La production inductrielle de ferments nécessite une étape de stabilisation qui affecte la qualité des cellules. Ce phénomène étroitement lié à l’espèce, voire à la souche bactérienne considérée, dépend également des conditions mises en œuvre lors de la conduite du procédé de production. Dans ce contexte, ce travail de thèse vise à améliorer les performances de Lactobacillus buchneri R1102 et Bifidobacteium longum R0175 à la lyophilisation et au stockage, et à identifier les réponses physiologiques associées.Dans une première partie, l’effet du temps de récolte sur les caractéristiques membranaires et les performances industrielles de Lb. Buchneri R1102 et B. lolngum R0175 a été anlysé. Une récolte en phase stationnaire conduit à une meilleure tolérance au cours de la congélation pour B. longum R0175 mais ne permet pas de maintenir une activité acidifiante élevée pour Lb. Buchneri R1102. Ces résultats sont reliés à une rigidificatioin de la membrane et à une augmentation de la proportion en acides gras saturés et cycliques en phase stationnaire de croissance.Dans une deuxième étape, les cellules de Lb. Buchneri R1102 ont été soumises à différentes conditions de stress osmotique. Un stress osmotique avec du KCl 0.1 M augmente la survie au cours de la lyophilisation mais ne modifie les caractéristiques membranaires des cellules. Un ajout de KCl 0.6 M en début de fermentation améliore la survie au cours du stockage à l’état lyophilisé. Ce phénomène est expliqué par une rigidification de la membrane lié à une augmentation de la concentration en acides gras cycliques et à une accumulation de bétaïne intracellulaire.Dans une troisème partie, l’effet de différentes atmosphères de culture sur l’état physiologique et les performances de Lb. Buchneri R1102 et B. longum R0175 a été étudié.Pour Lb. Buchneri R1102, l’apport d’air accélère significativement la croissance et la concentration bactérienne (air à 1.2 vvm) en fluidifiant les membranes cellulaires et en orientant le flux métabolique vers la production d’acétate. A l’inverse, l’apport d’azote ou d’un mélange de gaz N2H2 allonge les fermentations en diminuant le potentiel d’oxydoréduction. Enfin, l’apport des gaz air, N2 et N2H2 dégrade l’activité acidifiante de Lb. Buchneri R1102 mais augmente sa survie au cours du stockage, en lien avec des modifications de composition an acides gras et de synthèse protéique. Pour B. longum R0175, une concentration cellulaire plus élevée est obtenue lorsqu’un bullage N2 ou N2CO2 est effectué en début de culture. L’activité acidifiante des ferments est préservée au cours du procédé pour toutes les conditions testées, en lien avec une augmentation de la proportion d’acides gras insaturés et cycliques, mais sans variation de fluidité membranaire.Enfin, une meilleure survie cellulaire est obtenue lorsque les cellules sont cultivées avec du N2CO2 pendant toute la fermentation.Ce travail se conclut par la validation, à l’échelle pilote, des conditions conduisant à une amélioration de la stabilité biologique des ferments lyophilisés, tout en préservant les performances des fermentations. / Industrial starter’s production requires a stabilization step that affects the quality of the cells. This phenomenon is closely linked to the used species and strains, and depends on the procedures applied during the production process. In this context, this thesis aims at improving the performances of Lactobacillus buchneri R1102 and Bifidobacterium longum R0175 during freeze-drying and storage, and to identify the corresponding physiological responses.In the first part of this work, the effect of the harvesting time on membrane characteristics and industrial performances of Lb. buchneri R1102 and B. longum R0175 has been analyzed. Harvesting the cells in stationary phase led to a better tolerance during freezing of B. longum R0175 but did not allow the maintenance of elevated acidification activity for Lb. buchneri R1102. These results have been related to a rigidification of the membrane and to an increase of the proportion of saturated and cyclic fatty acids in cellular membranes of cells recovered in stationary growth phase.In a second step, cells of Lb. buchneri R1102 have been submitted to different conditions of osmotic stress in order to improve their performances. An osmotic stress with 0.1 M KCl increased the cells survival during freeze-drying, without changing their membrane characteristics. In addition, adding 0.6 M KCl in the beginning of the fermentation improved the survival during storage on freeze-dried form. This phenomenon was explained by a rigidification of the membrane that was linked to an increase of cyclic fatty acids content and intracellular betaine concentration.The third part was devoted to the study of the effect of various gaseous atmospheres during the cultures, on the physiological state and the performances of Lb. buchneri R1102 and B. longum R0175. For Lb. buchneri R1102, aeration (air at 1.2 vvm) significantly accelerated the growth and the final cell concentration by increasing membrane fluidity and by directing metabolic flux towards acetate production. Conversely, adding nitrogen or the gas mixture N2H2 delayed the fermentations by decreasing redox potential. Lastly, injecting different gases (air, N2, N2H2) decreased acidification activity Lb. buchneri R1102 but increased its survival during storage, as a result of modifications of fatty acids composition and proteins synthesis. For B. longum R0175, a higher cell concentration was obtained when the culture medium was bubbled with N2 or N2CO2 at the beginning of the fermentation. In addition, acidification activity of these starters was well maintained for all tested conditions, which was linked to an increase of unsaturated and cyclic fatty acids proportion, but without any change in membrane fluidity. Lastly, a better cell survival was obtained for cells grown with N2CO2 all along the fermentation.Finally, this work is concluded finish with the validation, at pilot scale, of the conditions leading to an improvement of the biological stability of freeze-dried starters, while maintaining their performances during fermentation.

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O tipo biológico influenciado pela genética Bos taurus indicus garante maior adaptação aos animais em regiões com altas temperaturas, no entanto exibe alguns atributos de carcaça e associados à palatabilidade da carne inferiores quando comparados ao tipo biológico predominantemente Bos taurus taurus. Existe a hipótese de que tais diferenças estejam associadas ao conteúdo mitocondrial na musculatura destes animais. Objetivou-se avaliar as diferenças no metabolismo oxidativo, pela medida de respiração mitocondrial em fibras permeabilizadas submetidas a duas temperaturas (38,5 e 40 °C) utilizando respirômetro de alta resolução (Oroboros Instruments), do Longissimus lumborum imediatamente após abate, entre os tipos biológicos Brahman e Angus com taxa e extensão da proteólise distintas ao longo de 14 dias de maturação. Foram investigadas as atividades enzimáticas de lactato desidrogenase e citrato sintase, pH, bem como autólise de &mu;-calpaína e degradação de proteínas miofibrilares de 18 animais das raças Brahman (6), Brangus (6) e Angus (6). A taxa de acidificação das carcaças foi diferente entre os tipos biológicos (P = 0,049) e entre os tempos postmortem (P < 0,001), sendo que as carcaças dos animais Brahman às 6h postmortem apresentaram pH tão alto quanto as carcaças de Brangus e Angus às 3h posmortem. A atividade de citrato sintase 1h postmortem também foi diferente (P = 0,086) entre os tipos biológicos, sendo que maior atividade (P = 0,075) foi identificada em Brahman comparado a Brangus. O fluxo de consumo de oxigênio mitocondrial no estado 4 (ST4_O), apresentou interação (P = 0,050) entre os tipos biológicos e temperatura, assim como a respiração mitocondrial do sistema de transporte de elétrons desacoplado da produção de ATP (P = 0,047), ambos superiores para Brahman a 38,5 °C na comparação entre tipos biológicos. Todavia, ocorreu uma queda da ST4_O, apenas para os animais Brahman, quando a temperatura foi aumentada. A maior resistência a acidificação e maior respiração mitocondrial imediatamente após o abate para o tipo biológico Brahman, foram acompanhadas pela redução (P = 0,058) da autólise completa de &mu;-calpaína às 24h postmortem. A degradação da titina após 7d de maturação foi reduzida (P = 0,056) e se manteve menor (P = 0,003) aos 14d para Brahman comparado aos outros tipos biológicos. O aparecimento da banda 150 kDa da alfa-II-espectrina às 24h postmortem também é menor (P = 0,011) para Brahman, assim como a degradação da desmina (P = 0,019) e troponina-T (P = 0,001). As duas últimas proteínas tiveram sua degradação reduzida ao longo dos 14d postmortem para este tipo biológico. Portanto, o tipo biológico Brahman tem um mecanismo muscular adaptativo que envolve maior conteúdo mitocondrial, com maior vazamento de prótons pelo sistema de transporte de elétrons e que pode estar relacionado a redução da taxa de ativação da &mu;-calpaína, redução da degradação proteica e, consequentemente, a redução da taxa e da extensão do amaciamento da carne destes animais. / Biological type influenced by Bos taurus indicus ensures higher animals adaptation to warm environment, however exhibit less desirable carcass and palatability traits when compared to predominant Bos taurus taurus biological types. There is a hypothesis that muscle mitochondrial content is associated with those differences. It was aimed to evaluate the oxidative metabolism, measuring mitochondrial respiration in permeabilized fibers sumitted to two temperatures (38.5 and 40 °C) using high resolution respirometry (Oroboros Instruments), in Longissimus lumborum imediately after slaughter between biological types Brahman and Angus with different proteolysis rate and extension during 14d aging. Were investigated lactate dehydrogenase and citrate sinthase activities, pH, as well as &mu;-calpain autolysis and protein degradation between 18 animals from breeds Brahman (6), Brangus (6) and Angus (6). The carcass pH decline is different between biological types (P = 0.049) and between time postmortem (P < 0.001), with Brahman carcasses showing pH at 6h postmortem as high as Brangus and Angus pH at 3h postmortem. Citrate sinthase activity 1h postmortem is different (P = 0,086) between biological types, with Brahman showing higher (P = 0.075) values than Brangus animals. The mitochondrial oxygen flux consumption at state 4 (ST4_O) showed interaction (P = 0.050) between biological types and temperature, as well as respiration for electron transport system uncopled from ATP production (P = 0.047), both higher for Brahman at 38.5 °C in biological types comparison. However, decreased ST4_O was observed only for Brahman animals when temperature was increased. Higher resistance to pH decline and higher mitochondrial respiration after slaughter to Brahman cattle were followed by reduced (P = 0.058) complete &mu;-calpain autolysis at 24h postmortem. Titin degradation after 7d aging was reduced (P = 0.056) and kept lower (P = 0.031) after 14d to Brahman when compared to other biological types. The 150 kDa band from alpha-IIspectrin degradation at 24h postmortem is lower (P = 0.011) to Brahman, as well as desmin degradation (P = 0.019) and troponin-T (P = 0.001). Desmin and troponin-T had its degradation reduced extended until 14d aging for this biological type. Therefore, Brahman biological type has an adaptive muscular mechanism that involves higher mitochondrial content, with higher proton leak in electron transport system and that can be related with reduced rate for &mu;-calpain activation, reduced protein degradation and, consequentely, reduced rate and extension to beef tenderization for these animals.

O palmito pode ser obtido a partir de várias espécies de palmeiras. Devido à alta taxa de exploração das palmeiras do gênero Euterpe e ao seu baixo poder de regeneração, no mercado consumidor há falta de produto de boa qualidade. Palmeiras mais precoces e que produzam bom palmito têm sido pesquisadas, uma delas é a pupunha (Bactris gasipaes), nativa da Amazônia que apresenta características de precocidade, rusticidade e perfilhamento, com palmito de ótima qualidade, diferindo dos demais pelo sabor adocicado e a coloração amarelada. O seu cultivo pode ser feito em grande parte do território brasileiro. A porção comestível do palmito de pupunha é dividida em três partes: a basal ou caulinar (coração), a apical, e a central ou foliar (creme ou tolete). O comércio de palmito privilegia a parte central da palmeira, vendendo o palmito basal como subproduto. O presente estudo tem como objetivo demonstrar a equivalência da qualidade do palmito basal e do foliar de pupunha, priorizando-se o tratamento adicional com ácido acético, que mascara o seu sabor adocicado, comparado com o ácido cítrico, largamente utilizado nas indústrias. As amostras de palmito de pupunha foram cultivadas em área experimental pertencente a ESALQ/USP; para o processamento foram cortadas 120 palmeiras em março de 2007. Foram analisadas características físicas, químicas, bioquímicas e sensoriais do palmito basal e foliar de pupunha em seis períodos de armazenamento (1, 15, 30, 60, 90, 120 dias). O controle das operações durante o processamento foi eficiente, pois o peso e o preenchimento dos vidros não variaram entre as unidades. Durante o período de armazenamento a coloração amarelada dos palmitos basal e foliar de pupunha se manteve constante. Embora as enzimas polifenoloxidase e peroxidase tenham sido detectadas nas análises bioquímicas, seus valores foram baixos, e como a coloração foi a mesma durante o armazenamento, considera-se que as enzimas foram inativadas. A composição centesimal das amostras (umidade, proteína, matéria graxa, fração cinza, fibras e carboidratos) indicou que ambos os produtos possuem as mesmas características, as quais se assemelham muito à da palmeira juçara. A análise sensorial não mostrou diferença significativa entre as amostras, porém as notas mais baixas foram atribuídas às conservas acidificadas com ácido acético. Com relação à freqüência de consumo, observou-se que o palmito de pupunha é pouco utilizado na alimentação humana, sendo a resposta às vezes predominante. Os resultados mostraram que o palmito basal e o foliar de pupunha têm as mesmas características físicas, químicas e sensoriais, indicando que o primeiro também pode ser comercializado como palmito de primeira qualidade; o período de armazenamento não alterou as principais características dos produtos. / The palm can be obtained from several palms trees. Besides of high rate of exploration of Euterpe palms trees and his low regeneration power, there is a lack of product in the consumer market. More precocious palms trees and which produce good palm heart have been investigated, one of them is the peach palm (Bactris gasipaes), native of Amazon region that presents characteristics of precociousness, rusticity and tillering with palm heart with good quality, differing of others for the slightly sweet taste and the yellowed coloration. His cultivation can be done in great part of the Brazilian territory. The edible portion of the palm is divided in three parts: basic one or caulinar (heart), apical and central or foliaceous (cream or thole). The commerce of palm privileges the central part of the palm tree, selling heart as by-product. The aim of this study was to demonstrate the equivalence of the quality of heart and thole of peach palm, acidified with citric acid, widely used in the industries, and with acetic acid that masks the slightly sweet taste. The samples of peach palm were cultivated in experimental area of ESALQ/USP and for the processing 120 palms trees were cut in march of 2007. Heart and thole of the palm were analysed by physical, chemical, biochemical and sensorial characteristics for six periods of storage (1, 15, 30, 60, 90, 120 days). The control of the operations on the processing was efficient, since the weight and the filling out from the glasses did not vary between the unities. During the period of storage the coloration of the tholes and hearts of palm peach was yellowed, characteristic that remained constant. Even though the enzymes polyphenol oxidase and peroxidase have appeared in the biochemical analyses, its values were low, and the coloration was the same during the storage. The centesimal composition of the samples (humidity, protein, oily matter, ash, fibers and carbohydrates) indicated heart and thole of peach palm have the same characteristics, which liken very much to that of the palm tree Euterpe edulis. The sensory analysis did not show significant difference between the samples, however the lowest notes were attributed to the pickles acidified with acetic acid. Regarding the frequency of consumption, it was noticed that the palm heart of peach palm is little used in the feeding of people, being the answer \"sometimes\" the one that had major constancy. Data showed that heart and the thole of peach palm have the same physical, chemical and sensory characteristics, indicating that the first one also can be marketed like palm heart of first quality; the period of storage did not change principal characteristics of the products.

As bactérias ácido-láticas (BAL) são micro-organismos que auxiliam nas características organolépticas, funcionais e de bioconservação de produtos fermentados. A utilização do soro de leite como meio de cultivo natural enaltece o conceito da produção de biomoléculas de alto valor agregado, como bacteriocinas, já que é um subproduto gerado por indústrias de laticínios e considerado um agente poluidor. A inulina é um ingrediente prebiótico que promove seletivamente o crescimento de culturas probióticas. Nesse âmbito, o objetivo deste estudo foi avaliar o efeito da composição da cultura de Lactococcus lactis (LL) em cocultura com Streptococcus thermophilus (ST) e da suplementação da base de soro de leite com inulina: (i) nos parâmetros cinéticos de acidificacão, (ii) no crescimento celular, (iii) na viscosidade do produto e (iv) na atividade antimicrobiana da nisina. A fermentação do soro de leite com Lactococcus lactis em cocultura com Streptococcus thermophilus proporcionou a maior taxa de acidificação (Vmax=7,93x10-3 upH/min), assim como apresentou o menor tempo para atingir a velocidade máxima de acidificação (Tvmax=1,13 h). A adição de 2% de inulina ao soro de leite fermentado pela cocultura binária fez com que o tempo para completar o cultivo fosse o mais curto (TpH4,5=4,43 h) quando comparado aos demais ensaios. Quanto ao crescimento celular, pode-se observar que a inulina não afetou significativamente a contagem microbiológica, quando as cepas ST e LL foram utilizadas separadamente no processo fermentativo. Em particular, a adição de 4% de inulina reduziu em 1,2 LogUFC/mL e 0,92 LogUFC/mL a contagem de ST e LL (em monocultura), respectivamente. Por outro lado, em coculturas binárias (ST-LL), percebeu-se ganho na contagem microbiológica nos ensaios que receberam suplementação do ingrediente prebiótico, ou seja, quando adicionados 2% e 4% de inulina, houve aumento de 1 LogUFC/mL e de 1,34 LogUFC/mL na contagem de ST, respectivamente. No caso da cepa LL em cocultura com ST, a suplementação de 2% e 4% do prebiótico aumentou em 0,31 LogUFC/mL e 0,75 LogUFC/mL, respectivamente. A concentração de ácido lático também foi mais elevada nos cultivos realizados com a cocultura binária, sendo 4,56 g/L (na ausência de inulina), 5,28 g/L (com adição de 2% de inulina) e 5,71 g/L (com suplementação de 4% de inulina). A viscosidade foi influenciada tanto pela adição de inulina como pelo efeito sinérgico da cocultura, sendo que o maior valor (7,38 mPas) foi obtido pela cocultura ST-LL e pela adição de 4% do ingrediente prebiótico. Quanto à produção de nisina, observou-se que, no cultivo em cocultura (ST-LL), a concentração de 2% de inulina aumentou em 102% a atividade antimicrobiana quando comparada com a cultura pura LL. Vale ressaltar que ambas as cepas satisfizeram os requisitos tecnológicos relativos à produção de laticínios funcionais. / Lactic acid bacteria (LAB) are microorganisms that help in the organoleptic and functional characteristics and in the biopreservation of fermented products. The use of milk whey as a culture medium extols the concept of the production of high value-added biomolecules, such as bacteriocins, since it is a by-product generated by the dairy industry and considered a pollutant. Inulin is a prebiotic ingredient that promotes selectively the growth of probiotic cultures. In this context, the aim of this study was to evaluate the effect of culture composition Lactococcus lactis (LL) in co-culture with Streptococcus thermophilus (ST) and the supplementation of milk whey with inulin on: (i) the acidification kinetic parameters, (ii) the cell growth, (iii) the product viscosity, and (iv) the antimicrobial activity of nisin. The fermentation of milk whey by Lactococcus lactis in coculture with Streptococcus thermophilus provided the highest acidification rate (Vmax = 7.93x10-3 upH/min) and the shortest time to reach the maximum acidification rate ( TVmax = 1.13 h). The addition of 2% inulin in the binary coculture binary led to the shorter time to complete the fermentation (TpH4,5 = 4.43) compared to the other tests. With regard to cell growth, it can be observed that the addition of inulin did not affect the microbiological count of pure cultures of ST and LL strains in the fermentation process. In particular, the addition of 4% inulin reduced by 1.2 Log CFU/mL and 0.92 Log CFU/mL the counts of ST and LL (monoculture), respectively. In the other hand, the binary co-cultures cultivations (ST-LL) with the addition of 2% and 4% inulin increased by 1 LogCFU/mL and 1.34 Log CFU/mL in the case of the ST counts and 0.31 log CFU/mL and 0.75 log CFU/mL the counts of LL, respectively. Lactic acid concentration was higher in cultivations carried out by binary cocultures, thus being 4.56 g/L (in the absence of inulin), 5.28 g/L (with addition of 2% inulin) and 5.71g/L (supplemented with 4% inulin). The viscosity was influenced by the addition of prebiotic ingredient and by the synergistic effect of binary coculture, being the highest value (7.38 mPas) obtained by the addition of 4% inulin. Finally, as regards the production of nisin noted that in the binary coculture cultivations (ST-LL), the concentration of 2% inulin increased at 102% the antimicrobial activity when compared to the pure culture LL. It is worth mentioning that both strains met the technological requirements as regards the production of functional dairy products.

Environmental change is a major threat to marine ecosystems worldwide. Understanding the key biological processes and environmental factors mediating spatial and temporal species' responses to habitat alterations underpins our ability to forecast impacts on marine ecosystems under any range of scenarios. This is especially important for calcifying species, many of which have both a high climate sensitivity and disproportionately strong ecological impacts in shaping marine communities. Although geographic patterns of calcifiers' sensitivity to environmental changes are defined by interacting multiple abiotic and biotic stressors, local adaptation, and acclimation, knowledge on species' responses to disturbance is derived largely from short- and medium-term laboratory and field experiments. Therefore, little is known about the biological mechanisms and key drivers in natural environments that shape regional differences and long-term variations in species vulnerability to global changes. In this thesis, I examined natural variations in shell characteristics, both morphology and biomineralisation, under heterogeneous environmental conditions i) across large geographical scales, spanning a 30° latitudinal range (3,334 km), and ii) over historical times, using museum collections (archival specimens from 1904 to 2016 at a single location), in mussels of the genus Mytilus. The aim was to observe whether plasticity in calcareous shell morphology, production, and composition mediates spatial and temporal patterns of resistance to climate change in these critical foundation species. For the morphological analyses, the combined use of new statistical methods and multiple study systems at various geographical scales allowed the uncoupling of the contribution of development, genetic status, and environmental factors to shell morphology. I found salinity had the strongest effect on the latitudinal patterns of Mytilus shape. Temperature and food supply, however, were the main predictor of mussel shape heterogeneity. My results suggest the potential of shell shape plasticity in Mytilus as a powerful indicator of rapid environmental changes. I found decreasing shell calcification towards high latitudes. Salinity was the best predictor of regional differences in shell deposition, and its mineral and organic composition. In polar, low-salinity environments, the production of calcite and organic shell layers was increased, while aragonite deposition was enhanced under temperate, higher-salinity regimes. Interacting strong effects of decreasing salinity and increasing food availability on compositional shell plasticity predict the deposition of a thicker external organic layer (periostracum) at high latitudes under forecasted future conditions. This response potential of Mytilus shell suggests an enhanced protection of temperate mussels from predators and a strong capacity for increased resistance of polar and subpolar individuals to dissolving water conditions. Analyses of museum specimens indicated increasing shell calcification during the last century. Deposition of individual shell layers was more closely related to temporal changes in the variability of key environmental drivers than to alterations of mean habitat conditions. Calcitic layer and periostracum showed marked responses to alterations of biotic conditions, suggesting the potential of mussels to trade-off between the deposition of calcareous and organic layers as a compensatory response to strategy-specific predation pressure. These changes in biomineralisation indicated a marked resistance to environmental change over the last century in a species predicted to be vulnerable, and how locally heterogeneous environments and predation levels can have a stronger effect on Mytilus responses than global environmental trends. My work illustrates that biological mechanisms and local conditions, driving plastic responses to the spatial and temporal structure of multiple abiotic and biotic stressors, can define geographic and temporal patterns of unforeseen species resistance to global environmental change.

As bactérias ácido-láticas (BAL) são micro-organismos que auxiliam nas características organolépticas, funcionais e de bioconservação de produtos fermentados. A utilização do soro de leite como meio de cultivo natural enaltece o conceito da produção de biomoléculas de alto valor agregado, como bacteriocinas, já que é um subproduto gerado por indústrias de laticínios e considerado um agente poluidor. A inulina é um ingrediente prebiótico que promove seletivamente o crescimento de culturas probióticas. Nesse âmbito, o objetivo deste estudo foi avaliar o efeito da composição da cultura de Lactococcus lactis (LL) em cocultura com Streptococcus thermophilus (ST) e da suplementação da base de soro de leite com inulina: (i) nos parâmetros cinéticos de acidificacão, (ii) no crescimento celular, (iii) na viscosidade do produto e (iv) na atividade antimicrobiana da nisina. A fermentação do soro de leite com Lactococcus lactis em cocultura com Streptococcus thermophilus proporcionou a maior taxa de acidificação (Vmax=7,93x10-3 upH/min), assim como apresentou o menor tempo para atingir a velocidade máxima de acidificação (Tvmax=1,13 h). A adição de 2% de inulina ao soro de leite fermentado pela cocultura binária fez com que o tempo para completar o cultivo fosse o mais curto (TpH4,5=4,43 h) quando comparado aos demais ensaios. Quanto ao crescimento celular, pode-se observar que a inulina não afetou significativamente a contagem microbiológica, quando as cepas ST e LL foram utilizadas separadamente no processo fermentativo. Em particular, a adição de 4% de inulina reduziu em 1,2 LogUFC/mL e 0,92 LogUFC/mL a contagem de ST e LL (em monocultura), respectivamente. Por outro lado, em coculturas binárias (ST-LL), percebeu-se ganho na contagem microbiológica nos ensaios que receberam suplementação do ingrediente prebiótico, ou seja, quando adicionados 2% e 4% de inulina, houve aumento de 1 LogUFC/mL e de 1,34 LogUFC/mL na contagem de ST, respectivamente. No caso da cepa LL em cocultura com ST, a suplementação de 2% e 4% do prebiótico aumentou em 0,31 LogUFC/mL e 0,75 LogUFC/mL, respectivamente. A concentração de ácido lático também foi mais elevada nos cultivos realizados com a cocultura binária, sendo 4,56 g/L (na ausência de inulina), 5,28 g/L (com adição de 2% de inulina) e 5,71 g/L (com suplementação de 4% de inulina). A viscosidade foi influenciada tanto pela adição de inulina como pelo efeito sinérgico da cocultura, sendo que o maior valor (7,38 mPas) foi obtido pela cocultura ST-LL e pela adição de 4% do ingrediente prebiótico. Quanto à produção de nisina, observou-se que, no cultivo em cocultura (ST-LL), a concentração de 2% de inulina aumentou em 102% a atividade antimicrobiana quando comparada com a cultura pura LL. Vale ressaltar que ambas as cepas satisfizeram os requisitos tecnológicos relativos à produção de laticínios funcionais. / Lactic acid bacteria (LAB) are microorganisms that help in the organoleptic and functional characteristics and in the biopreservation of fermented products. The use of milk whey as a culture medium extols the concept of the production of high value-added biomolecules, such as bacteriocins, since it is a by-product generated by the dairy industry and considered a pollutant. Inulin is a prebiotic ingredient that promotes selectively the growth of probiotic cultures. In this context, the aim of this study was to evaluate the effect of culture composition Lactococcus lactis (LL) in co-culture with Streptococcus thermophilus (ST) and the supplementation of milk whey with inulin on: (i) the acidification kinetic parameters, (ii) the cell growth, (iii) the product viscosity, and (iv) the antimicrobial activity of nisin. The fermentation of milk whey by Lactococcus lactis in coculture with Streptococcus thermophilus provided the highest acidification rate (Vmax = 7.93x10-3 upH/min) and the shortest time to reach the maximum acidification rate ( TVmax = 1.13 h). The addition of 2% inulin in the binary coculture binary led to the shorter time to complete the fermentation (TpH4,5 = 4.43) compared to the other tests. With regard to cell growth, it can be observed that the addition of inulin did not affect the microbiological count of pure cultures of ST and LL strains in the fermentation process. In particular, the addition of 4% inulin reduced by 1.2 Log CFU/mL and 0.92 Log CFU/mL the counts of ST and LL (monoculture), respectively. In the other hand, the binary co-cultures cultivations (ST-LL) with the addition of 2% and 4% inulin increased by 1 LogCFU/mL and 1.34 Log CFU/mL in the case of the ST counts and 0.31 log CFU/mL and 0.75 log CFU/mL the counts of LL, respectively. Lactic acid concentration was higher in cultivations carried out by binary cocultures, thus being 4.56 g/L (in the absence of inulin), 5.28 g/L (with addition of 2% inulin) and 5.71g/L (supplemented with 4% inulin). The viscosity was influenced by the addition of prebiotic ingredient and by the synergistic effect of binary coculture, being the highest value (7.38 mPas) obtained by the addition of 4% inulin. Finally, as regards the production of nisin noted that in the binary coculture cultivations (ST-LL), the concentration of 2% inulin increased at 102% the antimicrobial activity when compared to the pure culture LL. It is worth mentioning that both strains met the technological requirements as regards the production of functional dairy products.

Thesis (Ph. D.)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2013. / Cataloged from PDF version of thesis. / Includes bibliographical references. / Predicting the response of net community calcification (NCC) to ocean acidification OA and declining aragonite saturation state [Omega]a requires a thorough understanding of controls on NCC. The diurnal control of light and net community production (NCP) on NCC confounds the underlying control of [Omega]a on NCC and must be averaged out in order to predict the general response of NCC to OA. I did this by generating a general NCC-[Omega]a correlation based on data from 15 field and mesocosm studies around the globe. The general relationship agrees well with results from mesocosm experiments. This general relationship implies that NCC will transition from net calcification to net dissolution at a [Omega]a of 1.0 ± 0.6 and predicts that NCC will decline by 50% from 1880 to 2100, for a reef of any percent calcifier cover and short reef water residence time. NCC will also decline if percent calcifier cover declines, as evidenced by estimates of NCC in two Caribbean reefs having declined by an estimated 50-90% since 1880. The general NCC-([Omega]a relationship determined here, along with changes in percent calcifier cover, will be useful in predicting changes in NCC in response to OA and for refining models of reef water [Omega]a. / by Whitney Nicole Bernstein. / Ph.D.

Submitted by (edna.saturno@ufrpe.br) on 2017-02-07T16:42:51Z No. of bitstreams: 1 Andreia Cybelle Marques Ferreira.pdf: 473419 bytes, checksum: ec38641e4f8a34c97d2ef665eeeb6165 (MD5) / Made available in DSpace on 2017-02-07T16:42:51Z (GMT). No. of bitstreams: 1 Andreia Cybelle Marques Ferreira.pdf: 473419 bytes, checksum: ec38641e4f8a34c97d2ef665eeeb6165 (MD5) Previous issue date: 2013-02-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Tilapia Oreochromis niloticus is one of the most widely cultivated species and the fillet is the main product for sale corresponding between 30 and 40% of the animal weight, the remainder being considered residue when discarded represent a serious environmental. These byproducts are high in protein and production of FPH (fish protein hydrolysed) represents an alternative for these residues. The present study aims to investigate the efficacy of different conservation methods in the elimination of pathogens and spoilage microorganisms in fish protein hydrolysate obtained from the by-products of tilapia (Oreochromis niloticus). The FPHs were subject at dry heat sterilization, moist heat, acidification (citric acid), gamma irradiation and studied at different storage temperatures. Microbiological analyzes were performed by count of mesophilics and psychrotrophics and search of pathogens and spoilage. The hydrolysates remained free of microbial contamination for 60 days, excepting the control showed values of 3.0 X 107 CFU/ml after 24 hours and FPH citric acid 30 °C reached 5.0 X 10² CFU/ml after 9 storage days. The results of microbiological analyses from hydrolysates treated by conservation methods were negative for coliforms at 45 ºC, Coagulase-positive staphylococci, Salmonella spp, yeast and mold, and Pseudomonas aeruginosa, excepting the FPH citric acid 4 °C, citric acid 30 °C and control that showed 9.5 x 103, 1.5 x 102 and 8.7 X 10² CFU/ml for yeast and mold respectively. The content of protein and lipid, in the most of the hydrolysates was not affected during storage. The treatments performed on hydrolysates were efficient in respect to the presence of pathogens confer food security by 60 days. / A tilápia Oreochromis niloticus é uma das espécies mais amplamente cultivadas e o filé é o principal produto de venda correspondente entre 30 e 40% do peso do animal, sendo o restante considerado resíduo, quando descartado, representam um problema ambiental. Estes subprodutos são ricos em proteína e a produção do HPP (hidrolisado protéico de peixe) é uma alternativa utilizada a que se destinam estes resíduos. O presente estudo tem por objetivo investigar a eficácia de diferentes métodos de conservação na eliminação de microorganismos patogênicos e deteriorantes em hidrolisado de proteína de peixe obtido a partir dos subprodutos de tilápia (Oreochromis niloticus). Os HPP foram submetidos à esterilização por calor seco, calor úmido, acidificação (ácido cítrico), irradiação gama e estudado em diferentes temperaturas de armazenamento. Análises microbiológicas foram realizadas através da contagem de microorganismos mesófilos e psicrotróficos e da pesquisa de patógenos e deteriorantes. Os hidrolisados permaneceram livres de contaminação microbiológica durante 60 dias, com exceção do controle com valores de 3,0 X 107 UFC/ml após 24 horas e do HPP Ácido cítrico 30 ºC que atingiu 5,0 X 10² UFC/ml após 9 dias de armazenamento. Os resultados das análises microbiológicas dos hidrolisados foram negativos para coliformes a 45 ºC, Estafilococos coagulase positiva, Salmonella spp, bolores e leveduras, e Pseudomonas aeruginosa com exceção dos HPP ácido cítrico 4 ºC, ácido cítrico 30 ºC e controle que apresentaram valores para bolores e leveduras de 9,5 x 103 UFC/mL, 2,5 x 102 UFC/mL e 8,7 X 10² UFC/mL respectivamente. O conteúdo proteico e lipídico, na maioria do hidrolisados, não foi comprometido mediante estocagem. Os tratamentos realizados nos hidrolisados foram eficientes quanto a presença de microorganismos patógenos, estando garantido a segurança do alimento por 60 dias.

O tipo biológico influenciado pela genética Bos taurus indicus garante maior adaptação aos animais em regiões com altas temperaturas, no entanto exibe alguns atributos de carcaça e associados à palatabilidade da carne inferiores quando comparados ao tipo biológico predominantemente Bos taurus taurus. Existe a hipótese de que tais diferenças estejam associadas ao conteúdo mitocondrial na musculatura destes animais. Objetivou-se avaliar as diferenças no metabolismo oxidativo, pela medida de respiração mitocondrial em fibras permeabilizadas submetidas a duas temperaturas (38,5 e 40 °C) utilizando respirômetro de alta resolução (Oroboros Instruments), do Longissimus lumborum imediatamente após abate, entre os tipos biológicos Brahman e Angus com taxa e extensão da proteólise distintas ao longo de 14 dias de maturação. Foram investigadas as atividades enzimáticas de lactato desidrogenase e citrato sintase, pH, bem como autólise de &mu;-calpaína e degradação de proteínas miofibrilares de 18 animais das raças Brahman (6), Brangus (6) e Angus (6). A taxa de acidificação das carcaças foi diferente entre os tipos biológicos (P = 0,049) e entre os tempos postmortem (P < 0,001), sendo que as carcaças dos animais Brahman às 6h postmortem apresentaram pH tão alto quanto as carcaças de Brangus e Angus às 3h posmortem. A atividade de citrato sintase 1h postmortem também foi diferente (P = 0,086) entre os tipos biológicos, sendo que maior atividade (P = 0,075) foi identificada em Brahman comparado a Brangus. O fluxo de consumo de oxigênio mitocondrial no estado 4 (ST4_O), apresentou interação (P = 0,050) entre os tipos biológicos e temperatura, assim como a respiração mitocondrial do sistema de transporte de elétrons desacoplado da produção de ATP (P = 0,047), ambos superiores para Brahman a 38,5 °C na comparação entre tipos biológicos. Todavia, ocorreu uma queda da ST4_O, apenas para os animais Brahman, quando a temperatura foi aumentada. A maior resistência a acidificação e maior respiração mitocondrial imediatamente após o abate para o tipo biológico Brahman, foram acompanhadas pela redução (P = 0,058) da autólise completa de &mu;-calpaína às 24h postmortem. A degradação da titina após 7d de maturação foi reduzida (P = 0,056) e se manteve menor (P = 0,003) aos 14d para Brahman comparado aos outros tipos biológicos. O aparecimento da banda 150 kDa da alfa-II-espectrina às 24h postmortem também é menor (P = 0,011) para Brahman, assim como a degradação da desmina (P = 0,019) e troponina-T (P = 0,001). As duas últimas proteínas tiveram sua degradação reduzida ao longo dos 14d postmortem para este tipo biológico. Portanto, o tipo biológico Brahman tem um mecanismo muscular adaptativo que envolve maior conteúdo mitocondrial, com maior vazamento de prótons pelo sistema de transporte de elétrons e que pode estar relacionado a redução da taxa de ativação da &mu;-calpaína, redução da degradação proteica e, consequentemente, a redução da taxa e da extensão do amaciamento da carne destes animais. / Biological type influenced by Bos taurus indicus ensures higher animals adaptation to warm environment, however exhibit less desirable carcass and palatability traits when compared to predominant Bos taurus taurus biological types. There is a hypothesis that muscle mitochondrial content is associated with those differences. It was aimed to evaluate the oxidative metabolism, measuring mitochondrial respiration in permeabilized fibers sumitted to two temperatures (38.5 and 40 °C) using high resolution respirometry (Oroboros Instruments), in Longissimus lumborum imediately after slaughter between biological types Brahman and Angus with different proteolysis rate and extension during 14d aging. Were investigated lactate dehydrogenase and citrate sinthase activities, pH, as well as &mu;-calpain autolysis and protein degradation between 18 animals from breeds Brahman (6), Brangus (6) and Angus (6). The carcass pH decline is different between biological types (P = 0.049) and between time postmortem (P < 0.001), with Brahman carcasses showing pH at 6h postmortem as high as Brangus and Angus pH at 3h postmortem. Citrate sinthase activity 1h postmortem is different (P = 0,086) between biological types, with Brahman showing higher (P = 0.075) values than Brangus animals. The mitochondrial oxygen flux consumption at state 4 (ST4_O) showed interaction (P = 0.050) between biological types and temperature, as well as respiration for electron transport system uncopled from ATP production (P = 0.047), both higher for Brahman at 38.5 °C in biological types comparison. However, decreased ST4_O was observed only for Brahman animals when temperature was increased. Higher resistance to pH decline and higher mitochondrial respiration after slaughter to Brahman cattle were followed by reduced (P = 0.058) complete &mu;-calpain autolysis at 24h postmortem. Titin degradation after 7d aging was reduced (P = 0.056) and kept lower (P = 0.031) after 14d to Brahman when compared to other biological types. The 150 kDa band from alpha-IIspectrin degradation at 24h postmortem is lower (P = 0.011) to Brahman, as well as desmin degradation (P = 0.019) and troponin-T (P = 0.001). Desmin and troponin-T had its degradation reduced extended until 14d aging for this biological type. Therefore, Brahman biological type has an adaptive muscular mechanism that involves higher mitochondrial content, with higher proton leak in electron transport system and that can be related with reduced rate for &mu;-calpain activation, reduced protein degradation and, consequentely, reduced rate and extension to beef tenderization for these animals.