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Characterisation of carbohydrate-graphene interactions using molecular simulationAlqus, Rasha January 2017 (has links)
Molecular dynamics (MD) simulations have been applied to study the interactions between different carbohydrates and graphene. In cellulose-graphene complexes, the behaviour of hydrophobic and hydrophilic faces of cellulose chains on a single layer of graphene in aqueous solvent have been investigated. The hydrophobic cellulose face forms a stable complex with graphene and the interface remains solvent-excluded over the course of the simulation. Cellulose chains contacting graphene preserved their intra- and inter-chain hydrogen bonds and maintaining a tg orientation of its hydroxymethyl groups that is similar to that found for the sugar in a vacuum environment. The solvent-exposed cellulose chains of the complex showed more flexibility. By contrast, over the course of the 300 ns MD simulation, the hydrophilic face of cellulose exhibits progressive rearrangement as it seeks to present its hydrophobic face, with disrupted intra- and inter-chain hydrogen bonding; sequential residue twisting to form CH-pie interactions with graphene; and permeation then expulsion of interstitial water. This transition is also accompanied by a more favourable cellulose-graphene adhesion energy as predicted at the PM6-DH2 level of theory. The stability of the cellulose-graphene hydrophobic interface in water reflects the amphiphilicity of cellulose and provides insight into favoured interactions within graphene-cellulose nanocomposites. Furthermore, water is observed to permeate cellulose during rearrangement of the hydrophilic face which may have application in addressing cellulose recalcitrance. In addition, the interaction of six different types of monosaccharide (β/alpha-D-Glc, β/alpha-D-Gal and β/alpha-D-Man) on the surface of graphene has been studied, using PM6-DH2 and PMF calculations in both gas phase and explicit water. The parameters studied included anomer, epimer, saccharide face, hydroxymethyl orientation and solvation. Binding of graphene to monosaccharide is more preferred in vacuum than in water; solvation of the complexes leads to reduction in the number of pie-interactions formed with graphene. In almost all studied complexes, β-anomers bind stronger to graphene compared to alpha-anomers in gas phase and water. Each monosaccharide has two unique faces parallel to the plane of the pyranose ring and these surfaces determine the interaction formed with graphene and water. Binding of graphene with different faces significantly influences the value of the computed interaction and binding free energy. We also find that the interactions between graphene and saccharide are mainly controlled by the number of CH-pie and OH-pie interactions formed between saccharides and graphene. The interaction energy and binding energy values suggest that the a-face of β-D-Glc is the most preferred to bind on graphene in vacuum while the b-face of β-D-Glc is preferred in the aqueous phase.
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Análise energética de sistemas de produção de etanol de mandica,cana-de-açúcar e milhoSalla, Diones Assis [UNESP] 20 May 2008 (has links) (PDF)
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salla_da_dr_botfca.pdf: 822291 bytes, checksum: 3cbc13b6d4fde04594959ca6c26eca33 (MD5) / A hipótese subjacente à pesquisa é a de que a cultura da mandioca consome menos energia no processo de obtenção de etanol do que as demais fontes amiláceas em análise. O objetivo principal deste trabalho é a análise energética de sistemas de produção de etanol utilizando como fonte de carboidratos a mandioca, a cana-de-açúcar e o milho. Como antecedentes da pesquisa procedeu-se a determinação dos balanços de massa de etanol, de CO2, de água e de resíduos gerados em cada estágio do processamento das raízes de mandioca. Os experimentos para essa etapa foram conduzidos no Laboratório de Processamento e Análise do Centro de Raízes e Amidos Tropicais - CERAT/UNESP e os valores obtidos foram produzidos em escala reduzida e apresentados para 1.000 kg de matéria-prima. Estudos complementares também foram realizados para examinar as energias exportadas do agroecossistema, referentes aos macronutrientes que estão contidos nas raízes da mandioca, nos colmos da cana-de-açúcar e nos grãos de milho. Os procedimentos metodológicos adotados nesse segmento foram embasados na revisão da literatura sobre fertilização da mandioca, do milho e da cana-deaçúcar e na conversão da biomassa em etanol. As pesquisas de campo foram realizadas na região do Vale do Médio Paranapanema, estado de São Paulo, para a obtenção de informações sobre o consumo e o requerimento energético das operações agronômicas de cultivo e de processamento industrial das matérias-primas em análise. O dispêndio de energia referente à parte agrícola é apresentado pelo consumo energético da etapa de produção de um hectare de cana-de-açúcar, de mandioca e de milho, nas operações de preparo da área, plantio, insumos, condução da lavoura, colheita, transporte à indústria e drenagem energética. O dispêndio de energia referente à parte industrial é apresentado pelo consumo energético... / The focus of this research is that the cassava crops consumes less energy to obtain ethanol than the sugar cane and the corn crops. The main objective of this work is the analysis of the energetic ethanol production systems using as a source of carbohydrates, cassava, sugar cane and maize crops. As background to the search proceeded a determination of the balance sheets of ethanol mass, CO2, water and waste generated at each stage of processing of cassava roots. The experiments were conducted in the Processing and Analysis Laboratory of the Centre for Tropical Root and starches - CERAT / UNESP and figures were produced in small scale and presented to 1,000 kg of raw material. Further studies were also performed to examine the energy exported from the agroecosystem, on macronutrients that are contained in the roots of the cassava, the stem of sugar cane and corn seed. The methodological procedures adopted in that segment were based in the review of literature on fertilization of cassava, corn and sugar cane and the conversion of biomass into ethanol. The searches were carried from the field in the Paranapanema River Valley, state of Sao Paulo and seek information on energy consumption and application of agricultural operations of cultivation and industrial processing of raw materials for analysis. The expenditure of energy concerning the agricultural part is made by the energy consumption of stage production of one hectare of sugar cane, cassava and corn, tillage and planting procedure, inputs, driving the crop, harvest, transport industry and energy draining. The expenditure of energy referring to the part is made by the industry energy consumption of stage processing of one tonne of sugar cane, cassava and corn, in the operations of disintegration / milling, hydrolysis / sacarificação / treatment of the broth, fermentation, distillation and maintenance of equipment...(Complete abstract, click electronic access below)
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Efeitos da suplementação de carboidratos na prevenção do estado de overtraining em rato wistar: aspectos bioquímicos, hormonais e molecularesOliveira, Caio Victor Coutinho de 25 July 2013 (has links)
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Previous issue date: 2013-07-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The ergogenic effects of carbohydrate supplementation in the sporting context are well accepted and documented in the literature. These effects have been demonstrated in various modalities and conditions of exercise, being able to improve the biochemical, hormonal, inflammatory and oxidative stress-related to physical activity. However, it has not yet been elucidated whether this ergogenic potential can be replicated under conditions of chronic and strenuous exercise, as in the case of overtraining (OT). Thus, this study aimed to verify whether carbohydrate supplementation is able to prevent and/or minimize the deleterious effects of an exercise protocol to induce OT in adult male Wistar rats. The animals (n = 32) were randomly divided into control group (C) (n = 9), exercise without supplementation (EX) (n = 10) and exercise with carbohydrate supplementation (EX-CHO) (n = 13) and underwent 11 weeks of treadmill training running, being the last 3 weeks aimed to induce the state of OT. Performance tests (Pr) were performed before the 1st week (Pr1) and at the end of the 8th (Pr2) and 11th (Pr3). Thirty-six hours after the last test, the animals were sacrificed. Levels of testosterone, cortisol, Malondialdehyde (MDA) and Creatine Kinase (CK) were measured. The activity of PI3-K, Akt-1, mTOR and GSK-3 were measured in the gastrocnemius. Weight and food consumption were monitored weekly. The training protocol was effective in causing decrement of performance when comparing Pr3 to Pr2 (decrease of 36% in EX, p> 0.05), but this reduction was not significant in the group who ingested carbohydrates. These animals of EX group showed a reduction in food intake in week 11 compared to C (17.07±0.2 g/day vs. 26.31±3.6 g/day, respectively, p <0.001), but EX-CHO kept the same intake (18.62±5.4 g/day in EX-CHO vs. 26.31±3.6 g/day in C, p> 0.05). Additionally, EX-CHO finished the protocol with corrected gastrocnemius muscle weight greater than C (5.39±0.48 g vs. 4.89±0.27 g, respectively, p=0.02), the same has not occurred in EX. The training protocol promoted decrease in testosterone (p=0.001) and elevation of MDA (p=0.009) in both exercise groups compared to C, without influence of supplemented carbohydrates in these variables (p>0.05). Meanwhile, CK and cortisol levels did not increase in both exercise groups compared to C. Considering the molecular assays, the activity of Akt-1 was higher only in EX-CHO compared to C (p=0.013), whereas mTOR showed no differences between the groups (p>0.05). We conclude that carbohydrate supplementation promotes slight attenuation in performance decrement, inhibition of anorexia and increase muscle mass in animals subjected to OT protocol. This muscle gain was accompanied by greater activity of anabolic and anti-catabolic molecular signaling Akt-1. On the other hand, it did not prevent changes in markers of OT oxidative stress, hormonal profile and muscle damage. / Os efeitos ergonênicos da suplementação de carboidratos no contexto esportivo são bem aceitos e evidenciados na literatura. Estes efeitos foram demonstrados em diversas modalidades e condições de exercício, sendo capazes de melhorar aspectos bioquímicos, hormonais, inflamatórios e de estresse oxidativo relacionados à prática de atividade física. No entanto, ainda não foi elucidado se esse potencial ergogênico pode ser replicado em condições de exercícios extenuantes e crônicos, como no caso do overtraining (OT). Assim, este estudo objetivou verificar se a suplementação de carboidratos é capaz de prevenir e/ou minimizar os efeitos deletérios de um protocolo de exercícios destinado a induzir OT em ratos Wistar machos adultos. Os animais (n=32) foram divididos aleatoriamente em grupo controle (C) (n=9), exercício sem suplementação (EX) (n=10) e exercício com suplementação de carboidratos (EX-CHO) (n=13) e submetidos a 11 semanas de treinamento de corrida em esteira, sendo as 3 últimas semanas destinadas a induzir o estado de OT. Testes de performance (Pr) foram realizados antes da 1ª semana (Pr1) e ao término da 8ª (Pr2) e 11ª (Pr3). Após 36h do último teste, os animais foram sacrificados. Níveis de testosterona, cortisol, Malondialdeído (MDA) e Creatina Kinase (CK) foram dosados. A atividade da PI3-K, Akt-1, mTOR e GSK-3 foram mensuradas no gastrocnêmio. Peso ponderal e consumo alimentar foram monitorados semanalmente. O protocolo de treinamento foi eficaz em promover redução da capacidade de desempenho no momento Pr3 em relação ao Pr2 (decréscimo de 36% em EX, p<0,05), mas esta redução só foi significativa no grupo que não ingeriu carboidratos. Estes animais do grupo EX apresentaram redução do consumo alimentar na 11ª semana em relação a C (17,07±0,2g/dia vs 26,31±3,6g/dia, respectivamente, p<0,001), sendo que EX-CHO manteve a mesma ingestão (de 18,62±5,4g/dia de EX-CHO vs 26,31±3,6g/dia de C, p>0,05). Adicionalmente, EX-CHO terminou o protocolo com peso corrigido do músculo gastrocnêmio maior que C (5,39±0,48g vs 4,89± 0,27g respectivamente, p=0,02), sem que o mesmo tenha ocorrido em EX. O protocolo de treinamento promoveu diminuição da testosterona (p=0,001) e elevação de MDA (p=0,009) nos dois grupos exercício em relação a C, sem que a suplementação de carboidratos tenha influenciado estas variáveis (p>0,05). Enquanto isso, níveis de CK e cortisol não se elevaram nos dois grupos exercício em relação ao grupo C. Considerando os ensaios moleculares, a atividade da Akt-1 apresentou-se maior apenas em EX-CHO comparado a C (p=0,013), enquanto que a da mTOR não apresentou diferenças entre os grupos (p>0,05). Conclui-se que a suplementação de carboidratos promove discreta atenuação na queda da performance, inibição da anorexia e aumento da massa muscular em animais submetidos a protocolo de OT. Este ganho muscular foi acompanhado pela maior atividade do sinalizador molecular anabólico e anti-catabólico Akt-1. Por outro lado, não preveniu alterações nos marcadores de OT estresse oxidativo, perfil hormonal e dano muscular.
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Effect of processing on the starch and glycemic properties of Digitaria spp.Jordaan, Michelle Bernitta January 2013 (has links)
Thesis (MTech (Food Technology))--Cape Peninsula University of Technology, 2013. / Acha starch was isolated and purified from clean and milled acha grain.
Functional, thermal and physicochemical properties of acha starch were
analysed using appropriate methods. Wheat starch was used as the
reference standard. Acha bread from acha grain was baked and the
consumer sensory acceptability was evaluated and white wheat bread was
used as the reference standard. The effect of baking, boiling, steaming and
microwaving on the starch and glycemic properties of the acha starch was
evaluated. With regard to thermal properties, gelatinisation temperature of
acha and iburu starches typifies that of waxy starch. Acha starch has similar
retrogradation temperature profiles as that of wheat. There were however
significant differences in some of the functional properties (pasting and
turbidity) and physico-chemical properties (in vitro starch digestibility), but no
significant difference in the texture profile analysis (TPA) and water binding
capacity (WBC). WBC of both acha varieties was higher than that for wheat
starch. Due to its high break down viscosity, white acha starch can be
included in foods that are subjected to high temperature processing. This
indicates that both acha starch varieties can be used for hot and cold desserts
as well as for soft jelly like sweets and confectionery toppings. A prescreening
exercise using carboxymethyl cellulose (CMC), Xanthan gum, yeast
and acha starch as the variables was successful in concluding a recipe which
rendered acha bread with the optimum specific loaf volume for both white and
black acha bread. The optimum recipe consisted 8.0 % acha starch, 2.0 %
xanthan gum, 2.0 % CMC and 1.0 % yeast. The majority of the consumer
panellists found the crust colour, taste and aroma to be moderately desirable.
This implies that most consumers find acha bread to have the potential to be
marketed as wheat free bread. The different processing methods baking,
boiling, microwaving and steaming, affected the black and white acha starch
hydrolysis. The amount of starch hydrolysed for the different processing
methods was in the following order: baking > boiling > microwaving >
steaming. It can thus be concluded that different processing methods affects
the micro structure and physical properties of the acha and wheat samples which thus influence their starch hydrolysis. The equilibrium percentage of
starch hydrolysed after 180 min incubation was affected differently for the
various starches, black acha, white acha and wheat starch by the different
processing methods and times. In the case of baking black acha starch and
wheat bread were affected similarly. However, this was not the case for
microwaving, steaming and boiling, where both acha starch varieties and
wheat starch were affected in the same way. The rate of starch hydrolysis for
both acha varieties and wheat grain for the different processing methods,
steaming, boiling, microwaving and baking was affected to the same degree
respectively.
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Utilização de carboidratos digestíveis em dietas para pacu, Piaractus mesopotamicus (Holmberg, 1887) /Muñoz Ramírez, Adriana Patrícia. January 2005 (has links)
Orientador: Dalton José Carneiro / Banca: Gilberto Moraes / Banca: Nilva Kazue Sakomura / Banca: Debora Machado Fracalossi / Banca: Elisabeth Criscuolo Urbinati / Resumo: O valor nutricional dos vários tipos de carboidratos parece estar relacionado com sua complexidade. A utilização quantitativa e qualitativa de sete diferentes fontes de carboidratos (amido de milho regular, amido de milho ceroso, amido de milho regular pré-gelatinizado e modificado, fécula de mandioca modificada e pré-gelatinizada, dextrina, maltodextrina e glicose-dextrose) em dietas para o pacu foi estudada, para verificar o efeito sobre o desempenho, eficiência nutricional, metabolismo energético e atividade amilásica no trato gastrintestinal. Num ensaio de digestibilidade foram estudadas sete fontes de carboidratos em dois níveis de inclusão (20 e 40%). Utilizaram-se 14 dietas semipurificadas isoprotéicas contendo farinha de peixe, carboximetil celulose, celulose microfina, óleo de soja e suplemento mineral e vitamínico. Para a coleta de fezes utilizaram-se coletores seguindo o sistema Guelph modificado. Foram determinados os coeficientes de digestibilidade aparente da matéria seca, dos nutrientes (proteína bruta, extrato etéreo, extrativo não nitrogenado) e da energia das dietas. No segundo ensaio foi avaliado o crescimento de juvenis de pacu, durante 60 dias em condições de laboratório, utilizando-se 126 peixes com peso médio de 49,1l8,3 g. Nos peixes alimentados com sete dietas semipurificadas isoprotéicas peletizadas, contendo 40% de cada uma das fontes de carboidratos foram avaliados os parâmetros de desempenho, composição corporal e eficiência de utilização de nutrientes e energia. Adicionalmente, três peixes de cada parcela do ensaio de crescimento foram sacrificados e amostras de sangue, fígado, músculo e trato gastrointestinal foram coletadas e processadas. Foram avaliados os índices hepatosomático e viscerosomático e o metabolismo energético por meio da determinação dos intermediários metabólicos: ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The nutritional value of many forms of carbohydrates seems to be related to its complexity. The quantitative and qualitative utilization of seven different carbohydrates sources (regular corn starch, waxy corn starch, pregelatinized and modified regular corn starch, modified and pregelatinized cassava starch, dextrin, malt dextrin, and glucose-dextrose) on diets for pacu were studied, aiming to achieve maximum performance efficiency and reduce costs of protein use. Fourteen semipurified isoproteic pelletized diets were used in a nutrient and energy digestibility trial of the carbohydrate sources, with a basic nutrient composition (fish meal, carboxymethyl cellulose, fine cellulose, soybean oil, mineral, and vitamin supplement) and two levels (20 and 40%) of included carbohydrates sources. Feces of 480 juveniles' pacu (69.6l17.9 g) were collected using collectors according Guelph modified system. Dry matter, nutrients (crude protein, ether extract, and nitrogen free extract), and energy apparent digestibility coefficients of the diets were determined. The second trial, conducted for 60 days in the laboratory, evaluated the growth of juveniles pacu of 126 fishe with average weight of 49.1l8.3g. The parameters of productive performance, body composition, nutrients, and crude energy utilization efficiency of fish fed semipurified isoproteic pelletized diets, each containing 40% of the studied carbohydrates sources, were evaluated. On the last trial, three fishes of each plot of the growth trial were sacrificed and samples of blood, liver, muscle, and gastrointestinal tract were collected and processed. The hepatosomatic and visceralsomatic indexes and energetic metabolism were evaluated by determining metabolic mediators: plasmatic glucose, cholesterol and total proteins, hepatic and muscular glycogen, plasmatic triglyceride and iv free amino acids, hepatic and muscular free fatty acids... (Complete abstract, click electronic address below). / Doutor
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Novos tensoativos derivados da 2-D-glucosamina / New surfactants based on 2-D-glucosamineReinaldo Camino Bazito 13 December 2001 (has links)
Foram sintetizadas duas novas séries de tensoativos de açúcar derivados da 2-D-glucosamina: os metil 2-acilamido-2-deóxi-6-O-sulfonato-D-glucopiranosídeos de sódio (aniônicos) e os cloretos de metil 2-acilamido-2,6-dideóxi-6-trimetilamônio-D-glucopiranosídeos (catiônicos). Os tensoativos aniônicos foram obtidos pela acilação da 2-D-glucosamina com cloretos de acila (com 8, 12 e 16 carbonos), seguida pela metilação desses derivados com metanol em meio ácido, e posterior sulfatação dos metil glucosídeos com complexo trióxido de enxofre-piridina. Os tensoativos catiônicos foram obtidos pela tosilação dos metil glucosídeos, seguida pela quaternização com trimetilamina e troca do contra-íon tosilato por cloreto com resina de troca-iônica. Esses tensoativos apresentaram c.m.c. similares a de outros tensoativos iônicos de cadeia hidrofóbica de igual comprimento, mas energias livres de transferência do grupo polar para a micela muito mais favoráveis. Esse fato foi atribuído à formação de ligações de hidrogênio entre os grupos polares do tensoativo na micela, e à hidrofobicidade do açúcar. As micelas formadas apresentaram números de agregação maiores que os obtidos para outros tensoativos, provavelmente devido às interações atrativas entre os grupos polares. / Two new sugar-based surfactant series were synthesized from 2-D-glucosamine: sodium methyl 2-acylamido-2-deoxi-6-O-sulfonate-D-glucopyranosides (anionic) and methyl 2-acylamido-2,6-dideoxi-6-trimethylamonium-D-glucopyranoside chlorides (cationic). The anionic surfactants were obtained by the acylation of 2-D-glucosamine with acyl chlorides (with 8, 12 and 16 carbons), followed by the methylation of these derivatives with methanol in acidic media, and the sulfation of the methyl glucosides with sulfur trioxide-pyridine complex. The cationic surfactants were obtained by the tosylation of methyl glucosides followed by the quaternization with trimethylamine and exchange of the tosylate contra-ion with chloride ions on an ion exchange resin. These surfactants showed c.m.c. similar to other ionic surfactants with equal hydrophobic chain lengths, but more favorable free energies of transfer of the polar head to the micelle. This fact is attributed to hydrogen bonding between the head groups of the surfactant in the micelle, and the hydrophobicity of the sugar moiety. The micelles of these surfactants showed aggregation numbers larger than those obtained for other surfactants, problably because of head-group attractive interactions.
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Glicose de milho em dietas para frangos de corte de 1 a 7 dias de idadeLIMA, Tayara Soares de 20 July 2012 (has links)
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Previous issue date: 2012-07-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The objective of this study was to determine the values of apparent metabolizable energy (AME) and apparent corrected by nitrogen balance (AME) and the coefficient of apparent metabolizable crude energy (CMAEB) of the corn glucose for broilers from 1 to 7 days of age using four levels of substitution of the reference diet by the ingredient tested. Was conducted a metabolism trial, using 360 male broiler chicks of the lineage Cobb500 1-7 days old, allocated in metabolic cages in a completely randomized design with five treatments and six replicates of 12 birds. The treatments consisted of a basal diet and four test diets with different levels of basal diet by replacing corn glucose (5, 10, 15 and 20%). Glucose corn used was produced by Corn Products Brazil and in its composition contained 81.39% dry matter and 3824 kcal / kg gross energy.Was used method of total excreta collection. The data were subjected to analysis of variance and regression at 5% probability. The corn glucose showed the highest energy when it was used 20% of the diet by replacing glucose, with 3550 kcal / kg DM, 3648 kcal / kg DM and 95.38% for AME, AME n and CMAEB respectively. Recommended the level of substitution of 20% glucose for the determination of their energy values for broilers 1 to 7 days. / O objetivo desta pesquisa foi determinar os valores de energia metabolizável aparente (EMA) e aparente corrigida pelo balanço de nitrogênio (EMAn) assim como o coeficiente de metabolizabilidade aparente da energia bruta (CMAEB) da glicose de milho para frangos de corte de 1 a 7 dias de idade utilizando 4 níveis de substituição da ração referência pelo ingrediente teste (glicose de milho). Para tanto, foi realizado um ensaio de metabolismo, utilizando 360 pintos de corte machos da linhagem Cobb500 de 1 a 7 dias de idade, alojados em gaiolas metabólicas em delineamento inteiramente casualizado com cinco tratamentos e seis repetições de 12 aves. Os tratamentos consistiram em uma ração referência e quatro rações testes com diferentes níveis de substituição da ração referência pela glicose de milho (5, 10, 15 e 20%). A glicose de milho utilizada foi produzida pela Corn Products do Brasil e continha em sua composição 81,39% de matéria seca e 3824 kcal/kg de energia bruta. Foi utilizado o método de coleta total de excretas. Os dados obtidos foram submetidos à análise de variância e de regressão a 5% de probabilidade. A glicose de milho apresentou os maiores valores energéticos quando foi utilizado 20% de substituição da ração pela de glicose, sendo 3550 kcal/kg MS, 3648 kcal/kg MS e 95,38% para EMA, EMAn e CMAEB, respectivamente. Recomenda-se o nível de 20% de substituição da glicose para determinação dos seus valores energéticos para frangos de corte de 1 a 7 dias de idade.
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Efeito da suplementação de carboidrato associado à proteína no desempenho de corredores / Effect of carbohydrate supplementation associated with protein on performance of runnersGabriel Silveira Franco 07 October 2015 (has links)
O pedestrianismo vem se tornando cada vez mais expressivo na atualidade, principalmente por assegurar condições de bem-estar físico, psicológico e social ao praticante. Partindo-se do pressuposto que deficiências nutricionais prejudicam o desempenho durante a corrida, corredores de longa duração vêm usufruindo da suplementação esportiva com o intuito de otimizar o rendimento. Todavia, faltam evidências científicas quanto aos recursos ergogênicos proporcionados pelos diversos suplementos alimentares comercializados. Sendo assim, o objetivo desta pesquisa foi comparar o desempenho de corredores de longa duração em um protocolo de exercício físico em esteira composto por três situações diferentes de suplementação: placebo, carboidrato e carboidrato associado à proteína hidrolisada. A amostra foi composta por 14 atletas do sexo masculino e o estudo apresentou design cross over com caráter duplo-cego. Inicialmente, foi realizada avaliação cardiorrespiratória e nutricional, sendo que esta última foi composta por antropometria (peso e estatura) e composição corporal (dobras cutâneas). Os indivíduos foram submetidos a um exercício físico em esteira constituído por 60 minutos com velocidade e inclinação correspondente ao Limiar Anaeróbio e posteriormente perduraram a atividade até a exaustão com intensidade 10% acima desta variável. Foi analisado o consumo alimentar por meio drae feinrgeenstetã ao energética diária e da quantidade de macronutrientes ingeridos nas 24 e 2 horas antecedentes aos exercícios. Mensurou-se a glicemia, o lactato sanguíneo, a percepção subjetiva de esforço e a frequência cardíaca durante os três protocolos de suplementação. A glicemia inicial e 5 minutos após a exaustão foi menor para o grupo placebo quando comparada aos outros dois grupos. Houve um aumento na glicemia e no lactato nos três grupos ao comparar momentos antes e durante o exercício (60 minutos) com momentos após o término da atividade (exaustão e 5 minutos após este estágio). Observou-se aumento na percepção subjetiva de esforço e na frequência cardíaca nos três grupos concomitantemente ao aumento da duração e/ou intensidade do exercício. Ao analisar o consumo alimentar e o tempo de exaustão dos atletas não foram constatadas diferenças estatísticas entre os três suplementos utilizados. Diante disto, analisando agudamente, não há justificativa para adicionar proteína ao suplemento de carboidrato durante a realização de exercícios de endurance com características semelhantes ao de nosso estudo. / The pedestrianism is becoming increasingly significant nowadays, mainly for ensuring conditions of physical, psychological and social well-being practitioner. Starting from the assumption that nutritional deficiencies impair performance during the race, long runners come enjoying the sports supplementation in order to optimize performance. However, they lack scientific evidence about the ergogenic resources provided by the various food supplements marketed. Thus, the aim of this study was to compare the performance of long runners in a physical exercise protocol on a treadmill consists of three different situations supplementation: placebo, carbohydrate and carbohydrate associated with hydrolyzed protein. The sample consisted of 14 male athletes and this study was double-blind with crossover design. Initially, individual performed cardiopulmonary and nutritional evaluation and the latter consisted of anthropometry (weight and height) and body composition (skinfold). The subjects underwent a physical exercise on a treadmill consists of 60 minutes with speed and inclination corresponding to Anaerobic Threshold and then endured the activity to exhaustion intensity with respect to 10% higher this variable. Food consumption through daily energy intake and the amount of macronutrients ingested in 24 and 02 hours before the exercise was analyzed. blood glucose, blood lactate, the perceived exertion and heart rat eI td wurainsg m theea stuhrreede supplementary protocols. The initial blood glucose and 5 minutes after the exhaustion was lower in the placebo group compared to the other two groups. There was an increase in blood glucose and lactate in the three groups when comparing time before and during exercise (60 minutes) with moments after the end of the activity (exhaustion and 5 minutes after this stage). There was an increase in perceived exertion and heart rate in the three groups concomitantly with increasing duration and/or intensity of exercise. By analyzing the food consumption and time to exhaustion of athletes were not found statistical differences between the three supplements used. Given this, there would be no acute justification for adding protein to carbohydrate supplement when performing endurance exercise with characteristics similar to our study.
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Estudo da hidrólise de carboidratos em meio neutro, utilizando uma mistura de ésteres derivados do óleo de mamona / Study of carbohydrates hydrolysis in neutral medium, using a mixture of esters derided from castor oilJuliana Ribeiro Gabriel 22 October 2009 (has links)
A sacarose é o dissacarídeo mais abundante na natureza, encontrado na forma pura. É formada pela ligação da hidroxila do C1 da α-D-glicose com a hidroxila do C2 da β-D-frutose. Sua hidrólise em meio ácido produz 1 mol de glicose e 1 mol de frutose. O mecanismo envolve a presença de um intermediário, que corresponde à etapa lenta da reação de hidrólise. A sacarose foi hidrolisada em meio neutro, utilizando-se uma mistura de ésteres derivados do óleo de mamona, produzida pelo Laboratório de Química Analítica e Tecnologia de Polímeros (GQATP). O mecanismo da hidrólise em meio neutro, se assemelhou com o mecanismo da hidrólise ácida, apresentando também um complexo aquoso, que determinou a velocidade da reação. Uma solução de sacarose 0,1 mol L-1 foi hidrolisada pela mistura de ésteres dando como produtos finais 0,019 mol L-1 de glicose e 0,017 mol L-1 de frutose. Verificou-se que a produção dos monossacarídeos foi possível depois do oitavo dia de reação. Soluções de sacarose com diferentes concentrações de cloreto de sódio (NaCl) também foram hidrolisadas, uma vez que este estudo foi importante para se observar a influência da força iônica na velocidade da reação de decomposição. Uma solução de sacarose 10 -3 mol L-1, que apresenta força iônica igual a 5,0 x 10 -4 mol L-1, ao reagir com a mistura de ésteres, apresentou uma quantidade igual a 9,99 x 10 -4 mol L-1 de açúcares redutores formados, ou seja, 99% de sacarose foi hidrolisada. Mesmo com uma maior velocidade de reação, ainda houve a formação de um complexo aquoso, pois a reação não foi instantânea. Com valores de forças iônicas maiores, houve uma menor produção de glicose e frutose. Já a celulose é um polissacarídeo composto de moléculas de D-glicose, unidas por ligações glicosídicas β-1,4, sendo o principal material estrutural das plantas. O mecanismo da hidrólise da celulose em meio ácido assemelha-se à hidrólise ácida da sacarose, em que, antes de se chegar aos produtos finais da reação, ocorre a formação de um complexo intermediário. A celulose também foi hidrolisada em meio neutro utilizando-se a mistura de ésteres, e foi possível observar a presença de um complexo aquoso, antes de se chegar aos produtos finais de sua decomposição, ou seja, celobiose e/ou glicose. Partindo-se de uma solução 0,2 g L-1 de celulose, chegou-se a formação de 0,14 g L-1 de açúcares redutores. Isso corresponde a 70% de celulose hidrolisada. Com relação ao estudo cinético de decomposição da celulose, comprova-se que se trata de uma reação de segunda ordem, e que o tempo de meia-vida da celulose na mistura de ésteres é de 15,29 dias. Como não se sabe a proporção da mistura de ésteres que reage com a celulose, tanto o tempo de meia-vida quanto a lei de velocidade, foram calculadas somente com relação à celulose. / Sucrose is the most abundant disaccharide in nature, found in pure form. It is formed by binding the C1 hydroxyl of the α-D-glucose with the hydroxyl of the C2 of β-D-fructose. Hydrolysis in acid produces 1 mol of glucose and 1 mol of fructose. The mechanism involves the presence of an intermediary, which is the slow step of the hydrolysis reaction. Sucrose was hydrolyzed in neutral, using a mixture of esters derived from castor oil, produced by the Laboratory of Analytical Chemistry and Technology of Polymers (GQATP). The mechanism of hydrolysis in neutral medium, resembled the mechanism of acid hydrolysis, and also provides an aqueous complex, which determined the rate of reaction. A solution of sucrose 0,1 mol L-1 was hydrolyzed by the mixture of esters giving as final products 0,019 mol L-1 glucose and 0,017 mol L-1 of fructose. It was found that the production of monosaccharides was possible after the eighth day of reaction. Sucrose solutions with different concentrations of sodium chloride (NaCl) were also hydrolysed, since this study was important to observe the influence of ionic strength on reaction rate of decomposition. A sucrose solution 10-3 mol L-1, which represents the ionic strength equal to 5,0 x 10-4 mol L-1 and reacted with a mixture of esters, showed a count of 9,99 x 10-4 mol L-1 of reducing sugars formed, ie, 99% sucrose was hydrolyzed. Even with a higher speed of reaction, there was still the formation of an aqueous complex, because the reaction was not instantaneous. With values higher ionic strengths, there was a lower production of glucose and fructose. Since cellulose is a polysaccharide composed of molecules of D-glucose, linked by glycosidic β-1,4, and the main structural material of plants. The mechanism of hydrolysis of cellulose in an acid similar to the acid hydrolysis of sucrose, in which, before reaching the final products of the reaction causes the formation of an intermediate complex. Cellulose was also hydrolyzed in neutral solution using a mixture of esters, and we observed the presence of an aqueous complex, before we get to the final products of decomposition, ie, cellobiose and/or glucose. Starting from a solution of 0,2 g L-1 of cellulose, it was the formation of 0,14 g L-1 of sugars. This corresponds to 70% of hydrolyzed cellulose. Regarding the kinetics of decomposition of cellulose, we find that it is a second-order reaction, and that the half-life of the mixture of cellulose esters is 15,29 days. As we do not know the proportion of mixed esters which reacts with the cellulose, both the half-life as the rate law, were calculated only with respect to cellulose.
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Identification and characterization of microorganisms associated with marine macroalgae Splachnidium rugosumAlbakosh, Mouna Abdalhamed January 2014 (has links)
>Magister Scientiae - MSc / Marine macroalgae are known to carry diverse bacterial communities which interact with their hosts in both harmful and beneficial ways. Algae hosts provide the bacteria with a rich source of carbon in the form of carbohydrate polysaccharides such as fucoidan, agar and alginate, which the bacteria enzymatically degrade. Splachnidium rugosum is a brown alga (Phylum: Phaeophyta) that grows exclusively in the Southern Hemisphere along the temperate shores of South Africa, New Zealand and Australia. While several studies have investigated S. rugosum distribution and fucoidan production, the microbiome of S. rugosum remains largely uncharacterized. Thus, the major objective of the present study was to isolate, identify and characterize epiphytic bacterial communities associated with S. rugosum. Algae were sourced from Rooi Els (Western Cape, South Africa) during winter 2012. Culture based methods relied on a range of selective marine media including marine agar, nutrient sea water agar, nutrient agar and thiosulfate-citrate-bile-salts-sucrose agar to determine the composition and uniqueness of bacterial communities associated with S. rugosum. Epiphytic isolates were identified to species level by 16S rRNA gene sequence analysis and encompassed 39 Gram-negative and 2 Grampositive bacterial taxa. Isolates were classified into four phylogenetic groups, Gamma - Proteobacteria, Alpha-Proteobacteria, Firmicutes and Bacteriodetes. Bacteria belonging to the phylum Gamma-Proteobacteria were the most abundant, with Vibrio and Pseudoalteromonas being the dominant genera. Three isolates with low sequence identity (˂97%) to their closest relatives could possibly represent novel species. These isolates were grouped into the genera Shewanella, Sphingomonas and Sulfitobacter. All bacterial isolates (41) were screened for antimicrobial activity against the following test strains: Escherichia coli, Bacillus cereus, Staphylococcus epidermidis, Mycobacterium smegmatis Micrococcus luteus and Pseudomonas putida. Fifteen isolates (36%) displayed antimicrobial activity against one or more of the test strains, while one isolate (Pseudomonas species) showed broad spectrum antimicrobial activity against all the test strains except for E. coli. This study provides the first account of the diversity and composition of bacterial populations on the surface of S. rugosum, and demonstrates the ability of these bacteria to produce antimicrobial compounds. Despite recent advances in metagenomics, this study highlights the fact that traditional culturing technologies remain a valuable tool for the discovery of novel bioactive compounds of bacterial origin.
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