Salmonella embedded biofilms were formed on whole black peppercorns and treated with ethanol vapor under atmospheric pressure conditions and under vacuum assisted pressure conditions. The effect of ethanol vapor, heat and vacuum pressure on the survival of multiple Salmonella enterica serovars within a biofilm contained on low moisture food products (Aw 0.30-0.40) was observed in this study. Samples were exposed to zero, one, five and ten minute ethanol vapor treatments at atmospheric boiling temperature (Atmospheric Pressure Boiling Method, AB), and at reduced temperature and pressure conditions, -20 inHg (Vacuum-Assisted Boiling Method, VB). The AB treatments showed 4.0 log CFU/g reductions on nonselective media that included native microbiota, and 6.0 log CFU/g reductions on Salmonella selective media. The VB treatments showed 2.69 log reductions on Tryptic Soy Agar and 4.55 log reductions on Xylose Lysine Tergitol-4 agar. Ethanol vapor treatments should be further investigated as an alternative to ethylene oxide or ionizing radiation processes to treat dry spices to control Salmonella. / Master of Science in Life Sciences

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O pedúnculo de caju é carnoso, suculento, nutritivo, de aroma agradável e perecível. Sua baixa aceitação para o consumo in natura se deve aos taninos, que são os fenólicos causadores da adstringência. Para reduzir essa sensação, deve-se polimerizar os taninos com o acetaldeído, tornando-os insolúveis e incapazes de reagir com as enzimas da boca. O objetivo do trabalho foi estudar métodos de redução da adstringência de pedúnculos de caju e seus efeitos sobre qualidade físico-química, nutricional e aromática. Os experimentos conduzidos testaram dose, tempo e temperatura de exposição dos cajus ao etanol ou dióxido de carbono e o melhor filme plástico para obtenção da atmosfera modificada passiva. O teor de etanol, acetaldeído, proantocianidinas (taninos) e polifenois dos cajus foram influenciados pela dose, mas não pelo de tempo de exposição ao etanol, sendo 3,50 mL kg-1 por 12 h o mais indicado. A destanização não sofreu influência da temperatura, mas quando feita a 25°C, resultou em cajus com maior podridão e menor firmeza. O DPPH foi correlacionado com as proantocianidinas e fenóis, tendo maior perda na destanização a 25°C. O FRAP na fração lipossolúvel foi correlacionado com as quercetinas, sofrendo maior perda na destanização a 5°C. A análise de perfil dos compostos aromáticos identificou 26 ésteres, 12 álcoois, 8 aldeídos, 8 terpenos, 2 ácidos carboxílicos, 2 cetonas, 2 fenóis e 2 hidrocarbonetos. Os dias de armazenamento tiveram maior relevância do que a destanização para a presença e intensidade dos aromas, independentemente da temperatura. Portanto, a aplicação de 3,5 mL etanol por kg de caju, por 12 h e 5°C remove a adstringência e pouco afeta a qualidade nutricional e o perfil dos compostos aromáticos. A aplicação do CO2 induziu a respiração anaeróbica, reduziu as proantocianidinas e adstringência e não fermentou os cajus. O uso de 100% de CO2 por 12 e 24 h e 80% por 48 h reduziram o teor ácido ascórbico, antocianinas, DPPH e FRAP hidrossolúvel nos primeiros dias do armazenamento. Cajus submetidos a 80% de CO2 por 48 h tiveram as maiores perdas de massa. A destanização a 24 e 48 h reduziu a incidência de podridão. A dose de 100% de CO2 por 24 h é a mais indicada por reduzir a adstringência de forma imediata, não prejudicar a qualidade fisico-química e resultar nas menores perdas nutricionais dos pedúnculos de caju. O uso dos filmes poliamida/polietileno (PA/PE) 100 μm e polipropileno de camada biorientada (BOPP) 50 μm reduziu a adstringência, ampliou a vida útil dos cajus em 12 dias e conservou a coloração da epiderme, o teor de antocianinas e quercetinas e a atividade antioxidante. A comparação entre eles mostrou diferença apenas no teor de ácido ascórbico e no DPPH no 24º dia de armazenamento, quando pedúnculos embalados em PA/PE apresentaram os melhores resultados. Entretanto, esses pedúnculos apresentaram odor característico de fermentado desde o dia 3. Dessa forma, o BOPP 50 μm é o filme mais indicado para redução da adstringência e conservação dos pedúnculos de caju. / The cashew apple is fruity, juicy, nutritive, with a pleasant aroma and perishable. The low acceptance for it fresh consumption is due to the tannins, that are the phenolics compounds responsible for astringency. To reduce this sensation, the tannins should be polymerized with acetaldehyde, rendering them to an insoluble form, unable to react with the mouth enzymes. The objective of this work was to study methods to reduce the astringency of cashew apple and their effects on physicochemical, nutritional and aromatic quality. The conducted experiments tested dose, time and temperature of exposure of cashew apples to ethanol or carbon dioxide and the best packing film to achieve the passive modified atmosphere. The ethanol, acetaldehyde, proanthocyanidins (tannins) and polyphenols content of the cashew apples were influenced by the dose, but not by the time of exposure to etanol, which has the 3.50 mL kg-1 for 12 h the most indicated. The detanization was not influenced by temperature, but the cashews showed higher decay and lower firmness when it was done at 25°C. The DPPH was correlated with proanthocyanidins and phenols, undergoing higher loss in detanization at 25°C. The FRAP in the liposoluble fraction was correlated with the quercetins, showing higher loss in destanization at 5°C. The profile analysis of the aromatics compounds identified 26 esters, 12 alcohols, 8 aldehydes, 8 terpenes, 2 carboxylic acids, 2 ketones, 2 phenols and 2 hydrocarbons. The storage days had greater relevance than the detanization for the presence and intensity of the aromatics, regardless of temperature. Therefore, the application of 3.5 mL ethanol per kg of cashew apple, for 12 h and 5°C removes the astringency and slightly affects the nutritional quality and profile of the aromatic compounds. The CO2 application induced anaerobic respiration, reduced the proanthocyanidins content and astringency and it didn´t ferment the cashew apples. The aplication of 100% CO2 for 12 and 24 h and 80% for 48 h reduced ascorbic acid ant anthocyanin content, DPPH and FRAP water-soluble on early days of storage. Cashew apples treates with 80% of CO2 for 48 h had the highest weight loss. Detanization at 24 and 48 h reduced the decay incidence. The dose of 100% of CO2 for 24 hours is the most indicated because it reduces the astringency of immediate form, it doesn´t impair the physicalchemical quality and results in the lower nutritional losses of the cashew apples. Packing the fruit with polyamide/polyethylene (PA/PE) 100 μm and bioriented layer polypropylene (BOPP) 50 μm films reduced astringency, extended the shelf-life of the fruit in 12 days and maintained the color of the peel, the anthocyanins and quercetins content and the antioxidant activity. The comparison between the films showed difference only in ascorbic acid content and DPPH in the 24th day of storage, when peduncles packaged in PA/PE presented the best results. However, these fruit presented fermented odor since day 3. Thus, BOPP 50 μm is the most suitable film for reducing the astringency and conservation of the cashew apples.

(Doctoral Thesis, 2016, Mgr. Tomáš Faukner, IONIC POLYACETYLENE TYPE POLYMERS AND POLYMER NETWORKS BY CATALYST FREE QUATERNIZATION POLYMERIZATION) The composition and structure of a series of ionic π-conjugated poly(monosubstituted acetylene)s prepared via catalyst-free quaternization polymerization (QP) of 2-ethynylpyridine (2EP) activated with equimolar amount of alkyl halide [RX = ethyl bromide, ethyl iodide, nonyl bromide and haxadecyl (cetyl) bromide] as a quaternizing agent (QA) have been studied in detail. The performed QPs gave ionic polymers well soluble in polar solvents, with approximately half of pyridine rings quaternized, which implies that also non-quaternized monomers were involved in the process of QP. The configurational structure of polyacetylene main chains was suggested based on 1 H NMR, IR as well as Raman (SERS) spectral methods. The QPs in bulk gave more expected irregular cis/trans polymers while the QPs in acetonitrile solution gave high-cis polymers. A series of prepared symmetrical bi-pyridylacetylene based monomers has been polymerized via QP approach resulting into a series of new ionic π-conjugated poly(disubstituted acetylene) type materials. It is therefore obvious that the mechanism of quaternization activation frequently applied on monosubstituted...