to a crop of crucial importance, rice. To abolish meiotic recombination would allow the clonal propagation by seeds of F hybrids, which exhibit a 20% yield enhancement compared to that of pure lines in rice but remain rarely used in subsistence farming. In a first part, we showed that rice plants cumulating 3 mutations inactivating Ososd1, pair1 and Osrec8, formed clonal diploid male and female gametes. This apomeiotic phenotype, called MiMe (Mitosis instead of meiosis) in Arabidopsis, can serve as material to assay several strategies of parthenogenetic induction that would result in seed forming diploid clonal plants. Further optimization of the mechanisms would allow the use of apomixis to fix heterosis in hybrid seeds. Global and local enhancement of recombination is another desirable goal since it would allow a reduction in breeding population size and a downsizing of the introgressed chromosomal segments in elite plant materials. In a second part, we showed that mutation in the DNA helicase gene OsRECQl4 conducted to a 3.3 fold increase of recombination and inflated the genetic map size from de 1670 cM to 5538 cM, without altering plant fertility nor meiosis progression. Plants altered in a second DNA helicase, OsFANCM, exhibited a more modest 2.2 fold recombination enhancement. Recombination increase operated along the whole chromosome arms except at the centromere level. These results confirms the negative regulator role of RECQ4 and FANCM on crossing overs (CO), previously reported in Arabidopsis. On going combination of these mutations together with that altering the l’AAA-ATPase FIGL1 should conduct to an even higher recombination enhancement. These results pave the way to the use of anti-CO genes to enhance recombinant recovery in crosses of rice and possibly of other cereals. To provide breeders with a workable anti-CO system, we eventually showed that the CRISPR/Cas9 technology can be used to abolish OsFANCM, OsRECQl4 and OsFIGL1 expression.

abstract: This dissertation is a detailed rhetorical analysis of interviews with rice farmers in central Java, Indonesia and documents published by the global NGOs United Nations Food and Agriculture Organization (FAO) and CGIAR. Using theories of materiality, literacies, and environmental rhetorics, I examine how seemingly distinct and disparate humans, organizations, and inanimates are actually entangled agents in a dynamic conversation. I have termed that conversation the discourse of rice farming. Studying local and global together challenges conventional dichotomous thinking about farming and food. Looking at this conversation as an entanglement reveals what Karen Barad has defined in Meeting the Universe Halfway as the intra-relatedness of all agents. I focus on rice farming because rice is a food staple around the world and a major component of global agriculture initiatives by FAO and CGIAR. I argue that farmers construct their jobs in terms of production, food sovereignty, and community. The NGOs construct agriculture in terms of consumption, food security, and poverty alleviation. In my project I emphasize the need for global agents to better account for how farmers construct agriculture. Accounting for how all agents impact the discourse of rice farming is the only way to come to an objective understanding rice farming's impact on local and global scales. My argument adds to the field of environmental rhetorics because most published case studies are about the United States and thus are limited in their applicability. And it enriches global conversations about food security and food justice because it shares accounts from actual farmers who are often conspicuously absent from literature on those topics. / Dissertation/Thesis / Doctoral Dissertation English 2015

Orientador: Paulo Cezar Ceresini / Banca: Antonio de Goes / Banca: Daniel Augusto Schurt / Resumo: O complexo de manchas da bainha do arroz engloba três doenças causadas por diferentes espécies de Rhizoctonia: a queima-da-bainha (causada R. solani AG-1 IA), a mancha agregada da bainha (R. oryzae-sativae) e a mancha da bainha (R. oryzae). Distinguir os agentes causais é um passo crítico para manejá-los eficazmente. Em levantamento recente efetuado em cinco áreas de cultivo de arroz no Vale do Paraíba, Brasil, e nos Llanos na Colômbia, R. oryzae-sativae, o patógeno da mancha agregada da bainha, foi a espécie predominante em ambos os países. Neste estudo, nosso principal objetivo foi determinar a estrutura genética das populações de R. oryzae- sativae do arroz no agroecossistema da região do Vale do Paraíba e nos Llanos Colombianos. Inferiu-se sobre o fluxo gênico entre populações do patógeno, dentro e entre os países, e sobre o modo reprodutivo predominante. Nosso segundo objetivo foi determinar o potencial de duas populações brasileiras de R. oryzae-sativae em adaptar-se a espécies forrageiras do gênero Urochloa. Uma vez que essas espécies de forrageiras são cultivadas em áreas adjacentes ou em rotação com arroz, podem estar exercendo elevada pressão de seleção sobre as populações de R. oryzae- sativae. Análises da estrutura genética de populações foram baseadas na genotipagem de isolados de quatro populações do patógeno usando cinco marcadores microssatélites. Populações próximas e distantes apresentaram indícios de fluxo gênico. Evidências de reprodução sexuada nas populações do patógeno e a baixa fração clonal, indicaram a predominância de um sistema reprodutivo recombinante. É provável que basidiósporos desempenhem papel mais importante no ciclo da doença do que se supunha anteriormente. Isolados das duas populações brasileiras de R. oryzae-sativae foram patogênicos e apresentaram variação na agressividade à Urochloa spp., porém com baixos índices de herdabilidade,... / Abstract: The rice sheath-blight complex comprises three diseases caused by different Rhizoctonia species: sheath blight (caused by R. solani AG-1 IA), aggregated sheath spot (R. oryzae-sativae), and sheath spots (R. oryzae). To be able to distinguish among the causal agents is a critical step in order to manage them effectively. In a recent survey in five rice cropping areas from the Paraíba Valley region, Brazil, and from the Llanos in Colombia, R. oryzae-sativae (the aggregated sheath spot pathogen) was the predominant species on both countries. In this study, our primary objective was to determine the genetic structure of populations of R. oryzae-sativae from rice paddy fields sampled from the Paraiba Valley and the Colombian Llanos. We inferred about gene flow among populations within and between countries and the pathogen's main reproductive mode. The second objective was to infer the potential of the two brazilian populations of R. oryzae-sativae to adapt and become pathogen of forage pastures of the genus Urochloa. Once these forage species are intensively cropped in adjacent areas or under rotation with rice, they might be exerting strong selection pressure on R. oryzae-sativae populations. Population structure analyses were based on genotyping fungal isolates from four populations of the pathogen using five microsatellites markers. Gene flow was detected among geographically close and distant populations. Evidences of sexual reproduction and low clonal fraction found in the populations, indicated the predominance of a mixed reproductive system. It is plausible that basidiospores play a more important role on the disease cycle than previously thought. Isolates from the two brazilian populations of R. oryzae-sativae were pathogenic and varied on aggressiveness to Urochloa spp. However, low levels of heritability for aggressiveness were detected, indicating a yet limited adaptation to Urochloa spp / Mestre

Made available in DSpace on 2014-10-09T12:28:15Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:03Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Orientador: Orivaldo Arf / Banca: Kuniko Iwamoto Haga / Banca: Carlos Alexandre Costa Crusciol / Resumo: Grandes avanços foram alcançados com a melhoria do nível tecnológico na cultura do arroz de terras altas, entre eles pode-se citar a utilização de irrigação por aspersão e o maior uso de insumos, como fertilizantes. Entretanto isto tem causado frequentemente o acamamento das plantas, devido ao aumento do seu porte e espiguetas mais pesadas. Embora novas cultivares menos suscetíveis a esse problema vem sendo utilizadas, há ainda produtores que preferem cultivares com plantas do tipo intermediário, devido excelente qualidade dos grãos. O acamamento causa entre outros problemas a redução da produtividade e interfere negativamente na colheita. A utilização de reguladores de crescimento para redução da altura das plantas e consequentemente redução do acamamento é uma das alternativas para prevenir ou minimizar esse problema. Assim o objetivo do trabalho foi avaliar o efeito de doses e épocas de etil-trinexapac sobre características agronômicas, grau de acamamento e produtividade de grãos em arroz de terras altas irrigado por aspersão. O delineamento experimental utilizado foi de blocos ao acaso, com esquema fatorial 6 x 3 com quatro repetições. Os tratamentos foram constituídos de doses de etil-trinexapac (zero, 50, 75, 100, 125 e 150 g ha-1 do ingrediente ativo) e três épocas de aplicação (diferenciação floral, ½ dose na diferenciação floral e ½ no emborrachamento e no emborrachamento). O experimento foi desenvolvido no município de Selvíria-MS, durante os anos agrícolas de 2010/11 e 2011/12. Concluiu-se que o regulador de crescimento etil-trinexapac deve ser aplicado na dose de 50 g ha-1, por ocasião da diferenciação floral na cultivar BRS Primavera, considerando a redução na altura de plantas, a eliminação do acamamento e a produtividade de grãos / Abstract: Great advances have been achieved by improving the technological level in the crop of upland rice, among them we can mention the use of sprinkler irrigation on a complementary and greater use of inputs such as fertilizers. However, this has often caused the plant lodging, due to the increase of its size and heavier spikelets. Although new cultivars low susceptible to this problem has been used, there are still producers who have a preference to older cultivars, because excellent grain quality. The lodging cause other problems to reduced grain yield and cause problems in the harvest. The use of growth regulators reduce plant height and consequently reduce the lodging and is one of the alternatives to prevent or circumvent this problem. Among the growth regulators etil-trinexapac has been investigated and has been shown to be effective for this purpose. Thus the aim of this study was to evaluate the effect of levels and times of etil-trinexapac application on agronomic characteristics, degree of lodging and grain yield of upland rice under sprinkler irrigation. The experimental design was randomized complete blocks, with treatments in factorial arrangement 6 x 3. The treatments were constituted of six levels of etil-trinexapac (zero, 50, 75, 100, 125 and 150 g of ha-1 of active ingredient) and three application times (floral differentiation, ½ dose in floral differentiation and ½ at booting and booting ). The experiment was developed in Selvíria, Mato Grosso de Sul State, Brazil, during the growing seasons of 2010/2011 and 2011/2012. It was concluded that the ethyl-trinexapac could be applied at the rate of 50 g ha-1, during the floral differentiation, considering the reduction in plant height, in lodging, and grain yield / Mestre

Esta dissertação é composta por 5 artigos. / CNPq / INTRODUÇÃO E OBJETIVOS: O arroz é um dos cereais mais consumidos no mundo e durante o seu beneficiamento, obtém-se o farelo que representa cerca de 8% do peso total do grão. O farelo de arroz desengordurado contém aproximadamente 15% de proteínas de alto valor nutricional. As técnicas de extração permitem além de extrair, selecionar e separar e determinadas substâncias. A extração das proteínas do farelo de arroz em meio alcalino é muito utilizada porque neste pH sua solubilidade é máxima e há a ruptura das paredes celulares. Podem ser usados métodos mecânicos e não mecânicos. A agitação mecânica com a movimentação de líquidos por meio de impulsores giratórios auxilia no rompimento das paredes celulares durante processos de extração. A extração assistida por ultrassom (EAU) utiliza frequências acima de 20 kHz para gerar cavitação em meios líquidos, que nada mais é que o colapso de microbolhas de gás e vapor que ocorre quando as mudanças de pressão no meio são grandes o suficiente, para literalmente dilacerá-lo sob a influência do ultrassom. Com este colapso, há o rompimento celular e a transferência de massa para o meio. Um concentrado de proteína do farelo de arroz (CPFA) deve ter boa solubilidade, propriedades funcionais apropriadas, características organolépticas aceitáveis para serem utilizados como um ingrediente alimentar, e possuir aminoácidos essenciais. Os objetivos deste trabalho foram avaliar os efeitos do pH, temperatura, velocidade da agitação, tempo de agitação, tempo em banho ultrassônico e amplitude da potência na extração das proteínas do farelo de arroz, além de analisar a cor, funcionalidade do CPFA (capacidade de absorção de água e óleo, formação de espuma, estabilidade da espuma, capacidade emulsificante, estabilidade da emulsão e formação de gel), solubilidade, perfil de aminoácidos e sua aceitabilidade quando aplicado em suco de caju. MÉTODOS ─ Verificou-se o rendimento proteico em três tipos de extração alcalina: agitação, banho ultrassônico a 37 kHz e banho ultrassônico a 80 kHz. Numa primeira etapa, aplicou-se o planejamento fatorial fracionário 24-1 (com dois níveis, três repetições no ponto central), totalizando 11 ensaios, tendo como variáveis independentes para a extração com agitação: pH, tempo de agitação (min), velocidade da agitação (rpm) e temperatura (ºC), e para a extração em banho de ultrassom (37 e 80 kHz): pH, tempo de ultrassom (min), temperatura (ºC) e amplitude da potência (%). Na segunda etapa, as variáveis com efeitos significativos (p < 0,05) de cada tipo de extração foram submetidas ao Delineamento Composto Central Rotacional (DCCR) 22 (quatro pontos axiais, três repetições no ponto central), totalizando 11 ensaios. As variáveis dependentes, resposta experimental e predita, foram expressas em g.100 mL-1 de extrato ± desvio padrão médio. Os efeitos foram validados pela Análise de Variância, por meio do software Statistica 8.0, sendo considerada a melhor condição de extração aquela com maior teor proteico e desta, obtido o concentrado. O teor de proteína bruta foi determinado por Kjeldahl e multiplicado por 5,95, e o rendimento, razão do conteúdo total da proteína no farelo de arroz pelo encontrado no CPFA. A cor do concentrado extraído por agitação e por ultrassom foi verificada por colorimetria instrumental e deste último método de extração, determinou-se a composição centesimal (%), minerais (µg.g-1), proteínas solúveis (%), capacidade de absorção de água e óleo (g de água.g-1 de amostra; g de óleo.g-1 de amostra), capacidade de formação de espuma (%), estabilidade da espuma (%), capacidade emulsificante (%), estabilidade da emulsão (%) e capacidade de formar gel, perfil de aminoácidos (g.100 g-1). A aplicabilidade foi verificada por avaliação sensorial de suco de caju (ordenação por preferência e aceitabilidade dos atributos: sabor, cor, aroma e impressão global). PRINCIPAIS RESULTADOS ─ A resposta ótima na extração alcalina com acompanhamento de agitação foi do teor de proteína de 48,53 % (b.s.), em pH 10, velocidade de agitação de 80 rpm, tempo de agitação de 300 min e temperatura de 45 ºC, representando o rendimento de 34,51% na extração. A interação entre as variáveis independentes pH, tempo de agitação e temperatura promoveram efeitos favoráveis para a técnica de extração das proteínas, enquanto que a velocidade de agitação não interfere de modo significativo. O planejamento experimental utilizado foi adequado para estudar os efeitos da associação da agitação mecânica ao processo de extração alcalina das proteínas do farelo de arroz. Nessas condições, o CPFA obtido apresentou forma de pó fino e textura aveludada, com valores de L* de 78,29 ± 0,95, a* -4,97 ± 0,05 e b* 16,51 ± 0,10 para a medida instrumental de cor. Quando se avaliou a extração alcalina associada ao banho ultrassônico, comparou-se o desempenho das frequências de 37 e 80 kHz, comprovou-se que na menor frequência houve maior extração. No ensaio com maior rendimento obteve-se um concentrado proteico com teor de proteína de 83,36% (b.s.), quando utilizado o pH 10, 30 min de ultrassom, 100% de amplitude da potência (30ºC) representando um rendimento de 4,74 % na extração. Portanto, a extração assistida pode ultrassom ser utilizada como um método alternativo para extrair proteínas do farelo de arroz, reduzindo o tempo de extração e consumindo menos energia. A EAU é uma técnica promissora e avançada para a extração de substâncias de interesse alimentar, oferecendo potencial para o desenvolvimento de novos produtos. O CPFA apresentou-se na forma cristalina com valores de L* de 60,42 ± 2,15, a* -1,31 ± 0,53 e b* 20,29 ± 1,39 para a medida instrumental de cor, observou-se menor solubilidade em pH 2, 3, 4 e 5, e maior solubilidade na faixa de pH 6 a 10. A capacidade de absorção de água e de óleo de 1,04 ± 0,07 g.g-1, e 11,75 ± 0,67 g.g-1, respectivamente, superior ao da referência Albumina Bovina Sérica (BSA). A maior quantidade de espuma formada ocorreu em pH 4 e 8 (41,17% ± 2,30; 48,47% ± 1,15) e menor em pH 6 (9,96% ± 0,00), porém a estabilidade das espumas formadas foi baixa em todos os pHs, e em ambos os casos, a BSA apresentou característica espumante superior. CPFA apresentou boa capacidade emulsificante em pH 2, 4, 6 e 8 (56,20% ± 5,39; 66,19% ± 6,57; 67,86% ± 0,19; 72,92% ± 2,95) comparáveis a BSA, mas emulsões menos estáveis em pH 2 (32,50% ± 3,54). Em temperatura de 30 ºC e 8 ºC, o CPFA apresentou baixa capacidade geleificante, com um gel frágil e pouco consistente. O perfil de aminoácidos do CPFA indicou a presença de ácido glutâmico, glicina, histidina, arginina, treonina, valina, metionina, isoleucina, leucina, fenilalanina e lisina, essenciais para a síntese das proteínas. O desempenho sensorial do CPFA foi avaliado em formulações de suco de caju adoçado contendo 0,1%; 0,3% e 0,5% de CPFA e ordenadas de acordo com a preferência de 60 provadores não treinados. Constatou-se que não houve diferença significativa entre as amostras (p > 0,05). Em função deste resultado, um teste de aceitação foi aplicado a 64 provadores não treinados, utilizando uma fórmula de suco de caju adoçado adicionada de 0,5% de CPFA e a Controle (sem CPFA). Verificou-se que houve diferença significativa (p < 0,05) entre as amostras nos atributos cor, sabor, aroma e impressão global. Os provadores gostaram moderadamente do Controle, mas foram indiferentes a fórmula com 0,5% de CPFA, uma vez que acentuou as características sensoriais do arroz ao suco de caju. O CPFA apresentou excelentes propriedades funcionais que o tornam um ingrediente promissor para a indústria alimentícia. / INTRODUCTION AND OBJECTIVES: Rice is the cereal most consumed in the world and during the processing, it is obtained the rice bran which represents 8% of the total weight of the grain. The defatted rice bran contains approximately 15% of protein of high nutritional value. The extraction techniques permit besides to extract, also to select and to separate substances. The extraction of rice bran proteins by alkaline medium is often used because they reach the maximum solubility in the pH and to assist in rupture of cell walls of a food. Mechanical and non-mechanical methods may be used. Mechanical stirring with the movement of liquid through rotating impellers assists in the disruption of the cell walls during extraction processes. The extraction assisted by the ultrasound (EAU) uses frequencies above 20 kHz to generate cavitation in liquids, which is the collapse of microbubbles of gas and vapor that occurs when the pressure changes in the middle are large enough to literally lacerate it under the influence of ultrasound. With this collapse, there is the cell disruption and the mass transfer to the environment. A rice bran protein concentrate (RBPC) should have good solubility, appropriate functional properties, acceptable sensory characteristics to be used as a food ingredient e to have essential amino acids. The objectives of this study were evaluate the effects of pH, temperature, speed of stirring, stirring time, time in ultrasonic bath and amplitude of the power in the extraction of rice bran protein, and analyzing the color, RBPC functionality (water and oil retention capacity, foaming, foam stability, emulsifying capacity, emulsion stability and gel formation), solubility, amino acid profile and its acceptability when applied in cashew juice. METHODS ─ It was verified the protein yield in three types of alkaline extraction: agitation, ultrasonic bath at 37 kHz and ultrasonic bath at 80 kHz. As a first step, it was applied the Fractional Factorial Planning 24-1 (with two levels, three replicates in the central point), totaling 11 trials, with the independent variables for extraction with stirring: pH, agitation time (min), speed stirring (rpm) and temperature (°C) and for the extraction in an ultrasound bath (37 and 80 kHz): pH, ultrasound time (min) temperature (°C) and power range (%). In the second stage, the variables with significant effects (p < 0.05) of each type of extraction were subjected to Design Central Composite Rotational (DCCR) 22 (four axial points, three repetitions at the central point), totaling 11 trials. The dependent variables, the experimental and predicted response were expressed in g.100 mL-1 extract ± average standard deviation. The effects were validated by analysis of variance, using software Statistica 8.0, being considered the best extraction condition one with the highest protein content and thus, obtained the concentrate. The crude protein content was determined by Kjeldahl and multiplied by 5.95. The yield was calculated as the ratio of the total content of protein in rice bran by the one found in the RBPC. The color of the concentrate extracted by stirring and by ultrasound was checked by instrumental colorimetry and from the latter extraction method, it was determined the chemical composition (%), minerals (μg.g-1), soluble protein (%), water and oil retention capacity (g water.g-1 sample; g oil.g-1 sample), foaming capacity (%), foam stability (%), emulsifying capacity (%), stability of emulsion (%), ability to form gel and amino acid profile (g.100 g-1). The applicability was checked by sensory evaluation of cashew juice (preference and acceptability of attributes as taste, color, smell and global impression). MAIN RESULTS ─ The optimal response in the alkaline extraction with monitoring of stirring was of 48.53% protein (DB), at pH 10, stirring speed of 80 rpm, stirring time of 300 min and temperature of 45 °C, representing the yield of 34.51% in extraction. The interaction between the independent variables as pH, stirring time and temperature promoted favorable effects on protein extraction technique while the stirring speed does not interfere significantly. The experimental planning used was adequate to study the effects of the combination of mechanical stirring to alkaline extraction process of rice bran protein. Under these conditions, RBPC obtained presented as a fine powder and velvety texture, with values of L* 78.29 ± 0.95, a* -4.97 ± 0.05 and b* 16.51 ± 0.10 for the instrumental color measurement. When assessing the alkaline extraction associated with the ultrasonic bath, it was compared the performance of the frequencies of 37 and 80 kHz, and it was proved that the lower frequencies have shown higher extraction. In the test with increased yield obtained a protein concentrate with a protein content of 83.36% (DB), when used pH 10, 30 min of ultrasound, 100% power range (30 °C), representing a yield of 4,74% extraction. Therefore, the UAE can be used as an alternative method for extracting rice bran protein, reducing the extraction time and consuming less power. UAE is a promising and advanced technique for extracting substances from food interest, offering potential for the development of new products. The RBPC presented in the crystalline form with values L* 60.42 ± 2.15, a* -1.31 ± 0.53 and b*20.29 ± 1.39 for instrumental measurement of color. It was observed a lower solubility at pH 2, 3, 4 and 5, but greater solubility in the pH range 6 to 10. The water and oil absorption capacity was 1.04 ± 0.07 g.g-1 and 11.75% ± 0.67 g.g-1, respectively, higher to reference Bovine Serum Albumin (BSA). The greater amount of foam was formed in pH 4 and 8 (41.17% ± 2.30, 48.47% ± 1.15) and lower at pH 6 (9.96% ± 0.00), but the stability of the formed foam was low at all pHs and in both cases, and BSA showed higher foaming characteristics. RBPC showed good emulsifying capacity at pH 2, 4, 6 and 8 (56.20% ± 5.39, 66.19% ± 6.57, 67.86% ± 0.19, 72.92% ± 2.95) comparable to BSA, but less stable emulsions at pH 2 (32.50% ± 3.54). In temperature of 30 °C and 8 °C, the RBPC showed low gelling capacity with a fragile gel and little consistent. The amino acid profile of the RBPC presented good amounts of glutamic acid, glycine, histidine, arginine, threonine, valine, methionine, isoleucine, leucine, phenylalanine and lysine, essential for protein synthesis. The sensory performance of the RBPC was evaluated in formulations of sweetened cashew juice containing 0.1%; 0.3% and 0.5% RBPC and ordered according to the preference of 60 untrained panelists. It was observed that there was no significant difference between the samples (p > 0.05). Due to this result, an acceptance test was applied to 64 untrained panelists using a formula of sweetened cashew juice added with 0.5% of RBPC and the control formula (without RBPC). It was found that there was a significant difference (p < 0.05) between samples in attributes as taste, color, smell and overall impression. Tasters liked moderately the control formula, but were indifferent to the formula with 0.5% RBPC because the sensory characteristics of the rice were accentuated. The RBPC presented excellent functional properties that make it a promising ingredient for the food industry. / 5000