Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / The food industry uses chemical additives to extend the shelf life of its products and maintain their sensory and microbiological characteristics acceptable. However, the presence of preservatives in foods may interfere in the quantification of total antioxidant activity. Therefore, this study aimed to evaluate the influence of food preservatives on total antioxidant activity and on the sensory and microbiological quality of acerola tropical juice. The fruits were washed, sanitized (200 ppm sodium hypochlorite), pulped and then were formulated with water and its specific preservatives. The juices were heat treated (90ÂC/60 seconds) and hot filled in glass bottles, which were closed, cooled until 35ÂC and stored at 25ÂC for 180 days. The formulations tested were: control juice without additive (C); juice with addition of 0.004 g/100 mL of sodium metabisulphite (SMS); juice with addition of 0.08 g/100 mL of potassium sorbate (SSP); juice added of 0.05 g/100 mL of sodium benzoate (SBS); juice added of 0.002 g/100 mL of sodium metabisulfite and 0.04 g/100 mL of potassium sorbate S(MS+ SP); juice with addition of 0.002 g/100 mL of sodium metabisulfite and 0.025 g/100 mL of sodium benzoate S(MS + BS). It was carried out chemical determinations for ascorbic acid, total carotenoids, total anthocyanins, total extractable polyphenolics and total antioxidant activity by ABTS and DPPH methods. Commercial sterility testing was performed on samples to determine the hygienic and sanitary processing and to check for any microbiological changes. In sensory acceptance tests were used acerola nectars, prepared by dilution from the acerola tropical juice and added sucrose to obtain 11 ÂBrix, using a 9-point hedonic scale for flavor, color, aroma, sweetness, appearance, body and overall impression. The experiments were performed at three time points (0, 90 and 180 days) and the determinations were made in triplicate. The results were analyzed by the interaction between the juice type and storage time. Regarding anthocyanins content, all samples showed an average of 1.0 mg/100mL (P> 0.05). The acid ascorbic contents remained stable during the storage and ranged from 256.22 mg/100mL (C juice) to 301mg/100mL (SMS and SSP juices). The total carotenoid in treatments with or without preservatives did not vary significantly among themselves, with mean values of 0.04 mg/100mL. The yellow flavonoids showed no significant difference between the juice type (P> 0.05), averaging 5.30 mg/100 mL. For soluble dark pigments, SMS obtained the lowest range in absorbance at 90 days time (0.170 to 0.240), and greater variation for the control juice (from 0.230 to 0.320). All samples showed high losses of phenolics during storage, observing greater losses at times of 0 and 90 days, which ranged from 36.59% for S(BS + MS) and 42.97% for SMS. There was a significant variation of total antioxidant activity with time by the DPPH test (P≤0.05). The values ranged from 877.41 to 978.44 g/g DPPH for C and SMS juices, respectively. A similar behavior was observed for contents analyzed by the ABTS testing: 58.46 mM Trolox/g for SMS and 49.80 mM Trolox/g for control juice. A significant and positive correlation was verified between polyphenols and ABTS (r = 0.78) and DPPH (r = 0.44); anthocyanins and ABTS (r = 0.39) and DPPH (r = 0.44). Yellow flavonoids and ABTS and DPPH assays were negatively and significantly correlated (r = -0.83 and r = -0.52), respectively. There was no significant correlation between ascorbic acid and ABTS and DPPH assays. There was no significant interaction between any treatment and storage time (P> .05). Sodium metabisulphite and its combinations did not influence sensorial acceptance of acerola nectars, with assessments within the acceptable range for all analyzed attributes along storage time. The potassium sorbate and sodium benzoate singly were the additives that contributed most to a higher rejection sensory of products. The employed chemical preservatives, associated with the heat treatment, were effective for maintaining the commercial sterility of acerola tropical juices. / A indÃstria de alimentos utiliza-se de conservantes quÃmicos para prolongar a vida Ãtil de seus produtos e manter suas caracterÃsticas sensoriais e microbiolÃgicas aceitÃveis. Contudo a presenÃa desses conservantes nos alimentos pode interferir na quantificaÃÃo da atividade antioxidante total. Portanto, este trabalho objetivou avaliar a influÃncia dos conservantes alimentares na atividade antioxidante total, na qualidade sensorial e microbiolÃgica de sucos tropicais de acerola. As frutas foram lavadas, sanitizadas (200mg/L de cloro ativo) e despolpadas, em seguida, formuladas com Ãgua e seus conservantes especÃficos. Os sucos foram tratados termicamente (90ÂC/60 segundos) e acondicionados a quente em garrafas de vidro, que foram fechadas, resfriadas atà 35ÂC e armazenadas à temperatura de 25ÂC por 180 dias. As formulaÃÃes testadas foram: suco controle, sem aditivo (C); suco com adiÃÃo de 0,004 g de metabissulfito de sÃdio/100 mL (SMS); suco com adiÃÃo de 0,08g sorbato de potÃssio /100 mL de (SSP); suco adicionado de 0,05g de benzoato de sÃdio /100 mL (SBS); suco com 0,002g de metabissulfito de sÃdio e 0,04 g/100 mL de sorbato de potÃssio/100 mL S(MS+SP)); suco com adiÃÃo de 0,002g/100 mL de metabissulfito de sÃdio e 0,025 g/100 mL de benzoato de sÃdio S(MS+BS). Foram realizadas determinaÃÃes quÃmicas de Ãcido ascÃrbico, carotenÃides totais, antocianinas totais, polifenÃis extraÃveis totais e quantificaÃÃo da atividade antioxidante total pelos mÃtodos ABTS e DPPH. Foi realizado o teste de esterilidade comercial nas amostras para determinar as condiÃÃes higiÃnico-sanitÃrias do processamento e verificar as possÃveis alteraÃÃes microbiolÃgicas. Os testes sensoriais de aceitaÃÃo foram utilizados nÃctares de acerola, preparados por diluiÃÃo a partir do suco tropical de acerola e adicionado de sacarose atà obtenÃÃo de 11 ÂBrix, os quais foram avaliados quanto aos atributos impressÃo global, cor, aparÃncia, aroma, doÃura, sabor e corpo utilizando uma escala hedÃnica estruturada de nove pontos. Os experimentos foram realizados em trÃs tempos (0, 90 e 180 dias) e realizados em triplicata. Os resultados foram tratados por anÃlise de interaÃÃo entre os diferentes tratamentos e tempo de armazenamento. Para o teor de antocianinas, todas as amostras apresentaram mÃdia de 1,0mg/100g (P>0,05). O teor de Ãcido ascÃrbico se manteve estÃvel durante o armazenamento, variando de 256,22 mg/100mL para o suco C, a 301mg/100mL, para os sucos SMS e SSP. Os teores de carotenÃides totais nos tratamentos com ou sem conservantes nÃo diferiram entre si (P>0,05), apresentando valor mÃdio de 0,04mg/100mL. Os flavonoides amarelos nÃo apresentaram diferenÃa significativa (P>0,05), apresentando mÃdia de 5,30mg/100mL. Para pigmentos escuros solÃveis o SMS obteve a menor variaÃÃo na absorbÃncia no tempo de 90 dias (0,170 a 0,240), e a maior variaÃÃo para o suco controle (0,230 a 0,320). Todas as amostras apresentaram perdas elevadas de fenÃlicos durante o armazenamento, observando-se perdas maiores entre 0 e 90 dias, que variaram de 36,59% para S(MS+BS) e 42,97% para SMS. Houve variaÃÃo significativa com o tempo para a atividade antioxidante total pelo ensaio DPPH (P≤0,05). Os valores variaram entre 877,41 e 978,44 g/g DPPH para os sucos C e SMS, respectivamente. Comportamento semelhante foi observado para os teores analisados pelo mÃtodo ABTS, observando-se para o SMS, 58,46 ÂM Trolox/g; e para o suco controle, 49,80 ÂM Trolox/g. A correlaÃÃo positiva e significativa foi verificada entre polifenÃis e o ensaio ABTS (r = 0,78) e para DPPH (r = 0,44). Antocianinas totais e ABTS (r = 0,39) e DPPH (r = 0,44). Os flavonÃides amarelos e os ensaios ABTS e DPPH se correlacionaram negativamente e significativamente (r = -0,83 e r= -0,52; respectivamente). NÃo foi observada interaÃÃo significativa entre os tratamentos e os tempos de armazenamento (P > 0,05). O metabissulfito de sÃdio e suas combinaÃÃes nÃo influenciaram na aceitaÃÃo sensorial dos nÃctares de acerola, com avaliaÃÃes dentro da faixa de aceitaÃÃo para todos os atributos analisados ao longo do tempo de armazenamento. Os aditivos sorbato de potÃssio e benzoato de sÃdio isoladamente contribuÃram para uma maior rejeiÃÃo sensorial dos produtos. Os conservantes quÃmicos utilizados, associados ao tratamento tÃrmico empregado, foram eficientes para a manutenÃÃo da esterilidade comercial dos sucos tropicais de acerola.

A produção de resíduos pelas indústrias alimentícias têm se tornado um problema ambiental. Esses subprodutos sem o devido descarte se acumulam no meio ambiente causando poluição que leva a contaminações que podem provocar danos ao organismo humano. A sustentabilidade deve ser prioritária para o setor de processamento alimentício, realizando o aproveitamento de qualquer despejo industrial que possa se transformar em foco de contaminação ambiental. A cebola (Allium cepa L.) é um dos vegetais mais consumidos mundialmente, e em consequência disso, seu processamento gera uma grande quantidade de resíduos. A casca desse alimento apresenta teores consideráveis de flavonoides, compostos bioativos de elevada capacidade antioxidante. A transformação desse resíduo em um produto de fácil utilização e que possa agregar valor à matrizes alimentares torna-se uma alternativa para utilização desse resíduo que até então não apresenta um aproveitamento valioso para o setor alimentício. Três variedades de casca de cebola foram processadas na forma de pós e analisadas quanto a sua composição química e quanto à sua ação antioxidante. O produto elaborado que apresentou maior capacidade antioxidante foi o pó de casca de cebola roxa que em seguida foi adicionado ao produto cárneo de frango para avaliar seu potencial frente à oxidação lipídica. Houve o controle na estabilidade oxidativa do produto, porém a adição do conservante natural alterou os parâmetros de cor das almôndegas de frango, tornando mais escura a coloração do produto. Diante do exposto, a elaboração do produto a partir do resíduo da cebola pode se constituir em uma alternativa viável aos produtos sintéticos utilizados para fins da conservação em produtos cárneos uma vez que mostrou-se um potencial antioxidante. / Waste production by food industries have become a serious environmental problem. These by-products without proper disposal may accumulate in the environment causing pollution or contamination that may cause damage to the human body. Sustainability should be a priority in processing food sector, realizing use of any industrial dump it can become the focus of environmental contamination. The onion (Allium cepa l.) is one of the most consumed vegetable worldwide, and as a consequence, its processing generates a large amount of waste. The peel of this food has considerable amounts of flavonoids, bioactive compounds of high antioxidant capacity. The transformation of this waste in an easy-to-use product that can add value to food matrices becomes an alternative to the use of this waste that does not present a valuable use for the food industry. Three varieties of onion peel were processed as into powders and their chemical composition, mainly antioxidant activity were analysed. In the present study, the elaborated product that showed the highest antioxidant capacity was the purple onion peel powder which was added to the meat product processed chicken to assess its potential against lipid oxidation. There was the fat decay control of the product, however the addition of natural preservative caused differences in the color parameters of chicken meatballs, making the darker the color of the product. Therefore, the elaboration of a product from the onion waste was a viable alternative to synthetic products used for conservation purposes in meat products and proved to be a potential antioxidant.

Thesis (M. Tech. Environmental health) -- Central University of technology, Free State, 2011 / Microbial pathogens play an important role in the food industry where they could cause disease and subsequently significant economic losses. Limited information is available on the situation with regard to Listeria in food products in South Africa. However, much research is being done in the rest of the world on Listeria indicating serious problems as a result of resistance development against various antimicrobial agents, including the organic acids. It is hypothesised that the situation with regard to resistance development may be more serious than generally admitted. Isolation of 200 different food samples was done by using a slightly modified EN ISO 11290-1/A1:2004 standard method. Identification of presumptive positive colonies was confirmed as Listeria by API (Analytical profile index) Listeria. API positive cultures were subjected to 16S rDNA sequencing to compare and confirm identification. Isolates and standard strains were screened for resistance to food preservatives such as organic acids and antibiotics used in the current treatment regime for Listeria infections. The organisms evaluated included isolated strains namely Listeria monocytogenes, Listeria welshimeri, Listeria innocua and their corresponding ATCC (American type culture colletion) strains. An agar dilution method as described by the Clinical and Laboratory Standard Institute (CLSI) was used to determine the minimum inhibitory concentrations (MICs) of 11 antibiotics and 13 organic acids and salts for all the isolates. Overall antibiotic susceptibility patterns of all the isolates indicated high level susceptibility to all the antibiotics tested. Susceptibility to all the organic acids was notably reduced at pH 7 in all the isolates and control strains. Eight highly susceptible strains were selected for induction and represented each of the species isolated. These isolates were exposed to increasing concentrations of three antibiotics and three organic acids. MICs were again determined for all the induced strains for five antibiotics and three organic acids. Proteins extracted from the induced strains were separated on discontinuous SDS-PAGE slab gels to generate total protein profiles. Notable variations were observed in MICs, although induction with antibiotics as well as organic acids did not result in general resistance development. However, evidence was provided that continuous exposure to antimicrobial agents may cause Listeria spp. to develop resistance to different antimicrobial agents. Further research and in depth studies on mechanisms involved in the development of resistance to food preservatives would, therefore, be required. Finally, it is concluded that Listeria monocytogenes may be a possible threat in the Central South African food industry, which deserves more attention. The situation may actually pose a problem that is overseen, because only a small percentage of people that get sick from food, would seek medical advice.

Mechanisms of adsorption of alkaline copper quat (ACQ) components in wood were investigated with emphasis on: copper chemisorption, copper physisorption, and quat adsorption. Various factors were investigated that could affect the adsorption of individual ACQ components in red pine wood. Copper chemisorption in wood was affected by ligand types coordinating with Cu and the stability of the Cu-ligand complexes in solution. For Cu-monoethanolamine (Cu-Mea) system, the prevailing active solvent species at the solution pH, [Cu(Mea)2-H]+ complexes with wood acid sites and loses one Mea molecule through a ligand exchange reaction. The amount of adsorbed Cu was closely related to the cation exchange capacity of wood. An increase in Mea/Cu ratio increased the proportion of the uncharged Cu-Mea complex and resulted in decreased Cu chemisorption in wood. Copper precipitation is also an important Cu fixation mechanisms of Cu-amine treated wood. X-ray diffraction analysis revealed that in vitro precipitated Cu was a mixture of copper carbonates (azurite and malachite) and possibly Cu2O. Higher concentration Cu-amine solutions retarded the Cu precipitation to a lower pH because of higher free amine in the preservative-wood system. The changes in zeta potential of wood in relationship to the quaternary ammonium (alkyldimethylbenzylammonium chloride: ADBAC) adsorption isotherm showed two different adsorption mechanisms for quat in wood: ion exchange reaction at low concentration and additional aggregation form of adsorption by hydrophobic interaction at high concentration. Because of the aggregation effect, when wood was treated with ACQ, high amounts of ADBAC were concentrated near the surface creating a steep gradient with depth. This aggregated ADBAC was easily leached out while the ion exchanged ADBAC had high leaching resistance. Free Mea and Cu of ACQ components appeared to compete with ADBAC for the same bonding sites in wood.

Mechanisms of adsorption of alkaline copper quat (ACQ) components in wood were investigated with emphasis on: copper chemisorption, copper physisorption, and quat adsorption. Various factors were investigated that could affect the adsorption of individual ACQ components in red pine wood. Copper chemisorption in wood was affected by ligand types coordinating with Cu and the stability of the Cu-ligand complexes in solution. For Cu-monoethanolamine (Cu-Mea) system, the prevailing active solvent species at the solution pH, [Cu(Mea)2-H]+ complexes with wood acid sites and loses one Mea molecule through a ligand exchange reaction. The amount of adsorbed Cu was closely related to the cation exchange capacity of wood. An increase in Mea/Cu ratio increased the proportion of the uncharged Cu-Mea complex and resulted in decreased Cu chemisorption in wood. Copper precipitation is also an important Cu fixation mechanisms of Cu-amine treated wood. X-ray diffraction analysis revealed that in vitro precipitated Cu was a mixture of copper carbonates (azurite and malachite) and possibly Cu2O. Higher concentration Cu-amine solutions retarded the Cu precipitation to a lower pH because of higher free amine in the preservative-wood system. The changes in zeta potential of wood in relationship to the quaternary ammonium (alkyldimethylbenzylammonium chloride: ADBAC) adsorption isotherm showed two different adsorption mechanisms for quat in wood: ion exchange reaction at low concentration and additional aggregation form of adsorption by hydrophobic interaction at high concentration. Because of the aggregation effect, when wood was treated with ACQ, high amounts of ADBAC were concentrated near the surface creating a steep gradient with depth. This aggregated ADBAC was easily leached out while the ion exchanged ADBAC had high leaching resistance. Free Mea and Cu of ACQ components appeared to compete with ADBAC for the same bonding sites in wood.

The foods are excellent nutrient sources for a wide variety of microorganisms, such as filamentous fungi and yeast or bacteria. They are therefore vehicle for a number of infectious diseases. So the man has sought to prevent such proliferation microbial, and maintain the integrity of the product to be sold or consumed, through physical and chemical barriers. To reduce the risk of multiplication of microorganisms and the consequent deterioration of food, the industries are using, in addition to heat treatment, increasingly, chemical additives (preservatives). Among them, sulphur dioxide, sorbic acid and benzoic acid, and derivatives of them, have been employed in the steps of processing. Thus, seeking to provide subsidies to reduce the use of inadequate quantities of preservatives in the food industry, and therefore unfit to ingestion by the population, it was determined in this work the minimum concentrations of sodium metabisulphite, sodium benzoate and sorbate, potassium necessary for the inhibition of the development of heat-resistant fungi, such as Byssochlamys fulva, Neosartorya fischeri and Talaromyces flavus, and of bacteria, such as Salmonella Enteritidis, S. Typhimurium, Escherichia coli and Bacillus cereus in vitro. The growth-media used were Potato-Dextrose-Agar (PDA) and Tripton- Soybean-Agar (acidified with citric acid, pH 3.5 and 5), for tests with fungi and bacteria, respectively. To these media were added the preservatives in different quantities, in order to obtain concentrations of 100, 150, 200, 250, 300, 400, 500, 600, 700, 800 and 1000 mg.L-1 of them. After inoculation and incubation (28 and 30 ± 2 ° C, in the dark), it was observed that the lowest concentrations of sodium metabisulphite showed greater efficiency in inhibiting the growth of all microorganisms, in comparison with the other preservatives tested in vitro. The lowest concentrations of sodium benzoate, on the other hand, were more effective in inhibiting bacterial growth. Already the potassium sorbate showed greater action to combat the heat-resistant fungi. / Fundação de Amparo a Pesquisa do Estado de Alagoas / Os alimentos se constituem em ótimos suprimentos para uma grande diversidade de microrganismos, sendo eles fungos filamentosos e leveduriformes ou bactérias. São, portanto, veículo de uma série de doenças infecciosas. Assim o homem tem buscado evitar tal proliferação microbiana, mantendo a integridade do produto a ser comercializado ou consumido, através de barreiras físicas e químicas. Para reduzir os riscos de multiplicação de microrganismos e a conseqüente deterioração dos alimentos, as indústrias estão utilizando, além do tratamento térmico, cada vez mais, aditivos químicos (conservantes). Entre eles, o dióxido de enxofre, ácido benzóico e o ácido sórbico, além de derivados dos mesmos, têm sido empregados em linhas de processamento. Assim, visando fornecer subsídios para se reduzir a utilização de quantidades inadequadas de conservantes pela indústria de alimentos e, portanto, a ingestão imprópria dos mesmos pela população, determinou-se neste trabalho as concentrações mínimas de metabissulfito de sódio, benzoato de sódio e sorbato de potássio necessárias à inibição do desenvolvimento dos fungos termorresistentes Byssochlamys fulva, Neosartorya fischeri e Talaromyces flavus, e das bactérias Salmonella Enteritidis, S. Typhimurium, Escherichia coli e Bacillus cereus in vitro. Os meios de cultura utilizados foram Batata-Dextrose- Agar (BDA) e Triptona-Soja-Agar (acidificado com ácido cítrico, pH 3,5 e 5), respectivamente para os ensaios com fungos e com bactérias. A esses meios adicionaram-se os conservantes em diferentes quantidades, de modo a obterem-se concentrações compreendidas entre 80 e 1000 mg.L-1 dos mesmos. Após inoculação e incubação (28 e 30 ± 2 ºC, no escuro), observou-se que as menores concentrações do metabissulfito de sódio apresentaram uma maior eficiência em inibir o crescimento de todos os microrganismos em comparação com os demais conservantes testados in vitro. As menores concentrações do benzoato de sódio, por outro lado, foram mais efetivas em inibir o crescimento bacteriano. Já o sorbato de potássio apresentou maior ação no combate aos fungos termorresistentes.

Orientador: Fernando Leite Hoffmann / Banca: Vanerli Beloti / Banca: Crispin Humberto Garcia Cruz / Resumo: No Brasil, o leite possui uma posição de destaque, tanto do ponto de vista social como do econômico. Devido a sua composição peculiar rica em proteínas, gorduras, carboidratos, sais minerais e vitaminas, é considerado como um excelente meio de cultura, pois constitui um ambiente adequado para o desenvolvimento de vários microrganismos. A contaminação microbiana altera a qualidade do alimento e pode agir como veículo de microrganismos patogênicos, que podem provocar o desenvolvimento de doenças infecciosas ou intoxicações alimentares, que colocam em risco a saúde do consumidor e levam à condenação do leite, além da perda da qualidade nutricional do produto. O leite é freqüentemente relacionado com surtos de toxinfecções alimentares, o que justifica a necessidade de avaliações constantes de sua qualidade garantindo a sua condição de consumo. Neste trabalho foram coletadas 23 amostras de leite pasteurizado tipos A, B e C, obtidas no comércio varejista da região de São José do Rio Preto - SP, que foram submetidas as seguintes análises microbiológicas: contagem de bactérias aeróbias mesófilas, enumeração de bolores e leveduras, determinação do Número Mais Provável (NMP) de coliformes totais e fecais, pesquisa de Escherichia coli e de Salmonella spp. Das amostras de leite analisadas foram isoladas 31 culturas de leveduras, submetidas às provas taxonômicas, morfológicas, fisiológicas e de assimilação de diversas fontes de carbono. De acordo com os resultados obtidos, observou-se que apenas 2 (8,70%) amostras apresentaram coliformes fecais acima do limite da legislação, resultado este, inferior aos diversos trabalhos encontrados em leite pasteurizado desenvolvidos em diferentes regiões do Brasil. A presença de Escherichia coli foi constatada em apenas 3 amostras, sendo todas do tipo C. A de Salmonella spp não foi verificada em nenhuma...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In Brazil, milk has a prominent position, as much of social point of view as of economic, due to its particular composition rich in proteins, fats, carbohydrates, mineral salts and vitamins, and consequently it is considered like an excellent medium, because it’s an adequate atmosphere for the development of several microorganism. The microbial contamination changes the food quality, so that it may act like vehicle of pathogenic microorganism, promoting disease or food poisoning, risking consumer’s health and milk may be condemned; besides the loss of product’s nutritional quality. Milk is frequently related to outbreaks of food toxinfection, what justify the need for constant evaluations of its quality as well as the guarantee of its condition of consumption. In this study 23 samples of kinds A, B and C pasteurized milk were obtained from the retail trade of São José do Rio Preto (SP) region and were done the following microbiological analyses: counting of mesophilic aerobic bacteria, listing of molds and yeasts, determination of most probable number (MPN) of total coliforms and fecal coliforms, research of E. coli and Salmonella spp.. Thirty one yeast cultures were isolated from the samples. They were submitted to taxonomic, morphological, and physiological tests and to carbon source assimilation test. According to the results obtained, only 2 (8.70%) had fecal coliforms above the regulation limit. The percentage out of the microbiological standard (8.70%) was lower than several studies found in pasteurized milk, developed in different regions of Brazil. E. coli was detected in 3 samples of kind C. Salmonella spp. was not detected in any sample analyzed, what is in accordance with the current regulation. In conclusion, most of the samples (91.30%) had coliforms a 45°C 4 MPN/mL, xii consequently were labeled as "products in satisfactory sanitary conditions, therefore "products...(Complete abstract click electronic access below) / Mestre

Aujourd’hui, l’impact des conservateurs sur l’homme est remis en question. Il a été entrepris de mieux comprendre les agents antimicrobiens d’un point de vue physico-chimique pour fournir des règles de formulation, qui pourront être utilisées pour proposer à nos laboratoires de formulation des alternatives aux antimicrobiens classiquement utilisés. Ce travail a consisté en la compréhension des caractéristiques structurelles de molécules ayant, entre autre, des propriétés antimicrobiennes ; l’analyse des mécanismes physico-chimiques qui relient ces caractéristiques structurelles à leurs propriétés ; l’optimisation, à la lumière de ces informations, de la formulation de ces molécules. L’étude des familles chimiques, complétée par une étude plus large reliant la modélisation QSAR aux propriétés antimicrobiennes, a permis de conclure que certaines familles d’alcools et dérivés sont des alternatives de choix aux antimicrobiens usuels. Les caractéristiques permettant les meilleures performances étant : une structure asymétrique marquée ; une tête polaire comportant deux groupements hydrophiles, type diol ou mono glycéride ; une longueur de chaîne apolaire comprenant entre 6 et 12 carbones, avec un optimum entre 7 et 10 carbones ; le calcul du HLB résultant de ces caractéristiques donne un HLB compris entre 7 et 11. Les dérivés acides ou la famille des décanols ont permis de préciser l’intérêt d’une insaturation ou la présence d’un β-hydroxy. L’impact de la formulation d’une molécule modèle, le caprate/caprylate de glycérol a montré que dans une émulsion directe, les tensioactifs hydrophiles piègent dans leurs micelles l’actif, ce qui induit une diminution de l’activité antimicrobienne. L’épaisseur hydrophile des têtes polaires empêchent le passage de l’actif en dehors de la micelle vers le micro-organisme. Il est donc recommandé d’utiliser la quantité de tensioactif utile pour tapisser sans excès la surface des gouttes d’huiles. L’épaisseur des têtes polaires hydrophile peut être réduite en sélectionnant les tensioactifs, par exemple des ioniques phosphatés. D’autres paramètres ont été démontrés comme influant, dans une moindre mesure : il est recommandé de privilégier les gélifiants aux tensioactifs lors de l’élaboration d’une texture, d’optimiser le taux d’actif antimicrobien sur taux d’huile et d’utiliser de préférence des huiles peu solvantes de l’actif. / Nowadays, preservatives in personal care are obviously a current issue. The aim of this study was to find out rules for molecular design and formulation conception dealing with a physico-chemistry point of view, in order to avoid classic preservatives. We have studied on structural features for antimicrobial activity and their behaviors in direct emulsions. After studies of various structural families, and a wide QSAR analysis, the result was that molecule with one or two alcohol groups are among the better antimicrobial agents. Especially, we focus on some characteristics, which improve considerably the antimicrobial activity : an asymmetric structure ; a two-hydroxylated polar head like diols or monoglycerids ; the main hydrocarbon tail should contain between 6 and 12 carbons with an optimum between 7 and 10 ; with these characteristics, the HLB value must be located between 7 and 11. An unsaturated bond in a linear chain or a β-hydroxylated group leads to an increase of decontamination. The impact of the formulation in direct emulsions of a model molecule, glycerol octanoate/decanoate, seemed to show that hydrophilic surfactants trap in their micelles the active product, which induces a decrease of the antimicrobial activity. The hydrophilic thickness of polar heads prevents the passage of the active product beyond the micelle to the micro-organism. It is therefore recommended that the quantity of surfactant used to create and stabilize the drops of oil be reduce to a minimum. The hydrophilic thickness of polar heads may be reduced by selecting the surfactants, for example an ionic phosphate. Other parameters have been demonstrated as affecting, to a lesser extent: it is recommended polymers and micro gels are used rather than surfactants in the preparation of a texture to customize the ration antimicrobial on oil and to use preferably non-polar oil.

The purpose of this research was to quantify properties of strandboard panels manufactured with various preservatives at loading levels effective against native termites. Panels were manufactured using nine different formulations. The method of preservative addition was also examined for some preservative formulations, increasing the total number of preservative treatments to twelve. Panels were manufactured with one target retention for each preservative treatment. An effective preservative loading relative to termites was established by previous studies or referencing current standards. Mechanical testing performed included static bending and internal bond. Physical testing included water absorption, thickness swell, and linear expansion. Few treatments met the Canadian standards for strandboard, but several preservatives performed well. Copper naphthenate, bifenthrin, and copper betaine each deserve further investigation to optimize manufacturing variables to meet required mechanical and physical properties.

O potencial farmacológico de espécies do gênero Lippia no tratamento de infecções é conhecido popularmente, assim foi considerado o estudo da atividade da Lippia salviaefolia nativa do cerrado brasileiro. O objetivo do trabalho foi avaliar a atividade antimicrobiana de extratos de Lippia salviaefolia Cham. e sua citotoxicidade, visando aplicação como conservante natural em formulações cosméticas. O ensaio antimicrobiano foi realizado através do método de difusão em placa e determinação do CMI por de microdiluição em microplacas, utilizando os microrganismos: P. aeruginosa ATCC 9027, S. aureus ATCC 6538, E. coli ATCC 8739, C. albicans ATCC 10231. Desenvolveu-se e avaliou-se a estabilidade acelerada de cremes, geis e xampus contendo o extrato de Lippia salviaefolia. As formulações de melhor desempenho quanto à estabilidade foram submetidas ao teste de eficácia de conservante. Avaliou-se segurança das formulações in vitro, em substituto cutâneo dermo-epidérmico por meio de estudos histológicos e o teste de citotoxicidade em cultura de queratinócitos humanos. No teste de atividade antimicrobiana verificou-se que a fração de acetato de etila e a fração de clorofórmio foram frações mais ativas com CMI de 0,2 % para bactérias e fungos. Os testes de eficácia de conservante das formulações contendo fr. ac. etila de L. salviaefolia apresentaram atividade antimicrobiana para bactérias e C. albicans em creme, gel e xampu, para A. niger apresentaram atividade adequada somente em xampu. No teste de citoxicidade foi verificado segurança em concentrações a partir de 0,05 %. Sendo que na concentração de 0,2 %, correspondente ao CMI, se atinge a faixa de segurança apenas com meia hora de contato. Os resultados sugerem que a fração de acetato de etila da Lippia salviaefolia Cham. pode ser utilizada como conservante natural em produtos cosméticos. / The pharmacological potential of species of the Lippia in the treatment of infections has been known popularly, thus was considered the study of the activity of the native salviaefolia Lippia of the Brazilian Cerrado. The purpose of the work was to evaluate the antimicrobial activity of extracts of Lippia salviaefolia Cham. and its citotoxicy aiming the application as natural preservative in cosmetic formulations. The assay antimicrobial was carried through the method of diffusion in plate and determination of the MIC by microdilution, having used the microorganisms: P.aeruginosa ATCC 9027, S. aureus ATCC 6538, E. coli ATCC 8739, C. albicans ATCC 10231. It has developed and evaluated the stability of creams, gels and xampus with the extract of Lippia salviaefolia Cham. The formulations of the best stability performance have submitted to preservative efficacy test. The safe of the formulations has histological evaluated by in vitro. In the test of antimicrobial activity it has verified that the ethyl acetate and the chloroform fraction have been the most active and with CMI of 0.2 % for bacteria and fungus. The tests of effectiveness of preservatives have showed of the formulations contend the ethyl acetate fraction presented antimicrobial activity for bacteria and C. albican in cream, gel and shampoo. On the other hand, against A.niger it has been suitable activity in shampoo. In the citotoxity test, the 0,05 % ethyl acetate fraction has presented interval of security. And in the concentration of 0,2%, corresponding to CMI, safety\'s strip is just reached with half hour of contact. The results have suggested that the ethyl acetate extract of the Lippia salviaefolia Cham. should be used as natural preservative in cosmetic products.