The sulphation and sulphate decomposition occurring during the oxidation of nickel concentrates were studied by thermal analysis. Samples of industrial nickel concentrates were heated in inert gas to temperatures between 400°C and 850°C and oxidized isothermally in air or in a 4%O2-96%N2 mixture. During isothermal oxidation of the concentrates, SO2 evolved from the roasting reactions led to partial formation of metal sulphates. Following the oxidation and sulphation of the sample, the decomposition of the formed sulphates was studied. This was completed either by heating the sulphated sample to 950°C to thermally decompose the sulphates, or by lowering the partial pressure of oxygen while holding the sample at the isothermal oxidation temperature. The sulphation of the sample was found to follow the parabolic rate law, implying diffusion as the rate controlling-step. The thermal decomposition of the sulphates occurred at a near constant rate, implying zero-order kinetics.

Submitted by Socorro Pontes (socorrop@ufersa.edu.br) on 2018-02-16T15:03:17Z No. of bitstreams: 1 HeliaMSL_TESE.pdf: 1102082 bytes, checksum: 960a39ace6d2fbbcba482fe77e6ee546 (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2018-02-20T14:28:49Z (GMT) No. of bitstreams: 1 HeliaMSL_TESE.pdf: 1102082 bytes, checksum: 960a39ace6d2fbbcba482fe77e6ee546 (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2018-02-20T14:31:08Z (GMT) No. of bitstreams: 1 HeliaMSL_TESE.pdf: 1102082 bytes, checksum: 960a39ace6d2fbbcba482fe77e6ee546 (MD5) / Made available in DSpace on 2018-02-20T14:31:17Z (GMT). No. of bitstreams: 1 HeliaMSL_TESE.pdf: 1102082 bytes, checksum: 960a39ace6d2fbbcba482fe77e6ee546 (MD5) Previous issue date: 2017-09-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of the study was to evaluate the effect of different proportions of high-level diets on finishing lambs in feedlot system on performance. However, there is no ingestive and physiological behavior, as well as carcass characteristics, quality physical and chemical characteristics of meat and production costs. For this purpose, whole corn grain associated with the protein-mineral-vitamin supplement was used in three proportions of concentrate: bulky (100%, 80:20 and 60:40%), a concentrated portion of the diet composed of 85 % of whole corn grain and 15% of supplement and bulky portion of Tifton hay). Twentyfour non-castrated males with no defined racial pattern were used with initial weight of 20.9 ± 1.0 kg at the age of 6 months. Weight gain was achieved in the three diets tested from 0.302g / day for 100% diet, 0.254g / day to 80:20 and 0.259g / day for 60:40 Minor rumination time (P≤0.05) in lambs of the treatment based on grain 100% when compared to the lambs of the other treatments. The 100% diet presented higher feed efficiency (EAL) and also more efficient rumination (ERU). Evaluating a temperature of the rumen region, it can be seen that the animals that received a 100% diet showed the variation of the temperature of the reen region, as 80:20 and 60: 40% diets affect nearby temperatures. As evaluated diets contributed to the performance with satisfactory gains, although preferences of use of diet of high grade, these guarantee like basic actions. There was a significant effect on carcass yield. A 100% concentrated diet showed a carcass yield of 47%, while for 80: 20% and 60: 40% diets obtained carcass yield values of 43.5% and 43.4%, respectively. The gastrointestinal content also had an effect, being lower in treatments 100% and 80: 20%. (P> 0.05) in the variables pH, temperature, color, water retention capacity and shear force. The 100% treatment presented a weight loss in cooking as well as superior thiobarbituric acid (TBARS) when compared with other diets. The 100% diet, when compared with other diets, obtained an additional carcass weight of 2.30 kg per animal. The use of the 100% concentrated diet in lamb termination systems is a more viable alternative from a productive and economical point of view / RESUMO: Objetivou-se com o estudo avaliar o efeito de diferentes proporções de dietas de alto grão na terminação de cordeiros em sistema de confinamento sobre o desempenho e alterações no comportamento ingestivo e fisiológico, assim como as características de carcaça, qualidade físicas e químicas da carne e custos de produção. Utilizou-se para tal, grão de milho inteiro associando ao suplemento protéico-mineral-vitamínico em três proporções de concentrado:volumoso, (100%, 80:20% e 60:40%), sendo a porção concentrada da dieta composta de 85% de grão de milho inteiro e 15% de suplemento e a porção volumosa de feno de Tifton). Foram utilizados 24 machos não castrados, sem padrão racial definido com peso inicial de 20,9 ± 1,0kg com idade de 6 meses. Conseguiu-se obter ganhos de peso nas três dietas testadas de 0,302g/dia para dieta 100%, 0,254 g/dia para 80:20 e 0,259 g/dia para 60:40 O tempo de ruminação foi menor (P≤0,05) nos cordeiros do tratamento à base de grão 100% quando comparados aos cordeiros dos demais tratamentos. A dieta 100% apresentou maior eficiência de alimentação (EAL) e também mais eficiente na ruminação (ERU). Avaliando a temperatura da região do rúmen percebe-se que os animais que receberam a dieta 100% apresentaram acentuada variação de temperatura da região do rémen, as dietas 80:20 e 60:40% apresentam alterações de temperaturas próximas. As dietas avaliadas contribuíram para o desempenho com ganhos satisfatórios, apesar de ocorrer alterações comportamentais com uso da dieta de alto grão, estas garantem as ações básicas necessária para manter a saúde ruminal adequada. Houve efeito significativo para rendimento de carcaça. A dieta 100% concentrado apresentou um rendimento de carcaça de 47%, enquanto as dietas 80:20% e 60:40% obtiveram valores para rendimento de carcaça de 43,5% e 43,4% respectivamente. O conteúdo gastrointestinal também apresentou efeito, sendo menor nos tratamentos 100% e 80:20%. Para os parâmetros físicos da carne, não foi observado diferenças significativa (P>0,05) nas variáveis pH, temperatura, cor, capacidade de retenção de água e força de cisalhamento. O tratamento 100% apresentou uma menor perda de peso na cocção assim como também apresentou ácido tiobarbitúrico (TBARS) superior quando comparado as demais dietas. A dieta 100%, quando comparado as demais dietas, obteve-se um peso adicional de carcaça de 2,30 Kg por animal. O uso da dieta 100% concentrado em sistemas de terminação de cordeiros é a alternativa mais viável do ponto de vista produtivo e econômico / 2018-01-31

Master of Science / Food Science Institute - Animal Sciences & Industry / Jayendra K. Amamcharla / High-protein dairy powders are added to a variety of products to improve nutritional, functional, and sensory properties. To have the intended properties, the powder must be soluble. The solubility is effected by processing storage, and dissolution conditions, as well as the type of powder. Various tests are used to determine solubility, but they are time-consuming and subjective. Literature has shown that ultrasound spectroscopy can characterize the solubility of high-protein dairy powders, but it requires expensive equipment and skilled technicians. An economical alternative is to use an ultrasonic flaw detector, which is commonly used in the construction industry. For this study, an ultrasonic flaw detector based method was developed to characterize the solubility of high protein dairy powders. To evaluate the method, commercially available milk protein concentrate (MPC) was obtained and stored at 25°C and 40°C and stored for four weeks to produce powders with different dissolution properties. To test the powders, a 5% (w/w) concentration of powder was added to water. A focused beam reflectance measurement (FBRM) and solubility index were used as a reference method. After powder addition, data was collected at regular intervals for 1800s. The FBRM and solubility index showed that the powders lost solubility as the storage time and temperature increased. From the ultrasound data, one parameter was extracted from the relative velocity and three parameters were extracted from the attenuation data. A soluble powder had a low relative velocity standard deviation from 900-1800s, high area under the attenuation curve, low peak time, and high peak height. The ultrasonic flaw detector detected differences in solubility before the solubility index. When testing MPC with protein contents ranging from 85% to 90% and at a dissolution temperature of 40°C and 48°C, data from the ultrasonic flaw detector and FBRM showed that the solubility decreased as the protein content increased and increasing the dissolution temperature improved the solubility of the powder. Overall, the ultrasonic flaw detector can characterize the solubility of high-protein dairy powders.

Made available in DSpace on 2014-06-11T19:28:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-07-02Bitstream added on 2014-06-13T19:16:12Z : No. of bitstreams: 1 oliveira_psn_me_jabo.pdf: 143666 bytes, checksum: 8917daa47b0787a19d0ef98f6d336e3a (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O estudo foi conduzido para avaliar o efeito de duas proporções de concentrado, 70 e 80%, com duas fontes energéticas, milho e farelo de gérmen de milho, e volumoso à base de silagem de milho, sob o consumo de nutrientes, desempenho, características de carcaça, não componentes de carcaça e qualidade da carne de 28 novilhas Nelore confinadas, com aproximadamente 14 meses de idade e peso corporal médio de 200 kg, objetivando o abate. O delineamento experimental utilizado foi o inteiramente casualizado segundo esquema fatorial 2 x 2 ( 2 proporções de concentrado x 2 fontes energéticas) totalizando 4 tratamentos e 7 repetições, sendo as médias comparadas pelo teste de Tukey a 5%. Não houve interação da proporção de concentrado x fonte energética da dieta sobre o consumo de MS. Houve efeito significativo da interação proporção de concentrado x fonte energética da dieta para os consumos de proteína bruta (PB) e fibra em detergente neutro (FDN), sendo que a maior proporção de concentrado, associada ao milho, possibilitou maior consumo diário de PB (1,17 kg/dia) e FDN (4,05 kg/dia). Observou-se valor médio de consumo de fibra em detergente ácido superior para as dietas com 80% de concentrado, tanto para a dieta com milho quanto com farelo de gérmen de milho. Houve efeito significativo da fonte energética da dieta sobre o peso final dos animais, sendo que os animais alimentados com as dietas contendo milho apresentaram valor médio de peso final (326,14 kg) superior aos alimentados com as dietas contendo farelo de gérmen de milho (292,07 kg). A associação de altas proporções de concentrado, com milho como fonte energética, proporciona resultados satisfatórios de ganho em peso e desempenho de novilhas Nelore, já a substituição total do milho pelo farelo de gérmen de milho, associado à altas proporções de concentrado ricos em fibra... / The objective of this study was to evaluate the effect of two proportions of concentrate, 70 and 80%, with two energy sources, corn and corn germ meal, and roughage basis of corn silage on the intake of nutrients, performance, characteristics of a carcass, non components of carcass and meat quality of confined 28 Nellore heifers. The experimental design was a completely randomized design in factorial scheme 2 x 2 (2 proportions of concentrate x 2 energy sources) 4 replications and 7 treatments, and the averages has been compared by Tukey 5% test.. There was no interaction proportion of concentrate x energy source on the intake of dry matter. There was a significant effect of interaction proportion of concentrate x energy source intake for crude protein (CP) and neutral detergent fiber (NDF), suggesting that a higher proportion of concentrate, with the corn, allowed greater intake of CP (1.17 kg / day) and NDF (4,05 kg / day). It was observed average intake of acid detergent fiber than for diets with 80% concentrate, with both the diet with corn as the corn germ meal. There was a significant effect of dietary energy source on the final weight of animals, and the animals fed the diets with corn had average final weight (326.14 kg), above the fed with diets with corn germ meal (292.07 kg). The association of high proportions of concentrate with corn as an energy source, provided satisfactory results in performance of Nellore heifers, since the replacement of the corn germ meal, associated with high proportions of concentrate rich in fiber, not was recommended for young Nellore heifers. There was a significant effect the energy source of the diet on the weight of empty body, and the animals that received the diets with corn showed the average value of empty body weight (309.44 kg) than the diets of with corn germ meal (276.42 kg). The carcass yield, the thickness... (Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:24:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2001-08Bitstream added on 2014-06-13T19:31:36Z : No. of bitstreams: 1 cezar_vrs_me_botfca.pdf: 277022 bytes, checksum: e2ef8481db1680f1d57833a37bb026b7 (MD5) / Com o intuito de avaliar o efeito da biodigestão anaeróbia sobre a solubilização e a eficiência agronômica de diferentes fontes de fertilizantes fosfatados, foi desenvolvido um experimento no Departamento de Recursos Naturais/Ciência do Solo em Botucatu (SP). O estudo realizado foi dividido em duas etapas, onde a primeira constou da construção de três biodigestores e a produção de biofertilizantes enriquecidos ou não, pelas diferentes fontes de fósforo. O biofertilizante gerado foi caracterizado quimicamente em relação a sua solubilidade pelos diferentes extratores. Após a análise química, o biofertilizante foi utilizado na etapa seguinte, sendo aplicado ao solo e avaliado o Índice de Eficiência Agronômica (IEA) das fontes quanto à produção de matéria seca da parte aérea e a quantidade de fósforo nas plantas de milho, as quais foram cultivadas durante 30 dias após a emergência. Foram realizados dois cultivos consecutivos, onde as fontes de fósforo foram aplicadas apenas no primeiro cultivo, na dose de 200 mg de P kg-1 de solo... / An experiment was realized with the objective of evaluate the anaerobic disgestion effect about the solubilization and agronomic efficiency of different phosphate fertilizer. The research was realized in two phases, than the first was the construction of three reactors and the biofertilizer production. The biofertilizer generated was characterizated chemically relationship its solubility in different extractors. After the chemical analysis, the biofertilizer was used in the next phase, it being applicated into soil and it was evaluate about the agronomic efficiency of the phosphorous fonts, that dry matter production and phosphorous amount in the corn plants. The corn plants were cultivated during 30 days after its emergence. Two consecutives cultivation were realized, where the phosphorous fonts were only applicated in the first cultive (200mg P Kg-1 of soil). The study conclusions were: because some extractor solutions used in the assays doesn’t digest the organic matter present in the material, and yet, the difficult to have homogenous biofertilizer samples by reactors... (Complete abstract, click electronic access below)

Foram utilizados quatro éguas, da raça brasileiro de hipismo, com idade aproximada de 24 meses, com peso médio de 500 Kg, em um delineamento experimental Quadrado Latino balanceado 4X4, com arranjo fatorial 2X2 dos tratamentos e medidas repetidas no tempo, sendo o primeiro fator dois concentrados, um somente peletizado (CT) e o outro peletizado com pré-extrusão do ingrediente milho (CM), e o segundo fator é constituído pela diferença na ordem de fornecimento do concentrado e do volumoso onde um o concentrado é fornecido às 7:00h e às 19:00h e o volumoso às 9:00h e às 21:00h (C7V9); e o outro o inverso (V7C9). Não houve efeito dos tratamentos na aceitabilidade, na digestibilidade aparente total da matéria seca (51,2; 54,5; 53,4; 58,2%) da matéria orgânica (54,1; 57,5; 56,1; 60,7%), do amido (98,2; 98,3; 98,2; 98,2%), da proteína bruta (65,6; 70,3; 68,9; 72,6%), da fibra em detergente neutro (42,5; 44,6; 42,9; 49,3%) e da fibra em detergente ácido (34,8; 37,3; 37,0; 42,3%), porém noto-se uma tendência de melhora para os fatores V7C9 e CM. A resposta glicêmica plasmática foi analisada pela área abaixo da curva de glicose com valores obtidos para CTC7V9 de 493,7; CTV7C9, 407,6; CMC7V9, 430,7 e CMV7C9, 387,8, porém não houve efeito do fator concentrado, já o fator sistema de alimentação sofreu diferença estatística com aumento para o sistema C7V9, o que demonstra uma curva menos acentuada para V7C9, demonstrando uma absorção mais uniforme da glicose. / Four mares had been used, of the race Brazilian of jumping, with approach age of 24 months, average weight of 500 kg, in balanced Latin Squared experimental delineation 4X4, with factorial arrangement 2X2 of the treatments and measures repeated in the time, being the first factor two concentrates, one only pelletized (CT) and the other pelletized with daily pay-drawing of the ingredient maize (CM), and as the factor is constituted by the difference in the order feeding the concentrate and the voluminous one where one the concentrate is feeded 7:00h and to 19:00h and voluminous 9:00h and 21:00h (C7V9); e the other the inverse one (V7C9). It did not have effect of the treatments in acceptability, in the total apparent digestibilidade of dry substance (51,2; 54,5; 53,4; 58,2%) of organic substance (54,1; 57,5; 56,1; 60,7%), of starch (98,2; 98,3; 98,2; 98,2%), of rude protein (65,6; 70,3; 68,9; 72,6%), of the fiber in neutral detergent (42,5; 44,6; 42,9; 49,3%) and of the fiber in acid detergent (34,8; 37,3; 37,0; 42,3%), however I notice a trend of improvement for factors V7C9 and cm. The plasmatic glucose it was analyzed by the area below of the glucose curve with values gotten for CTC7V9 of 493,7; CTV7C9, 407,6; CMC7V9, 430,7 and CMV7C9, 387,8, however did not have effect of the concentrated factor, already the factor feeding system suffered to difference statistics with increase for system C7V9, what it less demonstrates an accented curve for V7C9, demonstrating an absorption more uniform of the glucose.

Não consta resumo na publicação. / Abstract not available.

Magister Scientiae Dentium - MSc(Dent) / BACKGROUND: Fluorine is an abundant trace element in the Earth’s crust. The presence of fluorine in bedrocks is the primary source fluoride in ground water, though fluoride occurrence varies with the different rock types. High concentrations of fluoride ions are found in regions of volcanic activities. Volcanoes are the main persistent natural source of fluoride in ground water and in the atmosphere. The occurrence of high concentrations of fluoride in ground water has been reported worldwide. Dental fluorosis is a developmental disturbance of enamel that results from ingestion of high amounts of fluoride during tooth mineralization. Consumption of untreated fluoridated ground water remains the main cause of dental fluorosis in rural settlements. AIM: To establish the risk factors and knowledge of dental fluorosis in three communities of the Far North Region of Cameroon. METHODOLOGY: This study was descriptive and cross-sectional study with an analytic component and was conducted in three communities in Far North Region of Cameroon. The study population was a convenience sample irrespective of age, but who must have been living in the selected study sites for a minimum of 6 to 8 years. Structured questionnaires were administered to elicit socio-demographic characteristics, perceptions dental fluorosis and oral health practices. Oral examination was conducted to determine the extent of dental fluorosis that was scored according to the Thylstrup and Fejerskov index. Participants declared their water sources and water samples were obtained from these sources. Samples of commercial bottled mineral water was purchased from various local outlets. These samples were sent to a certified laboratory for fluoride analysis and are reported in milligrams of fluoride per litre.

Whey proteins have restricted use in many food applications because of limited functional properties. Whey proteins' relatively high content of disulfide bonds may be responsible for their lack of functionality, especially in extrusion applications. To determine the effect of disulfide bond content on functional properties and extrudate performance, whey protein concentrate was treated with sodium sulfite to achieve four levels of disulfide bond sulfonation (0, 31, 54, and 71%). Sulfonated whey protein functional properties, extrusion-expanded snack properties (32% total protein), and extrusion-textured fibrous product properties (48% protein) were determined. Correlation analysis was performed to determine relationships between functional properties and extrudate performance. Sulfonation of whey protein concentrate (80% protein) increased foaming and emulsion properties and decreased melt temperatures. These changes were largely attributed to increased protein unfolding and flexibility. Sulfonation decreased gel strength and increased resolubilization after heat treatment. These changes were likely the result of increased electric charge on the proteins, limiting protein-protein interactions during heating. Snack products extruded from the 31 and 71% sulfonated samples were less expanded and released less protein and carbohydrate during extrudate solubilization. Sulfonation may have promoted protein unfolding, thereby exposing interaction sites and increasing the formation of insoluble protein-starch aggregates . In support of this suggestion, negative correlation s were found between extrusion performance and protein functional properties related to flexibility , including emulsification activity index, foam stability, and melt onset temperature. The anomalous behavior of the 54% sulfonated sample may be the result of significant structural and functional changes of a-Lb that are predicted to occur at approximately 50% sulfonation. Although the textured extrudate produced from all levels of sulfonation (including the control) did not possess typical fibrous texture, sulfonation at 31% and higher decreased stability after hydration . Decreased stability and fibrous texture may have resulted from decreased protein-protein interactions caused by the repulsion of electric charges contributed by sulfite groups. In conclusion, sulfonated whey protein functional and extrudate properties were influenced by disulfide bond content. Changes in these properties were attributed primarily to increased protein unfolding and flexibility. Increased electric charge on proteins also played a role where protein-protein interactions were important.

There is considerable interest among food manufacturers to incorporate protein into food products in both developed and developing countries. Dairy proteins are excellent choices for many different applications, as they are known to have several nutritional and functional benefits. Membrane filtration techniques are often utilized as the preferred method of fractionation, due to the high throughput and continuous nature of the process. One such product produced from membrane filtration of skim milk is called milk protein concentrate. This product is valued for its high protein content, but it has historically exhibited poor solubility when reconstituted into water, which severely restricts the food applications for which it is suitable. There is some existing evidence that milk protein concentrates which contain elevated levels of sodium exhibit higher solubility upon reconstitution into water. The main objective of this thesis project was to demonstrate the effect of sodium chloride, added to diafiltration (DF) water utilized during the manufacturing process, on the solubility of milk protein concentrate. It was observed that the addition of sodium chloride into diafiltration water at levels of 50 mM, 100 mM, and 150 mM had a beneficial effect on the solubility of milk protein concentrate across a variety of reconstitution conditions. For example, when milk protein concentrate was mixed for 1 h on a stage mixer at 23 °C ± 1 °C, a significant increase (p < 0.001) in mean solubility was observed when at least 50 mM NaCl had been incorporated into DF water. The incorporation of 50 mM NaCl into DF water significantly increased (p < 0.001) the mean solubility of milk protein concentrate from 59.81 % to between 64.34 % and 71.78 %. The addition of 100 mM NaCl significantly increased (p < 0.001) the solubility to between 88.80 % and 96.24 %, and the addition of 150 mM NaCl significantly increased (p = 0.005) the solubility to between 92.79 % and 100 %. Minerals analysis of dry powders revealed a significant increase (p < 0.001) in levels of sodium. The addition of 50 mM NaCl into DF water was associated with a significant increase (p < 0.001) in powder Na content to between 2.48 mg/g and 7.44 mg/g. The addition of 100 mM NaCl into DF water was associated with a significant increase (p = 0.002) in powder Na content to between 5.80 mg /g and 10.75 mg/g, and the addition of 150 mM NaCl into DF water was associated with a significant increase (p = 0.001) in powder Na content to between 9.57 mg/g and 14.53 mg/g. A significant difference (p < 0.001) in magnesium level was also detected. Differences in calcium content were not found to be statistically significant (p = 0.016) at α = 0.01. Preliminary observations of milk protein concentrate upon reconstitution were made using a confocal laser scanning microscopy method. This method showed evidence of possible differences in powder particle rehydration and affinity for lipid association between powder particles manufactured at different treatment levels. As the level of NaCl incorporated into DF water increased, particle structures upon rehydration appeared more porous, and the incidence of lipid material that was not associated with powder particles appeared to increase. Overall, this study demonstrates the importance of sodium content in determining the solubility of milk protein concentrate.