Made available in DSpace on 2014-06-12T16:32:21Z (GMT). No. of bitstreams: 2 arquivo6396_1.pdf: 2066198 bytes, checksum: 7da381e97eac11d3301bae9f124bb322 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2006 / O presente estudo teve como objetivos obter misturas de pré-formulados dos fármacos metronidazol (MT), paracetamol (PC) e hidroclorotiazida (HZ) secos pela técnica de Spray Drying (SpDr) bem como analisar termicamente tais formulações comparando-as com as misturas convencionais que não sofreram processo de secagem. Para tanto, utilizou-se um aparelho SpDr de bancada da marca LabPlant®, modelo SD-05, com uma agulha de 0,5 mm de diâmetro e fluxo co-corrente. A análise calorimétrica foi realizada num calorímetro Shimadzu, modelo DSC-50, no qual foram obtidas curvas na razão de aquecimento de 10 ºC.min-1 até 500 ºC em atmosfera de nitrogênio (50 mL.min-1). O aparelho DSC foi calibrado pelo ponto de fusão e variação de entalpia do padrão índio (156,6 ºC  0,3; ÄH = 410,6 ºC  0,3). Os dados fotovisuais das curvas calorimétricas foram obtidos através do acoplamento do calorímetro ao sistema fotovisual, modelo VCC-520, conectado a um microscópio da marca Olympus e a uma câmara fotográfica da marca Sanyo, em atmosfera de nitrogênio (50mL.min-1), até uma temperatura de 500 ºC. O sistema fotovisual foi conectado a um computador pelo programa Assimetrix, através do qual a imagem da amostra era visualizada em tempo real. As fotos foram obtidas de acordo com o perfil calorimétrico das curvas DSC observando-se as variações de transição de fases da amostra (± 2,0 mg). As curvas termogravimétricas foram obtidas em aparelho Shimadzu modelo TGA-50H, calibrado com oxalato de cálcio monohidratado, no qual obtiveram-se curvas dinâmicas e isotérmicas em atmosfera de nitrogênio (50mL.min-1) com ar sintético (20mL.min-1). As curvas de TG dinâmicas foram obtidas na razão de aquecimento de 10 °C.min-1 até uma temperatura de 900 °C. As curvas isotérmicas foram realizadas nas temperaturas: 150, 160, 170, 180 e 190 °C para o MT; 160, 170, 180 e 190 ºC para o PC; 260, 270, 280 e 290 ºC para a HZ; com duração de 120 min. A massa das amostras analisadas era de 5,0  0,5 mg. Os dados de DSC convencional e acoplado ao sistema fotovisual mostraram homogeneidade na qualidade das misturas de MT convencionais e pré-formuladas independentemente ao tamanho de partículas. Através dos dados de TG, foi possível comparar termicamente a estabilidade das diferentes misturas, evidenciando comportamento similar em relação ao estágio de decomposição do MT com os excipientes utilizados nas misturas convencionais e pré- formuladas. Em relação ao PC, os dados de DSC convencional e acoplado ao sistema fotovisual mostraram ligeiras alterações nas temperaturas de fusão, porém, não relacionadas a incompatibilidades. Ainda, a técnica de TG avaliou termicamente a estabilidade das misturas, evidenciando que a tecnologia de secagem via SpDr levou a um aumento da estabilidade quando as misturas foram processadas. Os dados de DSC convencional e acoplado ao sistema fotovisual para a HZ mostraram alterações nas temperaturas de fusão das misturas pré- formuladas, sugestivas de possíveis incompatibilidades; a ordem de reação para tais misturas calculada segundo Arrhenius e confirmada por Ozawa, foi zero, o que tornou possível determinar as pressões de vapor de tais misturas e evidenciar que o processo de perda de massa dá-se através de volatilização da amostra

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Visando obter informaÃÃes sobre a influÃncia da inclusÃo do farelo da amÃndoa da castanha de caju (FACC) sobre o consumo de mateÃria seca e os parÃmetros seminais de ovinos em confinamento, dezesseis carneiros mestiÃos de Santa InÃs, com idade mÃdia de 24 meses, foram distribuidos ao acaso em dois lotes de oito animais cada e confinados individualmente. Os animais experimentais foram submetidos, inicialmente, a um perÃodo de adaptaÃÃo de 15 dias. ApÃs o perÃodo de adaptaÃÃo, foram iniciados os tratamentos T1 e T2, com duraÃÃo total de 85 dias. O T1 foi constituÃdo por uma alimentaÃÃo à base de concentrado isoprotÃico e isocalÃrico com 18% de FACC, que foi administrado numa proporÃÃo de 1,2% do peso vivo (P.V.), e volumoso (feno de capim Tifton) ad libitum. O T2 foi constituÃdo com o mesmo concentrado isoprotÃico e isocalÃrico com 0 % de FACC. As raÃÃes (concentrado) foram administradas uma vez ao dia em cochos individuais. A sobra de volumoso foi coletada e pesada durante todo o perÃodo experimental. Os valores mÃdios encontrados para as caracterÃsticas estudadas foram: ganho de peso diÃrio (T1) 0,068 g e (T2) 0,094 g; consumo total de matÃria seca (T1) 1,255 g + 0,23 e (T2) 1,302 g + 0,22; circunferÃncia escrotal (T1) 30,38 cm + 2,26 e (T2) 31,16 + 2,13 cm ; volume do ejaculado (T1) 0,9 ml + 0,38 e (T2) 1,0 ml + 0,46; concentraÃÃo espermÃtica (T1) 2,44 x 109 e (T2) 3,15 x 109 sptz / ml; motilidade massal (T1) 3,05 + 1,28 e (T2) 3,24 + 1,26; motilidade individual progressiva (T1) 3,56 + 0,68 e (T2) 3,58 + 0,72; percentagem de espermatozÃides mÃveis (T1) 69,16 e (T2) 70,31. NÃo houve diferenÃas significativas (P>0,05) para os diferentes parÃmetros entre os dois tratamentos. Desta forma, conclui-se que a inclusÃo de 18% de farelo de amÃndoa da castanha de caju (FACC) no concentrado, para suplementaÃÃo alimentar em reprodutores ovinos à viÃvel, tendo em vista que os parÃmetros estudados nos dois tratamentos nÃo foram afetados negativamente pela presenÃa do FACC. / Seeking to obtain information on the influence of the inclusion of the bran of the almond of the cashew nut (FACC) on the dry mater consumption and seminal parameters of sheeps under feedlot, sixteen Santa InÃs crossbred sheeps, with medium age of 24 months, were randomly distributed to two lots of eight animals each and confined individually. The experimental animals were submitted, initially, to a adaptation period of 15 days. After the adaptation period, the treatments T1 and T2 were initiated, with a total length of 85 (eighty five) days. The T1 was constituted by a feeding based on a isoproteic and isocaloric concentrate with 18% of FACC, that was administered in a proportion of 1,2% of live weight (P. V. ), and roughage (Tifton grass hay) âad libitumâ. The T2 was constituted with the same isoprotÃico and isocalÃrico concentrate with 0% of FACC. The rations (concentrated) were administered once a day in individual hods. The roughage surpluses were collected and weighted during the whole experimental period. The mean values found for the studied traits were: daily weight gain (T1) 0,068 g and (T2) 0,094 g; total dry mater consumption (T1) 1,255 g + 0,23 and (T2) 1,302 g + 0,22; scrotal circunference (T1) 30,38 cm + 2,26 and (T2) 31,16 + 2,13 cm ; ejaculated volume (T1) 0,9 ml + 0,38 and (T2) 1,0 ml + 0,46; spermatic concentration (T1) 2,44 x 109 and (T2) 3,15 x 109 sptz / ml; massal motility (T1) 3,05 and (T2) 3,24; progressive individual motility (T1) 3,56 + 0,68 and (T2) 3,58 + 0,72; percentage of movable spermatozoids (T1) 69,16 and (T2) 70,31. There were not significant differences (P>0,05) for the different parameters among the two treatments. In this way, it was concluded that the inclusion of 18% of bran of almond of the cashew nut (FACC) in the concentrate, for feed suplementation of sheep sires is viable, tends in view that the parameters studied in the two treatments they were not negatively affected by the presence of FACC.

O metabolismo ósseo é influenciado por fatores endócrinos, genéticos, de crescimento, sistema RANK/RANKL/OPG, além de uma variedade de moléculas regulatórias, como as citocinas. Citocinas têm sido implicadas na patogênese de doenças ósseas, no entanto, ainda pouco se sabe sobre os mecanismos envolvidos na interação entre o sistema ósseo e imunológico no processo de reparo ósseo. O objetivo deste estudo foi caracterizar o papel de TNF-α e IL-10 no reparo ósseo alveolar em condições homeostáticas (controle [C]) e infecciosas (alveolite experimental [A]) pós exodontia em camundongos C57Bl/6 (WT), TNFp55KO e IL-10KO. Após a cirurgia nos grupos infectados foi induzida a alveolite por meio de isquemia do alvéolo e uma suspensão de secreção purulenta. As maxilas foram coletadas em 0h, 7, 14 e 21 dias após a extração do incisivo superior para análises histológica, histomorfométrica e molecular (RealTimePCR). Na análise histomorfométrica foram quantificados os parâmetros coágulo, células inflamatórias, fibras, fibroblastos, vasos sanguíneos, matriz óssea, osteoblastos, osteoclastos, e outros espaço do líquido intersticial e medula óssea. Na análise molecular (RealTimePCR) foram quantificados a expressão de fatores de crescimento, marcadores ósseos e de matriz extracelular, citocinas e quimiocinas envolvidos no processo. Os dados obtidos foram submetidos ao teste OneWay ANOVA seguido do teste de comparação múltipla de Tukey. Os resultados demonstraram que nos camundongos WT-C houve a formação inicial de coágulo (0 hora) com início da expressão de BMP2, BMP4, BMP7, TGFb1 and VEGFa que tiveram aumento gradativo com pico em 7 dias. A expressão de TNF-α e IL10 também tiveram seus picos aos 7 dias em paralelo com contagem de leucócitos, associado com a expressão de CCL2, CCL5 e CXCL1. Nos períodos seguintes houve uma diminuição inflamatória e o aumento de marcadores osteoblásticos/osteogênicos. A indução da alveolite experimental em WT-A resultou no aumento marcante na expressão de TNF-α, acompanhada por uma maior expressão de CXCL1 e CCL5, contagem aumentada de leucócitos e diminuição na expressão de IL-10 que só atingiu seu pico aos 14 dias, além de proeminente infiltrado leucocitário e tecido de granulação, bem como evidências histológicas de atraso no reparo ósseo. O impacto negativo da alveolite foi atenuado nos camundongos TNFp55KO, caracterizado por um reparo adequado, diminuição no número de leucócitos e osteoclastos em relação aos WTA. Por outro lado, um atraso no reparo foi observado nos animais IL10KO, evidenciado por uma menor densidade de osteoblastos e de matriz óssea do que o respectivo controle. Em conclusão, os resultados mostraram que ambas citocinas interferem no reparo ósseo alveolar por meio de mecanismos que envolvem o controle da migração de células inflamatórias e modulação de quimiocinas e a expressão de marcadores osteogênicos, uma vez que a ausência de IL-10 está associada a uma maior atividade inflamatória e reabsorção óssea concomitante com menor formação ósseo, já a deficiência de TNF-α afeta o recrutamento de leucócitos e a cinética de reparo óssea alveolar em condições homeostáticas e infecciosas. / Bone metabolism is influenced by endocrine, genetic and growth factors, RANK/RANKL/OPG system, besides a variety of regulatory molecules, such as cytokines. Cytokines have been implicated in pathogenesis of bone diseases, however, little is known about the mechanisms involved in the interaction between skeletal and immune system in the bone repair process. The objective of this study was characterized the role of TNF-α and IL-10 in alveolar bone repair under homeostatic (control [C]) and infectious (experimental alveolitis [A]) conditions in C57Bl/6 (WT), TNFp55KO and IL-10KO mice. After surgery, in infectious groups was induced by ischemia alveolitis the well and a suspension of pus. The maxillas were collected at 0h, 7, 14 and 21 days after extraction of the maxillary incisor for histologic, histomorphometric and molecular (RealTimePCR). In histomorphometric analysis parameters were measured clot, inflammatory cells, fibers, fibroblasts, blood vessels, bone matrix, osteoblast, osteoclast, and other space - the interstitial fluid and bone mar row. Molecular analysis (RealTimePCR) were quantified the expression of growth factors, bone markers and extracellular matrix, cytokines and chemokines involved in the process. The data were submitted to the OneWay ANOVA test followed by Tukey\'s multiple comparison test. The results showed that in WT-C initial clot formation (0 hours) with early expression of BMP2, BMP4, BMP7, and TGFb1 VEGFa who had gradual increase peaking in 7 days. The expression of TNF-α and IL10 also peaked at 7 days in parallel with leukocyte count, associated with CCL2, CCL5 and CXCL1. In late periods there were decrease of inflammation and markers osteoblastic / osteogenic increased. Induction of experimental alveolitis in WT resulted in a marked increase in expression of TNF-α accompanied by increased expression of CXCL1 and CCL5, increased leukocyte count and decreased of IL10 expression that peaked at 14d, besides prominent leukocyte infiltration and granulation tissue, as well as histological evidence of delayed bone repair. Negative impact of alveolitis was attenuated in TNFp55KO mice, characterized by appropriate repair rate, decreased of the number of leukocytes and osteoclasts that WT-A. On the other hand, a lessened repair was observed in IL10KO animals, evidenced by lower density of the density of osteoblasts and bone matrix than respective control. In conclusion, the results show that both cytokines interferes in alveolar bone repair through mechanisms that involve the control of inflammatory cell migration and modulation of chemokines and osteogenic markers expression, since that the absence of IL-10 is associated with higher inflammatory activity and bone resorption concomitant with lower bone formation, while the deficiency of TNF-αa affect the recruitment of leukocytes and the kinetics of alveolar bone healing both in homeostatic and infectious conditions.

A alveolite seca (AS) é uma das complicações pós-operatórias mais comuns e sintomáticas na odontologia, porém, até o momento não há um protocolo de tratamento definido. O composto fenólico guaiacol (Gu) é um dos materiais utilizados para revestimento intra-alveolar devido às suas propriedades analgésicas, antioxidantes e antimicrobianas. Contudo, sua desvantagem é a dificuldade de manipulação decorrente da sua baixa estabilidade, alta volatilidade e sensibilidade à oxidação. Para melhorar suas propriedades e aumentar sua aplicabilidade clínica, um complexo de inclusão de Gu com ß-ciclodextrina (ßcd) foi desenvolvido. A formação do complexo supramolecular de Gu:ßcd foi caracterizada mediante a ressonância magnética nuclear (RMN), nos experimentos de 1H e 2D ROESY. A atividade antibacteriana do Gu e Gu:ßcd frente a Escherichia coli, Staphylococcus aureus, Streptococcus mitis, Streptococcus mutans, Streptococcus sanguis e Aggregatibacter actinomycetemcomitans foi analisada pelo método da microdiluição e sua citotoxicidade em osteoblastos de calvária de rato, foi estudado com o ensaio do MTT. O processo de reparo alveolar induzido pelo Gu:ßcd foi avaliado histologicamente após tratamento de alveolite seca em molares inferiores de ratos. A RMN mostrou correlações espaciais entre os hidrogênios internos (H3 e H5) da ßcd e os hidrogênios aromáticos, H(a) e H(b) do Gu, confirmando a formação do complexo. A complexação do Gu na ßcd potencializou seu efeito antibacteriano e reduziu sua citotoxicidade em osteoblastos. O estudo in vivo evidenciou a ocorrência de ossificação no ápice alveolar dos ratos tratados com Gu:ßcd, no 7o dia. No 14o dia, as trabéculas ósseas ocuparam também o terço médio do alvéolo e no 21o dia, todo o alvéolo se encontrava preenchido por osso neoformado. Estes resultados foram similares ao controle negativo e superiores ao controle positivo (Alvogyl®). Os benefícios obtidos pela inclusão do Gu na ßcd foram demonstrados pela melhora das propriedades biológicas do Gu in vitro e o adequado reparo alveolar in vivo. / Dry socket is one of the most common and symptomatic complications in dentistry, however, there is still not a settled treatment for this condition. The phenolic compound guaiacol (Gu) is one of several alveolar dressings used in dry socket because it has analgesic, antioxidant and antimicrobial properties. Nevertheless, its disadvantage is the difficulty of manipulation due to its low stability, high volatility and sensitivity to oxidation. To improve its properties and increase its clinical applicability, an inclusion complex of Gu with ß-cyclodextrin (ßcd) was developed. The Gu:ßcd supramolecular complex was characterized by Nuclear Magnetic Ressonance (NMR), in the 1H and 2D ROESY experiments. The antibacterial activity of Gu and Gu:ßcd over Escherichia coli, Staphylococcus aureus, Streptococcus mitis, Streptococcus mutans, Streptococcus sanguis and Aggregatibacter actinomycetemcomitans was analyzed using the microdilution method and its cytotoxicity in rat calvaria-derived osteoblast was evaluated with the MTT assay. The alveolus repair process induced by Gu:ßcd was histologically studied after the treatment of dry socket in rat mandibular molars. The NMR showed spatial correlations between internal hydrogens (H3 and H5) of ßcd and aromatic hydrogens, H(a) and H(b), of Gu confirming the inclusion complex formation. Gu:ßcd complex potentiated Gu antibacterial effect and reduced its cytotoxicity in osteoblasts. The in vivo study revealed that ossification occurred in the alveolar apex of rats treated with Gu:ßcd, by day 7. In the 14th day, the trabecular bone occupied the apical and middle thirds of the socket and on the 21st day, the entire alveolus was filled by newly formed bone. These results were similar to the negative control and superior to the positive control (AlvogylTM). Benefits gained from inclusion of Gu in cyclodextrin have been particularly demonstrated by the improvement in Gu biological properties in vitro and the appropriate alveolus repair in vivo.

M.Tech. (Chiropractic) / Myofascial pain and dysfunction syndrome (MPDS) is presently considered to be the leading diagnosis amongst pain management physicians and the leading diagnosis amongst pain sufferers reporting to general practitioners (Harden, Bruehl, Gass, Niemiec & Barbick, 2000). The goal of dry needling and the other above mentioned soft tissue treatments is to alleviate the MTrP’s in the muscle, thereby restoring the muscle to its normal tissue mobility and returning it to proper functional capacity (Travell & Simons, 1999). A post-needling protocol may be used to reduce post-needling soreness at the needling site, to facilitate tissue repair after needling and to normalise muscle function and ROM after needling (Travell & Simons, 1999). The aim of this study is to compare the efficacy of dry needling on its own and in combination with a widely prescribed post-needling protocol of heat, active range of motion (ROM) exercises and passive stretches, with regards to changes in pressure pain threshold, pain and cervical spine ranges of motion, to determine which the superior treatment is. Participants who went to the University of Johannesburg Chiropractic Day Clinic were eligible to participate in the study once they met the inclusion and exclusion criteria. Participants were recruited by means of word of mouth as well as with the use of advertisements that were placed around the respective campuses of the University of Johannesburg. Thirty participants were randomly assigned into one of two groups, each consisting of 15 participants. Group A received only dry needling to the upper trapezius muscle TP1 or TP2 whereas group B received dry needling to the upper trapezius muscle TP1 or TP2, moist heat, active ROM exercises and passive stretching of the upper trapezius muscles. Participants were treated for a total of 6 visits. Subjective and objective measurements were done at visits 1, 4 and a final visit 7 during which only measurements were taken.

Philosophiae Doctor - PhD / The Eastern Antarctic Dry Valley region is a polar desert, where conditions of extreme aridity, high temperature fluctuations and high irradiation levels make it one of the most extreme environments on earth. Despite the harsh environment, the soils in this region yield a wide range of bacterial and eukaryotic phylotypes in greater abundance than previously believed. In the Dry Valleys, highly localized niche communities colonise the underside of translucent quartz rocks and present macroscopic growth. / South Africa

Sorghum bicolour (L.) Moench is an important staple cereal in Africa, where it ranks second after maize. Despite its importance, the sorghum food industry remains non vibrant, constrained in part by inadequate milling technology. Presently, Prairie Research Laboratory (PRL) type abrasive dehullers and hammer mills, which apparently produce meals of inconsistent quality and low output, are generally used for industrial milling of sorghum. Efforts to improve sorghum milling require an in-depth understanding of how milling process and grain type affect the sensory characteristics of the final food products. Such knowledge is currently lacking. Therefore, this study investigated the effects of milling process and sorghum type on the quality of sorghum meal and porridge. Twelve sorghum types with diverse physico-chemical properties were milled by roller milling (RM), abrasive decortication-hammer milling (ADHM) and hand pounding (HP), and the effects on meal extraction and meal quality were evaluated. Porridges were prepared using standardised Botswana recipe, and their sensory profiles were characterised using Descriptive Sensory Analysis. Additionally, factors that affect the texture of sorghum porridge were investigated, and suggestions for improving the sorghum milling process are given. Both the sorghum type and the milling process affected the quality of the meal and the sensory characteristics of the porridge, but the milling process was found to have more effects on these characteristics than the sorghum type, because of the diverse milling principles of the milling processes. RM gave far better extraction rate and had substantially higher throughput than HP and ADHM. However, meals obtained with RM had slightly more ash and were a little darker, and gave porridges which were correspondingly darker in colour, had slightly more branny aroma, more astringency and bitter taste, than meals obtained with the other two milling processes, indicating higher bran contamination of the meals, presumably caused by fragmentation of the pericarp. Clearly, even with tempering the pericarp was still friable, and hence, requires indepth sorghum tempering studies. Grain hardness proved to be important for milling, as it correlated positively with extraction rate with ADHM and HP, but not with RM. Hard grains generally gave coarser and better refined meals, and produced porridges that were firmer, compared to soft grains. Weathered and pigmented pericarp sorghums produced dark and specky meals, and gave porridges with apparently undesirable sensory qualities, because of staining caused by the pericarp pigments, showing that these characteristics affect the quality of sorghum foods negatively. When used with hard and light coloured sorghums, ADHM gave more appealing meal and porridge qualities (light coloured, firm texture and enhanced cereal aroma), indicating that dry abrasive decortication is advantageous for production of sorghum products with superior sensory qualities. Firmness varied considerably among the porridges, caused by differences in the meal particle sizes, which was predominantly a consequence of the milling process. An increased proportion of coarse endosperm particles, as was the case with HP meals, caused increased porridge firmness. The coarse particles absorbed water slowly, thus restricting swelling of the starch granules, such that a high proportion of non-ruptured gelatinised starch granules that reinforce the porridge matrix resulted. The sorghum type also influenced porridge firmness, whereby the corneous sorghum types with high protein content produced firmer porridges, owing to presence of the hard and less waterpermeable protein-starch matrix in the endosperm meal particles. Because abrasive decortication gave meals and porridges with superior sensory qualities, while roller milling prduced high throughputs, a roller milling system that is preceded by a dry abrasive decortication process is recommended as a versatile milling process for industrial processing of diverse sorghum products that have superior sensory qualities. / Thesis (PhD)--University of Pretoria, 2009. / Food Science / unrestricted

Pearl millet is a staple food in Namibia. It is milled into flour by traditional and industrial dry milling processes. This research was conducted to help determine how to improve the nutritional value and acceptability of pearl millet. The traditional milling process involves a lactic acid fermentation step which lowers the pH of kernels. The effects of the traditional Namibian and industrial “dry milling” processes on the physical and nutritional composition of pearl millet grain were compared. Additionally, the effect of steeping three different Namibian pearl millet varieties (Kangara, Kantana and Okashana 2) in lactic acid and water on the colour and the phenolic content of the flour were determined. Regarding comparing the milling processes, variety Kangara was conditioned and decorticated traditionally with a pestle and mortar and industrially with an abrasive decorticator. The traditional decorticated grain was steeped and sun dried for 24 h before hammer milling, whereas the industrially decorticated grain was roller milled. Tristimulus colorimetry and proximate analyses were conducted on the samples. Concerning acid steeping, kernels were steeped in a pH 3.5 solution and in water as a control. Colour, total polyphenol and c-glycosyl flavone contents were determined. The determination of cglycosylflavone content was particularly important because these compounds are considered goitrogenic. The traditionally milled flour was lighter in colour than industrial milled flour. However, it was significantly lower in protein, ash and c-glycosyl flavone contents in comparison to industrial milled flour. This was due to the removal of more pericarp and germ in the traditional process. The industrial dry milling process therefore produces flour with a higher nutrient content in terms of protein, fat and minerals. However, the traditional Namibian milling process makes the colour of the pearl millet flour lighter, which is probably the reason that it is more acceptable to consumers. Kernels steeped in a lactic acid solution were lighter in colour than those steeped in water. Irrespective of the steeping media, the total polyphenol content was significantly lower in steeped kernels compared to those unsteeped. A similar trend was observed for the cglycosyl flavone content. This indicates that some of these compounds may have leached out during steeping. For all varieties, kernels steeped in lactic acid had a significantly higher total polyphenol content than those in water, probably due to the dissociation of metal-polyphenol complexes in the acidic medium whereby these polyphenols became free and available for measurement. Thus, steeping in a lactic acid solution can lead to better colour improvement of kernels compared to steeping in water. Thus, lactic acid steeping can improve the sensory quality of pearl millet products. An industrial process can thus be designed to include tempering the grain with food grade lactic acid to produce sour taste and leach out the colour pigments, particularly the cglycosyl flavones hence lightening the colour of the industrial milled flour. This produces a product with high nutritional content, lighter in colour and has the sour taste that consumers find appealing. Copyright 2007, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. Please cite as follows: Barrion, SC 2007, Pearl millet milling : comparison between traditional Namibian fermentation - semi-wet milling and dry milling, MSc(Agric) dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-01282009-132241 / > E1209/gm / Dissertation (MSc(Agric))--University of Pretoria, 2009. / Food Science / unrestricted

La Digestion Anaérobie (DA), ou méthanisation, est un procédé qui permet le traitement de déchets organiques et la production d’énergie renouvelable sous forme de biogaz. La DA par voie sèche permet en particulier la valorisation de substrats solides, offrant plusieurs possibilités aux traitements de résidus d’origine agricole tels les fumiers, des substrats constitués d’un mélange de paille, fèces et urine accumulés dans les litières des étables. Parmi les technologies disponibles en méthanisation, les « leach-bed reactors » (LBRs), constituent une option valide mais toutefois peu connue et peu développée soit au niveau scientifique qu’industriel.Dans le but d’optimiser ce procédé, plusieurs problématiques ont été affrontées : (i) la caractérisation bio-physico-chimique du fumier et du potentiel énergétique exprimé dans un LBR; (ii) l’optimisation de l’inoculation des réacteurs et de la température de digestion ; (iii) la co-digestion du fumier avec un substrat facilement biodégradable et la problématique reliées à la gestion des acides gras volatiles (AGVs) ainsi produits.Les résultats montrent que le fumier est un substrat lentement biodégradable qui nécessite un long temps de digestion. Cependant, il s’agit d’un déchet agricole adapté à la valorisation par méthanisation et dont les rendements de dégradation et de production de méthane en LBRs sont intéressants industriellement. Ce substrat est par conséquent une ressource organique précieuse dans le contexte agricole.Il a été montré que le fumier bovin contient une population méthanogène active capable de démarrer un procédé de digestion anaérobie efficacement sans l’ajout d’un inoculum externe spécifique, autant en mode mésophile que thermophile. Une analyse économique a démontré que cette propriété peut être exploitée afin de diminuer les coûts d’investissement initiaux d’un projet à l’échelle industrielle, en favorisant de cette manière le développement de la filière. De plus, les résultats montrent que pour la digestion du fumier en LBRs le mode thermophile ne comporte aucun intérêt par rapport à la production finale de méthane (qui est similaire pour les deux régimes) et que, au contraire, la valorisation par cogénération du méthane produit en thermophile diminue le rendement de production électrique surtout à cause d’une production de méthane très importante en début de digestion. Le régime mésophile parait donc être le mode de fonctionnement le plus adapté dans ce contexte.Enfin, le rôle joué par la percolation du lixiviat sur la mobilisation des AGV accumulés dans la fraction solide a été mis en lumière dans un réacteur de co-digestion traitant une fraction de lentement biodégradable (le fumier) et une fraction facilement biodégradable. Une stratégie a été développée afin d’étudier le problème de l’extraction et de la consommation des AGV dans le but d’améliorer le rendement global du procédé.Pour conclure, ce travail a permis d’optimiser certains paramètres fondamentaux dans la gestion d’un LBR. Cette technologie s’est révélée efficace dans le traitement du fumier, autant en mono-digestion qu’en co-digestion avec un substrat facilement biodégradable. Ces recherches montrent que l’utilisation des LBR est appropriée au contexte agricole et que la modification des paramètres de contrôle permet à ce procédé de répondre efficacement aux problématiques du terrain. Ce travail représente une avancée significative vers la compréhension et le développement des LBRs pour le traitement des résidus agricole et, plus globalement, des énergies renouvelables mobilisant des biomasses agricoles / Anaerobic Digestion (AD) is a process which allows the treatment of organic waste and the production of renewable energy. In particular, dry AD allows the treatment of solid organic substrates, offering several possibilities to the enhancement of agricultural waste such as spent livestock bedding (a mixture of straw, faeces and urine). Among the available biotechnologies in AD, leach-bed reactor (LBRs) is a promising but yet poorly known process both at scientific and industrial level.In order to develop this process, several issues have been studied: (i) the bio-physico-chemical characterization of spent animal bedding and its digestion potential in LBRs; (ii) the optimization of the start-up and the operating temperature of the digesters; (iii) the co-digestion of spent animal bedding with an easily-degradable substrate and the issues connected to the management of the volatile fatty acids (VFAs) produced.The results showed that spent animal bedding is a slowly-degradable substrate which needs a long digestion time. However, it is a substrate suitable to be treated through AD displaying high degradation and methane production rates when processed in LBRs. This substrate is, therefore, a valuable organic resource in the agricultural context.Spent animal bedding was shown to contain an active methanogenic population able to start the process efficiently, both in thermophilic and mesophilic temperature, without requiring a specific external inoculation. An economic study at industrial scale proved that this peculiarity can be used to diminish the investment costs and then promote the development of this process. Moreover, thermophilic temperature was proved to be less advantageous over mesophilic condition. In fact, despite the very close methane yield reached in both temperature range, the different biogas production rates in thermophilic conditions would lead to a reduction of the final electric energy production in this condition. Mesophilic temperature was then shown to be the best operating condition for this process.Finally, the role played by the leachate recirculation in the mobilization of the VFAs accumulating in the solid bulk was highlighted in the case of a reactor co-digesting slowly- (spent livestock bedding) and easily-degradable substrates. A strategy was even proposed to efficiently face such a problem by optimizing both the VFA extraction and consumption with the objectives of increasing the overall process efficiency.In the end, this work allowed to optimize some important parameters for the correct management of the LBRs. This technology was proved to be efficient in the treatment of spent livestock bedding, both as a sole substrate or in co-digestion with an easily-degradable substrate. This research study demonstrates that LBRs is an adapted process for the agricultural context and this technology can easily answer to the full scale issues usually encountered. This work represents a significant advance towards the comprehension and development of LBRs to treat agricultural waste and, more generally, to the development of renewable energies based on biomass

M.Ing. (Mechanical Engineering) / In snow shooting, pressurised liquid carbon dioxide is injected via a lance into a permeable snow bag mounted near the ceiling of an insulated transport container. The decrease in pressure causes the liquid carbon dioxide to convert to "snow" and vapour inside the snow bag. The snow bag acts as a phase separator, allowing the sublimated snow to cool down the products inside a container. In this thesis the heat transfer coefficients of such a snow bag were determined experimentally and theoretically. It was found, that on average the measured heat transfer coefficient was 31% lower than the theoretical prediction. The theoretical model was used to correlate the experimental heat transfer coefficient as function of snow height. With this correlation it was possible to predict the time of the snow life to within 24%.