<i>Cryptosporidium parvum</i> is a protozoan parasite historically associated with waterborne and more recently foodborne outbreaks of diarrheal illness. Contamination of certain foods, such as unpasteurized apple cider, with infective oocysts may occur as oocysts are shed in the feces of common ruminants like cattle and deer that graze in and around orchards. Cryptosporidiosis can result in a severe illness for previously healthy individuals and a life-threatening illness in immunocompromised individuals. Disease occurs after the ingestion of small infective oocysts (4 to 5 mm in size). The relatively thick membrane of the oocysts allows them to be resistant to chlorine and many other environmental pressures, making oocysts difficult to inactivate. In this study, alternative treatments to pasteurization were evaluated for their ability to inhibit <i>C. parvum</i> oocyst viability in fruit juices. Oocyst viability was analyzed with a cell culture infectivity assay, using a human illeocecal cell line (HCT-8) that is most similar to human infection. The percent inhibition of infection by each treatment was determined along with the corresponding log reduction for the treatments found to be most effective. Infection by treated oocysts was compared to that of control untreated oocysts. Cell monolayers were infected with 10⁶ treated oocysts or a series of 10-fold dilutions. Parasitic life stages were visualized using an immunohistochemistry system and 100 microscope fields counted per monolayer. Organic acids and H₂O₂ were added on a wt/vol basis to apple cider, orange juice, and grape juices. Malic, citric, and tartaric acids at concentrations from 1%-5% inhibited <i>C. parvum</i> infectivity of HCT-8 cells by up to 88%. Concentrations ranging from 0.025%-3% H₂O₂ were evaluated where addition of 0.025% H₂O₂ to each juice resulted in a >5 log reduction of C. parvum infectivity as determined with an MPN-based cell culture infectivity assay. Treating apple cider, orange juice, and grape juice with ozone for a time period of 30 seconds up to 15 minutes at 6° and 22°C (0.9 g/L flow rate) inhibited C. parvum viability to > 90% as monitored in the cell culture assay. It is hypothesized that oocyst wall proteins that are necessary for infection are oxidized by the reactive oxygen species generated from the decomposition of the ozone and hydrogen peroxide treatments. These treatments or combinations thereof may offer potential alternatives to traditional pasteurization for fruit juices to successfully inhibit <i>C. parvum</i> viability. / Ph. D.

0 comportamento higroscópico do suco de laranja liofilizado, e aditivado com malto-dextrinas e lactose, e de misturas mecânicas do suco liofilizado com os aditivos secos, foi estudado através da cinética e das isotermas de sorção de água, em diferentes temperaturas. Avaliou-se as características espectrais no visível e ultravioleta, e o teor de vitamina C, de amostras de suco de laranja liofilizado expostas a diferentes umidades relativas e temperaturas. Estudou-se a influência do valor de pH e natureza do tampão sobre a retenção do limoneno emulsionado em soluções de lactose, liofilizadas. A liofilização praticamente não alterou o teor de vitamina C e as características espectrais do suco de laranja, mas aumentou o valor monomolecular da malto-dextrina (dextrose equivalente de 9 a 12%). A lactose liofilizada apresentou-se no estado amorfo. Os teores de umidade de equilíbrio das misturas aditivadas liofilizadas, foram menores que os das misturas mecânicas. Os aditivos reduziram a sorção de umidade em função do tempo. A retenção do limoneno foi influenciada pela sua concentração inicial, sendo que ocorreu a major perda, durante a liofilização na major concentração utilizada. / The higroscopic behavior of freeze-dried orange juice, with added maltodextrins and lactose and mechanical mixtures with this additives was studied through the kinetics and isoterms of water sorption in different temperatures. It was evaluated the spectral characteristics, in the visible and ultraviolet range, and the vitamin C content from samples of freeze-dried orange juice exposed at different relative humidities and temperatures. It was studied the influence of pH and buffer composition, on the limonene retention of freeze-dried emulsions. The spectral characteristics and vitamin C content showed no alterations after liofilization the maltodextrin (9-12 % dextrose equivalent monomolecular value increased. Freezedried lactose was amorphous. The equilibrium humidity content of the samples with additives were reduced when compared with mechanical mixtures. The additives also reduced the rate of water sorption. The limonene retention during freeze-drying was influenced by the initial concentration of the emulsion. The greater concentration studied showed the lower retention value.

Orientador: Roger Darros-Barbosa / Banca: Maria Aparecida Mauro / Banca: José Fernando Durigan / Resumo: A recuperação dos sólidos solúveis presentes na membrana central da laranja, separada durante a etapa de extração industrial do suco, normalmente produz um suco contendo de 5 a 6ºBrix e uma série de outros compostos insolúveis (cerca de 9%), muitos dos quais contribuem para a baixa qualidade do suco, sendo responsáveis pelo amargor e adstringência. O presente trabalho propôs-se a clarificar esse suco contendo sólidos recuperados, empregando um pré-tratamento com enzimas pectinolíticas seguido por tratamento por flotação por injeção de ar comprimido auxiliada por agentes clarificantes: bentonita, sílica sol e colágeno hidrolisado. Constituíram-se os objetivos: (i) a determinação das melhores condições (tipo de enzima pectinolítica, duas hidrolases e duas pectinases, e tempo de incubação) para a degradação enzimática da pectina presente; (ii) a determinação da melhor combinação dos agentes clarificantes visando obter um subproduto clarificado através do monitoramento de parâmetros físico-químicos (capacidade floculante e transmitância) e (iii) a avaliação do processo de flotação com diferentes concentrações de bentonita (500, 1.000 e 1.500 mg L-suco-1 e pressões (490, 680 e 880 kPa) pela determinação do grau de clarificação através de monitoramento da transmitância do clarificado, pela determinação da velocidade de flotação/separação das fases, através da verificação das frações volumétricas das fases separadas (clarificado, sedimentado e flotado), em intervalos de tempos regulares durante o processo de flotação e pela análise do produto final clarificado. Os produtos clarificados foram analisados com relação ao conteúdo de sólidos solúveis e insolúveis, pH, acidez titulável, polpa, transmitância, cor (parâmetros L*, a*, b*) proteína, pectina total, sódio, hesperidina, polifenóis e bioflavonóides. Para o tratamento... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Core membrane of the orange fruit separated during the juice extraction step in the citrus processing industrial plant, is currently submitted to a soluble solids recovery process, normally producing a by product (secondary) juice containing about 5 to 6º Brix and other insoluble components (about 9%), which contribute to the juice's low quality, since many are responsible for the bitterness and adstringency. This research aimed to clarify this by-product juice containing recovered solids, by enzyme pre-treatment with pectic enzymes, followed by a flotation treatment with compressed air injection using fining agents: bentonite, silica sol and hydrolyzed collagen. The objectives were (i) to determine the best conditions (enzyme type, two hydrolyses and two pectin-liases and incubation time) for the enzyme treatment for pectin degradation; (ii) to determine the best combination of the fining agents to obtain a clarified by-product through monitoring physical chemical parameters (flocculating ability and product transmittance); and (iii) to evaluate the flotation process and the effects of bentonite concentration (500, 1.000 and 1.500 mg L-juice-1) and saturation pressure (490, 680 and 880 kPa) by determining the degree of clarification through monitoring the product transmittance and by determining the flotation rate (and phase separation) through measurements of volumetric fractions of the separated phases (clarified, floated and sediment) over time during the flotation and phase separation processes. Both untreated and clarified juices were analyzed for soluble and insoluble solid contents, pH, total titratable acidity, pulp content, transmittance, color (parameters L*, a* and b*), protein and pectin contents, sodium, hesperidine, poliphenols and bioflavonoids. The results indicates a purified poligalacturonase as the adequate for the enzyme treatment in 1 hour, 45ºC, with 0,05 mL... (Complete abstract click electronic access below) / Mestre

La gestion de la chaîne logistique a gagné en maturité depuis l’extension de son champ d’application qui portait sur des problématiques opérationnelles et économiques s’est élargi à des questions environnementales et sociales auxquelles sont confrontées les organisations industrielles actuelles. L’addition du terme «vert» aux activités de la chaîne logistique vise à intégrer une conscience écologique dans tous les processus de la chaîne d'approvisionnement. Le but de ce travail est de développer un cadre méthodologique pour traiter la gestion de la chaîne logistique verte (GrSCM) basée sur une approche d'optimisation multi-objectif, en se focalisant sur la conception, la planification et les opérations de la chaîne agroalimentaire, à travers la mise en oeuvre des principes de gestion et de logistique de la chaîne d'approvisionnement verte. L'étude de cas retenu est la filière du jus d'orange. L'objectif du travail consiste en la minimisation de l'impact environnemental et la maximisation de la rentabilité économique pour des catégories de produits sélectionnés. Ce travail se concentre sur l'application de la GrSCM à deux questions stratégiques fondamentales visant les chaînes d'approvisionnement agroalimentaire. La première est liée au problème de la sélection des fournisseurs en produits « verts » (GSS) pour les systèmes de production agricole et à leur intégration dans le réseau globalisé de la chaîne d'approvisionnement. Le second se concentre sur la conception globale du réseau de la chaîne logistique verte (GSCND). Ces deux sujets complémentaires sont finalement intégrés afin d'évaluer et exploiter les caractéristiques des chaînes d'approvisionnement agro-alimentaire en vue du développement d’un éco-label. La méthodologie est basée sur le couplage entre analyse du cycle de vie (ACV), optimisation multi-objectifs par algorithmes génétiques et technique d’aide à la décision multicritère (de type TOPSIS). L’approche est illustrée et validée par le développement et l'analyse d'une étude de cas de la chaîne logistique de jus d'orange, modélisée comme une chaîne logistique verte (GrSC) à trois échelons composés de la production d’oranges, de leur transformation en jus, puis de leur distribution, chaque échelon étant modélisé de façon plus fine en sous-composants. D’un point de vue méthodologique, le travail a démontré l’intérêt du cadre de modélisation et d’optimisation de GrSC dans le contexte des chaînes d'approvisionnement, notamment pour le développement d’un éco-label dans le domaine de l’agro-alimentaire. Il peut aider les décideurs pour gérer la complexité inhérente aux décisions de conception de la chaîne d'approvisionnement agroalimentaire, induite par la nature multi-objectifs multi-acteurs multi-périodes du problème, empêchant ainsi une prise de décision empirique et segmentée. D’un point de vue expérimental, sous les hypothèses utilisées dans l'étude de cas, les résultats du travail soulignent que si l’on restreint l’éco-label "bio" à l'aspect agricole, seule une faible, voire aucune amélioration sur la performance environnementale de la chaîne d'approvisionnement n’est atteinte. La prise en compte des critères environnementaux pertinents sur l’ensemble du cycle de vie s’avère être une meilleure option pour les stratégies publiques et privées afin de tendre vers des chaînes agro-alimentaires plus durables. / Supply chain and operations management has matured from a field that addressed only operational and economic concerns to one that comprehensively considers the broader environmental and social issues that face industrial organizations of today. Adding the term “green” to supply chain activities seeks to incorporate environmentally conscious thinking in all processes in the supply chain. The aim of this work is to develop a Green Supply Chain (GrSC) framework based on a multi-objective optimization approach, with specific emphasis on agrofood supply chain design, planning and operations through the implementation of appropriate green supply chain management and logistics principles. The case study is the orange juice cluster. The research objective is the minimization of the environmental burden and the maximization of economic profitability of the selected product categories. This work focuses on the application of GrSCM to two fundamental strategic issues targeting agro food supply chains. The former is related to the Green Supplier Selection (GSS) problem devoted to the farming production systems and the way they are integrated into the global supply chain network. The latter focuses on the global Green Supply Chain Network Design (GSCND) as a whole. These two complementary and ultimately integrated strategic topics are framed in order to evaluate and exploit the unique characteristics of agro food supply chains in relation to eco-labeling. The methodology is based on the use of Life Cycle Assessment, Multi-objective Optimization via Genetic Algorithms and Multiple-criteria Decision Making tools (TOPSIS type). The approach is illustrated and validated through the development and analysis of an Orange Juice Supply Chain case study modelled as a three echelon GrSC composed of the supplier, manufacturing and market levels that in turn are decomposed into more detailed subcomponents. Methodologically, the work has shown the development of the modelling and optimization GrSCM framework is useful in the context of eco-labeled agro food supply chain and feasible in particular for the orange juice cluster. The proposed framework can help decision makers handle the complexity that characterizes agro food supply chain design decision and that is brought on by the multi-objective and multi-period nature of the problem as well as by the multiple stakeholders, thus preventing to make the decision in a segmented empirical manner. Experimentally, under the assumptions used in the case study, the work highlights that by focusing only on the “organic” eco-label to improve the agricultural aspect, low to no improvement on overall supply chain environmental performance is reached in relative terms. In contrast, the environmental criteria resulting from a full lifecycle approach is a better option for future public and private policies to reach more sustainable agro food supply chains.

Made available in DSpace on 2016-06-02T19:52:00Z (GMT). No. of bitstreams: 1 5215.pdf: 2573740 bytes, checksum: b0159c517597ec5097315a913808cb47 (MD5) Previous issue date: 2012-10-05 / Financiadora de Estudos e Projetos / Brazil is the largest producer and exporter of the world market of frozen concentrated orange juice (FCOJ), and the State of São Paulo stands out as the largest producer and exporter of that commodity in Brazil. In recent years, the State of Paraná has increased its production and export of FCOJ. Through the survey of secondary data and interviews with key players, this study identified and evaluated the main critical aspects of the competitiveness of the agri-food chain of FCOJ in Paraná. Through the rapid appraisal method (method of quick research) were possible to evaluate 11 drivers of competitiveness, focusing on the links of agricultural production and processing of that chain. A total of 24 interviews were conducted, using questionnaires and interviews screenplays. It was possible to identify which are the drivers of competitiveness, considered in the context of this research, which are considered favorable, neutral and unfavorable for the competitiveness of the links of agricultural production and processing of the agri-food chain of FCOJ in Paraná. From these analyses it was also possible to verify that none of the drivers of competitiveness, considered in this dissertation, was regarded as very favorable or very unfavorable for the competitiveness of the link of agricultural production of that chain. From these analyses it was also possible to verify that none of the drivers of competitiveness, considered in this dissertation, was regarded as very favorable for the competitiveness of the link of processing of that chain, and only a driver of competitiveness, of the set of drivers considered in this dissertation, was regarded as very unfavorable for the competitiveness of the link of processing. The analyses allowed to point out proposals for public policies and private strategies to enhance the competitiveness. In a general context, it was possible to conclude that the links of agricultural production and processing of the agri-food chain of FCOJ in Paraná have a great potential to continue to expand in Paraná. The citriculture in Paraná has a great potential to expand because it has a good technology, a good production capacity and productivity and a sufficient amount of available agricultural land to extend the exploration of the citriculture in Paraná, in addition, the economic agents that act in the citriculture in Paraná have contracts for the supply of orange to the economic organizations that have manufacturing plants that produce FCOJ in Paraná, so these contracts ensure the sale of the most part of the Paraná s orange production, which is good for the citrus growers who act in Paraná. The processor sector of orange also has a great potential to expand in Paraná because it has agro-industrial technologies of good level and a good production capacity, in addition to be able to expand without great difficulties its manufacturing capacity of FCOJ, moreover, the existence of contracts for orange supply between economic organizations who act in processing and citrus growers in Paraná, secures the supply of oranges, considered of good quality, for the producing plants of FCOJ installed in Paraná. / O Brasil é o maior produtor e exportador do mercado mundial de suco de laranja concentrado congelado (SLCC), sendo que o Estado de São Paulo destaca-se como o maior produtor e exportador nacional dessa commodity. Nos últimos anos, o Estado do Paraná tem aumentado a sua produção e exportação de SLCC. Por meio de levantamento de dados secundários e de entrevistas com agentes-chaves, identificou-se e avaliou-se os principais aspectos críticos da competitividade da cadeia agroindustrial de SLCC no Paraná. Por meio do método rapid appraisal (método de pesquisa rápida) foi possível avaliar 11 direcionadores de competitividade, com foco nos elos de produção agrícola e de processamento dessa cadeia. Um total de 24 entrevistas foram realizadas, utilizando-se de questionários e roteiros de entrevistas. Foi possível identificar quais são os direcionadores de competitividade, considerados no âmbito desta pesquisa, que são considerados favoráveis, neutros e desfavoráveis para a competitividade dos elos de produção agrícola e de processamento da cadeia agroindustrial paranaense de SLCC. A partir dessas análises também foi possível verificar que nenhum dos direcionadores de competitividade, considerados nesta dissertação, foi considerado como muito favorável ou muito desfavorável para a competitividade do elo de produção rural da cadeia agroindustrial paranaense de SLCC. A partir dessas análises também foi possível verificar que nenhum dos direcionadores de competitividade, considerados nesta dissertação, foi considerado como muito favorável para a competitividade do elo de processamento da cadeia de SLCC no Paraná, e somente um direcionador de competitividade, do conjunto de direcionadores considerados nesta dissertação, foi considerado como muito desfavorável para o desempenho competitivo do elo de processamento. As análises permitiram apontar propostas de políticas públicas e estratégias privadas que possam aumentar a competitividade. Em um contexto geral, pode-se concluir que os elos de produção rural e de processamento da cadeia agroindustrial de SLCC no Paraná têm um grande potencial para continuar a se expandir no território paranaense. A citricultura, no Paraná, tem um grande potencial para se expandir porque ela dispõe de boa tecnologia, de boa capacidade de produção e produtividade e de quantidade de terra agrícola disponível considerada como suficiente para ampliar a exploração da atividade citrícola no estado, além disso, os agentes econômicos que atuam na citricultura paranaense possuem contratos de fornecimento de laranja com as organizações econômicas que possuem usinas produtoras de SLCC instaladas no Paraná, assim, esses contratos asseguram a comercialização da maior parte da produção paranaense de laranja, o que é algo bom para os citricultores que atuam no Paraná. Já o setor processador de laranja também tem um grande potencial para se expandir no Paraná porque ele dispõe de tecnologias agroindustriais de bom nível e de boa capacidade de produção, além de ter condições de ampliar, sem maiores dificuldades, a sua capacidade de fabricação de SLCC, além disso, a existência de contratos de suprimento de laranja entre as organizações econômicas que atuam no processamento citrícola e os citricultores, no Estado do Paraná, assegura o abastecimento de laranja, considerada de boa qualidade, para as usinas produtoras de SLCC instaladas no Paraná.

Made available in DSpace on 2015-05-08T14:44:57Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 702224 bytes, checksum: d0803d0d78eba57fa012f42da176d61e (MD5) Previous issue date: 2008-02-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Brazil and the United States are considered great participants in the world market of the soybean and of the orange juice. The objective of this research is to analyze the influence of the American agricultural subsidies on the exports of the soybean and orange juice complex of Brazil, in the period between 1990 and 2006. The theoretical model to study the international trade was proposed by Brander and Spencer, with focus of imperfect competition incorporating the government intervention. In the empiric approach, he took place a junction of models of temporary series and of theory of the games, as instruments to evaluate the effect of the subsidies on the exports of those commodities. The conclusion of research is that the American protection harmed the capacity exporter of Brazil in that examined period. As conclusion is reinforced the participation activates of Brazil in the defense of the liberalization of the agricultural trade, for his access to the protected section and, also for the conquest of new trading partners. / O Brasil e os Estados Unidos são considerados grandes participantes no mercado mundial da soja e do suco de laranja. O objetivo da pesquisa é analisar a influência dos subsídios agrícolas americanos sobre as exportações dos complexos soja e suco de laranja do Brasil, no período entre 1990 e 2006. O modelo teórico para estudar o comércio internacional foi proposto por Brander e Spencer, com enfoque de competição imperfeita incorporando a intervenção governamental. Na abordagem empírica, realizou-se uma junção de modelos de séries temporais e de teoria dos jogos, como instrumentos para avaliar o efeito dos subsídios sobre as exportações dessas commodities. Concluiu-se que a proteção americana prejudicou a capacidade exportadora do Brasil nesse período examinado. Como conclusão reforça-se a participação ativa do Brasil na defesa da liberalização do comércio agrícola, para o seu acesso ao setor protegido e, também para a conquista de novos parceiros comerciais.

[pt] No atual ambiente competitivo globalizado, as empresas são cada vez mais levadas a estabelecer alianças estratégicas e redes de relacionamentos estratégicos para complementar seus recursos. A pesquisa avaliou como as implicações estratégicas das alianças e outros relacionamentos estratégicos, no caso de empresas situadas em um grupo estratégico, complementam a análise tradicional das implicações estratégicas dos fatores organizacionais e macroambientais. Sofisticou-se este estudo introduzindo-se o conceito de blocos estratégicos, complementar ao estudo dos grupos estratégicos, e cuja maior especificidade facilita o estudo do desempenho estratégico organizacional de empresas que estejam situadas em grupos e envolvidas em redes de relacionamento estratégicas. A investigação envolveu quatro empresas, incluindo um grupo estratégico que é, simultaneamente, um bloco estratégico, observado dentro de um escopo específico do sub-setor brasileiro de suco de laranja pronto para beber industrializado até fins do ano de 2001. Tratou-se de pesquisa descritiva e exploratória, com enfoque metodológico predominantemente positivista. Caracterizou-se como um múltiplo estudo de caso por envolver várias empresas, havendo complementado, com a abordagem relacional, a abordagem tradicional de ameaças e oportunidades ao rompimento das barreiras de mobilidade na migração inter-grupal das empresas. Para responder à pergunta central, foi realizada primeiramente uma pesquisa secundária, baseada em revisão bibliográfica e documental. Apontaram-se os construtos para análise das implicações estratégicas de redes e blocos para grupos estratégicos, aplicaram-se estes construtos para a análise dos grupos estratégicos pela perspectiva relacional, e indicaram-se as implicações relacionais às ameaças enfrentadas pelas empresas do grupo focal pela ótica tradicional. Em seguida, realizou-se a pesquisa primária, a qual: 1) retificou, de dois para três, o número de grupos estratégicos no setor analisado apontado na pesquisa secundária; 2) mostrou que as alianças estratégicas e redes de relacionamento dão margem a ameaças e oportunidades ao desempenho estratégico empresarial dificilmente identificadas pela ótica tradicional de análise do desempenho; 3) mostrou que as redes de alianças de uma empresa situada em um grupo estratégico podem capacitá-la a ultrapassar as barreiras inter- grupais, na medida em que complementam capacidades, provêm acesso a informações relevantes, proporcionam economias de escala, ajudam a gerenciar riscos e incertezas, reduzem os custos de entrada em novos mercados, e facultam o compartilhamento de recursos e competências complementares; 4) mostrou que, no caso das alianças estratégicas com clientes-chave - muito relevante no caso do segmento econômico pesquisado - esta capacitação à ultrapassagem das barreiras pode ser modulada pela forma como a empresa se posiciona no relacionamento, sendo menos intensa quando a empresa se vê como uma mera prestadora de serviços. Quatro recomendações a futuras pesquisas são destacadas. / [en] In the present globalized competitive environment, companies are continuoulsy pushed to establish strategic alliances and strategic relationship networks to complement their resources. The research studied how the strategic implications of alliances and other strategic relationships, in the case of companies in a strategic group, complement the traditional analysis about the strategic implications of the organizational and macroenvironmental factors.The study was sophisticated through the introduction of the strategic block concept created by Nohria & Garcia-Pont (1991), that complements the strategic groups study, and whose deeper specificity improves the study of the organizational strategic performance of companies located in groups and envolved in strategic relationship networks. The investigation envolved four companies,including a strategic group that simultaneously is a strategic block, observed in a specific scope of the Brazilian ready-to-drink industrialized orange juice subsector up to the end of 2001. The research was descriptive and exploratory, with a mainly positivist methodological vision. It is a multiple case study since it envolves several companies, and it complemented, through the relational approach, the traditional approach of opportunities and threats to the surpassing of the mobility barriers for the inter-group migration of companies. In order to answer the main question, first a secondary reasearch was made, based on bilbiographical and documental research. The constructs for the analysis of the strategic implications of networks and blocks for strategic groups were indicated, and were used in the analysis of strategic groups through the relational perspective. The relational implications to the threats faced by the companies of the focal group in the traditional perspective were indicated. In the following stage, the primary research was accomplished, and its results were: 1) it rectified, from two to three, the number of strategic groups in the sector analysed in the secondary research; 2) it showed that strategic alliances and relationship networks give birth to threats and opportunities to the strategic performance of the company that are hardly identified through the traditional approach of the performance analysis; 3) the alliance networks of a company located in a strategic group may enable it to surpass the intergroupal barriers, since they provide the company with capacities foreign to its core business; 4) in the case of strategic alliances with key clients - very relevant in the case of the analysed economic sector - this capacity of surpassing barriers may be modulated by the way the company positions itself in the relationship. Four recommendations for future research are proposed.

Abdominal surgery inhibits gastrointestinal motility, a phenomenon referred to as postoperative ileus. Since the postoperative ileus disturbs duodenal physiology it is important to minimize the side effects of this condition. Recent experiments in our laboratory show that treatment of anaesthetised rats with parecoxib, a selective cyclooxygenase-2 inhibitor, prevents duodenal postoperative ileus, increases duodenal mucosal bicarbonate secretion and improves other functions as well. One aim of the thesis was to investigate whether removal of luminal chloride affect the parecoxib- and the vasoactive intestinal peptide (VIP)-induced stimulation of duodenal mucosal bicarbonate secretion. The proximal duodenum of anaesthetised Dark Agouti rats was perfused with isotonic solutions containing zero or low Cl- and the effect on luminal alkalinisation determined. The basal as well as the parecoxib-induced increase in alkalinisation, but not that stimulated by VIP, were markedly reduced in the absence of luminal Cl-. One important function of the duodenum is to adjust luminal osmolality towards that in the blood. It is believed that the adjustment of osmolality in the duodenum is achieved by osmosis and diffusion of electrolytes along their concentration gradients and that these processes occur predominately paracellularly. Another aim of the thesis was to examine whether prevention of postoperative ileus affects the duodenal response to luminal hypertonicity. The proximal duodenum of anaesthetised Dark Agouti and Sprague-Dawley rats were perfused with hypertonic solutions of different composition and osmolality and the effects on duodenal motility, alkaline secretion, transepithelial fluid flux, mucosal permeability and the adjustment of luminal osmolality were determined in absence and presence of parecoxib. It is concluded that COX-2 inhibition increases duodenal mucosal bicarbonate secretion by stimulating apical Cl-/HCO3- exchange in duodenocytes. Furthermore, pretreatment of anaesthetised rats with parecoxib improves a number of duodenal functions in both rat strains that contribute to improve the ability to adjust luminal osmolality. The choice of rat strain is another important feature to consider when interpreting the results because the DA strain was more responsive to luminal hypertonicity than the SD strain. Finally, several evidences are provided to suggest that the adjustment of luminal osmolality in the rat duodenum is a regulated process.

0 comportamento higroscópico do suco de laranja liofilizado, e aditivado com malto-dextrinas e lactose, e de misturas mecânicas do suco liofilizado com os aditivos secos, foi estudado através da cinética e das isotermas de sorção de água, em diferentes temperaturas. Avaliou-se as características espectrais no visível e ultravioleta, e o teor de vitamina C, de amostras de suco de laranja liofilizado expostas a diferentes umidades relativas e temperaturas. Estudou-se a influência do valor de pH e natureza do tampão sobre a retenção do limoneno emulsionado em soluções de lactose, liofilizadas. A liofilização praticamente não alterou o teor de vitamina C e as características espectrais do suco de laranja, mas aumentou o valor monomolecular da malto-dextrina (dextrose equivalente de 9 a 12%). A lactose liofilizada apresentou-se no estado amorfo. Os teores de umidade de equilíbrio das misturas aditivadas liofilizadas, foram menores que os das misturas mecânicas. Os aditivos reduziram a sorção de umidade em função do tempo. A retenção do limoneno foi influenciada pela sua concentração inicial, sendo que ocorreu a major perda, durante a liofilização na major concentração utilizada. / The higroscopic behavior of freeze-dried orange juice, with added maltodextrins and lactose and mechanical mixtures with this additives was studied through the kinetics and isoterms of water sorption in different temperatures. It was evaluated the spectral characteristics, in the visible and ultraviolet range, and the vitamin C content from samples of freeze-dried orange juice exposed at different relative humidities and temperatures. It was studied the influence of pH and buffer composition, on the limonene retention of freeze-dried emulsions. The spectral characteristics and vitamin C content showed no alterations after liofilization the maltodextrin (9-12 % dextrose equivalent monomolecular value increased. Freezedried lactose was amorphous. The equilibrium humidity content of the samples with additives were reduced when compared with mechanical mixtures. The additives also reduced the rate of water sorption. The limonene retention during freeze-drying was influenced by the initial concentration of the emulsion. The greater concentration studied showed the lower retention value.

Made available in DSpace on 2016-06-02T19:50:05Z (GMT). No. of bitstreams: 1 2520.pdf: 1207796 bytes, checksum: d7395bbee81744b10cc9081ce73234c4 (MD5) Previous issue date: 2009-06-22 / This work aim at developing models using linear programming, goal programming and robust optimization to support decision making in the frozen concentrated orange juice planning process. The proposed model includes orange harvesting plan, which takes into account oranges maturation curves. This fact leads to a model that incorporates a large portion of the supply chain involved in the frozen concentrated orange juice sector. Another point to highlight is the inclusion of the blending process of different types of juices to match ratio specification of the product. This study uses orange acidity to calculate ratio specification of the product. This study also explores the importance of data uncertainty incorporation to the aggregate production planning for this business and evaluate results from different approaches of robust optimization to this problem. This author is not aware of previous work in the literature with such approach to the orange juice industry. The problem modeling uses blending problem concepts and production planning with multiple products, stages and periods concepts as well. To solve the linear programming, goal programming and robust optimization models, an algebraic modeling language and a state of art optimization solver of mathematical programming problems is used. A case study was developed in an orange juice company located in the São Paulo State. This company has many facilities and a worldwide distribution system, similar to other companies in this sector. The results show that the proposed approach can be used in real situations. / O objetivo deste trabalho é desenvolver modelos de programação linear, programação por metas e otimização robusta para apoiar decisões no processo de planejamento agregado da produção de suco concentrado congelado de laranja. A modelagem proposta incorpora o planejamento de colheita da laranja, levando-se em consideração as curvas de maturação das laranjas. Esse fato conduz a um modelo que incorpora grande parte da cadeia de suprimento envolvida no setor de produção de suco concentrado congelado de laranja. Outro ponto a destacar é a consideração do processo de mistura de diferentes tipos de sucos para a obtenção da especificação de ratio do produto acabado. No caso desse estudo, utiliza-se a acidez da laranja como base de cálculo para a especificação de ratio do produto acabado. Este estudo também explora a importância da incorporação de incerteza a determinados parâmetros envolvidos no processo de planejamento de produção nesse setor e analisa os resultados das diferentes abordagens de otimização robusta para o problema. Sendo que, este autor desconhece trabalhos anteriores na literatura com esta abordagem para a indústria de suco de laranja. A modelagem do problema utiliza conceitos de problemas de mistura e planejamento de produção com múltiplos produtos, estágios e períodos. Para resolver os modelos de programação linear, programação por metas e otimização robusta, utilizou-se uma linguagem de modelagem algébrica e um aplicativo de última geração de solução de problemas de programação matemática. Um estudo de caso foi realizado em uma empresa de suco de laranja localizada no Estado de São Paulo, envolvendo várias plantas e com uma rede de distribuição internacional com características típicas de outras empresas do setor. Os resultados indicam que a abordagem aqui proposta pode ser aplicada em situações reais.