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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Continuous-flow microwave thermal processing of cloudy apple juice. / Processamento térmico de micro-ondas de fluxo contínuo em suco de maçã não clarificado.

Érica Sayuri Siguemoto 18 July 2018 (has links)
Continuous-flow microwave heating is an alternative processing technology that can bring advantages to the pasteurization of food products, particularly, fruit-based beverages. This work aimed to study the continuous-flow microwave thermal processing of cloudy apple juice. Dielectric and electric properties of cloudy apple juices, obtained from different varieties and from an industrial plant, were determined from 500 to 3000 MHz and temperatures between 10 °C and 90 °C. At these frequencies, apple variety showed little influence and the permittivity decreased almost linearly with temperature. Inactivation kinetics of pathogen microorganisms (Escherichia coli O157:H7 and Listeria monocytogenes) and enzymes (polyphenol oxidase, peroxidase and pectin methylesterase) were studied and modeled to evaluate non-thermal effects of microwave radiation. For both processing technologies, it was possible to achieve a 5-log10 reduction of E. coli and L. monocytogenes, as recommended by the FDA. Microwave processing in comparison to conventional heating enhanced the microorganism inactivation in 18 out of 28 experiments. Predicted enzyme inactivation curves for pasteurization at 70 °C and 80 °C of the cloudy apple juice showed that pectin methylesterase has the highest thermal resistance and that there was no significant evidence of non-thermal microwave effects. A pilot scale unit used for pasteurizing fruit juices was evaluated and the process was modeled and simulated to determine the average time-temperature history. Mean residence times and dispersion parameters were obtained from internal volume measurements and residence time distribution experiments. Thermal processing experiments using water provided heat transfer coefficients as functions of Reynolds number and also microwave power absorption. Mathematical modeling was used to determine the temperature distribution along the product path and results were validated. Results showed that focused microwave heating provided the necessary temperature increase in a very short time, with a lethality contribution of only 0.7% as compared to 59-68% when using the conventional heat exchanger, which configures over-processing and can decrease product quality. Fresh cloudy apple juice was subjected to continuous flow microwave assisted pasteurization in a pilot scale unit at three processing temperatures (70 °C, 80 °C and 90 °C), two flow rate levels and two heating systems (conventional and focused microwave). Good results were obtained for polyphenol oxidase and peroxidase inactivation, but not for pectin methylesterase, which showed to be the most resistant enzyme. A comparative evaluation on quality changes was performed in cloudy apple juice samples pasteurized in the continuous-flow unit. Profile of volatiles of the microwave pasteurized apple juice was more similar to the nonpasteurized juice, in comparison with the conventionally pasteurized juice. However, total organic acids and total soluble sugar contents were not significantly different between both processing technologies. There was an increase of phenolic contents during processing of cloudy apple juice, possibly due to the extraction of phenolic compounds present in suspension of material. Furthermore, it was observed the same trend of antioxidant capacity by DPPH and ORAC methods. In conclusion, this PhD work presents the potential of the microwave-assisted pasteurization in cloudy apple juice regarding enzymatic, microbiological and quality aspects. / Aquecimento de micro-ondas de fluxo contínuo é uma tecnologia de processamento alternativa que pode proporcionar vantagens para a pasteurização de produtos alimentícios, particularmente, bebidas à base de frutas. Este trabalho teve como objetivo estudar o processamento térmico de micro-ondas de fluxo contínuo em suco de maçã não clarificado. As propriedades dielétricas e elétricas dos sucos de maçã não clarificados, obtidos de diferentes variedades de maçãs e de uma planta industrial, foram determinadas entre 500 e 3000 MHz e temperaturas entre 10 °C e 90 ° C. Nessas frequências, a variedade da maçã apresentou pouca influência e a permissividade elétrica diminuiu quase linearmente com a temperatura. Cinéticas de inativação de microrganismos patogênicos (Escherichia coli O157: H7 e Listeria monocytogenes) e enzimas (polifenol oxidase, peroxidase e pectina metilesterase) foram estudadas e modeladas a fim de avaliar os efeitos não térmicos da radiação de micro-ondas. Para ambas tecnologias de processamento foi possível obter uma redução de 5-log10 de E. coli e L. monocytogenes, como recomendado pelo FDA. O processamento de micro-ondas em comparação com o aquecimento convencional aumentou a inativação dos micro-organismos em 18 dos 28 experimentos. As curvas de inativação enzimática preditas para pasteurização a 70 ° C e 80 ° C do suco de maçã mostraram que a pectina metilesterase possui a maior resistência térmica e que não houve evidência de efeitos não térmicos. Uma unidade de escala piloto usada para pasteurizar sucos de frutas foi avaliada e o processo foi modelado e simulado para determinar o histórico de tempo-temperatura. Os tempos médios de residência e os parâmetros de dispersão foram obtidos a partir de experimentos de distribuição do tempo de residência e volumes. Experimentos do processamento térmico utilizando água, como produto alimentício, forneceram coeficientes de transferência de calor em função do número de Reynolds e absorção de energia de micro-ondas. A modelagem matemática foi utilizada para determinar a distribuição de temperatura do percurso do produto, e posteriormente, foram validados. Os resultados mostraram que o aquecimento por microondas focalizadas proporcionou o aumento necessário da temperatura em um tempo curto, com uma contribuição de letalidade de apenas 0,7% em comparação a 59-68%, quando usado somente o trocador de calor convencional, o que configura sobre processamento, podendo diminuir a qualidade do produto. O suco de maçã fresco não clarificado foi submetido à pasteurização por micro-ondas em fluxo contínuo em uma unidade de escala piloto em três temperaturas de processamento (70 ° C, 80 ° C e 90 ° C), dois níveis de vazão e dois sistemas de aquecimento (convencional e micro-ondas). Resultados positivos foram obtidos para polifenol oxidase e peroxidase, mas não para a pectina metilesterase demonstrando ser a enzima mais resistente. Uma avaliação comparativa das mudanças de qualidade foi realizada em amostras de suco de maçã pasteurizado na unidade de fluxo contínuo. O perfil de voláteis do suco de maçã pasteurizado por microondas foi mais semelhante ao suco não pasteurizado em comparação ao suco pasteurizado convencionalmente. Entretanto, ácidos orgânicos totais e açúcares solúveis totais não foram significativamente diferentes no processamento por estas duas tecnologias. Houve um aumento de compostos fenólicos durante o processamento do suco de maçã não clarificado, possivelmente devido a extração de compostos fenólicos presentes no material em suspensão. Além disso, foi observado a mesma tendência na atividade antioxidante determinada pelos métodos de DPPH e ORAC. Em conclusão, este trabalho de doutorado apresenta o potencial da pasteurização por micro-ondas em suco de maçã não clarificado quanto aos aspectos enzimáticos, microbiológicos e de qualidade.
32

Uso de modelos preditivos no crescimento e inativação de esporos de Alicyclobacillus acidoterrestris em suco de laranja e maça / Use of predictive models for growth and inactivation of alicyclobacillus acidterrestris spores in orange and apple juices

Luera Pena, Wilmer Edgard 24 May 2005 (has links)
Orientador: Pilar Rodriguez de Massaguer / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-04T11:48:31Z (GMT). No. of bitstreams: 1 LueraPena_WilmerEdgard_D.pdf: 1783533 bytes, checksum: 59fcd5288937a1e607c7124e74e4aef5 (MD5) Previous issue date: 2005 / Doutorado / Ciência de Alimentos / Doutor em Ciência de Alimentos
33

Hur påverkar olika lokala jäststammar aromutveckling och smak vid fermentering av äppeljuice? / How does different indigenous yeast strains influence the aroma development and taste during fermentation of apple juice?

Lavin, Philip January 2021 (has links)
Intresset för lokalproducerad dryck ökar. Konsumenten efterfrågar produkter med mer komplexa smaker. Främst gäller detta produktkategorin öl, vin och cider. Det har i flera studier visats att lokala stammar av mikroorganismer kan användas för att tillverka produkter med en större smakkomplexitet än de produkter som baseras på konventionella stammar. Detta har fått bryggare och vinmakare att experimentera med såväl val av råvara som mikroorganismer i syfte att ta fram unika produkter. I denna studie har tre lokala stammar av Saccharomyces cerevisiae undersökts avseende eventuella skillnader i fermenteringsförlopp och aromutveckling samt smak vid fermentering av äppeljuice. Resultatet från studien visar att alla stammarna överlag beter sig lika inklusive enskilda sensoriska attribut och att en fermentering på tre dagar ger upphov till högre totalt gillande av produkt än vid sju dagars fermentering. / There is an increasing interest in locally produced drinks. Consumers demand products with complex taste profiles. Especially when it comes to wine, beer and cider. Several studies have shown that indigenous strains of microorganisms can be used to produce products that’s deemed more complex than the products based on conventional strains. This has led brewers and winemakers to experiment with both the raw material as well as the local microorganisms in order to develop unique products. In this study, three local strains of Saccharomyces cerevisiae have been studied for potential differences regarding aroma development and taste during fermentation of apple juice. The results from the study showed that the different strains generally behaved the same, and that fermentation during three days resulted in greater taste liking compared to seven days.
34

Modelling, Simulation, and Optimisation of Reverse Osmosis Process with Application in Wastewater Treatment and Food Processing

Al-Obaidi, Mudhar A.A.R. January 2018 (has links)
Reverse Osmosis (RO) is a membrane-based separation process applied in several industrial and food processing applications. In this research, performance of RO process is investigated in respect of two applications (a) wastewater treatment (b) concentration fruit juices using model-based techniques. For this purpose, a number of models (both 1 and 2-dimensional steady state and dynamic) for spiral wound RO process are developed based on Solution-Diffusion model and Irreversible Thermodynamic model. The models are validated against actual experimental data reported in the literature before being used in further simulation and optimisation studies for both wastewater treatment and fruit juice concentration. Wastewater effluents of many industrial applications contain a variety of micro-pollutants and highly-toxic compounds, which are released into a variety of water resources. Such pollutants not only disrupt the biological ecosystem, but they also pose a real threat to the water supply for human consumption and to the aquatic ecosystems. The earlier chapters of the thesis evaluate the performance of RO process in terms of removal efficiency of toxic compounds such as chlorophenol, N-nitrosamine, etc. from wastewater. The effect of several operating parameters such as feed pressure, concentration, flow rate and temperature, on the performance of RO process are evaluated. Also, suitability of a number of different RO configurations for efficient removal of toxic compounds are evaluated. For example, (a) two-stage/two-pass RO design synthesis of RO network for the removal of chlorophenol (b) multistage multi-pass RO process with and without energy recovery option for the removal of N-nitrosamine are investigated. The dynamic response of the RO process for step changes in the operating parameters is investigated for the removal of phenolic compounds. Finally, in the context of wastewater treatment, a case study with multi compounds contaminants is suggested where a multi-objective optimisation problem has achieved the optimum rejection of all the compounds and recovery rate. In respect of food processing, RO has been considered as a prominent process in fruit juice concentration due to its ability to effectively retain the flavour, sensory, aroma and nutritional characteristics and concentrate the juice. This research elucidates one example of apple juice concentration process and focuses on highlighting successful modelling and optimisation methodology. This in turn provides an efficient method of RO process for concentrating apple juice by improving the reliability and efficiency of the underlying separation and concentration process. / Ministry of High Education and Scientific Research of Iraq
35

Discovery and dissemination of new knowledge in food science: Analytical methods for quantification of polyphenols and amino acids in fruits and the use of mobile phone-based instructional technology in food science education

Ma, Sihui 11 June 2019 (has links)
The discovery and dissemination of new knowledge are essential in food science. To advance our understanding of fruit chemistry, analytical methods were compared and applied. Polyphenols are secondary metabolites in fruits of particular importance in food science, as they contribute to the sensory attributes and health benefits of the products. Evaluation of common analytical methods for the quantification of polyphenols, including the Folin-Ciocalteu (F-C), Lowenthal permanganate (L-P), 4-dimethylaminocinnamaldehyde (DMAC) and the bovine serum albumin (BSA) precipitation methods, was conducted using analytical method validation procedures. The F-C method was not specific to polyphenols, and the L-P method had the widest working range but lacked accuracy. The DMAC method was the most specific to flavanols, and the BSA method was not suitable for quantification of smaller flavanols. Quantitative performance of these four methods was evaluated using a broad range of fruit-derived samples. Variation in quantitative results obtained using these four methods was explained by differences in polyphenol and matrix composition of these samples and differences in operating principles of the methods. The reactivity of individual polyphenol compounds (catechin, epicatechin, PC B2, PC pentamer, chlorogenic acid, phloretin, and quercetin) to the polyphenol and flavanol quantification results using Prussian blue (P-B), F-C, DMAC and BSA precipitation methods were also assessed and determined to differ by up to thirteen-fold, depending on the assay. Furthermore, the contribution and interactions of polyphenol compounds (catechin, PC B2, and chlorogenic acid) and potentially interfering compounds likely to be found in fruit and fruit products (ascorbic acid, glucose, and SO2) to the quantitative results of these methods were evaluated using a full factorial design. Significant interactions among polyphenol compounds, and among the interfering compounds were found. The standardized coefficient (β) for all factors and interactions of polyphenol compounds varied from 0.347 to 129, and from near 0 to -46.8 for all factors and interactions of interfering compounds. Our findings indicate that the choice of standards, polyphenol and matrix composition of the sample may cause disparity among the quantitative results of these methods. Amino acids in apple (Malus × domestica Borkh.) juice not only influence the quality of fermented cider through fermentation kinetics but also impact the flavor of the cider through yeast metabolism. Due to recent advances in analytical instrumentation, amino acids profiles in apple juice were determined much faster and more accurately than by previously applied methods. Twenty amino acids were quantified by UPLC-PDA in juices from 13 apple cultivars grown in Virginia. The relative amino acid profile was significantly different among the apple juices evaluated. The total amino acid concentration ranged from 18 mg/L in Blacktwig juice to 57 mg/L in Enterprise juice. L-Asparagine, L-aspartic acid and L-glutamine are the principal amino acids observed in most apple juices. These results will inform future research on yeast metabolism and nitrogen management during cider fermentation. To better disseminate knowledge gained through research to the next generation of food scientists, the effectiveness of new instructional technology—a cellphone-based personal response system—in food science education was evaluated. Students' academic performance was improved by the incorporation of this technology into lectures, and its use was well perceived by the students (easy to use and positively impacted their learning). This finding contributes to the scholarship of teaching and learning in food science by providing useful insight into the potential for application of such tools with improved student engagement and learning outcomes. Advances in food chemistry research will enable the development of value-added food products, and the pedagogical advancement in food science education will better convey new and existing knowledge to students, who will apply this knowledge to promote a safe and nutritious food supply that enhances human health and increases the value of specialty crops. / Doctor of Philosophy / In food science, both the discovery and dissemination of new knowledge are essential. To advance our understanding in fruit chemistry, several analytical methods were compared and applied. Polyphenols are important bioactive compounds in fruits associated with health benefits, and they also contribute to the bitterness and astringency of the products such as chocolate and red wines. Systematic evaluation of common analytical methods used to quantify polyphenols was conducted. When different methods were used to evaluate a broad range of fruit-derived samples, different results were obtained for a given sample, depending on the method applied. This was explained by the difference in polyphenol composition of these samples. Furthermore, different individual polyphenol compounds contributed differently to quantitative results for these methods. Interactions among polyphenol compounds and interference from constituents of the juice samples other than polyphenols were also found. These findings demonstrate that when comparing fruit chemistry (polyphenol concentration) results obtained using the methods evaluated, it is necessary to consider the polyphenol composition as well as the sample matrix composition. This knowledge will improve our ability to interpret and compare existing data on polyphenol content in fruits, advancing the understanding the polyphenols and health and informing producers to improve their fruit products with optimized quality and sensory characters. Secondly, amino acids in apple juice influence the quality of fermented cider, through not only controlling the fermentation rate, but also impacting the flavor of the cider through yeast metabolism. Twenty amino acids were quantified in juices from 13 apple cultivars grown in Virginia with potential use in cider making using a recently developed method in analytical chemistry. The relative amino acid profile was significantly different among the apple juices evaluated. L-Asparagine, L-aspartic acid and L-glutamine are the principal amino acids observed in most apple juices. This knowledge will help with the development of fermentation strategies for production of ciders with targeted sensory attributes. To better disseminate new knowledge in food science to the next generation, the effectiveness of a new educational technology application—a cellphone-based personal response system (similar to clickers)—in food science education was evaluated. Using this application during lecture resulted in improved quiz grades, and students felt that it was easy to use and positively impacted their learning. This application has the potential to improve effectiveness of lectures in higher education classrooms. Advances in food chemistry research will enable development of value-added food products, and the pedagogical advancement in food science education will better convey new and existing knowledge to students, who will apply this knowledge to promote a safe and nutritious food supply that enhances human health and increases the value of specialty crops.
36

ProduÃÃo de Biossurfactantes por FermentaÃÃo Submersa usando Substrato NÃo Convencional / Biosurfactants Production by Batch Fermentation using Alternative Substrate

Maria Valderez Ponte Rocha 09 February 2007 (has links)
AgÃncia Nacional do PetrÃleo / Este trabalho teve como objetivo avaliar a produÃÃo de biossurfactante por cepas de Pseudomona aeruginosa e Bacillus subtilis, utilizando suco de caju, integral e clarificado, como matÃria-prima nÃo convencional. Nos ensaios com P. aeruginosa ATCC 10145 em mesa agitadora, avaliou-se a suplementaÃÃo do suco de caju integral (CAJN) com Ãleo de soja, como fonte de carbono, e com diferentes fontes de nitrogÃnio: peptona, NaNO3 e (NH4)2SO4, sendo estes resultados comparados com os obtidos utilizando caldo nutritivo e com meio CAJN. A maior reduÃÃo na tensÃo superficial (41 %) foi obtida no suco de caju suplementado com peptona (CAJP) apÃs 24 h de cultivo. Neste ensaio, observou-se uma reduÃÃo da tensÃo superficial do meio de 50 para 29,5 dina cm-1. Jà em meio suplementado com NaNO3 e (NH4)2SO4, obteve-se, respectivamente, uma reduÃÃo na TS de 37,14 e 15,85% apÃs 72 horas de cultivo. Estudou-se a suplementaÃÃo do meio CAJP com glicerol e Ãleo de soja. Nestes ensaios, observou-se um alto crescimento celular, obtendo uma densidade Ãptica (a 600nm) de 5,0 com 48 h de cultivo, contudo uma pequena reduÃÃo da tensÃo superficial (16,51 %) ao utilizar glicerol. Com base nos resultados conduzidos em mesa agitadora, os meios CAJP e CAJNaNO3 foram selecionados para estudos em fermentador de bancada. Realizaram-se ensaios utilizando biorreator a 30ÂC, 200 rpm e sem aeraÃÃo, porÃm nÃo se observou o mesmo perfil de produÃÃo de ramnolipÃdeos ocorrido em mesa agitadora. Tal fato pode ter ocorrido devido à falta de oxigÃnio no meio de cultivo. Acompanhou-se a estabilidade tÃrmica, efeito da variaÃÃo de pH e da concentraÃÃo de NaCl, na atividade emulsificante do biossurfactante produzido em CAJP e sua composiÃÃo quÃmica. O biossurfactante produzido por P. aeruginosa demonstrou-se estÃvel a variaÃÃes de temperatura, pH e concentraÃÃes de NaCl, e emulsionou todos os hidrocarbonetos estudados e Ãleo de soja. Em paralelo, diferentes ensaios foram realizados visando otimizar o meio de cultivo para a produÃÃo de surfactina por B. subtilis usando CAJN e suco de caju clarificado (CAJC). Os melhores resultados foram obtidos quando se utilizou meio mineral suplementado com extrato de levedura e formulado com CAJC, de maneira que a concentraÃÃo de glicose fosse de 10 g.L-1. Nestes ensaios, obteve-se uma reduÃÃo de 21,37 % na tensÃo superficial e observou-se a presenÃa de surfactina atravÃs das anÃlises conduzidos em HPLC. No entanto, a mÃnima tensÃo superficial alcanÃada foi superior a 39 dina.cm-1. Portanto, avaliaram-se outras cepas de B. subtilis, doze ao total, quanto à capacidade de produzir surfactina utilizando CAJC. ApÃs 48 horas de cultivo com as cepas BE 08, a tensÃo superficial do meio de cultivo livre de cÃlulas atingiu 28,0  1,0 dina.cm-1, que tambÃm apresentou atividade emulsificante. Os resultados obtidos neste trabalho indicam que o suco de caju à uma matÃria-prima adequada para a produÃÃo de biossurfactantes. / The aim of this work was to investigate the use of natural and clarified cashew apple juice as an alternative raw material for biosurfactant production by Pseudomonas aeruginosa and Bacillus subtilis. In the assays with P. aeruginosa ATCC 10145 on rotary shaker, the influence of medium (CAJN) supplementation with soybean oil, as source carbon, and with different sources of nitrogen: peptone, NaNO3 and (NH4)2SO4, were investigated. Results were compared with the obtained when Nutritive Broth (NB) and CAJN were used as culture medium. Maximum reduction in the Surface Tension (41%)was obtained when P. aeruginosa was grown on CAJP, after 24 h of cultive. In these assays, the surface tension was reduced from 50 to 29.5 dina.cm-1. When P. aeruginosa was grown on CAJN supplemented with NaNO3 or (NH4)2SO4, the reduction in the Surface Tension was of 37.14 and 15.85 %, respectively, after 72 h of cultive. Evaluated CAJP supplemented with glycerol and soybean oil. In these assays, high growth was observed, an optical density of 5,0 at 600 nm with 48h of culture was observed, however small reduction in surface tension (16,51 %) was achieved using glycerol as carbon source. Based on the results in flasks, the mediums CAJP and CAJNaNO3 were selected for further studies in a biorreator. The assays were conduced in biorreator at 30ÂC, 200 rpm and without aeration. Nevertheless, the expected profile of rhamnolipids production was not observed. Such fact may have happened due to the lack of oxygen in the cultivation medium, since the process was conducted without aeration. The stability of biosurfactant produced by P. aeruginosa in CAJP against NaCl, pH and temperature and its chemical structure were evaluated. The biosurfactante produced by P. aeruginosa was stable to temperature and variations, as well as against different NaCl concentrations. Furthermore, it emulsified all the studied hydrocarbons and soybean oil. No protein was detected in the extracted biosurfactant; it however contained carbohydrate. The highest biosurfactant production occurred with 48h,when CAJP was used as culture medium (3.86 g of biosurfactant for 1000 mL de medium) and the poorest in NB. In parallel, different assays were performed to optimize the culture media for surfactin production by Bacillus subtilis using CAJN and clarified cashew apple juice (CAJC). Best results were obtained when mineral medium supplemented with yeast extract (5 g.L-1) was used and formulated with CAJC (glucose concentration - 10 g.L-1). In these assays, a reduction of 21.37 % in the surface tension was obtained and production of surfactin was observed by HPLC. However, best results of surface tension were higher than 39 dina.cm-1. Therefore, twelve strains of Bacillus sp. were evaluated regarding the ability of producing surfactin when grown on CAJC. After 48 hours of cultivation, with strain BE 08, the surface tension of the fermented broth, free of cells, reached 28.0  1.0 dina.cm-1,and it also presented emulsifying activity. The results obtained in this work indicate that the cashew apple juice is an appropriate raw material for biosurfactants production.
37

Estudo de EquilÃbrio e CinÃtica de AdsorÃÃo em Resinas de Troca IÃnica Aplicado à SeparaÃÃo CromatogrÃfica ContÃnua de Frutose e Glicose do Xarope de Caju / Studies on adsorption equilibrium and kinetics in ion exchange resins applied to the continuous chromatographic separation of fructose and glucose present in cashew apple syrup

Josy Eliziane Torres Ramos 31 March 2008 (has links)
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / A cajucultura à considerada uma das atividades sÃcio-econÃmicas mais importantes da regiÃo Nordeste do Brasil. Apesar de ser empregado industrialmente para fabricaÃÃo de polpa, bebidas e doces, o pedÃnculo do caju apresenta altÃssimos nÃveis de desperdÃcio. Pouco mais de 10% da produÃÃo agrÃcola à explorada comercialmente. Neste contexto, a obtenÃÃo de produtos de valor agregado a partir do pedÃnculo do caju â como xaropes de frutose e glicose â pode indicar rotas econÃmicas alternativas para as regiÃes produtoras, aproveitando a produÃÃo excedentÃria nÃo absorvida pelo mercado de sucos e doces industrializados. O leito mÃvel simulado constitui uma das mais inovadoras tecnologias cromatogrÃficas que realiza separaÃÃo de isÃmeros de forma contÃnua. Um dos pontoschave desta tecnologia à a escolha adequada das condiÃÃes de operaÃÃo (vazÃes e tempos de troca) que propiciem uma separaÃÃo adequada. Este trabalho apresenta estudos de equilÃbrio de adsorÃÃo de soluÃÃes sintÃticas de frutose e glicose, em condiÃÃes de sobrecarga de concentraÃÃo, visando à separaÃÃo destes aÃÃcares em leito mÃvel simulado para a produÃÃo de xaropes de caju enriquecidos em frutose e glicose. As isotermas de adsorÃÃo foram obtidas por cromatografia frontal, utilizando soluÃÃes sintÃticas de frutose e glicose com concentraÃÃo variando de 10 a 120g/L, nas temperaturas de 30, 40 e 60 ÂC, utilizando as resinas de troca iÃnica Dowex MTO 99Ca e Diaion UBK 555. As curvas de ruptura (breakthrough) das soluÃÃes sintÃticas foram confrontadas com curvas de breakthrough obtidas a partir do xarope de caju para validaÃÃo do modelo. A partir das mesmas, foram obtidas isotermas nÃo-lineares bem descritas pelo modelo de Langmuir. O modelo do transporte dispersivo foi empregado para reproduzir o comportamento das curvas de breakthrough e para estimar parÃmetros de transferÃncia de massa, utilizando o solver comercial gPROMS. Os dados de equilÃbrio de adsorÃÃo foram utilizados para gerar a regiÃo de completa separaÃÃo (razÃes de vazÃo nas zonas 2 e 3) em uma unidade de leito mÃvel simulado (LMS), com base na Teoria do EquilÃbrio (mÃtodo do triÃngulo) para prediÃÃo das condiÃÃes de operaÃÃo numa unidade piloto. / The cashew crop is considered one of the most important socio-economic activity in Northeastern Brazil. Despite being used industrially for the production of pulp, drinks and sweets, the cashew apple shows high levels of waste. A little more than 10% of crop is exploited commercially. In this context, adding value to products derived from the cashew apple - such as fructose and glucose syrups - may indicate alternative economical routes for producing regions, by consuming the surplus not absorbed by the market of juices and sweets. The simulated moving bed is one of the most innovative technologies that performs continuous chromatographic separation of isomers. One of the key points of this technology is the choice of operating conditions (flows and switching times) that provides adequate separation. This work presents studies of adsorption equilibrium of synthetic solutions of fructose and glucose, under overloaded conditions of concentration, aiming at the separation of these sugars in simulated moving bed for the production of high-fructose and high-glicose syrups. The adsorption isotherms were obtained by frontal analysis, using synthetic solutions with fructose and glucose concentrations ranging from 10 to 120g / L, at temperatures of 30, 40 and 60  C, using the ion exchange resins Dowex MTO 99Ca and Diaion UBK 555. The breakthrough curves of synthetic solutions were compared with those obtained from the cashew syrup for validation of data, tha sake of model validation. Tha measured isotherms were non-linear and well described by the Langmuir model. The dispersive transport model was used to reproduce the behavior of breakthrough curves and to estimate mass transfer parameters, using the gPROMS commercial solver. Adsorption data were used to generate the region of complete separation (flowrate ratios in sections 2 and 3) of a simulated moving bed (SMB unit), based on the equilibrium theory (the triangle method), in order to predict operating conditions in a pilot unit.
38

Suco de caju contendo oligossacarídeos prébioticos / Cashew juice containing prebiotic oligosaccharides

Silva, Isabel Moreira da January 2010 (has links)
SILVA, Isabel Moreira da. Suco de caju contendo oligossacarídeos prébioticos. 2010. 61 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Tecnologia de Alimentos, Fortaleza-CE, 2010 / Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-06-10T13:30:41Z No. of bitstreams: 1 2010_dis_imsilva.pdf: 509842 bytes, checksum: 99fe8ba547aa30fada3854402b582dfd (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-06-10T13:30:51Z (GMT) No. of bitstreams: 1 2010_dis_imsilva.pdf: 509842 bytes, checksum: 99fe8ba547aa30fada3854402b582dfd (MD5) / Made available in DSpace on 2016-06-10T13:30:51Z (GMT). No. of bitstreams: 1 2010_dis_imsilva.pdf: 509842 bytes, checksum: 99fe8ba547aa30fada3854402b582dfd (MD5) Previous issue date: 2010 / Functional foods are now a research priority due to growing demand for foods that, besides the basic function of nurture, can bring benefits. Thus, studies for the development of prebiotics become interesting. The enzyme dextransucrase in a medium containing sucrose and an acceptor as substract synthesizes prebiotics oligosaccharides. The cashew apple juice works as a source of acceptors, since it is rich in glucose and fructose. The production of dextransucrase enzyme can be accomplished by fermentative process by inoculating the bacterium Leuconostoc mesenteroides NRRL B512F into a culture medium containing sucrose.Thus the aim of this work was the production of prebiotic oligosaccharides by enzymatic process with addition of the dextransucrase enzyme to the clarified cashew apple juice. Based on the results we can conclude that the clarified cashew apple juice can be used as low cost alternative substrate for the synthesis of prebiotic oligosaccharides through enzyme synthesis using the dextransucrase enzyme. Dextran yeld was favored by the combination of low concentrations of sucrose and reducing sugars. The formation of oligosaccharides was favored by increasing the concentration of reducing sugars and by the combination of high concentrations of sucrose and reducing sugars, where the largest concentration of oligosaccharides obtained was 104.73 g/L using 75g/L sucrose in combination with 75g/L of reducing sugars and finally the qualitative analysis shows that at concentrations of 25 g/L and 75g/L sucrose and reducing sugar, respectively, is possible to obtain oligosaccharides of degree of polymerization up to 12. / Os alimentos funcionais constituem hoje prioridade em pesquisas devido a crescente busca dos consumidores por alimentos que além da função básica de nutrir possam trazer outros benefícios. Dessa forma, estudos para o desenvolvimento de prebióticos tornam-se interessantes. A enzima dextrana-sacarase quando em meio contendo sacarose e um aceptor como substrato produz oligossacarídeos prebióticos. O suco de caju funciona como fonte de aceptores, uma vez que é rico em glicose e frutose. A produção da enzima dextrana-sacarase pode ser realizada via processo fermentativo através da inoculação da bactéria Leuconostoc mesenteroides NRRL B512F ao meio de cultura contendo sacarose. Dessa forma o objetivo desse trabalho foi a produção de oligossacarídeos prebióticos via processo enzimático com adição da enzima dextrana–sacarase ao suco de caju clarificado. Com base nos resultados obtidos, pode-se concluir que o suco de caju clarificado pode ser empregado como uma alternativa de substrato de baixo custo para a síntese de oligossacarídeos prebióticos, por via enzimática utilizando a enzima dextrana-sacarase. O rendimento em dextrana foi favorecido pela combinação de baixas concentrações de sacarose e açúcares redutores. A formação de oligossacarídeos foi favorecida pelo aumento da concentração dos açúcares redutores e pela combinação de elevadas concentrações de sacarose e açúcares redutores. Neste trabalho a maior concentração de oligossacarídeos obtida foi de 104,73 g/L utilizando-se 75 g/L de sacarose em combinação com 75 g/L de açucares redutores e por fim a análise qualitativa mostrou que em concentrações de 25 g/l e 75 g/l de sacarose e açúcar redutor, respectivamente foi possível obter oligossacarídeos de grau de polimerização até 12.
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Aproveitamento do pedúnculo do caju para síntese de oligossacarídeos prebióticos / Exploitation of the cashew of the prebiootic synthesis

Rabelo, Maria Cristiane January 2008 (has links)
RABELO, Maria Cristiane. Aproveitamento do pedúnculo do caju para síntese de oligossacarídeos prebióticos. 2008. 102 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Departamento de Tecnologia de Alimentos, Curso de Mestrado em Ciências e Tecnologia de Alimentos, Fortaleza-CE, 2008 / Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-06-17T15:45:41Z No. of bitstreams: 1 2008_dis_mcrabelo.pdf: 720591 bytes, checksum: 97be0059816995ce0d171844b7250e9c (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-06-17T15:45:56Z (GMT) No. of bitstreams: 1 2008_dis_mcrabelo.pdf: 720591 bytes, checksum: 97be0059816995ce0d171844b7250e9c (MD5) / Made available in DSpace on 2016-06-17T15:45:56Z (GMT). No. of bitstreams: 1 2008_dis_mcrabelo.pdf: 720591 bytes, checksum: 97be0059816995ce0d171844b7250e9c (MD5) Previous issue date: 2008 / Leuconostoc mesenteroides B742 produces the enzyme dextransucrose in a medium containing sucrose (carbon source), a nitrogen source and mineral salts. This enzyme catalyses dextran synthesis when the only carbon source is sucrose. When acceptors (maltose, fructose, glucose or other simple sugar) are present as the main substrate and sucrose is the second one, the enzyme synthesizes prebiotic oligosaccharides. These carbohydrates are not digested by humans and reach the large intestine where they are metabolized by bifidobacteria and lactobacilli, the intestine endogenous microbiota, increasing their growth. The most published papers about oligosaccharides synthesis using dextransucrase from Leuconostoc mesenteroides are related to the strain B512F and the synthesis is carried out using synthetic substrates. The cashew tree, largely grown in Ceará state, has a peduncle (pseudofruit) which is wasted. Considering that the peduncle corresponds to 90 % of the fruit weight, its annual estimated production is about 1,5 millions tons. However, only 5% of this production is industrially used or consumed in natura, being large amounts wasted in the field. This work aimed to the study of the prebiotic oligosaccharide synthesis through the acceptor reaction with dextransucrase enzyme from Leuconostoc mesenteroides B742 in natura clarified cashew apple juice. The partial substitution of yeast extract by ammonium sulfate as nitrogen source was also investigated. According to the results obtained, the clarified cashew apple juice can be used as low cost alternative substrate to grow L.mesenteroides B742 and to produce prebiotic oligosaccharide through enzyme synthesis. The crude enzyme showed higher stability in the clarified cashew apple juice when compared to the synthetic medium, making this substrate interesting for industrial applications because enzyme purification protocols are one of the most expensive steps in enzyme process. The partial substitution of yeast extract by ammonium sulfate also showed technical viability without enzyme yield losses. / O Leuconostoc mesenteroides B742 produz a enzima dextrana-sacarase em meio sintético contendo sacarose (fonte de carbono), fonte de nitrogênio e sais. Esta enzima catalisa a formação de dextrana quando em meio contendo acarose como único substrato. Entretanto, quando em meio contendo um aceptor (maltose, frutose, glicose ou outro açúcar simples) como substrato predominante e sacarose como segundo substrato, a enzima produz oligossacarídeos prébióticos. Estes carboidratos não são digeridos por humanos e ao chegarem no intestino grosso são metabolizados pelas bifidobactérias e lactobacilos, ali presentes, estimulando o seu crescimento. A maioria dos trabalhos publicados sobre a síntese de oligosscarídeos com dextrana-sacarase de Leuconostoc mesenteroides são relativos à linhagem B512F e utilizam substratos sintéticos. O caju, largamente cultivado no Ceará, possui castanha (verdadeiro fruto) e pedúnculo (pseudofruto) que é fonte de vitamina C. Considerando-se que o pedúnculo corresponde a 90% do peso do caju, calcula-se que o país produza cerca de 1,5 milhão de toneladas desse produto. No entanto, apenas 5% desse total é aproveitado industrialmente ou para consumo in natura, sendo grande parte perdida no campo. Dessa forma, o presente trabalho teve como objetivo o aproveitamento do pedúnculo como substrato para a síntese de oligossacarídeos prebióticos pela reação do aceptor com a enzima dextranasacarase, obtida via processo fermentativo a partir do Leuconostoc mesenteroides B742 no suco de caju clarificado in natura. A substituição parcial do extrato de levedura por sulfato de amônio como fonte de nitrogênio foi também avaliada. Com base nos resultados obtidos pode-se concluir que o suco de caju clarificado pode ser empregado como uma alternativa de substrato de baixo custo para o crescimento do Leuconostoc mesenteroides B742 e para a produção de oligossacarídeos prebióticos via síntese enzimática. A enzima bruta apresentou estabilidade superior no suco de caju quando comparada ao meio sintético, tornando este substrato bastante interessante do ponto de vista industrial, uma vez que a purificação da enzima é uma das etapas mais caras em processos enzimáticos. A substituição parcial do extrato de levedura por sulfato de amônio na produção da enzima se mostrou eficaz não causando perdas na produção da enzima.
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Technical and economic feasibility of ethanol production in cashew apple juice from Saccharomyces cerevisiae flocculant / Viabilidade tÃcnica e econÃmica da produÃÃo de etanol a partir do suco de caju por Saccharomyces cerevisiae floculante

Ãlvaro Daniel Teles Pinheiro 05 May 2015 (has links)
nÃo hà / Given the current situation in which it is the global energy sector, biofuels have been gaining more space, earning special attention the ethanol, which has shown growing demands. From this scenario, the objective of this work was to develop a bioprocess technically and economically practicable for ethanol production from cashew apple juice, using yeast Saccharomyces cerevisiae (CCA008) genetically modified containing a flocculent gene (FLO5α). The work was divided in 4 four stages that are linked throughout the study. In the first stage was evaluated the temperature influence (26, 30, 34, 38 and 42ÂC), the inoculum concentration (3, 5, 8 and 10 g.L-1) and the stirring speed (80, 150, 300, 490, 650 and 800 rpm), so it could be determined the best conditions to maximize ethanol production. It was observed that the temperature operating parameter, the initial cellular concentration, substrate concentration and stirring exerted influence on the alcoholic fermentation of the cashew apple juice. The best performance to the fermentative process (98,8 %) happened when the process was conducted at 34 ÂC, under 150 rpm stirring and 5 g.L-1 of initially cell concentration. The second stage was intended to describe the process efficiency in face of the operation parameters evaluated in fermentation. To this end, it was successfully used statistic models to describe the interaction between the initial substrate concentration, temperature, initial cell concentration, stirring and their possible effects on the yield. The model that best fit the experimental data was used to obtain the optimum conditions from the operating variables, indicating the following conditions as great: substrate concentration (S0) of 102 g.L-1, temperature (T) at 34ÂC, inoculum concentration (X0) of 5 g.L-1 and stirring (Agit) of 140 rpm, predicting a 98,80 % of efficiency. In the third stage was studied ethanol production in optimum conditions, being used to implement the scale up process, in which the data obtained in a 1L bioreactor batch were used to predict the fermentation behavior in a 14L bioreactor batch, using the volumetric power consumption as a parameter to scale-up. Using this factor as being of 10,67 kW/m3, it was possible to calculate the fermenter stirring power in a 14 times bigger volume, as well as foresee which stirring would be necessary so the fermentation can occur, similarly as in the lower volume fermenter. Results showed that yield from the 14L bioreactor were satisfactory, having a small difference (96,56 %  0,3 %) between yield from the 1L bioreactor (98,80 %  1,6 %). The fourth and last stage was rated the technical and economic viability of the process. Analyzing results, it is possible to say the industrial process here proponed has shown technical viability, since the value obtained for the process yield (68 L/ton), was close to sugar cane fermentation (61 â 72 L/ton). However, it did not show economic viability since the industrial unity provides negative cash flow (- R$ 93.840.874) in the end of 10 years that was analyzed. So, new studies must be conducted in order to make this process economically viable, this possibility being observed in various scenarios generated in analyzing the sensibility of process, which presents possible economically viable settings. / Diante da conjuntura atual em que se encontra o setor energÃtico mundial, os biocombustÃveis vÃm ganhando cada vez mais espaÃo, merecendo atenÃÃo especial o etanol, o qual apresenta demanda crescente. A partir desse cenÃrio, o objetivo do presente trabalho foi desenvolver um bioprocesso tecnicamente e economicamente viÃvel para produÃÃo de etanol a partir do suco de caju, utilizando levedura Saccharomyces cerevisiae (CCA008) geneticamente modificada contendo gene floculante (FLO5α). O trabalho foi dividido em 4 quatro etapas que se interligam durante todo o estudo. Na primeira etapa foi avaliada a influÃncia da temperatura (26, 30, 34, 38 e 42ÂC), da concentraÃÃo de inÃculo (3, 5, 8 e 10 g.L-1) e da velocidade de agitaÃÃo (80, 150, 300, 490, 650 e 800 rpm) para que as condiÃÃes Ãtimas que maximizam a produÃÃo de etanol, fossem determinadas. Observou-se que os parÃmetros operacionais de temperatura, concentraÃÃo celular inicial, concentraÃÃo de substrato e agitaÃÃo exerceram influÃncia na fermentaÃÃo alcoÃlica do suco de caju. O melhor rendimento para o processo fermentativo (98,8 %) ocorreu quando o processo foi conduzido a 34 ÂC, sob agitaÃÃo de 150 rpm e contendo incialmente 5 g.L-1 de cÃlulas. Na segunda etapa, pretendeu-se descrever o rendimento do processo em funÃÃo dos parÃmetros operacionais avaliados na fermentaÃÃo. Para tanto, utilizaram-se, com sucesso, modelos estatÃsticos para descrever a interaÃÃo entre a concentraÃÃo inicial de substrato, temperatura, concentraÃÃo celular inicial, agitaÃÃo e seus possÃveis efeitos no rendimento. O modelo que melhor se ajustou aos dados experimentais foi utilizado na obtenÃÃo das condiÃÃes Ãtimas das variÃveis operacionais, indicando as seguintes condiÃÃes como Ãtimas: concentraÃÃo de substrato (S0) de 100 g.L-1, temperatura (T) igual a 34 ÂC, concentraÃÃo de inÃculo (X0) igual a 5 g.L-1 e agitaÃÃo (Agit) de 140 rpm, predizendo um rendimento de 98,80 %. Na terceira etapa, realizou-se o estudo da produÃÃo de etanol nas condiÃÃes Ãtimas, sendo as mesmas utilizadas para implementar a ampliaÃÃo de escala do processo, na qual os dados obtidos em biorreator batelada de 1L foram utilizados para predizer o comportamento da fermentaÃÃo em biorreator batelada de 14L, utilizando a potÃncia por unidade de volume como parÃmetro de scale-up. Utilizando tal fator como sendo de 10,67 kW/m3, foi possÃvel calcular a potÃncia de agitaÃÃo do fermentador de volume 14 vezes maior, assim como prever qual agitaÃÃo seria necessÃria para que a fermentaÃÃo ocorresse de forma semelhante à ocorrida no fermentador de menor volume. Os resultados mostraram que o rendimento obtido no biorreator de 14L foi satisfatÃrio, apresentando uma pequena diferenÃa (96,56 %  0,3 %) para o biorreator de 14L em relaÃÃo ao rendimento obtido para o de 1L (98,80 %  1,6 %). Como quarta e ultima etapa, avaliou-se a viabilidade tÃcnica e econÃmica do processo. Analisando os resultados obtidos, à possÃvel afirmar que o processo industrial proposto apresentou viabilidade tÃcnica, uma vez que o valor obtido para o rendimento do processo (68 L/ton), foi prÃximo ao da fermentaÃÃo da cana-de-aÃÃcar (61 â 72 L/ton). Contudo, o mesmo nÃo apresentou viabilidade econÃmica, uma vez que a unidade industrial proporciona um fluxo de caixa negativo (- R$ 93.840.874) ao final dos 10 anos em que foi analisado. Assim, novos estudos devem ser realizados com o intuito de tornar tal processo economicamente viÃvel, sendo esta possibilidade observada nos vÃrios cenÃrios gerados na anÃlise de sensibilidade do processo, o qual apresenta possÃveis configuraÃÃes economicamente viÃveis.

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