RCAAP Repository

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Due to the abundance of agricultural resources, last advances in animal nutrition, animal breeding and animal welfare there are a solid background in economics and management in Brazilian Animal agribusiness. Nevertheless, the sanitary improvements in animal breeding they are exposed to pathogenic microorganism responsible for gastrointestinal infections and others disturbs. In this context, antimicrobial agents are used therapeutically, prophylactically, and as growth promoters. But they can be the cause of health risks due to the development of antibiotic resistance and can be toxic to humans if improperly applied, so this use remains a source of deep concern and the replace of antimicrobial agents by probiotics are becoming very commonly. This work is motivated by the fact that the guarantee of the viability and stability of probiotic foods during the production and shelf-life is a technological challenge. In this dissertation were studied the stability of three kinds of solid state probiotic: alginate, milk cream and beeswax formulations. According to the results all formulations demonstrated better stability than dried cells and cells dried with nutrient media composed of fermented milk and beeswax formulations presented the better stability. The comparison between the formulations in three solid bases shows that: a) alginate formulations have better stability than milk cream formulations; b) ascorbic acid reduced the stability of formulations containing milk cream and alginate; c) the initial cell viability was not responsible for the observed stability; d) the formulation stability is partially correlated to low water activity; e) the conditions used to dry the formulations provide high initial cell viability. The survival analysis in accordance with the Weibull distribution show solid preparations tested have no protective effect related to tested additives.

West Indian cherry (Malpighia emarginata) is rich in vitamin C and other bioactive compounds. Brazil is one of the three largest producers of fruit in the world, being one of the greatest producer of agricultural residues. Drying is a method to allow the reuse of these residues. The residue of West Indian cherry has a low flowability in the spouted bed due to the low density of biomass and high moisture, thus it could be used soybean as an auxiliary material to keep the fluid dynamic stability and maintain the food characteristics of the final product. As this process involves a mixture of solids of different sizes, shapes and densities, it is subjected to particle segregation phenomena. In order to quantify the segregation, the Index of Mixture was defined as the ratio between the final local concentration and the initial global concentration of west Indian cherry. During the drying, there is a change in the contents of the bioactive compounds due to the influence of temperature and air flow rate. The present paper studied the fluid dynamic of the mixture of West Indian cherry residue and soybean in a spouted bed operating with different mass fraction of biomass in different heights of static bed. It was analyzed the mixture segregation and from the achieved results was possible to quantify the effect of the west Indian cherry concentration on degree of mixing and to conclude that there is a concentration of West Indian cherry residue on the top of the bed for all the static bed heights and mass fractions studied. It were also quantified the contents of phenolics, flavonoids, ascorbic acid, as well as moisture in different drying times and it was possible to verify the equilibrium moisture as well as an increase on the bioactive compounds contents quantified after drying.

Conselho Nacional de Desenvolvimento Científico e Tecnológico

The definition of functional food was born as substances and biologically active components that are added to food which offer the potential of enhanced health. In this way, probiotics are marketed as functional foods and have become increasingly used because of their hole for modify gut microflora and improve health. In present master dissertation, chocolate s probiotic formulations have been developed using lactobacilli with special focus on Lactobacillus acidophilus LA 5. The formulations were evaluated in terms of cell death kinetics, survival, physicochemical and sensory analysis. The obtained results have indicated that: a) chocolate-based products containing lactobacilli can be used for probiotic formulations, but the use of ascorbic acid and vegetable aqueous extract of Camellia sinensis reduced the stability of probiotic tested; b) three fermentation medium tested are adequate for fermentation, but fermentation broth composed by brewer\'s yeast and glucose presented the best results when compared with the others; c) there is difference in taste (p<0.001) among chocolate and probiotics chocolate, but chocolate containing probiotic is accepted by consumers.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Motivated by the search of alternative sources of production of fuels, this dissertation had the objective of studying the activity and the selectivity of cobalt supported on niobium oxide (Co/Nb2O5) for the synthesis reaction of Fischer-Tropsch in slurry reactor. The following variables were evaluated: cobalt loading, reaction temperature, reaction pressure and H2/CO ratio of the syngas. The catalysts were prepared by the precipitation method and characterized by atomic absorption spectroscopy, BET surface area, particle size analysis and temperature programmed CO desorption (TPD-CO). The increase of temperature favored the increase of the activity of the catalyst. The catalyst 10%Co/Nb2O5, at 250ºC and 20 bar, obtained a maximum of production of heavy hydrocarbons (73%) allied with a high activity (XCO=65%). The reduction of the pressure from 20 to 10 bar caused a reduction in the activity of the catalyst, but did not influenced the distribution of products. The composition of the syngas had great influence in the activity, selectivity, and lower H2/CO ratio resulted on a high selectivity to heavy hydrocarbons.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Natural organic matter (NOM) is found in all surface, ground and soil waters. During recent decades, reports worldwide show a continuing increase in the color and NOM of the surface water, which has an adverse affect on drinking water purification. For several practical and hygienic reasons, the presence of NOM is undesirable in drinking water. Various technologies have been proposed for NOM removal with varying degrees of success. The properties and amount of NOM (natural organic matter) can hardly affect the process efficiency and it is known that raw water total organic carbon (TOC) levels have a potential to produce concentrations of trihalomethanes (THM). In order to improve and optimize these processes, the characterization and quantification of NOM at different purification and treatment processes stages is important. In this work, experimental measurements were conducted to reduce the level of natural organic matter for small amounts of Uberabinha River water. Treatment was tested for its efficacy to reduce raw water NOM using gravity filtration with recycled granular activated carbon. Four different particle sizes were used in the experiments. Samples of filtrate were collected in intervals of one hour and were analyzed for conductivity, pH and UV254 absorbance. The results showed that the system was able to reduce organic compounds. The use of recycled activated carbon showed a significant removal of total organic carbon (TOC). It was verified that pH and conductivity of the final product have not changed comparing to the raw water initial values. Also, the influence of pressure and the carbon particle size was clearly observed in the quantity and quality of the filtrate. The results indicated that the pressure variation influences the % removal of organic matter. The variation of time during the filtration did not impair the efficiency of each filter. In a nutshell, gravity filtration with recycled granular activated carbon was capable of reducing NOM to an acceptable level encouraging its recycling and use. With these results it seems that it could be appropriate as a device in the treatment of water in remote areas where water treated isn´t provided.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

The product of the hydration process of lime, milk of lime, is a byproduct of lime commonly used industrially because it is present in the industrial processes of steel mill, chemical and sugar and alcohol. But the hydration process has been little studied and this dissertation aims to study the influence of the hydration process in the quality of product and the influence of quality of milk of lime in the efficiency of the industrial process which milk of lime is used. Through industry data found that the hydration process current and more useful for industrial is inappropriate and produces high amounts of residues that provide the company losses. In the industrial process the quality of milk of lime improves the performance of the industrial process by reducing the amount of material used and the amount of residue formed, consequently its accumulation in the equipment. And to produce a lime milk of good quality, high surface area and low amount of residue, you should use a mixing process suitable for the suspensions of lime milk with low particle sizes of lime and heating of initial water of hydration. And especially an efficient and appropriate agitation Therefore, the pilot of a unit of hydration was proposed and through this became the rheological behavior of suspensions of milk of lime and with these data, made up the study of power consumed by the agitator. It was also proposed changes on impeller to improve the efficiency of agitation and a system of residue removal at the end of hydration through rotary screens.

In the present study, the behavior of La1-xCexNiO3 (x = 0; 0.05 and 0.10) perovskite-type oxides catalysts was investigated, acting as catalysts, in reactions of dry reforming of methane (DRM) and biogas reforming (BR). The catalysts were synthesized by sol-gel method (or citrate) and by combustion with urea. Later, they were structurally evaluated and studied on the catalytic performance. The synthesized perovskite-type oxides were characterized by X-ray diffraction, nitrogen adsorption temperature programmed reduction and thermal gravimetric analysis. The catalysts showed low values of specific area (< 10 m2 g-1). The LaNiO3 phase present in all the calcined samples was converted into La2O3, Ni0 and La(OH)3 after reduction, keeping the phase CeO2 in the doped samples with cerium. It was observed more evident La(OH)3 phase in the samples synthesized by combustion method. The average crystallite sizes, on the main stage LaNiO3, remained between 13 to 17 nm. La0,90Ce0,10NiO3 synthesized by combustion had the lowest average crystallite size whereas La0, 95Ce0,05NiO3 and La0,90Ce0,10NiO3 synthesized by sol-gel method has the highest value. The sol-gel method produced NiO grains (20-25 nm) smaller than those produced by the combustion method (31 - 38 nm). But for all samples is observed a decrease in average Ni0 grain sizes after reduction. In the samples synthesized by combustion method the mean Ni0 crystallite size were similar (20, 19 and 21 nm), whereas the values increased with Ce addition (13 21 nm) in the samples synthesized by sol-gel method. All samples with 1:9 dilution (catalyst/ inert SiC) were active, stable and resistant to deactivation by coke deposition after 24 h of DRM and BR reactions, but with molar ratio H2/CO < 1. The La0,90Ce0,10NiO3 catalyst synthesized by sol-gel method, with 1:1 dilution (catalyst/ inert SiC) showed the greatest resistance to the carbon formation (1,06 mg Carbon / gcat h). The catalysts synthesized by the combustion method, when 1:9 diluted, showed TOFCH4 values between 13 - 16 in the DRM and between 15 - 19 in BR, with molar ratio H2/CO next 1. The catalysts synthesized by combustion method, with 1:1 dilution (catalyst/inert SiC) were more active (TOFCH4 8 13 h-1) in BR reaction than the catalysts synthesized by sol-gel method (TOFCH4 3 4 h-1). The lower values for the stoichiometric H2/CO <1 indicate favoring the reverse reaction of water-gas shift in catalytic tests, supported by the fact that higher CO2 conversion in all reactions usin catalysts with 1:9 dilution. There was a molar ratio H2/CO increase in the RB, especially when used as the catalyst with 1:1 dilution (catalyst/inert SiC), indicating that reverse water-gas shift reaction is less favored when feed CH4: CO2 = 2 and using a larger amount of catalyst.

Ammonium is one of the main raw materials for the production of different types of fertilizers, such as monoammonium phosphate (MAP), diammonium phosphate (DAP), urea and ammonium sulfate. The Triângulo Mineiro region is an important MAP producer. It is produced by the reaction between ammonium and phosphoric acid. The ammonium used is not produced at this fertilizer production facility. It is received and stored at an industrial unit that contains heat exchangers, compressors, pumps, flash vessels, etc. Due to changes in the specification of the ammonium supply, and to operational conditions different of those projected for the storage unit, the quality of the ammonium sent to the MAP production units may not be satisfactory. The ammonium industrial storage unit was simulated with the aid of COCO, a free-ofcharge computer software, based on the CAPE-OPEN protocol, in order to analyze the process sensibility to variables set-point changes. The simulation was based on the Peng- Robinson equation of state. It was possible to verify that COCO had good accuracy with reality through the simulation of the project data of the unit. The current operational data were also simulated, and it was found through parametric analysis that the specification of the received ammonium does not have any influence on the other process variables of the industrial unit. On the other hand, the elevation of the operational pressure of the storage spheres increases the temperature of the ammonium exported to the MAP facilities in 6K. This elevation increases the ammonium s vapor pressure, its tendency to volatilize and causes pump cavitation. Through simulation, a new operational point was proposed. It was possible to obtain an energetic gain of 28.61 kW at the pumps and compressors. This gain corresponds to an energy cost reduction of 3.34% at these equipment. At this new condition, the temperature of the ammonium sent to the MAP units returned to its original projected values.

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Conselho Nacional de Desenvolvimento Científico e Tecnológico