Plant-derived protein such as pea protein is a promising replacement for animal protein and is becoming popular in recent years because of its high nutritional value and potential reduction of environmental footprint. However, the increasing demand for plant-derived proteins is accompanied by the increase of wastes during protein processing such as wastewater containing dilute protein content, which may raise the cost for the downstream processing. Therefore, there is an emerging need to develop novel processing strategies to reduce waste while valorizing useful ingredients. Several researchers suggest that foam fractionation technology can be a viable approach to extract and concentrate protein from dilute wastewater effluent. This technology has already been applied to the chemical and food industry for the extraction of surfactant and animal proteins from wastewater. To design and apply foam fractionation to the plant-derived protein industry, fundamental knowledge on foaming properties of dilute plant-derived protein solution is needed and is currently lacking. Therefore, the objective of this thesis is to advance a fundamental understanding of the foaming properties of dilute pea protein solutions (protein concentration ≤ 1wt%). To achieve the objective, a multiscale approach is used, which is comprised of a detailed investigation of both bulk and interfacial properties of pea protein solutions and foaming properties such as foaming capacity and stability with the help of bubble structure and foam volume kinetics. The focus of this thesis is on the effect of protein concentration. Results demonstrate that protein adsorption kinetics can be characterized by four distinctive regimes: lag phase, diffusion-limited regime, transitional regime, and conformation change regime, which are highly dependent on the protein concentration. However, apparent viscosity is less affected by the protein concentration. Results also show that depending on the protein concentration, two regimes can be distinguished for foam capacity and foam stability. For the first time, these regimes can be rationalized by contrasting characteristics times of protein adsorption kinetics and processing time scale – residence time of bubbles during the foam formation. New findings from this fundamental research will shed light on the control and optimization of foaming properties of plant-derived protein solutions for applications ranging from food processing design to food product development.

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Canada is a major global producer of pulse products including pulse starch, which notably contributes to a healthy diet. Strategically, Canada is taking steps to research methods of adding greater value to these crop products, and functional foods like resistant starch are particularly interesting. The primary objectives of this study were to develop an effective reactive extrusion process to produce gelatinized lipid complexed pea starches with enhanced enzyme resistance and examine the effects of bulk lipid complexing conditions on physicochemical and functional properties of extruded pea starches. One type of commercially available pea starch, Nutri-Pea, was chosen as the research subject in this study. A number of methods including; Englyst digestion method, differential scanning calorimetry (DSC), infrared spectroscopy (FTIR), contact angle, titrations, residence time distribution (RTD) and rapid visco analysis (RVA) were used to characterize the properties of extruded pea starches. The effects of feed formulation and extrusion conditions on lipid complexing and Englyst digestion profiles were systematically examined on two mixing devices. An extensive kinetics study was conducted on a lab scale twin-screw compounder, DSM-Xplore. The process was then scaled up to produce bulk lipid complexed pea starch on a Leistritz twin-screw extruder. The results showed that lipid complexing and digestion profiles were highly dependent on feed moisture and induced screw shear. Reactive extrusion of pea starches under optimized conditions achieved a significant but moderate increase in either resistant starch (RS) content (from 13.3% to 20.2%) or slowly digestible starch (SDS) content (from 7.85% to 23.3%) compared to their native counterparts. However, RS and SDS content could not be improved simultaneously based on the pea starch and extrusion process in this study. Increased degree of substitution (DS) was found for myristic acid complexed pea starches (nominal DS= ~0.8) when compared to palmitic acid complexed pea starch (nominal DS= ~0.5). Contact angle measurements, FTIR and DSC thermograms confirmed the presence of lipids. Lipid complexed starch films showed increasing hydrophobicity with increasing lipid content. As an alternative product compared to functional foods, the modified starch was considered as a biodegradable film for industrial applications. The material was produced at the highest moisture content for extruded native starch and two concentrations of lipid complexed starch using an intensive screw design. Preliminary results show that increasing lipid content and adding 1% glycerol to samples decreases the force per film thickness required to puncture films. However further investigation is required to determine effect of heat and moisture deformation. / Thesis / Master of Applied Science (MASc) / Incorporation of pulses into food products has been a major area of Canadian research for its potential to create new avenues of enzyme resistant food starches. Extrusion cooking is commonly used in industry for producing various food products such as snacks and cereals but little research has been reported on using an extruder to rapidly produce resistant pulse starches as a functional ingredient on a large scale; resistant starch is a functional food beneficial to humans in the same manner as insoluble fiber but exhibits improved textural properties. This study aimed to develop an effective reactive extrusion process to produce lipid complexed pea starches with enhanced enzyme resistance (i.e. increased slowly digestible starch (SDS) and resistant starch (RS) content) by an examination of the effects of reaction conditions on the properties of extrusion products. The lipid complexed pea starches under optimized conditions achieved a significant but moderate increase in either RS content or SDS content depending on the sample formulation compared to their native counterparts. However, RS and SDS content could not simultaneously be improved in this study.

The main objectives of this study were to develop an effective process to produce modified pea starch with enhanced enzyme resistance property (RS) for food applications. The work compares a non-chemical method (heat moisture treatment) versus a chemical method (crosslinking). One type of commercial pea starch (Nutri-Pea) was used exclusively as the raw material in this study. A number of methods were used to characterize the properties of the modified pea starches: water solubility index (WSI), titration (conversion, iodine value), intrinsic viscosity, infrared spectroscopy (FT-IR), Englyst digestion method, total starch content, and rapid visco analysis (RVA). The effects of heat-moisture treatment on native pea starch and enzyme treated pea starch were examined. The results showed that the produced samples with both native starch and enzyme treated starch exhibited a sharp increase in intrinsic viscosity. Overall, this method was deemed undesirable and not extensively examined past preliminary evaluations. The main focus of the study was on a citric acid crosslinking reaction, chosen for its food compliancy. A temperature of 120 oC was considered ideal for the reaction. FT-IR confirmed the presence of the citric acid incorporation in the starch samples. To improve the extent of reaction, Butanetetracarboxylic acid (BTCA) was considered as a replacement for citric acid and its treated samples showed higher conversion and lower water solubility index than that of the citric acid treated samples. Sodium propionate (NaP) was also considered in the reaction, this time as a food-grade catalyst and found to have minor benefit in cross-linking. BTCA/NaP treated sample reached the highest conversion of the study (96.8±2.3 %) and the lowest WSI (13.1±2.0 %), which increased the RS fraction of the starch from 18% to 32%. The RVA pasting profiles examined were too low to compare due to the high degree of cross-linking. Further improvements to RS were sought by debranching the starch before acid crosslinking. A BTCA/NaP treated sample with enzyme treatment showed a low WSI (31.7±2.3 %) yet substantially higher RS fraction (80.81±0.18 %). Similar to the non-debranched acid modified samples, there were no significant RVA pasting results because of the high cross-linking. Finally, crosslinking with an epoxidized oil was tested to continue looking at food-grade solution yet possible increase the rate of the crosslinking reaction. The results of WSI indicated that this method had little influence on cross-linking, possibly due to the low epoxidation efficiency of vegetable oils, as determined by iodine value. / Thesis / Master of Applied Science (MASc)

A₂bu composed 20-40% of total free amino acids in flatpea tissues and constituted 2-4% of the tissue dry weight. Higher concentrations of A₂bu were found in the leaves than in the roots. A₂bu concentration in leaves and stems increased slightly with plant age. Higher nitrogen availability increased the content of A₂bu in flatpea, a response accompanied by an increase in the contents of soluble protein and other nitrogenous compounds. When exogenous nitrogen supply was decreased, A₂bu levels decreased significantly. Rhizobium infection had no effect on the A₂bu production by flatpea. Ammonium was toxic to flatpea growth. Together with typical toxic symptoms, A₂bu elevation was observed in flatpea plants fed with ammonium. Water-deficit stress also elevated A₂bu content of flatpea. The elevation of A₂bu concentration in aerial tissues of flatpea under stress may not be high enough to decrease the value of flatpea as a forage. 4-Aminobutyric acid (Abu), homoserine (Hse), and asparagine (Asn) were the other major free amino acids in flatpea. As with A₂bu, levels of Hse were higher in the leaves than in the roots. The opposite was true for Abu and Asn. The concentration of Abu in the stems increased consistently with plant age. In response to stress conditions, Abu accumulated in flatpea, especially in stems and roots. Asn was the most prevalent free amino acid in the roots of flatpea. Asn levels in roots increased with plant age and accounted for the greatest portion of the increase in the free amino acid pool in the roots of plants subjected to the water stress or supplied with nitrogen in the form of ammonium ions. Levels of Hse in flatpea were changed little in response to the experimental treatments. Relative amounts of major amino acids in flatpea changed with respect to plant organs and experimental factors. If expressed as ratios, the resulting values suggest metabolic relationships. / Ph. D. / incomplete_metadata

Dans ce travail, le comportement des protéines de pois vis-à-vis de la gélification enzymatique par la transglutaminase microbienne (MTGase) a été évalué à l’état natif et après dénaturation (réduction chimique ou thermo-dénaturation). L’application finale concernait la formation de microparticules protéiques permettant d’encapsuler la riboflavine, choisie comme molécule active hydrophile modèle. Le procédé d’extraction des fractions protéiques de pois a été optimisé de manière à affecter le moins possible la structure des protéines et de récupérer des fractions natives riches en albumines (Alb) et en globulines (Glob), ou leur mélange. La mise en place des méthodes de suivi de la réaction enzymatique a permis de mettre en évidence leur complémentarité ainsi que leurs limites. Deux nouvelles méthodes de suivi de la réticulation enzymatique ont été développées. L’une basé sur la RMN permet la détermination simultanée de la quantité du fragment glutamine-lysine, produit de la réaction enzymatique, et le degré de réticulation ; l’autre méthode, basée sur les techniques de mesure de taille (SDS-PAGE et DLS), permet de visualiser les liaisons intramoléculaires. L’étude du traitement enzymatique appliqué aux fractions Alb et Glob de pois à l’état natif et dénaturé, ainsi qu’en mélange natif, a montré que la réaction enzymatique est fortement liée à la structure et à la conformation des protéines. Contrairement à la fraction Alb, la fraction Glob constitue un bon substrat pour la MTGase et la réticulation met en jeu des sous-unités constitutives des globulines différentes pour chaque condition de traitement. Néanmoins, la fraction Alb peut être utilisée en tant que booster de réaction enzymatique ce qui peut faire l’objet d’une voie innovante d’amélioration de la susceptibilité des protéines vis-à-vis de la MTGase. Le mécanisme semble basé sur un phénomène d’affinité sélective. Les bonnes propriétés mécaniques et de capacité de rétention d’eau du gel de la fraction protéique de pois totale ont été exploitées pour produire des microparticules à partir de la dispersion de la solution protéique sous forme d’émulsion suivie d’une gélification enzymatique par la MTGase. Les microparticules ont été pratiquement insolubles dans les milieux gastro-intestinaux en absence d’enzymes et lentement dégradable en présence d’enzymes. La libération de la riboflavine est gouvernée par un phénomène de diffusion en absence d’enzyme et de dégradation de support en présence d’enzymes selon des cinétiques compatibles avec des applications nutraceutiques. / In this work, pea proteins behavior toward enzymatic gelation by microbial transglutaminase (MTGase) was studied at native state and after denaturation (chemical reduction or thermal denaturation). The final application was the formation of protein microparticules to encapsulate riboflavin, chosen as hydrophilic active molecule model. The extraction process of the pea protein fractions has been optimized in such a way to minimize as possible protein denaturation and recover native fractions rich in albumin (Alb) and globulin (Glob) or a mixture of both.The setting up of the enzymatic reaction monitoring methods has brought out their complementarity as well as their limits. Two new monitoring methods of enzymatic cross-linking reaction have been developed. The first one, based on the NMR, allows to the simultaneous determination of the glutamine-lysine isopeptide bond, product of the enzymatic reaction, and the degree of crosslinking; the second method, based on size measuring techniques (SDS-PAGE and DLS), permit to view the intramolecular links. The study of enzymatic treatment applied to pea Alb and Glob at the native and denatured states, as well as thier native mixture showed that the enzymatic reaction is strongly related to the structure and conformation of proteins. Unlike Alb, the Glob fraction is a good substrate to transglutaminase and crosslinking reaction involves different subunits constituting globulins for each treatment condition. However, the Alb can be used as a booster of enzyme reaction which can be an innovative way for improving the proteins susceptibility toward transglutaminase treatment. The mechanism seems to be based on a selective affinity phenomenon. The good mechanical properties and water holding capacity of total pea proteins gel have been exploited to produce microparticles from a water-in-oil emulsion followed by enzymatic gelation. The produced microparticles were practically insoluble in gastrointestinal media in the absence of enzymes and slowly degradable in the presence of enzymes. The release mechanisms of riboflavin in digestive environments are governed by a diffusion phenomenon in the absence of enzymes and by support degradation phenomenon in the presence of enzymes according to kinetics compatible with nutraceutical applications.

L'étude de la ramification chez le pois, à partir des mutants hyper-ramifiés ramosus (rms) a permis de mettre en évidence l'existence d'une nouvelle famille d'hormones végétales : les strigolactones, inhibant la ramification des plantes à graines. La découverte de cette hormone végétale ouvre de nouvelles pistes de recherche sur la biosynthèse et la perception de cette nouvelle hormone. Nous avons montré le rôle du gène PsBRC1, codant un facteur de transcription de type TCP et homologue du gène TEOSINTE BRANCHED1 du maïs, dans la voie de signalisation des strigolactones. L’étude de ce gène nous a permis d'avoir une meilleure compréhension de l’interaction entre strigolactones et cytokinines dans le contrôle de la ramification, de la dynamique de la levée de dormance des bourgeons axillaires, et d'effectuer les premières études de relations structure-activité des strigolactones sur l’inhibition de la ramification chez le pois.Nous avons étudié et caractérisé d'autres éléments dans la voie de signalisation. Chez le pois, deux mutants, autres que Psbrc1, ne répondent pas à l’application de strigolactones, rms3 et rms4. Le gène RMS4 code pour une protéine à boîte F. Nous nous sommes focalisés ici sur le mutant hyper-ramifié rms3. Nous avons montré que RMS3 est l'homologue du gène D14 du riz, codant pour une protéine de la superfamille des α-β/hydrolases. Ces protéines peuvent avoir une activité enzymatique et ainsi pourraient modifier les strigolactones en un composé actif. Le récepteur des gibbérellines GID1 appartient aussi à cette famille, RMS3 est donc un bon candidat pour être le récepteur des strigolactones. Nous avons utilisé une strigolactone radiomarquée afin d’étudier le métabolisme de l'hormone. Nous avons découvert que la strigolactone synthétique, 3H-GR24 est clivée en un composé inconnu au contact des racines, indépendamment de l'activité de la protéine RMS3. Ce composé de structure inconnue se retrouve aussi dans la sève du xylème alors que 3H-GR24 y est absent.Outre un phénotype hyperbranché les mutants rms présentent une diminution de la taille de leurs entre-nœuds, qui n'est pas due à l’augmentation de la ramification. Nous avons étudié l'origine du nanisme des mutants déficients en strigolactones et affectés dans la réponse à l’hormone. Des approches génétiques et moléculaires ont été utilisées pour tester une interaction possible entre les strigolactones et les gibbérellines. Nous avons montré que les strigolactones régulaient l’élongation des entre-nœuds indépendamment des gibbérellines.Le pois est un excellent modèle en génétique et en physiologie. Avec le développement de nouvelles techniques à l'INRA (TILLING; UNIGENE : ensemble de plus de 40000 séquences exprimées de pois), nous avons pu identifier de nouveaux gènes de biosynthèse des strigolactones chez le pois et obtenir plusieurs nouveaux mutants de pois. Ces mutants seront essentiels pour les futures études du laboratoire et pourront permettre d'identifier de nouveaux intermédiaires dans la biosynthèse et le métabolisme des strigolactones. / The study of shoot branching in pea, using the high branching ramosus (rms) mutants has highlighted the existence of a new family of plant hormones: the strigolactones, inhibiting shoot branching in seed plants. The discovery of this novel plant hormone opens novel research areas in the deciphering of strigolactone biosynthesis and strigolactone perception. We have shown the role of the pea TCP transcription factor, PsBRC1, the homolog of the maize TEOSINTE BRANCHED (TB1) in strigolactone signaling. The PsBRC1 gene was shown to have a role in integrating strigolactone and cytokinin pathways, and allowed to have a better understanding of the dynamics of bud outgrowth, and to perform the first strigolactone Structure-Activity Relationship studies for branching inhibition in pea. We investigated and characterized other elements in the signaling pathway, including the strigolactone receptor. In pea, two mutants, other than Psbrc1, do not respond to the application of strigolactones, rms3 and rms4. The RMS4 gene encodes an F-BOX protein and here we focused on the high branching rms3 pea mutant. We have shown that RMS3 is the homolog of the rice D14 gene encoding a protein of the α-β/hydrolase superfamily. Consequently RMS3 may have an enzymatic activity to modify strigolactone into an active compound. The gibberellin receptor GID1 also belongs to this family, therefore RMS3 is also a good candidate for the strigolactone receptor. We used a radiolabeled synthetic strigolactone, 3H-GR24, to investigate the metabolism of the hormone. We discovered that the synthetic strigolactone, 3H-GR24 is cleaved in an unknown compound in the root media independently of RMS3 activity, compound which is also found in the xylem sap in contrast to 3H-GR24. The rms mutants exhibit not only a high branching phenotype but also a reduced height which is not due to this high branching. We investigated the origin of the dwarfism of strigolactone-deficient and response mutants in pea. Genetic and molecular approaches have been used to test a possible interaction between strigolactones and gibberellins. We have shown that strigolactones regulate stem elongation independently of gibberellin. Pea is a powerful model plant for genetics and physiology. With the development of new facilities at INRA (TILLING; UNIGENE set of more than 40000 expressed sequences), we were able to identify new biosynthesis genes in pea and to obtain several novel pea mutants. These mutants will be essential for future studies of the laboratory in particular to identify new intermediates in strigolactone biosynthesis and metabolism.

No Brasil, os solos hidromórficos são basicamente utilizados no cultivo de arroz, principalmente na região Sul do Brasil. O plantio de outras culturas em substituição ao arroz, pode ser uma alternativa viável para a melhor exploração destes solos durante o inverno e no pousio da área. O presente trabalho foi realizado em casa de vegetação do Departamento de Engenharia Rural da Escola Superior de Agricultura "Luiz de Queiroz" em Piracicaba, SP, tendo como objetivos avaliar os efeitos do rebaixamento do nível freático no desenvolvimento e na produtividade de plantas de soja, cv. BR-16 e de ervilha, cv. Axé, pelos parâmetros produtivos: altura e massa seca da parte aérea da planta, número de vagens e de grãos produzidos e peso total de grãos por planta; determinar o estádio de desenvolvimento das culturas mais sensível ao excesso de umidade no solo e determinar a velocidade de rebaixamento do nível freático mais adequada ao desenvolvimento das plantas de soja e de ervilha, dentro das condições experimentais propostas. As plantas foram conduzidas em lisímetros construídos em tubos de concreto preenchidos com Latossolo Vermelho-Amarelo Álico. Os ensaios foram realizados nos estádios vegetativo e reprodutivo das culturas, com o rebaixamento do nível freático (NF) em 10, 20, 30, 40 e 60 cm por dia e comparando-se com um tratamento de controle, somente irrigado. O delineamento experimental adotado foi inteiramente casualizado, arranjado em esquema fatorial [(2x5)+1], com 4 repetições. Os efeitos do rebaixamento do NF foram observados na massa seca da parte aérea das plantas, número de vagens, número de grãos por planta e peso de grãos em soja e ervilha, em comparação com as plantas testemunhas. O peso de grãos de soja produzidos em plantas inundadas durante o estádio reprodutivo, foi 3% maior do que verificado na testemunha, indicando que certos períodos de inundação podem aumentar o peso de grãos. Já as plantas de soja inundadas no estádio vegetativo apresentaram reduções significativas de 37% do peso do grão, demonstrando maior susceptibilidade à inundação neste estádio. Foram observadas reduções no peso de grãos de ervilha em ambos os estádios, sendo o reprodutivo o mais afetado (52%). Os efeitos causados pela inundação do solo, observados no número de vagens e de grãos produzidos pelas plantas de soja e de ervilha foram proporcionais ao tempo em que as raízes permaneceram submersas e variaram com a cultura e com estádio de desenvolvimento da planta. Acredita-se que velocidades de rebaixamento do NF superiores a 30 cm por dia são capazes de promover uma adequada aeração do solo, situação observada na rápida recuperação das plantas de soja inundadas no estádio vegetativo e submetidas ao rebaixamento do NF em 30 cm por dia e também no aumento da taxa de transpiração das plantas de ervilha submetidas à inundação do solo no estádio vegetativo e reprodutivo, após o rebaixamento de 30 cm do NF. O maior prejuízo à produtividade das culturas foi causado pela velocidade de rebaixamento do NF em 10 e 20 cm de profundidade. / In Brazil, most of hidromorfic soils are cultivated with rice. The growth of alternative crops to rice, is a feasible option for better use of hidromorfic soils. The present work was realized in the Department of Rural Engineering of Escola Superior de Agricultura "Luiz de Queiroz" in Piracicaba, São Paulo - Brazil. The objectives were to study the effects of the water table drawdown in the growth and crop yield of soybean, cv. BR-16, and pea, cv. Axé, at specific stages of their cycle. Yield parameters for these crops were valuated, such as: plant height, dry shoot weight, number of pods per plant, number of seed per plant and seed weight per plant. Also, to determine the growth stage of crop clycle more sensitive to waterlogging and the more appropriate velocity of water table lowering for to development of soybeans and peas plants, by the analysis of the yield parameters, in the experimental conditions proposed. Both crops were cultivated in lysimeters in a greenhouse. The soil used was the Orthic Hapludent. The study was realized in the vegetative and reproductive crop stages. The water table was lowered by 10, 20, 30, 40 e 60cm per day, from initial level. Control plants where only irrigated without flooding. The statistical experimental design was a randomized complete in factorial arrange [(2x5) + 1] with four replications. The effects from different drawdown velocity of water table, were observed in the all parameters in comparison with the control. For soybean, waterlogging during reproductive stage, caused a higher seed weight than control without waterlogging, showing that short waterlogging periods may increase seed weight. The waterlogging of plants at the vegetative stage crop cycle, showed significant reductions in seed weight in all treatments, indicating low waterlogging tolerance. In pea, the seed weight showed for all treatments was lower than control plants. The effects caused by waterlogging of the soil the number of the pods and soybean and pea seed, were proportional to root flooding time and to development stage of the plant. By physiologic responses of the soybeans and pea plants, was possible to determine that the lower limit of reduction of the water table was the 30 cm per day. The water table lowering by 10 and 20 cm per day severely affected the growth and seed yield, in the experiment conditions.

Existe uma vasta literatura evidenciando os determinantes que repercutem negativamente na acumulação de capital humano do menor de idade. O trabalho infantil seria uma dessas causas. Outros trabalhos mostram que um choque de renda sofrido pelas famílias pode estar por trás da oferta de trabalho de outros membros da família (esposa e filhos). Tal efeito é conhecido na literatura como efeito trabalhador adicional e pode estar relacionado, pelo menos no Brasil, à restrição de liquidez das famílias. O objetivo deste trabalho é averiguar o impacto de um choque de renda representado pela perda de emprego do chefe da família sobre a alocação do tempo dos filhos em idade escolar entre escola e mercado de trabalho. Para realizarmos este trabalho usamos dados da Pesquisa Mensal do Emprego, do IBGE, entre 2003 e 2012. De acordo com os resultados obtidos, o tratamento, ou melhor, o choque de renda representado perda de emprego do chefe da família não possui impacto significativo sobre a escolha das famílias de manter o filho apenas na escola ou de enviar o filho para o mercado de trabalho. Entretanto, nos casos em que o efeito do tratamento é persistente percebemos um impacto sensivelmente maior, apesar de ainda não ser estatisticamente diferente de zero. Na última subseção reproduzimos nosso modelo com dados da PME antiga com o intuito de checar a interferência da diferença de metodologia entre a PME antiga e a nova nos resultados. Notamos que com nosso desenho de modelo não encontramos os mesmos resultados de Duryea et al. (2007). / There is a vast literature demonstrating the determinants that negatively affect the human capital accumulation of child under eighteen. Child labor would be one of these causes. Other studies show that an income shock suffered by families may be behind the labor supply of other family members (spouse and children). This effect is known in the literature as additional worker effect and may be related, at least in Brazil, the liquidity constraint of households. The objective of this study is to investigate the impact of an income shock represented by the loss of employment of head of household on the time allocation of schoolage children between school and the labor market. To accomplish this work we use data from the Monthly Employment Survey, IBGE, between 2003 and 2012. According to the results, treatment, or better, the income shock represented by of the household head\'s job loss has no significant impact on the families\' choice to keeping the child in school or just send the child to the market job. However, in cases where the treatment effect is persistent, we noticed a substantially greater impact, although not statistically different from zero. In the last subsection we applied our model using the old PME data base aiming to check if the methodological differences interfere with the results. We noted that using our new model design, we didn\'t find out the same results as Duryea et al. (2007).

O complexo coletor de luz (LHC) do fotossistema II (PSII) é o principal complexo de proteínas associado a pigmentos situado na membrana dos tilacóides de cloroplastos em plantas. O LHCII funciona como uma antena de transferência de energia para a captura e direcionamento da energia luminosa do PSII para o PSI. A ação coordenada dos dois fotossistemas com o direcionamento do fluxo de elétrons gera a quebra da molécula de água, através da membrana do tilacóide, produzindo força assimilatória ATP e NADPH. A energia química produzida na fotossíntese é de suma importância para a assimilação de carbono, biossíntese de aminoácidos e metabólicos secundários. Portanto, este é um importante gene para estudos em biotecnologia. Linhagens transgênicas de tabaco (TR-1 e TR-2) as quais expressam constitutivamente o transgene Lhcb1*2 de ervilha obtidas por Labate e colaboradores (2004) foram utilizadas nesse trabalho. Estas plantas apresentaram diversos efeitos pleiotrópicos relacionados à anatomia, morfologia, bioquímica e fisiologia. Uma proteína pode não atuar isoladamente, mas freqüentemente interagindo com outras proteínas, influenciando diversos processos metabólicos. O perfil de proteômica dessas linhagens transformantes, em relação à planta selvagem (WT) foi investigado. As proteínas totais foram extraídas de folhas de plantas de três meses crescidas em câmaras de crescimento, então separadas por 2D-PAGE. As proteínas diferencialmente expressas foram identificadas por LC-MS/MS. Os resultados mostram que 244 spots apresentaram alterações significativas na expressão nas duas linhagens transgênicas em relação à WT. 122 spots são expressos exclusivamente nas linhagens transformantes, e 24 spots somente na selvagem. Muitas proteínas como ATP synthase e ribulose bisphosphate carboxylase/oxygenase activase foram mais expressas nas linhagens transgênicas, mas a glutamine synthetase, uma importante proteína na reciclagem de nitrogênio nos cloroplastos, teve sua expressão diminuída. Para analisar as alterações na expressãode genes relacionados ao ritmo circadiano entre outros, como a conformação do PSII, cotilédones de plântulas estioladas foram submetidas à luz e amostras coletadas depois de 0, 3, 6, 12 e 24 horas. O nível de transcritos foram analisados por PCR quantitativo. A diferenciação de plastídio à cloroplasto maduro foi analisado por microscopia eletrônica de transmissão, para se entender as diferenças entre os genótipos em estudo no desenvolvimento vegetal. A expressão constitutiva do gene Lhcb1*2 de ervilha em plantas transgênicas de tabaco acarretou a indução e repressão de várias proteínas e genes em distintos passos de vias metabólicas, estabilizando a homeostase celular, exercendo uma influência significativa no desenvolvimento vegetal e produção de biomassa. / The light harvesting complex (LHC) of photosystem II (PSII) is the major ensemble of pigmet-biding proteins situated in the thylakoid membranes of the chloroplast in plants. The LHCbII functions as an energy-transferring antenna for capturing and delivering light energy to the photosystems PSII and PSI. The coordinated actions of the two photosystems in turn drive the flow of electrons, generated by the splitting of water, through the thylakoid membranes to produce the assimilatory force ATP and NADPH. The chemical energy produced by photosynthesis is very important for the assimilation of carbon, amino acids biosynthesis, and secundary metabolism. Therefore it is an important gene for biotechnological studies. Transgenic tobacco lines (TR-1 and TR-2) which express the pea Lhcb1*2 transgene constitutively obtained by Labate et al. (2004) were used in this work. These plants presented pleiotropic effects related to anatomy, morphology, biochemistry and physiology. As a protein may not act by itself, but it is, frequently interacting with other proteins, influencing a lot of metabolic processes. The proteomic profile of these transgenic lines, in relation to the wild type (WT), was investigated. The total proteins extracted from leaves of three-month old plants grown in growth chambers were separated by 2DPAGE. The differentially expressed proteins were identified by LC-MS/MS. The results showed that 225 spots displayed significant changes in the expression of the two transgenic lines in relation to the WT. 122 spots were exclusively expressed in the transgenic lines, and 24 only in the wild type. Many proteins as ATP synthase and ribulose bisphosphate carboxylase/oxygenase activase are overexpressed in the transgenic lines, but the glutamine synthetase, an important protein tor nitrogen recycling in the chloroplasts, showed a reducted level of expression. In order to analyse the alterations of the expression of genes related to the circadian rhythm among others, involved in the conformation of the PSII, cotyledons from etiolated seedlings were thenexposed to light and samples collected after 0, 3, 6, 12 and 24 hours. The level of transcripts were analysed by RT/RT-PCR. The PSII conformation were analysed by transmition electron microscopy, with the aim of verifying the evolution of plastids into the chloroplasts which could be leading to changes in plant development. The overexpression of the pea Lhcb1*2 gene in transgenic tobacco plants, lead to the induction and suppression of several proteins and genes in key metabolic pathways, as a way to establish a cellular homeostasis, exerting a significant influence on plant development and biomass production.