This study is aimed to compare the fluidized bed and microwave drying with microwave assisted fluidized bed drying. For this purpose, macaroni beads (2.4&plusmn / 0.08 mm diameter) were dried from about 20% to 12% moisture content in a fluidized bed of 7.6 cm diameter, in a domestic microwave oven with a power of 609 W and in the fluidized bed placed in the microwave oven conditions. In the experiments with the fluidized bed three air temperatures / 50, 60 and 70&deg / C at an air velocity of 2.3 m/s and in those with the microwave oven two power levels / 50% and 100% were used. The drying curves indicated that the drying rate increased with the air temperature and microwave power in each drying method. Microwave assisted fluidized bed drying reduced the drying time by about 50% and 11% on the average compared with the fluidized bed and microwave drying, respectively. Therefore, it was concluded that the drying time was reduced more by the effect of microwave energy than the fluidization. The effective diffusivities in the fluidized bed and microwave assisted fluidized bed drying were found to be in the order of 4.125x10-11 and 8.772x10-11 m2/s on the average, respectively. The effective diffusivities for the fluidized bed drying were fitted to an Arrhenius type of equation and the magnitude of the activation energy was found to be in the order of 12595 kJ/kg mol.

Thesis (M.S.)--University of North Carolina at Wilmington, 2005. / Includes bibliographical references (leaves: [52]-55)

Made available in DSpace on 2015-04-17T14:49:44Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1875577 bytes, checksum: 8b2d453c0474ff8dba0a6ee6ea4c099d (MD5) Previous issue date: 2010-09-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The Spirulina platensis has been studied by presenting high protein content (50 70% of its weight), essential amino acids, vitamins (especially B12), minerals, and pigments (carotenoids, phycocyanin and chlorophyll), polyunsaturated fatty acids, including omega-3 fatty acids and other biologically active compounds. The objective of the present study was to develop a food product like macaroni fortified with S. platensis biomass for human consumption, with microbiological stability and satisfactory organoleptic and nutritional characteristics. To prepare the macaroni, tests were made to obtain biomass in two situations: photobioreactor and tank cultivation; being these harvested in exponential growth and stationary phase and dry in freeze dryer and adiabatic dryer. After considering the produced biomasses, the biomass cultivated in tank and harvested in the exponential growth phase and dried in the adiabatic dryer was used to elaborate the macaroni in three concentrations: 5, 10 and 15%. Analyses were realized for microbiological and physical-chemical parameters of S. platensis biomasses and macaroni. The elaborated macaroni was evaluated sensorially by a panel of 58 untrained panelists who performed sensory tests for acceptance and purchase intent for selection of the best formulation. The results obtained in the physical-chemical analyses of the biomass grown in the three situations showed that there is no significant difference between the centesimal composition of S. platensis for the content of protein, lipids, carbohydrates and calories, cultivated in photobioreactor and in tank or when the produced biomass was dried in freeze dryer or hothouse. For the biomass harvested in the exponential growth or stationary phase, as to composition, it was shown that there is an increase in the percentage of carbohydrates, lipids and ash and decrease in protein and calories content when the cyanobacteria is in the stationary phase. Based on the analysis of the macaroni‟s composition, it was observed that increasing the concentration of S. platensis in the formulations resulted in an increase in protein and minerals, and consequent increase in nutritional value. According to the sensorial evaluation results, the products had good acceptance, providing the formulation with 5.0% S. platensis score of like slightly , the same was also obtained by the one containing 15.0% and the formulation with 10.0% had a score of like moderately . The highest percentage of overall assessment was presented by the macaroni enriched with 10.0% of S. platensis, obtaining 93.10% of positive assessments. Therefore is possible to develop food products, like the macaroni added biomass of S. platensis, becoming another alimentary alternative with better nutritional characteristics and able to promote health benefits to the consumer. / A microalga Spirulina platensis tem sido objeto de estudo por apresentar elevado valor protéico (50 70 % de seu peso), aminoácidos essenciais, vitaminas (especialmente B12), sais minerais, além de pigmentos (carotenóides, ficocianinas e clorofilas), ácidos graxos poliinsaturados, incluindo os ácidos graxos ômega-3 e outros compostos biologicamente ativos. A presente pesquisa teve como objetivo elaborar um produto alimentício do tipo macarrão enriquecido com biomassa de S. platensis, destinado ao consumo humano, com estabilidade microbiológica e características nutricionais e organolépticas satisfatórias. Para a elaboração do macarrão foram realizados testes para obtenção de biomassa cultivada em duas situações: fotobiorreator e tanque; sendo estas colhidas em fase de crescimento exponencial ou estacionária e secas em liofilizador ou secador adiabático. Após analise das biomassas produzidas, utilizou-se a biomassa cultivada em tanque, colhida na fase de crescimento exponencial e seca em secador adiabático para a elaboração do macarrão em três concentrações: 5, 10 e 15 %. Foram realizadas análises quanto aos parâmetros microbiológicos e físico-químicos da biomassa de S. platensis e do macarrão. O macarrão elaborado foi avaliado sensorialmente por um painel de 58 provadores não treinados que realizaram testes sensoriais de aceitação e intenção de compra para seleção da melhor formulação. Os resultados obtidos nas análises físico-químicas da biomassa cultivada nas três situações demonstraram que não há diferença significativa entre a composição centesimal da S. platensis para os teores de proteínas, lipídios, carboidratos e calorias, cultivada em fotobiorreator e em tanque ou quando a biomassa produzida era seca em liofilizador ou estufa. Para a biomassa colhida na fase exponencial de crescimento ou na estacionária, quanto à composição centesimal, demonstrou-se que ocorre um aumento do percentual de carboidratos, lipídeos e resíduo mineral fixo e diminuição de proteína e calorias quando a cianobactéria se encontra na fase estacionária. Com base nos resultados da análise da composição centesimal do macarrão foi possível observar que o aumento da concentração de S. platensis nas formulações resultou em aumento no teor de proteínas e minerais, e consequente aumento do valor nutricional. De acordo com os resultados da avaliação sensorial, os produtos tiveram uma boa aceitação, apresentando a formulação com 5,0 % de S. platensis o escore de gostei ligeiramente , o mesmo também foi obtido pela que continha 15,0% e a formulação com 10,0% apresentou o escore de gostei moderadamente . O maior percentual de avaliação global foi apresentado pelo macarrão enriquecido com 10,0% de S. platensis obtendo 93,10% de avaliações positivas. Logo, é possível o desenvolvimento de produtos alimentícios, como o macarrão adicionado de biomassa de S. platensis, tornando-se, mais uma alternativa alimentar com melhores características nutricionais e podendo promover benefícios à saúde do consumidor.

South Georgia is renowned for the abundance of Antarctic krill (Euphausia superba) and a range of krill predators. Variability in krill availability at a range of scales, and the consequences of this for predator-prey interactions, mean that quantifying the spatially explicit demand for krill by those predators is essential to understanding the mechanisms underlying ecosystem changes in the region. In this thesis demand within a distinct study box to the northwest of the island has been assessed. The thesis has three sections; (1) the number of predators; (2) the distribution of predators; and (3) the demand for krill by those predators. (1) Predator densities with confidence intervals were determined from appropriately designed shipboard transect survey; counts of Antarctic fur seals (Arctocephalus gazella), macaroni penguins (Eudyptes chrysolophus), gentoo penguins (Pygoscelis papua), and Antarctic prions (Pachyptila desolata) were adjusted for sea state, distance from observer and dive behaviour. Providing the first at-sea predator density estimates for the region. (2) A comparison of the distribution of female Antarctic fur seals engaged in pup-rearing (using satellite telemetry) and the whole population that were not restricted to a single part of the population (from shipboard transect survey) was undertaken. Using two general additive models based on the relationship between seal distribution (one derived from transect and the other from telemetry) and the physical environment indicated that the spatial distribution of lactating females is representative of the general population. (3) Using the derived predator density, the local krill demand estimate was 2581 tonnes krill per day, a consumption rate of 0.45% per day of the concurrently estimated krill biomass (using shipboard acoustics). Antarctic fur seals accounted for 75% of this demand. This level of demand was less than the increase in biomass resulting from krill growth. However, based on the length-specific demand, determined from concurrent predator diet samples demand exceeded growth for krill >48mm.