Made available in DSpace on 2014-06-11T19:35:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2003-04-10Bitstream added on 2014-06-13T18:46:26Z : No. of bitstreams: 1 navickiene_s_dr_araiq.pdf: 800978 bytes, checksum: b4fe3a7bf6071ac49275c5ff867c6fd2 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Fungicidas, como pirimetanil, fluquinconazol e procloraz, e acaricidas, como clofentezina e cihexatina, são aplicados tanto no período de pré-colheita, como para preservar a qualidade e as características de cor e sabor das frutas durante a armazenagem, o transporte e a comercialização (procloraz). Contudo, devido à persistência dos seus resíduos nas frutas, monitoramentos devem ser realizados, empregando-se técnicas analíticas sensíveis, para avaliar se os resíduos de tais pesticidas atendem aos limites estabelecidos pelas legislações dos países exportadores e importadores. Um número reduzido de métodos para análise de resíduos dos fungicidas pirimetanil, procloraz e fluquinconazol e dos acaricidas cihexatina e clofentezina, usados no controle de doenças e pragas em culturas de frutas, estão descritos na literatura. Aliando este dado à importância econômica da produção de frutas em nosso país, foram desenvolvidos e/ou adaptados métodos eficientes, rápidos e simples para a determinação destes fungicidas e acaricidas na casca e na polpa de mamão (papaia), manga e laranja e no fruto inteiro de morango e uva. As metodologias são baseadas em extração líquido-líquido e análise individual por cromatografia a gás com detecção por captura de elétrons para procloraz e cihexatina e detecção termiônica... / Fungicides, as pyrimethanil, prochloraz and fluquinconazole, besides acaricides, as clofentezine and cyhexatin, have been used to preserve the quality of perishable fruits during their production, storage and commercialization. Also, these fungicides and acaricides are employed in the pre-harvest period. However, the presence of pesticide residues in fruits representes a serious problem, once the pesticides could become a risk to human consumption. So, the development of analytical methods looking for a rapid screening can ensure that the pesticide concentrations are below of the maximum residue limits allowed by the regulatory agencies. In the literature, some methods for the determination of pyrimethanil, prochloraz, clofentezine and cyhexatin in fruit matrices have been described. Respecting fluquinconazole, there is only a German review. Considering the subjects mentioned and that Brazil plays an important role in the worldwide production of fresh fruit, the purpose of this work was to develop simple and efficient methods for the determination of these fungicides and acaricides in peel and pulp of papaya, mango and orange, besides in grape and strawberry (entire fruit). The methodologies are based on liquid-liquid extraction. The analyses were performed by means of gas chromatography with thermionic specific detection for pyrimethanil and electron-capture detection for prochloraz and cyhexatin. In addition, pyrimethanil, prochloraz, fluquinconazole and clofentezine were analyzed employing a liquid...(Complete abstract, click electronic access below)

The use of wood-based composites has increased dramatically over the last two decades due to a number of factors. One reason is that Oriented Strand Board (OSB) is being increasingly utilized in residential applications in place of plywood. However, the use of OSB in residential construction is often limited because of its susceptibility to attack by biological pathogens such as mold and decay fungi. The environmental conditions that exist in certain use categories can be so adverse that the performance of these composites is negatively affected. This study was divided into two parts. The first phase examined the effectiveness of fungicides or combinations of fungicides (including some metal-containing preservatives) for enhancing the mold resistance of strandboard. During the second part of the study, preliminaryexperiments investigated the effectiveness of fungicides or combinations of fungicides using anagar-block test to estimate the preservative toxic threshold retention. The compatibility of the fungicide on the resin curing was studied by measuring change in the resin gelation and viscosity. After these screening experiments were completed, large size boards were prepared and mechanical and decay resistance properties were examined. It was found that mold and decay resistance properties of strandboard directly were related with the biocide type and its concentration. Greater protection of the strandboard was achieved with an increase in preservative retention levels. However, due to the relatively high cost of non-metallic (organic) preservatives, it is important to find the minimum amount of preservative that can protect the OSB against mold and decay fungi. One method of reducing the cost and increasing efficacy is to combine different fungicides to determine whether synergism exists. Even if synergism does not occur, it may reduce the overall cost by combining a less expensive biocide with a smaller amount of a more expensive biocide wheretheir biocidal efficacy complements each other. In addition, it is important to understand that high retention of preservative may also cause negative effects on the mechanical properties of strandboard. This maybe noticeable of the high retention level of the biocide when a greater negative effect on the internal bonding (IB) strength may be recorded. Lower IB strength for treated strandboard may be attributed to the formulation of chemical residue in the wood surface, which may interfere with the reaction between wood and phenol formaldehyde (PF) resin. Surface-active agents in the preservative may also cause the PF resin to over-penetrate into wood decreasing bond strength. Increasing moisture content of strands by the introduction of an emulsified aqueous biocide solution, may cause dilution of the resin, and reduced bonding. It should also be noted that high retention of preservative which cause a change in the viscosity and gelation time of PF resins would be problematic for the operation of an OSB plant. For viscosity change, it could significantly affect the flow properties of the resin on the wood furnish and its atomization as it is spraying onto the wood furnish. In addition, it may require further modification to the equipment that supplies the resin to the spray nozzle. For changes in the gelation time, this may require changes to the press time at the OSB plant. / Forestry, Faculty of / Graduate

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Thesis (MTech (Food Technology))--Cape Peninsula University of Technology, 2018. / Fungal diseases in vineyards are one of the main causes leading to economic losses within the viticultural sector and are continuously increasing over years. The most common of these fungal diseases are powdery mildew, downy mildew and grey mould. Commercial fungicides to treat the above-mentioned diseases are available and their usage is regulated under Act 36 of 1947 to comply with Good Agricultural Practises (GAP). However, the application of less-harmful, natural alternative fungicides to control vineyard diseases are currently an important research focus since the demand for organic products by consumers and retail companies are increasing. However, fungicide residues can alter the fermentation process and prevent some biochemical pathways of yeast metabolism involved in phenolic and/or aroma compound production that are critical for sensory quality. Therefore the aim of the study was to investigate the effect of fungicide treatments on the fermentation rate, yeast proteins expressed, aroma compounds released and sensory profile of wines produced. In the study, Chenin Blanc grapes treated with chemical and natural fungicides (1x treatment and 2x treatment) under Good Agricultural Practises (GAP) were used to produce small-scale wines and laboratory-scale fermentations. Laboratory-scale fermentations were conducted in duplicate using the commercial Saccharomyces cerevisiae (S. cerevisiae) Active Dry Wine Yeast (ADWY) strains VIN 13 and VIN 7. The fermentations were monitored by frequently weighing until they stabilised (CO2 weight loss). Small-scale wines were produced using the commercial S. cerevisiae ADWY strain VIN 13 only. Wines were made according to the standard Nietvoorbij experimental winemaking procedure. At the end of fermentation, lees samples were plated onto Yeast Extract Peptone Dextrose (YPD) agar and colonies grown were subjected to CHEF gel electrophoresis to confirm that the S. cerevisiae yeast strain inoculated at the beginning of the fermentation completed it. Moreover, fermenting wine samples, collected at the start (lag phase) and at end of fermentation (stationary phase), were subjected to protein extraction, quantification and characterisation in order to investigate fermenting wine yeast proteins. Furthermore, the final wines were subjected to chemical analyses as well as measurement of aroma enhancing metabolites (esters, higher alcohols, fatty acids and thiol compounds) using GC – FID and MS. Additionally, duplicate samples of the wines were evaluated sensorially by a trained panel of 12 winemakers and researchers, using an unstructured line scale. Wines were compared to the control wine according to visual (colour), flavour (tree fruit, tropical fruit, and wine foreign), taste (body mouthfeel, acidity) and overall quality. The data collected from the study was statistically analysed using a two-way analyses of variance (ANOVAs) and subject to a multiple factor analysis (MFA). From the results obtained in the above study, it was concluded that yeast strains used for winemaking completed the fermentations at a similar rate to their respective controls. In addition, small-scale cellar fermentations showed that fungicide treatments (1x treatment and 2x treatment) compared to the controls had no notable negative effects on wine aroma and sensory profiles although differences were observed in the proteins expressed after the fermentation. Overall, the fungicide treatments did not negatively affect the yeast performance, yeast protein expressed, aroma compounds released and sensory profiles of the wines produced. Further studies are recommended on other white as well as red wine grape cultivars to fully assess the effects of the fungicides.

Copies of author's previously published articles inserted. / Bibliography: leaves 184-197. / xxvi, 197 leaves, [5] leaves of plates : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Soil Science, 1995

Copies of author's previously published articles inserted. Bibliography: leaves 184-197.

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