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

Doctor of Philosophy / Department of Grain Science and Industry / Hulya Dogan / Jon M. Faubion / The overall hypothesis underlying this study is that the nature and extent of bran interactions with the gluten protein matrix play a dominant role in both 'in-process' dough and final product quality of whole grain baked goods. Therefore, the purposeful manipulation of those interactions should be able to minimize adverse processing or product characteristics resulting from bran inclusion/presence. The approach we took was to study the effects of bran milled to different particle sizes on dough development during and after dough mixing using fundamental rheology combined with traditional cereal chemistry approaches and x-ray microtomography (XMT). The research outcomes were used to create a better picture of how the bran is effecting the dough development and to suggest strategies that allow for the control of that effect. Study-I focused on characterization of the chemical properties, empirical rheological properties and baking performance of flours and dough with different bran contents from different sources. The development of dough microstructure and the resulting crumb texture in the presence of different bran were studied using XMT. HRW and SW bran additions resulted in higher water absorptions (WA) irrespective of the flour type and bran source. Fine bran caused slightly higher WA followed by coarse and as is bran. Both HRW and SW bran decreased the dough stability of HRW flour, while it improved the stability of SW flour doughs. Macro and microstructure of baked products were significantly affected both bran type and addition level. HRW bran added to HRW flour resulted in 8-23% decrease in loaf volume while SW bran added at the same level caused 3-11% decrease. XMT indicated that bran decreased the total number of air cells significantly. SW flour resulted in harder crumb texture than that of HRW flour breads. Overall, SW bran had less detrimental effects on mixing and baking performance of HRW flour. Study-II focused on specific bran particle size and composition on small and large deformation behavior of strong and weak flour doughs. Small deformation behavior was characterized using frequency and temperature sweep tests, while the large deformation behavior was studied using creep–recovery and uniaxial extensional testing. The results revealed that the rheological behavior of bran-enriched doughs depend on type of base flour, bran type, bran replacement level (0, 5, 10%), and the dough development protocol. Weak flour doughs benefited from inclusion of bran as inherently low peak height and stability of these doughs improved in the presence of bran. Temperature sweeps indicated a slight decrease in Gʹ and G" until around 55-60°C. In the same temperature range, presence of bran increased the moduli of composite four compared to that of the control flours. Creep compliance parameters indicated that both bran source and bran replacement had significant effect on maximum compliance (J[subscript max]) and elastic compliance (J[subscript e]). Finally, the bran type affected uniaxial extensional properties, maximum resistance (R[subscript max]) and elasticity (E), significantly independent from the type of base flour.

No description available.

A utilização de resíduos da agroindústria na produção de biomoléculas de interesse industrial agrega valor ao produto, por não utilizar meios sintéticos, reduzindo custos totais de produção e promovendo o desenvolvimento de tecnologias mais limpas e sustentáveis. Os exopolissacarídeos, ou simplesmente EPS são polímeros naturais, excretados por algumas espécies de bactérias e fungos. Possuem grande interesse no setor industrial, dado a versatilidade da biomolécula na utilização nas áreas médica, farmacêutica e química apresentando potencial de geração de diversos produtos. O presente trabalho teve como objetivo estudar a obtenção do exopolissacarídeo lasiodiplodana utilizando hidrolisados obtidos a partir de subprodutos agrícolas pelo fungo Lasiodiplodia theobromae. Foram realizados Delineamentos Compostos Centrais Rotacionais (DCCR) 22 com três repetições nos pontos centrais para avaliação de condições ótimas de produção de hidrolisados de farelos de arroz e milho com concentrações estimáveis de açúcares totais, açúcares redutores e proteínas totais. Os hidrolisados obtidos foram utilizados em ensaios fermentativos para obtenção da lasiodiplodana em meio de cultivo (LAS-M) e aderida à biomassa celular (LASC), bem como produção de células. Para elaboração dos ensaios foram utilizados DCCR 23 e 22 em hidrolisados de farelos de arroz e milho, respectivamente. As variáveis escolhidas para o DCCR 23 foram pH, volume de meio em frasco e adição de sais suplementares, enquanto o DCCR 22 apresentaram como variáveis o estudo da agitação e temperatura. Os delineamentos estudados geraram diversos modelos significativos para a produção de hidrolisados e obtenção de frações de lasiodiplodana. As frações de LAS-M e LAS-C obtidas foram caracterizadas parcialmente quanto a seus conteúdos de carboidratos e proteínas, sendo também analisadas por espectroscopia de infravermelho (FTIR) e análises cristalográficas de Raios-X. Os hidrolisados de farelo de arroz apresentaram concentrações aproximadas para açúcares totais (40 g/L), açúcares redutores (10 g/L) e proteínas (14 g/L) enquanto o hidrolisado de farelo de milho apresentou 170, 70 e 14 g/L dos respectivos componentes. Os hidrolisados foram tratados e utilizados em ensaios fermentativos apresentando concentrações de LAS-M de 7,8 e 5,73 g/L, LAS-C 4,93 e 3,0 g/L e biomassa celular de 10,68 e 4,47 g/L respectivamente para hidrolisados de farelos de arroz e milho, apresentando consumo dos açúcares totais de 94 e 84%. As frações de lasiodiplodana LAS-M apresentaram em sua composição concentrações de açúcares redutores correspondentes a 83,62 e 92,16%, enquanto as frações LAS-C apresentaram 82,19 e 88,42% para os respectivos hidrolisados. As análises de FTIR e Raios-X demonstraram que os biopolímeros obtidos neste trabalho apresentaram estruturas semelhantes aos citados na literatura. Evidenciou-se que os hidrolisados utilizados nas condições estudadas proporcionaram condições adequadas para o fungo L. theobromae sintetizar o exopolissacarídeo lasiodiplodana. / The utilization of agro-industrial wastes for industrial-interest biomolecules production generates add-value products, reducing total production costs and promoting the development of cleaner and more sustainable technologies. Exopolysaccharides, or simply EPS are natural polymers, excreted by some species of bacteria and fungi. They present a great interest from industrial sector, given the versatility of the biomolecule and its use in medical, pharmaceutical and chemical sectors, generating a diversity of products. The present work had as objective to study the exopolysaccharide lasiodiplodan by fermentation of hydrolysates obtained from agricultural by-products from filamentous fungi Lasiodiplodia theobromae. Rotational Central Compound Designs (DCCR) 22 were performed for the evaluation of optimum conditions for the production of hydrolysates from rice and corn brans with estimated concentrations of total sugars, reducing sugars and total proteins. The optimized hydrolysates were used in fermentative assays for obtaining lasiodiplodan from culture medium (LAS-M) and cell biomass (LAS-C), as well as cell production. For the elaboration of the tests, DCCR 23 and 22 were performed using rice bran and corn bran hydrolysates, respectively. The chosen variables for the DCCR 23 were pH, medium volume in flask and addition of supplemental salts, while the DCCR 22 presented agitation and temperature as variables. The studied designs presented several significant models for the hydrolysates production and its lasiodiplodan fractions. Obtained fractions of LAS-M and LAS-C were partially characterized due to carbohydrate and protein contents, as well as X-ray crystallographic analysis and Fourier-Transform Infrared Spectroscopy - FTIR. Rice bran hydrolysates presented estimated concentrations for total sugars (40 g / L), reducing sugars (10 g / L) and proteins (14 g / L) while corn bran hydrolysates showed 170, 70 and 14 g / L respectively. Treated rice and corn bran hydrolysates used for fermentative assays presented respective concentrations for LAS-M (7.8 and 5.73 g/L), LAS-C (4.93 and 3.0 g/L) and cellular biomass (10.68 and 4.47 g/L) and total sugar consumption of 94 and 84%, respectively. The lasiodiplodan fractions LAS-M presented reducing sugars compositions of 83.62 and 92.16%, while LAS-C fractions presented 82.19 and 88.42% for rice and corn bran hydrolysates. FTIR and X-ray anlysis showed that the present obtained biopolymers presented similar structures to those mentioned in the literature. It was evidenced that the hydrolysates used under the studied conditions provided adequate conditions for L. theobromae to synthesize the exopolysaccharide lasiodiplodan.

A utilização de resíduos da agroindústria na produção de biomoléculas de interesse industrial agrega valor ao produto, por não utilizar meios sintéticos, reduzindo custos totais de produção e promovendo o desenvolvimento de tecnologias mais limpas e sustentáveis. Os exopolissacarídeos, ou simplesmente EPS são polímeros naturais, excretados por algumas espécies de bactérias e fungos. Possuem grande interesse no setor industrial, dado a versatilidade da biomolécula na utilização nas áreas médica, farmacêutica e química apresentando potencial de geração de diversos produtos. O presente trabalho teve como objetivo estudar a obtenção do exopolissacarídeo lasiodiplodana utilizando hidrolisados obtidos a partir de subprodutos agrícolas pelo fungo Lasiodiplodia theobromae. Foram realizados Delineamentos Compostos Centrais Rotacionais (DCCR) 22 com três repetições nos pontos centrais para avaliação de condições ótimas de produção de hidrolisados de farelos de arroz e milho com concentrações estimáveis de açúcares totais, açúcares redutores e proteínas totais. Os hidrolisados obtidos foram utilizados em ensaios fermentativos para obtenção da lasiodiplodana em meio de cultivo (LAS-M) e aderida à biomassa celular (LASC), bem como produção de células. Para elaboração dos ensaios foram utilizados DCCR 23 e 22 em hidrolisados de farelos de arroz e milho, respectivamente. As variáveis escolhidas para o DCCR 23 foram pH, volume de meio em frasco e adição de sais suplementares, enquanto o DCCR 22 apresentaram como variáveis o estudo da agitação e temperatura. Os delineamentos estudados geraram diversos modelos significativos para a produção de hidrolisados e obtenção de frações de lasiodiplodana. As frações de LAS-M e LAS-C obtidas foram caracterizadas parcialmente quanto a seus conteúdos de carboidratos e proteínas, sendo também analisadas por espectroscopia de infravermelho (FTIR) e análises cristalográficas de Raios-X. Os hidrolisados de farelo de arroz apresentaram concentrações aproximadas para açúcares totais (40 g/L), açúcares redutores (10 g/L) e proteínas (14 g/L) enquanto o hidrolisado de farelo de milho apresentou 170, 70 e 14 g/L dos respectivos componentes. Os hidrolisados foram tratados e utilizados em ensaios fermentativos apresentando concentrações de LAS-M de 7,8 e 5,73 g/L, LAS-C 4,93 e 3,0 g/L e biomassa celular de 10,68 e 4,47 g/L respectivamente para hidrolisados de farelos de arroz e milho, apresentando consumo dos açúcares totais de 94 e 84%. As frações de lasiodiplodana LAS-M apresentaram em sua composição concentrações de açúcares redutores correspondentes a 83,62 e 92,16%, enquanto as frações LAS-C apresentaram 82,19 e 88,42% para os respectivos hidrolisados. As análises de FTIR e Raios-X demonstraram que os biopolímeros obtidos neste trabalho apresentaram estruturas semelhantes aos citados na literatura. Evidenciou-se que os hidrolisados utilizados nas condições estudadas proporcionaram condições adequadas para o fungo L. theobromae sintetizar o exopolissacarídeo lasiodiplodana. / The utilization of agro-industrial wastes for industrial-interest biomolecules production generates add-value products, reducing total production costs and promoting the development of cleaner and more sustainable technologies. Exopolysaccharides, or simply EPS are natural polymers, excreted by some species of bacteria and fungi. They present a great interest from industrial sector, given the versatility of the biomolecule and its use in medical, pharmaceutical and chemical sectors, generating a diversity of products. The present work had as objective to study the exopolysaccharide lasiodiplodan by fermentation of hydrolysates obtained from agricultural by-products from filamentous fungi Lasiodiplodia theobromae. Rotational Central Compound Designs (DCCR) 22 were performed for the evaluation of optimum conditions for the production of hydrolysates from rice and corn brans with estimated concentrations of total sugars, reducing sugars and total proteins. The optimized hydrolysates were used in fermentative assays for obtaining lasiodiplodan from culture medium (LAS-M) and cell biomass (LAS-C), as well as cell production. For the elaboration of the tests, DCCR 23 and 22 were performed using rice bran and corn bran hydrolysates, respectively. The chosen variables for the DCCR 23 were pH, medium volume in flask and addition of supplemental salts, while the DCCR 22 presented agitation and temperature as variables. The studied designs presented several significant models for the hydrolysates production and its lasiodiplodan fractions. Obtained fractions of LAS-M and LAS-C were partially characterized due to carbohydrate and protein contents, as well as X-ray crystallographic analysis and Fourier-Transform Infrared Spectroscopy - FTIR. Rice bran hydrolysates presented estimated concentrations for total sugars (40 g / L), reducing sugars (10 g / L) and proteins (14 g / L) while corn bran hydrolysates showed 170, 70 and 14 g / L respectively. Treated rice and corn bran hydrolysates used for fermentative assays presented respective concentrations for LAS-M (7.8 and 5.73 g/L), LAS-C (4.93 and 3.0 g/L) and cellular biomass (10.68 and 4.47 g/L) and total sugar consumption of 94 and 84%, respectively. The lasiodiplodan fractions LAS-M presented reducing sugars compositions of 83.62 and 92.16%, while LAS-C fractions presented 82.19 and 88.42% for rice and corn bran hydrolysates. FTIR and X-ray anlysis showed that the present obtained biopolymers presented similar structures to those mentioned in the literature. It was evidenced that the hydrolysates used under the studied conditions provided adequate conditions for L. theobromae to synthesize the exopolysaccharide lasiodiplodan.

Thesis (MSc (Hons))--Macquarie University, Division of Environmental & Life Sciences, Dept. of Chemistry & Biomolecular Sciences, 2006. / Bibliography: leaves 153-158. / Wheat is a major crop in Australia with around 25 million tonnes of grain harvested in an average year. Improved wheat grain cultivars and wheat grain milling can result in higher biological yields and flour quality. The introduction covers the general aspects of the wheat grain from bran development and structure through to millings and the importance of flour quality in flour-based products. It also highlights the problem with bran contamination in flour during milling and other factors that may have an effect on flour quality. Proteomics was used to identify proteins in three separate bran tissue fractions: the inner fraction (aleurone), intermediate fraction (nucellar tissue, testa, tube cells and cross cells) and the outer faction (hypodermis and epidermis). The aim of the project was to identify proteins in bran tissue fractions which may potentially be useful in improvements in wheat quality for farmers and consumers and flour yield for millers. The results show that more than 80% of the identified proteins in the outer and intermediate tissue factions are defence-and stress-related proteins (chitinase, xylanase, thaumatin-like protein, wheatwin 1, lipid-transfer protein, oxalatae oxidase (OXO), polyphenol oxidase (PPO), peroxidase (POX)). Almost 60% of the proteins identified in the inner tissue fraction are 7S Globulin storage proteins and around 15% are protein synthesis-and energy-related. Water-soluble proteins were also identified and it was found that endochitinase, OXO, PPO and POX all leach out from the grain durings imbibition. This study has added to the knowledge of bran tissue-specific proteins and has broad implications for improving crop yield and flour quality. / Mode of access: World Wide Web. / xiii, 158 leaves ill

This diploma thesis deals with the use of various types of bran as a by-product in the milling of cereals. Mills create a huge amount of this material per year. The most common way of processing bran is mostly incineration and to a lesser extent it is used as feed for livestock. Depending on the type of cereal, bran contains 10-20% of protein, which disappears from the food chain due to combustion. Within the framework of sustainability and valorisation of waste, which has recently been largely discussed, great emphasis is placed on waste minimization whether in the field of its production or further processing. Due to the relatively high protein content, bran appears to be a suitable starting material to produce protein supplements. Proteins can be extracted from bran based on their different solubility at different pH. In the alkaline method, the proteins are first dissolved in an alkaline pH and then precipitated in an acidic medium. Lyophilization is followed by characterization of the extract in terms of yield, protein content, moisture, amino acid profile and digestibility. The highest yield was obtained with the oat bran isolate (13,5 ± 0,6 g of isolate per 100 g of bran). In terms of protein content, the best protein isolate was also obtained from oat bran (95,2 ± 0,4% protein in the isolate). Another determination was the analysis of the amino acid profile, in which a high content of arginine was found in all analyzed protein isolates from bran. Determination of digestibility showed very good digestibility of all produced protein extracts from bran.

With the advent of industrialization and food processing techniques the sizes of the cereal bran have been drastically reduced. In my thesis, I have tested the effect, if any, of wheat bran and maize bran particle size, in vitro, on the gut microbiota community structure by 16S rRNA sequencing and their function, by Short chain fatty acids (acetate, propionate, butyrate) production. In turn, we also linked the microbiota and SCFA differences to different chemical composition amongst variously sized fractions of wheat and maize bran.

Gastrointestinal microflora has been shown to have a bi-directional relationship with the host immune system. A variety of fermentable carbohydrate polymers largely pass through the small intestine, providing fermentable substrates for gut microflora. Dietary fibre supplementation may provide a strategy for manipulating the intestinal bacterial profile, changing the interaction with the mucosal immune system, thereby modulating the host immune system. We used a BBc rat animal model to evaluate the effects of oat bran and wheat bran dietary fibre on the immune system. Previous collaborative efforts have shown that these dietary fibres can change the intestinal microflora, with wheat bran fibre showing a greater ability to influence colonic microbial community diversity. We have shown that dietary wheat bran fibre led to reduced IL-4 levels in the liver and T lymphocyte numbers in the Mesenteric Lymph Node and may be involved in reduced IgA levels in the cecal contents. In addition, IgA in the cecal contents was decreased while MLN B cell numbers increased in response to dietary wheat bran fibre. It was observed that neither wheat bran or oat bran treatments exerted any pro-inflammatory effects, with oat bran actually improving antioxidant status. These results suggest that both oat and wheat bran fibre treatments induce changes in the intestinal microflora, and that the microflora changes due to wheat fibre are associated with immunomodulatory effects on the host. This type of dietary fibre supplementation could ultimately provide a potential strategy for promoting health through microflora-associated effects on the immune system.

The rice is one of the cereals most consumed in world, consumption carried out mostly in the form of grains whose processing generates by-products such a rice bran, from which is obtained the rice bran oil. Due the presence of phospholipids, gums, waxes, this oil has a darker color and higher viscosity as compared to other vegetable oils. Also contains γ-orizanol, composed absent in other oils, which have been assigned antioxidants and hypocholesterolemics effects; but to become fit for consumed, the rice bran oil needs to be refined. The refining method modifies the oil composition; the chemical refining cause significant losses or changes in composition of rice bran oil; in the physical refining loss of these components is minimized, however the rice bran oil must have a phosphorus content below to 10 mg.kg-1 before to desodorization step, for to perform the physical refining. Thus, the aim of this study was to conduct studies on the degumming in order to make it fit the physical refining; and on the clarification, so that besides fit the physical refining, this is attractive to the consumer. Clarifying activity tests were performed two clarifiers lands: Tonsil ® Supreme 180 FF Tonsil ® and Actisil FF 280 added in different proportions (1.0, 1.5 and 2.0); degumming with water (0.6 and 5%) and phosphoric acid (0.2%), citric (0.5%); and clarification tests using the land and proportions that showed the best clarifying activity. There was the physicochemical characterization of crude, degummed oil and clarified oil with 2% of the earth Tonsil ® Supreme 180 FF and profile of fatty acids, γ-oryzanol content, tocopherols and tocotrienols content. The clarifier earth Tonsil ® Supreme 180 FF was the one with the best clarifying activity in the proportion of 2%, and when added at the rate of 1.5% showed the same activity clarifying that the earth Tonsil ® Actisil 280 FF added at a ratio of 2 0%; which was verified both in the clarifier activity tests, for the clarification test. The degumming with 5% water caused a reduction of the phosphorus content to less than 10 mg.kg-1. Thus, the degumming with 5% water, followed by clarification test using citric acid (50%) in the proportion of 0.5% to 2.0% addition of the clarifier earth Tonsil ® Supreme 180 FF, to provide a suitable oil physical refining, and the physical and chemical characteristics similar to crude oil and within the requirements specified by law. / O arroz é um dos cereais mais consumidos no mundo, principalmente na forma de grãos. O beneficiamento gera subprodutos, como o farelo de arroz, de onde se obtém o óleo bruto de arroz. Devido a presença de fosfolipídios, gomas, ceras este óleo apresenta uma coloração escura e maior viscosidade, quando comparado a outros óleos vegetais. Além disso, contem 1-2% de γ-orizanol, composto ausente em outros óleos, ao qual têm-se atribuído efeitos antioxidantes e hipocolesterolêmicos. Para tornar-se apto ao consumo, o óleo bruto necessita ser refinado. O método de refino modifica a composição do óleo; no refino químico, há perdas significativas de componentes durante o processo; no refino físico a perda desses componentes é minimizada, porém é necessário que o óleo chegue na etapa de desodorização com um teor de fósforo inferior a 10 mg.kg-1, para que seja possível realizar o refino físico. Portanto,o objetivo deste trabalho foi realizar estudos sobre a degomagem, a fim de torná-lo apto ao refino físico, e sobre a clarificação, para que este seja atraente para o consumidor. Foram realizados testes de atividade clarificante utilizando duas terras clarificantes: Tonsil ® Supreme 180 FF e Tonsil ® Actisil 280 FF adicionadas em diferentes proporções (1,0; 1,5; e 2,0%); de degomagem com água (0,6 e 5%) e ácidos fósforico (0,2%) e cítrico (0,5%); e testes de clarificação utilizando as terras e proporções que apresentaram a melhor atividade clarificante. Realizou-se a caracterização físico-química do óleo bruto, óleo degomado e óleo clarificado com 2% da terra Tonsil ® Supreme 180 FF, bem como perfil de ácidos graxos, teor de γ-orizanol, teor de tocoferóis e tocotrienóis. A terra clarificante Tonsil ® Supreme 180 FF foi a que apresentou a melhor atividade clarificante na proporção de 2%, e quando adicionada na proporção de 1,5% apresentou a mesma atividade clarificante que a terra Tonsil ® Actisil 280 FF adicionada na proporção de 2,0%; o que foi verificado tanto nos testes de atividade clarificante, quanto no teste de clarificação. A degomagem com 5% de água promoveu a redução do conteúdo de fósforo para valores menores que 10 mg.kg-1. Assim, a degomagem com 5% de água, seguida da clarificação utilizando ácido cítrico (50%) na proporção de 0,5% e adição de 2,0 % da terra clarificante Tonsil ® Supreme 180 FF, forneceram um óleo apto ao refino físico e com as características físico-químicas semelhantes ao óleo bruto e dentro dos requisitos especificados pela legislação.