The main objective of this study was to determine the pressure induced inactivation mechanism of pressure-resistant Escherichia coli O157:H7 933 and Staphylococcus aureus 485 in a low acid food. Firstly, inactivation curves of pathogens were obtained at 200 to 400 MPa at 40&ordm / C in peptone water and carrot juice. First-order and Weibull models were fitted and Weibull model described the inactivation curves of both pathogens more accurately than first-order model, revealing that food systems could exhibit either protective or sensitizing effect on microorganisms. Carrot juice had a protective effect on E. coli O157:H7 whereas it had a sensitizing effect on S. aureus, due to the naturally occurring constituents or phytoalexins in carrot roots that could have a toxic effect. Secondly, scanning electron microscopy (SEM) and fluorescent microscopy images of studied pathogens were taken. Developed software was used to analyze SEM images to calculate the change in the view area and volume of cells. Membrane integrity of pressurized cells was also examined using fluorescent microscopy images. The increase in average values of the view area and volume of both pathogens was significant for the highest pressure levels studied. The increase in volume and the view area could be explained by the modification of membrane properties, i.e., disruption or increase in permeability, lack of membrane integrity, denaturation of membrane-bound proteins and pressure-induced phase transition of membrane lipid bilayer. The change in volume and the view area of microorganisms added another dimension to the understanding of inactivation mechanisms of microbial cells by HHP.

High pressure applications are alternatives to conventional methods in food processing. They provide interesting modifications in food structures which leads to new product formulations. The aim of this study is to identify the effects of two different treatments, high hydrostatic pressure (HHP) and high dynamic pressure (HDP) on stability and rheological properties of model oil-in-water emulsions. Microfluidization was selected among the HDP homogenization techniques. The performance of each process was analyzed in terms of rheological modifications and emulsion stability improvements compared to the coarse emulsions which were prepared with colloid mill homogenization. Stability of emulsions was determined comparatively by using an analytical photo-centrifuge device employing a novel analysis technology. Whey protein isolate (WPI) was used as an emulsifier in combination with a food polysaccharide as a stabilizer. The polysaccharides used were xanthan gum, guar gum and locust bean gum which are widely used stabilizing ingredients in food industry. The effective disruption of oil droplets and the degradation of polysaccharides by the shear forces under high pressure in HDP microfluidization yielded finer emulsions with lower viscosities. The finer emulsions obtained with this homogenization technique led to distinctive improvements in emulsion stability. On the other hand, the improvements in stability by HHP treatment were due to the thickening of the emulsions mainly induced by protein unfolding. The corresponding increases in viscosity were intensified in emulsion formulations with higher oil content. Apart from these, HHP treatment was found to be relatively more contributing to the enhancements in viscoelastic properties.

The ability of high hydrostatic pressure (HHP) to extend the shelf life of Atlantic mackerel (Scomber scombrus) and red mullet (Mullus barbatus) was assessed in this study. For that purpose, fillets of both atlantic mackerel and red mullet were subjected to pressure treatments at 200, 300, 400 MPa at 5, 10, 15&deg / C for 5 and 15 minutes. The influence of the treatments on Trimethylamine Nitrogen (TMA-N) level, lipid oxidation stability (Thiobarbituric Acid, TBA level) was investigated as well as color changes. The suitable combinations for Atlantic mackerel were determined as 200 MPa, 15&deg / C for 5 min and 400 MPa, 5&deg / C for 5 min / and for red mullet 200 MPa, 15&deg / C for 5 min. In the second stage, the shelf life of fish samples, which were treated with these conditions and stored at 4&deg / C, were studied by measurement of pH, color, sensorial features (appearance and odor), TMA-N, TBA, Total Volatile Basic Nitrogen (TVB-N), Histamine and Total Mesophilic Aerobic Count (TMAC) formations. Based on these analyses, the unpressurised mackerel samples were acceptable up to only 7 days compared to 17 and 19 days after 200 and 400 MPa treatments / respectively. For red mullet samples pressurization at 200 MPa extended the shelf life an additional 3 days (from 1 week to 10 days). HHP treatment in combination with chilled storage can improve the shelf life and quality of fish.

In this study, the efficiency of high-pressure treatment (HHP, 250 - 450 MPa) with the combination of heat treatment (20 - 70oC) on peroxidase (POD) and lipoxygenase (LOX) inactivation in green beans, green peas and carrots was investigated for blanching purposes. Two steps treatments were also performed by pressurization at 250 MPa at 20&deg / C for 15- 60 min and then by water blanching at 40-70&deg / C. For green beans, 25 % residual activity was obtained by water blanching at 50&deg / C for 15 min after the pressurization at 250 MPa for 60 min. The enzyme inactivation in green peas was 78 % with water blanching at 50oC for 30 min after holding at 250 MPa for 60 min. When the carrots were water blanched at 50&deg / C for 30 min after HHP treatment at 250 MPa for 15min, 13 % residual activity was obtained. During the experiments, the stability gain or the activation of latent form of the enzymes were observed prior to inactivation. For carrots, LOX activity could not be measured. For green beans, 22 % LOX inactivation was obtained by holding at 250 MPa for 15 min and then by water blanching at 40&deg / C for 5 min. For green peas, the multiple treatment of 250 MPa for 30 min and water blanching at 50&deg / C for 30 min provided 70% inactivation. To obtain the enzyme inactivation higher than 90 % for blanching purposes, the pressure applied must be increased. Key words: high hydrostatic pressure, green bean, green pea, carrot, blanching, peroxidase, lipoxygenase

The quality and shelf-life of pressure processed (150, 200 and 250 MPa at 25 and 35&deg / C for 5, 10 and 15 minutes) orange, tomato and carrot juices were compared to fresh and thermally pasteurised (60&deg / C for 5, 10 and 15 minutes and 80&deg / C for 1 minute) juices. Treatments were capable of microbial inhibition of juices to non-detectable levels. The change in ascorbic acid content of HHP treated juices was not statistically significant (p&gt / 0.05). Both heat treatments at 60 and 80&deg / C, displayed a significant loss and induced a decrease in the free radical scavenging activity but was not affected by HHP treatments. Pressurization at 250 MPa at 35&deg / C for 15 minutes and thermal pasteurization at 80&deg / C for 1 minute and stored at 4 and 25&deg / C for shelf-life analysis. HHP treated juices showed a small loss of antioxidants (below 10%) at both storage temperatures whereas the loss is higher (about 30%) in the heat treated juices through shelf life (30 days). The pressurized juices, stored at 25&deg / C, contained ascorbic acid better than heat treated ones after 30 days. The total color changes were minor (&amp / #8710 / E=10) for all pressurized juices but for heat pasteurized samples, higher as a result of insufficient antioxidant activity. The pH of juices was not affected by treatment, storage temperature or time. HHP yielded a better product, regarding the studied parameters of the juices compared to the conventional pasteurization. Therefore, HHP treatment (250 MPa, 35&deg / C for 15 minutes) can be recommended for industrial production of fresh fruit and vegetables.

O presente trabalho teve como objetivo estudar o potencial de diferentes tecnologias na extração de pectina da casca do maracujá e está dividido em quatro etapas. A primeira etapa do trabalho consistiu em realizar a obtenção e caracterização da farinha da casca do maracujá por diferentes métodos de secagem (estufa a 60 ºC com circulação de ar e liofilização). Os resultados desta primeira etapa mostraram que a farinha da casca do maracujá, obtida por ambos os tratamentos de secagem, apresentou elevado conteúdo de fibras alimentares totais (63,98-72,62 % b.s) e conteúdo de pectina, que variou entre 6,98 e 19,6 % (b.s). O conteúdo de pectina foi maior para a amostra liofilizada e esses coprodutos apresentaram capacidade de retenção de água entre 6,30 e 14,9 g água/g amostra e capacidade de retenção de óleo que variou entre 2,6 e 6,5 g óleo/g amostra, sendo os maiores valores para as amostras liofilizadas. A segunda etapa do trabalho teve como objetivo estudar a extração da pectina assistida pela tecnologia de campo elétrico moderado e compará-la com a extração convencional da pectina. Para isso, diferentes condições de tempo de extração, temperatura, pH e tensão do campo elétrico moderado foram aplicadas na farinha da casca do maracujá. O rendimento de extração de pectina foi de 6,20 % (b.s) quando as condições de extração foram pH 2,0, razão sólido:líquido 1:30, 100 V, 50 °C e 15 min; para as mesmas condições sem o uso do campo elétrico moderado o rendimento obtido foi de 4,80 % (b.s). Na terceira etapa, a pesquisa foi voltada para a extração da pectina assista por alta pressão hidrostática. Para a realização dos ensaios dois planejamentos experimentais foram realizados. O primeiro planejamento consistiu em determinar as melhores condições de temperatura e pressão para a extração da pectina que, posteriormente, foram utilizadas como pré-tratamento para a extração convencional. O segundo planejamento foi realizado para determinar as melhores condições de tempo e temperatura da extração convencional, utilizando a alta pressão como pré-tratamento. Foi observado que a alta pressão hidrostática, combinada com temperatura moderada (300 MPa e 50 ºC ), tem potencial para ser utilizada como pré-tratamento na extração convencional, levando a um rendimento de extração de pectina de 14,34 %. Por fim, a última etapa do presente trabalho foi a extração da pectina assistida por ultrassom, tendo sido desenvolvido um planejamento experimental com duas variáveis, temperatura e intensidade de potência do ultrassom. Os resultados desta etapa demostraram que um maior rendimento de extração (12,67 % b.s) foi obtido na maior temperatura e intensidade de potência, 85 ºC e 664 W/cm2, respectivamente. Os resultados demostraram que a pectina tem potencial para ser melhor extraída da casca de maracujá com o uso das tecnologias emergentes empregadas neste trabalho, pois obteve-se um maior rendimento de extração em menor tempo de processo, quando comparada com a extração convencional. / The aim of this work was to study the potential of different technologies for extraction of pectin from passion fruit peel. The work is divided in four steps. The first step was performed to obtain and characterize the passion fruit peel powder by convective hot air-drying at 60 ºC and freeze-drying. The results showed that the passion fruit powder obtained by different methods of dehydration, had a high content of dietary fiber (63.98-72.62 % d.m) and the content of pectin ranged between 6.98 from 19.6 % (d.m). The content of pectin was high in freeze-dried samples. In addition, these fiber-rich co-products have potential applications as ingredients in products requiring hydration and viscosity development due to their high total dietary fiber content and good technological proprieties, especially their water holding (6.30-14.9 g H2O/g) and oil holding capacities (2.6–6.5 g oil/g), especially for the freeze-dried samples. The purpose of the second step was to explore the conventional and moderate electric field extractions of pectin from passion fruit peel. Different conditions of time, pH, temperature and voltage were applied. The extraction yield of pectin was 6.20 % (d.m) when the extraction conditions were pH 2.0, solid:liquid ratio 1:30, 100V, 50 ºC and 15 minutes; for the same conditions, without moderate electric field, the yield was 4.80 % (b.s). In the third step, the aim was to investigate the potential of high pressure to extract the pectin from passion fruit peel. Two experimental designs were performed; the first was used to determine the optimal conditions of pressure and temperature for pectin extraction and use these conditions as a pre-treatment for conventional extraction. The second experimental design was performed to determine the best conditions of the time and temperature using high pressure as a pre-treatment. The results showed that the yield of extraction enhance twice (7.4 to 14.34 %) when high pressure (300 MPa and 50 ºC) was used as a pre-treatment, using the same conditions of conventional extraction. Finally, the last step of this work was to explore the pectin extraction assisted by ultrasound using an experimental design. The independent variables were temperature and power intensity. The highest yield (12.67 %) of pectin was obtained using power intensity of 644 W/cm2 and temperature of 85 ºC. The results showed that the pectin from passion fruit peel can be extracted using emerging technologies, since the yield of extraction was high in less time comparing with conventional extraction.

O presente trabalho teve como objetivo estudar o potencial de diferentes tecnologias na extração de pectina da casca do maracujá e está dividido em quatro etapas. A primeira etapa do trabalho consistiu em realizar a obtenção e caracterização da farinha da casca do maracujá por diferentes métodos de secagem (estufa a 60 ºC com circulação de ar e liofilização). Os resultados desta primeira etapa mostraram que a farinha da casca do maracujá, obtida por ambos os tratamentos de secagem, apresentou elevado conteúdo de fibras alimentares totais (63,98-72,62 % b.s) e conteúdo de pectina, que variou entre 6,98 e 19,6 % (b.s). O conteúdo de pectina foi maior para a amostra liofilizada e esses coprodutos apresentaram capacidade de retenção de água entre 6,30 e 14,9 g água/g amostra e capacidade de retenção de óleo que variou entre 2,6 e 6,5 g óleo/g amostra, sendo os maiores valores para as amostras liofilizadas. A segunda etapa do trabalho teve como objetivo estudar a extração da pectina assistida pela tecnologia de campo elétrico moderado e compará-la com a extração convencional da pectina. Para isso, diferentes condições de tempo de extração, temperatura, pH e tensão do campo elétrico moderado foram aplicadas na farinha da casca do maracujá. O rendimento de extração de pectina foi de 6,20 % (b.s) quando as condições de extração foram pH 2,0, razão sólido:líquido 1:30, 100 V, 50 °C e 15 min; para as mesmas condições sem o uso do campo elétrico moderado o rendimento obtido foi de 4,80 % (b.s). Na terceira etapa, a pesquisa foi voltada para a extração da pectina assista por alta pressão hidrostática. Para a realização dos ensaios dois planejamentos experimentais foram realizados. O primeiro planejamento consistiu em determinar as melhores condições de temperatura e pressão para a extração da pectina que, posteriormente, foram utilizadas como pré-tratamento para a extração convencional. O segundo planejamento foi realizado para determinar as melhores condições de tempo e temperatura da extração convencional, utilizando a alta pressão como pré-tratamento. Foi observado que a alta pressão hidrostática, combinada com temperatura moderada (300 MPa e 50 ºC ), tem potencial para ser utilizada como pré-tratamento na extração convencional, levando a um rendimento de extração de pectina de 14,34 %. Por fim, a última etapa do presente trabalho foi a extração da pectina assistida por ultrassom, tendo sido desenvolvido um planejamento experimental com duas variáveis, temperatura e intensidade de potência do ultrassom. Os resultados desta etapa demostraram que um maior rendimento de extração (12,67 % b.s) foi obtido na maior temperatura e intensidade de potência, 85 ºC e 664 W/cm2, respectivamente. Os resultados demostraram que a pectina tem potencial para ser melhor extraída da casca de maracujá com o uso das tecnologias emergentes empregadas neste trabalho, pois obteve-se um maior rendimento de extração em menor tempo de processo, quando comparada com a extração convencional. / The aim of this work was to study the potential of different technologies for extraction of pectin from passion fruit peel. The work is divided in four steps. The first step was performed to obtain and characterize the passion fruit peel powder by convective hot air-drying at 60 ºC and freeze-drying. The results showed that the passion fruit powder obtained by different methods of dehydration, had a high content of dietary fiber (63.98-72.62 % d.m) and the content of pectin ranged between 6.98 from 19.6 % (d.m). The content of pectin was high in freeze-dried samples. In addition, these fiber-rich co-products have potential applications as ingredients in products requiring hydration and viscosity development due to their high total dietary fiber content and good technological proprieties, especially their water holding (6.30-14.9 g H2O/g) and oil holding capacities (2.6–6.5 g oil/g), especially for the freeze-dried samples. The purpose of the second step was to explore the conventional and moderate electric field extractions of pectin from passion fruit peel. Different conditions of time, pH, temperature and voltage were applied. The extraction yield of pectin was 6.20 % (d.m) when the extraction conditions were pH 2.0, solid:liquid ratio 1:30, 100V, 50 ºC and 15 minutes; for the same conditions, without moderate electric field, the yield was 4.80 % (b.s). In the third step, the aim was to investigate the potential of high pressure to extract the pectin from passion fruit peel. Two experimental designs were performed; the first was used to determine the optimal conditions of pressure and temperature for pectin extraction and use these conditions as a pre-treatment for conventional extraction. The second experimental design was performed to determine the best conditions of the time and temperature using high pressure as a pre-treatment. The results showed that the yield of extraction enhance twice (7.4 to 14.34 %) when high pressure (300 MPa and 50 ºC) was used as a pre-treatment, using the same conditions of conventional extraction. Finally, the last step of this work was to explore the pectin extraction assisted by ultrasound using an experimental design. The independent variables were temperature and power intensity. The highest yield (12.67 %) of pectin was obtained using power intensity of 644 W/cm2 and temperature of 85 ºC. The results showed that the pectin from passion fruit peel can be extracted using emerging technologies, since the yield of extraction was high in less time comparing with conventional extraction.

O presente trabalho teve como objetivo estudar o potencial de diferentes tecnologias na extração de pectina da casca do maracujá e está dividido em quatro etapas. A primeira etapa do trabalho consistiu em realizar a obtenção e caracterização da farinha da casca do maracujá por diferentes métodos de secagem (estufa a 60 ºC com circulação de ar e liofilização). Os resultados desta primeira etapa mostraram que a farinha da casca do maracujá, obtida por ambos os tratamentos de secagem, apresentou elevado conteúdo de fibras alimentares totais (63,98-72,62 % b.s) e conteúdo de pectina, que variou entre 6,98 e 19,6 % (b.s). O conteúdo de pectina foi maior para a amostra liofilizada e esses coprodutos apresentaram capacidade de retenção de água entre 6,30 e 14,9 g água/g amostra e capacidade de retenção de óleo que variou entre 2,6 e 6,5 g óleo/g amostra, sendo os maiores valores para as amostras liofilizadas. A segunda etapa do trabalho teve como objetivo estudar a extração da pectina assistida pela tecnologia de campo elétrico moderado e compará-la com a extração convencional da pectina. Para isso, diferentes condições de tempo de extração, temperatura, pH e tensão do campo elétrico moderado foram aplicadas na farinha da casca do maracujá. O rendimento de extração de pectina foi de 6,20 % (b.s) quando as condições de extração foram pH 2,0, razão sólido:líquido 1:30, 100 V, 50 °C e 15 min; para as mesmas condições sem o uso do campo elétrico moderado o rendimento obtido foi de 4,80 % (b.s). Na terceira etapa, a pesquisa foi voltada para a extração da pectina assista por alta pressão hidrostática. Para a realização dos ensaios dois planejamentos experimentais foram realizados. O primeiro planejamento consistiu em determinar as melhores condições de temperatura e pressão para a extração da pectina que, posteriormente, foram utilizadas como pré-tratamento para a extração convencional. O segundo planejamento foi realizado para determinar as melhores condições de tempo e temperatura da extração convencional, utilizando a alta pressão como pré-tratamento. Foi observado que a alta pressão hidrostática, combinada com temperatura moderada (300 MPa e 50 ºC ), tem potencial para ser utilizada como pré-tratamento na extração convencional, levando a um rendimento de extração de pectina de 14,34 %. Por fim, a última etapa do presente trabalho foi a extração da pectina assistida por ultrassom, tendo sido desenvolvido um planejamento experimental com duas variáveis, temperatura e intensidade de potência do ultrassom. Os resultados desta etapa demostraram que um maior rendimento de extração (12,67 % b.s) foi obtido na maior temperatura e intensidade de potência, 85 ºC e 664 W/cm2, respectivamente. Os resultados demostraram que a pectina tem potencial para ser melhor extraída da casca de maracujá com o uso das tecnologias emergentes empregadas neste trabalho, pois obteve-se um maior rendimento de extração em menor tempo de processo, quando comparada com a extração convencional. / The aim of this work was to study the potential of different technologies for extraction of pectin from passion fruit peel. The work is divided in four steps. The first step was performed to obtain and characterize the passion fruit peel powder by convective hot air-drying at 60 ºC and freeze-drying. The results showed that the passion fruit powder obtained by different methods of dehydration, had a high content of dietary fiber (63.98-72.62 % d.m) and the content of pectin ranged between 6.98 from 19.6 % (d.m). The content of pectin was high in freeze-dried samples. In addition, these fiber-rich co-products have potential applications as ingredients in products requiring hydration and viscosity development due to their high total dietary fiber content and good technological proprieties, especially their water holding (6.30-14.9 g H2O/g) and oil holding capacities (2.6–6.5 g oil/g), especially for the freeze-dried samples. The purpose of the second step was to explore the conventional and moderate electric field extractions of pectin from passion fruit peel. Different conditions of time, pH, temperature and voltage were applied. The extraction yield of pectin was 6.20 % (d.m) when the extraction conditions were pH 2.0, solid:liquid ratio 1:30, 100V, 50 ºC and 15 minutes; for the same conditions, without moderate electric field, the yield was 4.80 % (b.s). In the third step, the aim was to investigate the potential of high pressure to extract the pectin from passion fruit peel. Two experimental designs were performed; the first was used to determine the optimal conditions of pressure and temperature for pectin extraction and use these conditions as a pre-treatment for conventional extraction. The second experimental design was performed to determine the best conditions of the time and temperature using high pressure as a pre-treatment. The results showed that the yield of extraction enhance twice (7.4 to 14.34 %) when high pressure (300 MPa and 50 ºC) was used as a pre-treatment, using the same conditions of conventional extraction. Finally, the last step of this work was to explore the pectin extraction assisted by ultrasound using an experimental design. The independent variables were temperature and power intensity. The highest yield (12.67 %) of pectin was obtained using power intensity of 644 W/cm2 and temperature of 85 ºC. The results showed that the pectin from passion fruit peel can be extracted using emerging technologies, since the yield of extraction was high in less time comparing with conventional extraction.

Orientador: Carlos Francisco Sampaio Bonafe / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-10T21:45:48Z (GMT). No. of bitstreams: 1 Bispo_JoseAiltonConceicao_D.pdf: 6481701 bytes, checksum: eac9f13bfaae7f2d8718ad2773ff3e57 (MD5) Previous issue date: 2006 / Resumo: Sistemas reacionais em fase líquida compreendem boa parte dos processos físicoquímicos que são estudados para fins de pesquisa e aplicação industrial. Estes estudos são conduzidos em geral de forma a se obter parâmetros de caracterização que tornem possível a padronização e otimização de processos, sejam eles de aplicação químico industrial ou biotecnológica. Em meio a esta necessidade de compreensão de diversos processos físicoquímicos, um ponto que chama a atenção de muitos grupos de pesquisa é a necessidade de aperfeiçoamento dos sistemas de caracterização e modelagem destes processos de forma a tornálos mais informativos e eficientes, tanto no que diz respeito à sua capacidade de caracterização quanto à sua capacidade de previsão. Neste contexto, a maior parte dos sistemas estudados têm como base a metodologia de caracterização desenvolvida por Gibbs-Duhem a aprtir do comportamento de gases ideais. Desvios no comportamento pressão volume são, nestes casos, corrigidos através do parâmetro definido como atividade. Assim, a estrutura de base desenvolvida por Gibbs-Duhem para gases ideais é mantida, deixando praticamente inalterada a relação que expressa a variação do potencial químico. No presente estudo observou-se que este tipo de abordagem e caracterização não produz resultados satisfatórios para o processo de dissociação por pressão de grandes agregados protéicos, e em alguns casos gerou dificuldades matemáticas que impediram a sua implementação em processos bastante comuns. A solução encontrada e o objetivo desta tese foram então o de conduzir uma nova abordagem para a caracterização destes sistemas que envolvem a dissociação por pressão de macromoléculas a partir de equações mais flexíveis para as mudanças de volume que as dos g ases ideais utilizadas por Gibbs-Duhen. O resultado desta nova abordagem foram relações com grande potencial de informação, de fácil aplicação e com uma alta capacidade de previsão / Abstract: The reaction processes involving macromolecules in liquid phase represent a significant part of the studies aiming industrial and technological applications.These studies are in general performed aiming access the parameters of characterization that allows the optimiz ation of chemical and biotechnological processes. In this view, the needing of understand distinct physicochemical processes represent a point that deserves the attention of many laboratories due to the needing of improvement modeling systems that furnish more efficient and precise information about the protein behavior under solution. Although the most of the studies performed aiming to reach this goal are based on the processes of characterization developed by Gibbs-Duhen, deviations on the pressure/volume furnished by the ideal gas equation are usually observed and corrected by means of the activity coefficient. Thus, the structural basis of the Gibbs-Duhem approach is maintained in despite of more complexes systems sho ws a nonlinearbehavior that produces in some cases significant deviations. In the present studie s we observed that the processes of pressure dissociation/denaturation of macromolecules leads to significant errors in respect to the experimental data. In this case the correction of these approach by means of the activity coefficient was not possible since the characterization equations became very complex. The goal of the present work was than to find a new description for these complex systems that allows to determine the properties of system and a precise thermodynamic modeling of these kind of processes / Doutorado / Bioquimica / Doutor em Biologia Funcional e Molecular

Orientadores: Carlos Francisco Sampaio Bonafé, Marcelo Lancellotti / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-21T08:59:23Z (GMT). No. of bitstreams: 1 Souza_AncelmoRabelo_M.pdf: 2604011 bytes, checksum: 68977693022bd1bef29d71963a2562d5 (MD5) Previous issue date: 2012 / Resumo: Mycobacterium abscessus é um importante patógeno de origem hospitalar que contamina materiais cirúrgicos e biofarmacêuticos. Estes quando mal esterilizados tornam-se agentes infectantes gerando graves patologias nas pessoas que os utilizam. A crescente incidência desse patógeno, as dificuldades de tratamento, a gravidade clínica e, a dificuldade de esterilizar fômites contaminados com este patógeno motivou a investigação de processos alternativos de esterilização. Atualmente, utiliza-se a alta pressão hidrostática como método bastante adequado para reduzir a carga microbiana e esterilizar materiais hospitalares e biofarmacêuticos que são sensíveis à autoclave. Desta forma, investigou-se a inativação de M. abscessus induzida por pressão em diferentes condições de temperatura e de pH visando progredir em direção a um método de esterilização. De acordo com os resultados obtidos, tratamentos a 250 MPa não inativaram significativamente (5 a 8 ordens de magnitude) a bactéria em até 90 min a 20°C. Entretanto em -15°C a inativação foi completa. O tratamento a 250 MPa a 60ºC por 45 min promoveu significativa inativação bacteriana de até 9 unidades logarítmicas, incluindo o teste com PVC. Além disso, extremos de pH (4 ou 9) também diminuíram acentuadamente o número de bactérias tratados por alta pressão (250 MPa), com inativação completa após 45 min. Assim, este trabalho torna-se de suma importância, uma vez que aponta para o melhoramento de protocolos de descontaminação de fômites hospitalares / Abstract: Mycobacterium abscessus is an important hospital-acquired pathogen which induces infections from medical surgical and biopharmaceutical materials. The increasing incidence of this pathogen, the difficulties of treatment and clinical seriousness motivates the investigation of alternatives in sterilization processes. High hydrostatic pressure is a very adequate method for reducing microbial load and for sterilization of hospital materials and biopharmaceutical that are sensitive to autoclaving. We investigated the pressure-induced inactivation of M. abscessus combined with different temperatures and pH conditions aiming improvements toward a sterilization methodology. According to our findings, treatment at 250 MPa did not inactivate the bacteria significantly (5 to 8 orders of magnitude) up to 90 min at 20 oC, nevertheless at -15°C the inactivation was complete. The treatment at 250 MPa and 60ºC or above by 45 min promoted significant bacteria inactivation, at least 9 logarithmic units, including the test PVC. Extremes of pH values (4 or 9) also decrease very much the bacteria number induced by pressure (250 MPa), with complete inactivation at 45 min. The better knowledge of the effect of high hydrostatic pressure in micobacteria may contribute to improvements in the decontamination of medical materials and pharmaceuticals / Mestrado / Bioquimica / Mestre em Biologia Funcional e Molecular