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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.
51

RECOVERY OF PROTEIN AND ORGANIC COMPOUNDS FROM SECONDARY-FERMENTED THIN STILLAGE

2016 February 1900 (has links)
Wheat-based thin stillage (W-TS) is liquid by-product of wheat ethanol production and contains valuable chemical intermediates such as 1,3-propanediol (1,3-PD), acetic acid, and glycerophosphorylcholine. Unfortunately, these compounds cannot be recovered/extracted easily due to the presence of high boiling point and hygroscopic solutes and unfermented particles from ethanol fermentation. Fermentation improvement study using endemic bacteria augmented with Lactobacillus panis PM1B discovered that glucose, incubation temperature, micronutrients, and pH adjustment affected two-stage fermentation (TSF). Importantly, fermentation could be scaled to a 210 L fermenter where 2% (w/v) 1,3-PD was produced. Unfermented particles should be removed prior to compound recovery. TSF was effective in producing solutions that were virtually free of colloids. Bacteria present in TSF system produced anoxic gas and exopolysaccharides and the combined action produced substantially clear solution. On the other hand, recovered particles, rich in lactobacilli, had a high protein content (50%, w/w, dry basis), which might be useful as an animal feed ingredient. Washing processes could lower moisture content and recover a high protein slurry (60% w/w, dry basis). Practical processes that incorporated fermentation using Lactobacilli could add substantial value to thin stillage and increase the value of products from ethanol production. These processes are scalable and readily implemented.
52

Invert sugar from sugar cane molasses : a pilot plant study

Stolz, Hendrik Nicolaas Petrus 03 1900 (has links)
An investigation was done into the recovery of invert sugar from sugar cane molasses. A pilot plant was designed and constructed to evaluate the clarification and separation of molasses to produce invert sugar syrup. The aim of the pilot plant was to prove the process and deliver data so as to facilitate the design and prove the financial viability of a commercial plant. The pilot plant had to process 300 kg/day of molasses. The clarification of molasses by centrifugal separation, a known desludging process, did not produce a product of acceptable quality which could be used in a chromatographic separator. The results were disappointing. The product obtained was also not suitable for dead end pressure filtration. The turbidity remaining after the centrifugal separation also did not respond to a second flocculation process. Conventional settling clarification was investigated. Seven factors that could influence the consolidation and settling of suspended solids in molasses were identified, namely: the age of the diluted molasses, the temperature of the flocculated mixture, the variations across various batches of flocculant, the effect of reaction time of the phosphoric acid, the optimum flocculant dosing concentration, the optimum concentration of the molasses solution and the effect of increasing the acid dosage. The optimum conditions to clarify molasses through settling were found to be: fresh molasses, at 28 Brix and 60°C, allowing 10 min intervals between acidification with 3,75 g (as 100%) phosphoric acid/ kg dry material (assumed equal to Brix) and neutralisation with 5 g (as 100%) caustic/kg dry material (assumed equal to Brix), flocculation with any batch of flocculant 6195, dosed as a 1000 ppm solution. Commercial equipment was evaluated. The pilot plant E-cat clarifier was operated at 300 l/h and a thick sludge formed. The overflow was clear and it could be filtered. The molasses obtained was suitable for chromatographic separation. The recovery of sugars from molasses sludge has economic merit. From the evaluation of centrifugal separation and gravity separation it is clear that gravity separation again is the best method. The sweet-water obtained is consistent within the clarity requirement of 10 NTU/Brix and can be used to dilute raw molasses in the upstream processing step. The clarification process that was developed is patented. [Bekker, Stolz et.al. (2001)] A sugar recovery of 93.9 mass % at a purity of 99.7 mass % from molasses, was achieved using a simulated moving bed, ion exclusion, pilot plant. The operating conditions for this performance were: feed flow at 14 l/h and at a temperature above 60 °C; water flow at 63 l/h and at a temperature above 65 °C; extract flow at 21 l/h; raffinate flow at 56 l/h; loop flow at 78 l/h and step time at 1326 seconds. This relates to the following bed volumes of the various separation zones: Bed Volume Zone 1 = 0.694; Bed Volume Zone 2 = 0.591; Bed Volume Zone 3 = 0.661; Bed Volume Zone 4 = 0.383. There is a trade-off between purity and recovery and a reduction in water usage. A preliminary environmental impact assessment and conceptual mass balance were done. The proposed plant integrates well into the existing Komati Mill of TSB and does not pose any significant environmental threat. The plant requires certain services from the mill. The mass balance investigated the water and steam consumption of the plant. Process integration was done so as to obtain the optimum utility consumption. The utility consumption of the plant does not exceed the capacity available at the mill. A small boiler is however required to produce steam during the annual mill maintenance period. Various techniques were used in a cost estimation for the invert sugar plant. The internal rate of return (IRR) is 42% for a fixed capital investment of R94,270,000.00. The net return rate (NRR) for the project is 4%/year, the net present value (NPV) - discounted at a 30% cost-of-capital is R41,782,000.00. The net payout time (NPT) is 5.207 years. The project fulfils the financial requirements set by TSB. It is now possible and viable to desugarize cane molasses.
53

Extração, clarificação e estabilização de betalaínas provenientes de talos de beterraba vermelha (Beta vulgaris L.)

Santos, Cláudia Destro dos, Cassini, Aline Schilling January 2017 (has links)
Milhões de toneladas de resíduos são gerados pela agroindústria todos os anos, gerando problemas ambientais e econômicos; muitos destes resíduos, entretanto, são ricos em nutrientes e compostos funcionais, o que poderia tornálos subprodutos com valor agregado. A utilização de subprodutos possibilita enriquecimento dos alimentos processados, redução de descarte no meio ambiente e melhor aproveitamento dos recursos naturais. Os talos de beterraba são um exemplo de resíduo com potencial a ser explorado e, assim como os bulbos, são ricos em betalaína, composto responsável pela sua coloração vermelho-violeta. Esses pigmentos são aplicáveis na indústria alimentícia como corantes naturais, mas a sua estabilidade é um dos maiores desafios frente a sua utilização. Neste contexto, este trabalho tem como objetivo principal estudar a extração, a clarificação e a estabilização de betalaínas provenientes de talos de beterraba vermelha. Para tanto, foi inicialmente estudado a viabilidade da utilização dos talos de beterraba como fonte de betalaínas e, em sequência, a extração destes compostos via esmagamento. A utilização de diferentes processamentos com vistas à melhora da extração e o seu impacto na estabilidade das betalaínas presente no extrato foram investigados: o processamento por alta pressão (HPP do inglês High Pressure Processing) e o tratamento térmico com alta temperatura por curto tempo (HTST do inglês High Temperature Short Time). Por fim, foi realizado um estudo de clarificação do extrato por meio de processo de separação por membranas (PSM). A clarificação foi aplicada por microfiltração (MF) seguido por ultrafiltração (UF). Além disto, a MF também foi operada no modo diafiltração (DF). A redução da atividade da enzima peroxidase, as características físico-químicas, a cor e a taxa de degradação das betalaínas ao longo do armazenamento foram avaliados nos extratos antes e após a clarificação. Os resultados mostraram que os extratos obtidos via esmagamento possuíam em média 45% da quantidade de pigmentos presentes no extrato dos bulbos de beterraba. O processamento por HPP não foi considerado uma boa alternativa para melhorar a extração e também não contribuiu para o aumento na estabilidade dos pigmentos presentes nos extratos. O tratamento térmico HTST causou uma pequena degradação das betalaínas; porém, quando aplicado por 120 s a 85,7 °C nos extratos com alta concentração inicial, promoveu uma redução na taxa de degradação das betalaínas da amostra tratada de 1,2 para 0,4 mg de betanina/100 ml de extrato por dia após uma semana de armazenamento. No estudo de clarificação por PSM, os experimentos de MF e UF apresentaram reduções no fluxo do permeado ao longo do processo, além de elevada tendência ao fouling, em ambas as membranas. A aplicação da MF batelada seguida por UF ocasionou uma redução de 99,5% da atividade de peroxidase. Quando a MF foi operada em modo DF, a alimentação do processo foi modificada de duas bateladas de 2 L cada para uma batelada de 3 L, aproveitando melhor os pigmentos da alimentação. Além disto, a clarificação contribuiu para a estabilidade das betalaínas, uma vez que a taxa de degradação reduziu de 0,32 e 0,41 mg de betanina/100 ml de extrato por dia para 0,2 mg de betanina/100 ml de extrato por dia no 10° dia de armazenamento. Os processos de MF, em modo batelada e DF, seguidos por UF promoveram redução na turbidez e no teor de sólidos solúveis, além de extratos clarificados com cor mais intensa, luminosa e avermelhada. / Every year a huge amount of waste is generated by agricultural industry, becoming a serious environmental and economic problem; many of these wastes, however, contain nutrients and functional compounds, which could make them by-products with added value. The use of by-products allows the enrichment of processed foods and the reduction of discard in the environment, ensuring a better use of natural resources. The beet stalks are an example of waste with potential to be explored and, as the root, are rich in betalains, whose provide their red-violet color. These pigments are applicable in the food industry as natural dyes. The stability of these pigments, however, is one of the biggest challenges of using it. In this context, this work aims to study the extraction and clarification of betalains from red beet stalks. Initially it was studied the feasibility of using beet stalks like a betalain source and, after that, the extraction of these compounds through crushing was carried out. The utilization of different processing to improve the extraction and the impact on the betalain stability present in the extract were studied: the high pressure processing (HPP) and the thermal treatment high temperature short time (HTST). Lastly, a study of clarification of the extract using the membrane separation processes (PSM) was carried out. Clarification was first applied by microfiltration (MF) followed by ultrafiltration (UF). In addition, MF was also operated in diafiltration mode (DF). The peroxidase activity reduction, physico-chemical characteristics, color and degradation rate of betalains over the storage were evaluated in the extracts before and after the clarification. The results show that the stalks extract by crushing had about 45% of the pigments content in the extract from root of beet. HPP was not considered a suitable alternative to improve the extraction and did not contribute to the increase in the stability of the pigments present in the extracts. The thermal treatment HTST caused a small degradation of betalains. However, when it was applied for 120 s at 85.7 °C, in the extracts with high initial concentration, it promoted a reduction in the betalain degradation rate of the treated sample from 1.2 to 0.4 mg of betanin/100 ml of extract per day after one week of storage. In the PSM clarification study, the MF and UF experiments, showed permeated flux reduction, indicating high fouling tendency on both MF and UF membranes. The application of MF followed by UF caused a reduction of 99.5% in peroxidase activity. When MF was operated in DF mode, the process feed was modified from two batches of 2 L each to a 3 L batch, making better use of feed pigments. In addition, the clarification experiments contributed to the betalain stability, as the betalain degradation rate reduced from 0.32 and 41 mg of betanin/100 ml of extract per day to 0.2 mg of betanin/100 ml of extract per day on the 10th day of storage. The MF processes, batch and DF mode, followed by UF promoted a reduction in the turbidity and soluble solids content and the clarified extracts had color more intense, bright and reddish.
54

ObtenÃÃo de suco clarificado de aÃaà (Euterpe oleracea Mart.) com utilizaÃÃo de pectinas e quitosana / Obtaining clarified juice of aÃaà (Euterpe oleracea Mart.) using pectin and chitosan

Leiliane Teles CÃsar 02 February 2007 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / O aÃaà (Euterpe oleracea Mart.) pelo seu inegÃvel potencial como fonte natural de fitoquÃmicos antioxidantes e sua relevante capacidade de aproveitamento industrial, tem atraÃdo um grande interesse nas indÃstrias de processamento de suco de frutas tropicais, passando a ter importÃncia econÃmica em vÃrias regiÃes do Brasil, alÃm da regiÃo AmazÃnica. A aceitaÃÃo de sucos tropicais no mercado internacional requer melhoria nas tÃcnicas de processamento, tais como inclusÃo da etapa de clarificaÃÃo, resultando em matÃria-prima de alta qualidade para execuÃÃo dos processos de concentraÃÃo, para fabricaÃÃo de produtos como âcoolersâ, vinhos, refrigerantes e outros. A tecnologia de clarificaÃÃo do suco tropical de aÃaà atravÃs da remoÃÃo de lipÃdios e sÃlidos insolÃveis à um dos mÃtodos de otimizaÃÃo das propriedades sensoriais e de aceitabilidade mercadolÃgica. Para realizaÃÃo deste estudo, utilizou-se como matÃria-prima polpa de aÃaà tipo C proveniente do comÃrcio local de Fortaleza (CearÃ-Brasil). O objetivo deste trabalho foi a obtenÃÃo do suco clarificado de aÃaÃ, utilizando como agentes clarificantes pectinases e quitosana. A primeira etapa da pesquisa consistiu de estudos sobre a concentraÃÃo ideal de pectinase para a despectinizaÃÃo da polpa. Foram utilizados cinco lotes de 100 mL de polpa com concentraÃÃo da enzima variando de 0,01 a 0,2 % (v/v) mantidos a uma temperatura de 45 + 5ÂC, conservando o pH natural da polpa (em torno d e 4,0). A cada 15 min eram removidas amostras de 10 mL de polpa e efetuada uma inativaÃÃo enzimÃtica (90ÂC/10 min) sendo em seguid a feita a âProva do Ãlcoolâ para detecÃÃo da ausÃncia de pectina. Definidos os parÃmetros de tempo e concentraÃÃo enzimÃtica, procedeu-se à etapa de clarificaÃÃo. Foi preparado um suco com 30 % (v/v) de polpa tratada enzimaticamente sendo em seguida filtrado. Seis lotes de 50 mL de suco despectinizado foram adicionados de concentraÃÃes crescentes de soluÃÃo de quitosana 4 %, variando-se de 100 a 900 mg. A cada 30 min foi realizada uma filtraÃÃo para a definiÃÃo da concentraÃÃo ideal da quitosana baseando-se nas anÃlises da luminosidade, turbidez e no teste de âExcesso e insuficiÃncia de clarificaÃÃoâ. Uma vez definidos os parÃmetros de concentraÃÃo de pectinase e quitosana para obtenÃÃo do suco clarificado, foi realizada uma caracterizaÃÃo fÃsicoquÃmica e quÃmica do suco clarificado obtido, bem como da polpa e do suco tropical para efeitos comparativos. Ocorreu diferenÃa significativa ao nÃvel de 5 % de significÃncia entre as diferentes concentraÃÃes de quitosana e tempo de floculaÃÃo, bem como nas caracterÃsticas fÃsico-quÃmicas e quÃmicas da polpa e suco de aÃaà (tropical e clarificado). A utilizaÃÃo de pectinases como coadjuvantes do processo de clarificaÃÃo associada à quitosana para a remoÃÃo de sÃlidos em suspensÃo do suco tropical de aÃaÃ, mostrou-se satisfatÃria uma vez que ocorreu uma significativa reduÃÃo da turbidez e aumento de luminosidade. / AÃaà (Euterpe oleracea Mart.) for its undeniable potential as natural source of antioxidants and its excellent capacity of industrial exploitation, has attracted a great interest in the industries of tropical fruit juice processing, starting to acquire importance in some regions of Brazil, beyond the Amazon region. The tropical juice acceptance in the international market requires improvement in the processing techniques, such as inclusion of the clarification stage, resulting in a product of high quality for execution of the concentration processes, for manufacture of products as coolers, wines, fresh drinks and others. The technology of clarification of aÃaà tropical juice through the removal of lipids and insoluble solids is one of the methods for improvement of the sensorial properties and marketing acceptability. For accomplishment this study, type C aÃaà pulp from the local market of Fortaleza (CearÃ-Brazil) was used as raw material. The purpose of this work was to obtain the clarified aÃaà tropical fruit juice using as clarified aids pectinases and chitosan. The first stage of this research is to achieve the optimum concentration of pectinase for pulp despectinization. Five batches of 100 mL of aÃaà pulp were treated with 0.01 to 0,2% (v/v) of pectinase, kept to a temperature of 45 + 5ÂC, keeping the natural pH of the pulp (around 4.0). To each 15min was removed samples of 10 mL of pulp and the enzymatic inativation was performed at 90ÂC during 10 min and after that made the âTest of the alcoholâ for detection of the pectin absence. Once established the parameters of time and enzymatic concentration the clarification process was followed. A juice with 30% of treated pulp (v/v) was made and filtered afterwards. Six batches of 50 mL of treated juice were added of increasing concentrations of 4% chitosan solution raging from 100 to 900 mg. Each 30 min was made a filtration and samples were evaluated concerning to optimum chitosan concentration based on luminosity, turbity and the test of âExcess and insufficience of clarificationâ. Once choosed the pectin and chitosan concentrations the clarified aÃaà tropical fruit juice was processed. It was carried out a physico-chemistry and chemical characterization of clarified juice, as well as pulp and the tropical juice for comparative effect. Significant difference at a level of 5% occurred between the different concentrations of chitosan and flocculation time, as well as in the physico-chemistry and chemical characteristics of the pulp, tropical and aÃaà clarified tropical fruit juice. The use of pectinases as aids in clarification process associated to chitosan for suspensed solids removal in aÃaà tropical fruit showed satisfactory once occurred a significant reduction of turbidity and increase of luminosity.
55

Corrective feedback in online asynchronous and synchronous environments in spanish as a foreign language (sfl) classes

Castañeda, Martha E 01 June 2005 (has links)
This dissertation reports on an investigation of corrective feedback provided by instructors to learners in sixteen online asynchronous and synchronous interactions. The overarching objective of this study was to examine the provision of corrective feedback in computer-mediated communication (CMC) environments. This study also sought to examine the frequency of corrective feedback types and the relationship between learner error and corrective feedback provision. Finally, this study investigated what types of corrective feedback led to repaired learner responses.Over the course of one university semester, the instructors and students in four second-semester Spanish courses participated in bulletin board and chat room discussions and a detailed analysis of the transcripts revealed that instructors do provide learners with corrective feedback in online asynchronous and synchronous environments. The results also reveal that corrective feedback is more prevalent in the asynchronous environment than in the synchronous environment. A total of six corrective feedback typesexplicit correction, recasts, metalinguistic feedback, clarification request, elicitation, and repetitionwere found in these environments. All corrective feedback types were present in the asynchronous environment while repetition was not observed in the synchronous environment. The results indicate instructors overall preference for explicit correction in the asynchronous environment and preference for recasts in the synchronous environment. In the synchronous environment, different types of learner errors are followed by different types of corrective feedback. Recasts most often follow grammatical and lexical errors, while an opportunity to negotiate form is most often provided for multiple errors.
56

Obtenção de suco clarificado de açaí (Euterpe oleracea Mart.) com utilização de pectinas e quitosana / Obtaining clarified juice of açaí (Euterpe oleracea Mart.) using pectin and chitosan

César, Leiliane Teles January 2007 (has links)
CÉSAR, Leiliane Teles. Obtenção de suco clarificado de açaí (Euterpe oleracea Mart.) com utilização de pectinas e quitosana. 2007. 95 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Tecnologia de Alimentos, Fortaleza-CE, 2007 / Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-06-14T14:17:54Z No. of bitstreams: 1 2007_dis_ltcésar.pdf: 477804 bytes, checksum: 19effd47888531c4cfcda2ae65b6802d (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-06-14T14:18:14Z (GMT) No. of bitstreams: 1 2007_dis_ltcésar.pdf: 477804 bytes, checksum: 19effd47888531c4cfcda2ae65b6802d (MD5) / Made available in DSpace on 2016-06-14T14:18:14Z (GMT). No. of bitstreams: 1 2007_dis_ltcésar.pdf: 477804 bytes, checksum: 19effd47888531c4cfcda2ae65b6802d (MD5) Previous issue date: 2007 / Açaí (Euterpe oleracea Mart.) for its undeniable potential as natural source of antioxidants and its excellent capacity of industrial exploitation, has attracted a great interest in the industries of tropical fruit juice processing, starting to acquire importance in some regions of Brazil, beyond the Amazon region. The tropical juice acceptance in the international market requires improvement in the processing techniques, such as inclusion of the clarification stage, resulting in a product of high quality for execution of the concentration processes, for manufacture of products as coolers, wines, fresh drinks and others. The technology of clarification of açaí tropical juice through the removal of lipids and insoluble solids is one of the methods for improvement of the sensorial properties and marketing acceptability. For accomplishment this study, type C açaí pulp from the local market of Fortaleza (Ceará-Brazil) was used as raw material. The purpose of this work was to obtain the clarified açaí tropical fruit juice using as clarified aids pectinases and chitosan. The first stage of this research is to achieve the optimum concentration of pectinase for pulp despectinization. Five batches of 100 mL of açaí pulp were treated with 0.01 to 0,2% (v/v) of pectinase, kept to a temperature of 45 + 5°C, keeping the natural pH of the pulp (around 4.0). To each 15min was removed samples of 10 mL of pulp and the enzymatic inativation was performed at 90°C during 10 min and after that made the “Test of the alcohol” for detection of the pectin absence. Once established the parameters of time and enzymatic concentration the clarification process was followed. A juice with 30% of treated pulp (v/v) was made and filtered afterwards. Six batches of 50 mL of treated juice were added of increasing concentrations of 4% chitosan solution raging from 100 to 900 mg. Each 30 min was made a filtration and samples were evaluated concerning to optimum chitosan concentration based on luminosity, turbity and the test of “Excess and insufficience of clarification”. Once choosed the pectin and chitosan concentrations the clarified açaí tropical fruit juice was processed. It was carried out a physico-chemistry and chemical characterization of clarified juice, as well as pulp and the tropical juice for comparative effect. Significant difference at a level of 5% occurred between the different concentrations of chitosan and flocculation time, as well as in the physico-chemistry and chemical characteristics of the pulp, tropical and açaí clarified tropical fruit juice. The use of pectinases as aids in clarification process associated to chitosan for suspensed solids removal in açaí tropical fruit showed satisfactory once occurred a significant reduction of turbidity and increase of luminosity. / O açaí (Euterpe oleracea Mart.) pelo seu inegável potencial como fonte natural de fitoquímicos antioxidantes e sua relevante capacidade de aproveitamento industrial, tem atraído um grande interesse nas indústrias de processamento de suco de frutas tropicais, passando a ter importância econômica em várias regiões do Brasil, além da região Amazônica. A aceitação de sucos tropicais no mercado internacional requer melhoria nas técnicas de processamento, tais como inclusão da etapa de clarificação, resultando em matéria-prima de alta qualidade para execução dos processos de concentração, para fabricação de produtos como “coolers”, vinhos, refrigerantes e outros. A tecnologia de clarificação do suco tropical de açaí através da remoção de lipídios e sólidos insolúveis é um dos métodos de otimização das propriedades sensoriais e de aceitabilidade mercadológica. Para realização deste estudo, utilizou-se como matéria-prima polpa de açaí tipo C proveniente do comércio local de Fortaleza (Ceará-Brasil). O objetivo deste trabalho foi a obtenção do suco clarificado de açaí, utilizando como agentes clarificantes pectinases e quitosana. A primeira etapa da pesquisa consistiu de estudos sobre a concentração ideal de pectinase para a despectinização da polpa. Foram utilizados cinco lotes de 100 mL de polpa com concentração da enzima variando de 0,01 a 0,2 % (v/v) mantidos a uma temperatura de 45 + 5°C, conservando o pH natural da polpa (em torno d e 4,0). A cada 15 min eram removidas amostras de 10 mL de polpa e efetuada uma inativação enzimática (90°C/10 min) sendo em seguid a feita a “Prova do álcool” para detecção da ausência de pectina. Definidos os parâmetros de tempo e concentração enzimática, procedeu-se à etapa de clarificação. Foi preparado um suco com 30 % (v/v) de polpa tratada enzimaticamente sendo em seguida filtrado. Seis lotes de 50 mL de suco despectinizado foram adicionados de concentrações crescentes de solução de quitosana 4 %, variando-se de 100 a 900 mg. A cada 30 min foi realizada uma filtração para a definição da concentração ideal da quitosana baseando-se nas análises da luminosidade, turbidez e no teste de “Excesso e insuficiência de clarificação”. Uma vez definidos os parâmetros de concentração de pectinase e quitosana para obtenção do suco clarificado, foi realizada uma caracterização físicoquímica e química do suco clarificado obtido, bem como da polpa e do suco tropical para efeitos comparativos. Ocorreu diferença significativa ao nível de 5 % de significância entre as diferentes concentrações de quitosana e tempo de floculação, bem como nas características físico-químicas e químicas da polpa e suco de açaí (tropical e clarificado). A utilização de pectinases como coadjuvantes do processo de clarificação associada à quitosana para a remoção de sólidos em suspensão do suco tropical de açaí, mostrou-se satisfatória uma vez que ocorreu uma significativa redução da turbidez e aumento de luminosidade.
57

Extração, clarificação e estabilização de betalaínas provenientes de talos de beterraba vermelha (Beta vulgaris L.)

Santos, Cláudia Destro dos, Cassini, Aline Schilling January 2017 (has links)
Milhões de toneladas de resíduos são gerados pela agroindústria todos os anos, gerando problemas ambientais e econômicos; muitos destes resíduos, entretanto, são ricos em nutrientes e compostos funcionais, o que poderia tornálos subprodutos com valor agregado. A utilização de subprodutos possibilita enriquecimento dos alimentos processados, redução de descarte no meio ambiente e melhor aproveitamento dos recursos naturais. Os talos de beterraba são um exemplo de resíduo com potencial a ser explorado e, assim como os bulbos, são ricos em betalaína, composto responsável pela sua coloração vermelho-violeta. Esses pigmentos são aplicáveis na indústria alimentícia como corantes naturais, mas a sua estabilidade é um dos maiores desafios frente a sua utilização. Neste contexto, este trabalho tem como objetivo principal estudar a extração, a clarificação e a estabilização de betalaínas provenientes de talos de beterraba vermelha. Para tanto, foi inicialmente estudado a viabilidade da utilização dos talos de beterraba como fonte de betalaínas e, em sequência, a extração destes compostos via esmagamento. A utilização de diferentes processamentos com vistas à melhora da extração e o seu impacto na estabilidade das betalaínas presente no extrato foram investigados: o processamento por alta pressão (HPP do inglês High Pressure Processing) e o tratamento térmico com alta temperatura por curto tempo (HTST do inglês High Temperature Short Time). Por fim, foi realizado um estudo de clarificação do extrato por meio de processo de separação por membranas (PSM). A clarificação foi aplicada por microfiltração (MF) seguido por ultrafiltração (UF). Além disto, a MF também foi operada no modo diafiltração (DF). A redução da atividade da enzima peroxidase, as características físico-químicas, a cor e a taxa de degradação das betalaínas ao longo do armazenamento foram avaliados nos extratos antes e após a clarificação. Os resultados mostraram que os extratos obtidos via esmagamento possuíam em média 45% da quantidade de pigmentos presentes no extrato dos bulbos de beterraba. O processamento por HPP não foi considerado uma boa alternativa para melhorar a extração e também não contribuiu para o aumento na estabilidade dos pigmentos presentes nos extratos. O tratamento térmico HTST causou uma pequena degradação das betalaínas; porém, quando aplicado por 120 s a 85,7 °C nos extratos com alta concentração inicial, promoveu uma redução na taxa de degradação das betalaínas da amostra tratada de 1,2 para 0,4 mg de betanina/100 ml de extrato por dia após uma semana de armazenamento. No estudo de clarificação por PSM, os experimentos de MF e UF apresentaram reduções no fluxo do permeado ao longo do processo, além de elevada tendência ao fouling, em ambas as membranas. A aplicação da MF batelada seguida por UF ocasionou uma redução de 99,5% da atividade de peroxidase. Quando a MF foi operada em modo DF, a alimentação do processo foi modificada de duas bateladas de 2 L cada para uma batelada de 3 L, aproveitando melhor os pigmentos da alimentação. Além disto, a clarificação contribuiu para a estabilidade das betalaínas, uma vez que a taxa de degradação reduziu de 0,32 e 0,41 mg de betanina/100 ml de extrato por dia para 0,2 mg de betanina/100 ml de extrato por dia no 10° dia de armazenamento. Os processos de MF, em modo batelada e DF, seguidos por UF promoveram redução na turbidez e no teor de sólidos solúveis, além de extratos clarificados com cor mais intensa, luminosa e avermelhada. / Every year a huge amount of waste is generated by agricultural industry, becoming a serious environmental and economic problem; many of these wastes, however, contain nutrients and functional compounds, which could make them by-products with added value. The use of by-products allows the enrichment of processed foods and the reduction of discard in the environment, ensuring a better use of natural resources. The beet stalks are an example of waste with potential to be explored and, as the root, are rich in betalains, whose provide their red-violet color. These pigments are applicable in the food industry as natural dyes. The stability of these pigments, however, is one of the biggest challenges of using it. In this context, this work aims to study the extraction and clarification of betalains from red beet stalks. Initially it was studied the feasibility of using beet stalks like a betalain source and, after that, the extraction of these compounds through crushing was carried out. The utilization of different processing to improve the extraction and the impact on the betalain stability present in the extract were studied: the high pressure processing (HPP) and the thermal treatment high temperature short time (HTST). Lastly, a study of clarification of the extract using the membrane separation processes (PSM) was carried out. Clarification was first applied by microfiltration (MF) followed by ultrafiltration (UF). In addition, MF was also operated in diafiltration mode (DF). The peroxidase activity reduction, physico-chemical characteristics, color and degradation rate of betalains over the storage were evaluated in the extracts before and after the clarification. The results show that the stalks extract by crushing had about 45% of the pigments content in the extract from root of beet. HPP was not considered a suitable alternative to improve the extraction and did not contribute to the increase in the stability of the pigments present in the extracts. The thermal treatment HTST caused a small degradation of betalains. However, when it was applied for 120 s at 85.7 °C, in the extracts with high initial concentration, it promoted a reduction in the betalain degradation rate of the treated sample from 1.2 to 0.4 mg of betanin/100 ml of extract per day after one week of storage. In the PSM clarification study, the MF and UF experiments, showed permeated flux reduction, indicating high fouling tendency on both MF and UF membranes. The application of MF followed by UF caused a reduction of 99.5% in peroxidase activity. When MF was operated in DF mode, the process feed was modified from two batches of 2 L each to a 3 L batch, making better use of feed pigments. In addition, the clarification experiments contributed to the betalain stability, as the betalain degradation rate reduced from 0.32 and 41 mg of betanin/100 ml of extract per day to 0.2 mg of betanin/100 ml of extract per day on the 10th day of storage. The MF processes, batch and DF mode, followed by UF promoted a reduction in the turbidity and soluble solids content and the clarified extracts had color more intense, bright and reddish.
58

Extração, clarificação e estabilização de betalaínas provenientes de talos de beterraba vermelha (Beta vulgaris L.)

Santos, Cláudia Destro dos, Cassini, Aline Schilling January 2017 (has links)
Milhões de toneladas de resíduos são gerados pela agroindústria todos os anos, gerando problemas ambientais e econômicos; muitos destes resíduos, entretanto, são ricos em nutrientes e compostos funcionais, o que poderia tornálos subprodutos com valor agregado. A utilização de subprodutos possibilita enriquecimento dos alimentos processados, redução de descarte no meio ambiente e melhor aproveitamento dos recursos naturais. Os talos de beterraba são um exemplo de resíduo com potencial a ser explorado e, assim como os bulbos, são ricos em betalaína, composto responsável pela sua coloração vermelho-violeta. Esses pigmentos são aplicáveis na indústria alimentícia como corantes naturais, mas a sua estabilidade é um dos maiores desafios frente a sua utilização. Neste contexto, este trabalho tem como objetivo principal estudar a extração, a clarificação e a estabilização de betalaínas provenientes de talos de beterraba vermelha. Para tanto, foi inicialmente estudado a viabilidade da utilização dos talos de beterraba como fonte de betalaínas e, em sequência, a extração destes compostos via esmagamento. A utilização de diferentes processamentos com vistas à melhora da extração e o seu impacto na estabilidade das betalaínas presente no extrato foram investigados: o processamento por alta pressão (HPP do inglês High Pressure Processing) e o tratamento térmico com alta temperatura por curto tempo (HTST do inglês High Temperature Short Time). Por fim, foi realizado um estudo de clarificação do extrato por meio de processo de separação por membranas (PSM). A clarificação foi aplicada por microfiltração (MF) seguido por ultrafiltração (UF). Além disto, a MF também foi operada no modo diafiltração (DF). A redução da atividade da enzima peroxidase, as características físico-químicas, a cor e a taxa de degradação das betalaínas ao longo do armazenamento foram avaliados nos extratos antes e após a clarificação. Os resultados mostraram que os extratos obtidos via esmagamento possuíam em média 45% da quantidade de pigmentos presentes no extrato dos bulbos de beterraba. O processamento por HPP não foi considerado uma boa alternativa para melhorar a extração e também não contribuiu para o aumento na estabilidade dos pigmentos presentes nos extratos. O tratamento térmico HTST causou uma pequena degradação das betalaínas; porém, quando aplicado por 120 s a 85,7 °C nos extratos com alta concentração inicial, promoveu uma redução na taxa de degradação das betalaínas da amostra tratada de 1,2 para 0,4 mg de betanina/100 ml de extrato por dia após uma semana de armazenamento. No estudo de clarificação por PSM, os experimentos de MF e UF apresentaram reduções no fluxo do permeado ao longo do processo, além de elevada tendência ao fouling, em ambas as membranas. A aplicação da MF batelada seguida por UF ocasionou uma redução de 99,5% da atividade de peroxidase. Quando a MF foi operada em modo DF, a alimentação do processo foi modificada de duas bateladas de 2 L cada para uma batelada de 3 L, aproveitando melhor os pigmentos da alimentação. Além disto, a clarificação contribuiu para a estabilidade das betalaínas, uma vez que a taxa de degradação reduziu de 0,32 e 0,41 mg de betanina/100 ml de extrato por dia para 0,2 mg de betanina/100 ml de extrato por dia no 10° dia de armazenamento. Os processos de MF, em modo batelada e DF, seguidos por UF promoveram redução na turbidez e no teor de sólidos solúveis, além de extratos clarificados com cor mais intensa, luminosa e avermelhada. / Every year a huge amount of waste is generated by agricultural industry, becoming a serious environmental and economic problem; many of these wastes, however, contain nutrients and functional compounds, which could make them by-products with added value. The use of by-products allows the enrichment of processed foods and the reduction of discard in the environment, ensuring a better use of natural resources. The beet stalks are an example of waste with potential to be explored and, as the root, are rich in betalains, whose provide their red-violet color. These pigments are applicable in the food industry as natural dyes. The stability of these pigments, however, is one of the biggest challenges of using it. In this context, this work aims to study the extraction and clarification of betalains from red beet stalks. Initially it was studied the feasibility of using beet stalks like a betalain source and, after that, the extraction of these compounds through crushing was carried out. The utilization of different processing to improve the extraction and the impact on the betalain stability present in the extract were studied: the high pressure processing (HPP) and the thermal treatment high temperature short time (HTST). Lastly, a study of clarification of the extract using the membrane separation processes (PSM) was carried out. Clarification was first applied by microfiltration (MF) followed by ultrafiltration (UF). In addition, MF was also operated in diafiltration mode (DF). The peroxidase activity reduction, physico-chemical characteristics, color and degradation rate of betalains over the storage were evaluated in the extracts before and after the clarification. The results show that the stalks extract by crushing had about 45% of the pigments content in the extract from root of beet. HPP was not considered a suitable alternative to improve the extraction and did not contribute to the increase in the stability of the pigments present in the extracts. The thermal treatment HTST caused a small degradation of betalains. However, when it was applied for 120 s at 85.7 °C, in the extracts with high initial concentration, it promoted a reduction in the betalain degradation rate of the treated sample from 1.2 to 0.4 mg of betanin/100 ml of extract per day after one week of storage. In the PSM clarification study, the MF and UF experiments, showed permeated flux reduction, indicating high fouling tendency on both MF and UF membranes. The application of MF followed by UF caused a reduction of 99.5% in peroxidase activity. When MF was operated in DF mode, the process feed was modified from two batches of 2 L each to a 3 L batch, making better use of feed pigments. In addition, the clarification experiments contributed to the betalain stability, as the betalain degradation rate reduced from 0.32 and 41 mg of betanin/100 ml of extract per day to 0.2 mg of betanin/100 ml of extract per day on the 10th day of storage. The MF processes, batch and DF mode, followed by UF promoted a reduction in the turbidity and soluble solids content and the clarified extracts had color more intense, bright and reddish.
59

Untersuchung der Patientenzufriedenheit nach abdominaler Schnittentbindung

Hoffmann, Franziska 18 February 2013 (has links)
Objective: We aimed to analyze the birth experience of women with caesarean section (CS) and the influence of clarification. Furthermore weaknesses of care from women’s view should be determined. Method: Online survey of women who had at least one CS Results: We analyzed data of 383 women. 47,8% women had a primary, 52,2% a secondary CS . The birth experience ranged from wonderful (13,3%) to gruesome (25,1%). There were significant more women with secondary CS whose birth experience was associated with negative emotions. Regarded in hindsight for 29,0% the CS was better than expected and 39,6% stated it had been worse than assumed. Almost half of participants stated having coped (rather) bad with the CS and its concomitants. The opportunity of psychological consultation in hospital or at least addresses to contact when needed were repeatedly required. In this survey the birth experience as well as the meeting of expectations toward CS depended on the satisfaction with the antenatal discussion by obstetricians and the clarification by medical staff while for antenatal classes no significant influence could be proved. Conclusions: A substantial amount of women had a negative birth experience. More effort concerning clarification and patient-centered care is required.
60

Determining the effectiveness of water treatment process barriers for the removal of viruses in drinking water.

Setlhare, Khomotso Charity January 2018 (has links)
M. Tech (Department of Biotechnology, Faculty of Applied and Computer Sciences) Vaal University of Technology. / The presence of enteric viruses in drinking water poses a health risk to consumers. It is therefore very important for drinking water suppliers to provide water that is pathogen free and fit for human consumption. This can be achieved by an effective water treatment system that ensures the safety of water from the treatment plant until the water reaches the consumer. This study assessed the ability of a conventional water treatment system to remove viruses. The system consisted of three unit processes, namely, clarification, sand filtration and disinfection. These processes were simulated on a bench-scale to determine the effectiveness of each one at removing viruses. Clarification was conducted using a Phipps and Bird jar testing system and three different chemical treatments: (i) Polyelectrolyte (SUDFLOC 3835), (ii) a combination of lime and activated silica and (iii) a combination of lime, activated silica and ferric chloride. Sand filtration was simulated using a Phipps and Bird column filtration system. Disinfection was conducted using free chlorine. The findings from this study showed that the removal or inactivation of viruses increased with an increase in the concentration of chemicals added. For clarification, the combination of lime, activated silica and ferric chloride was the most effective treatment for the removal or inactivation of viruses. Sand filtration was found to be ineffective for the removal of viruses. Disinfection was shown to be the most effective process for the removal or inactivation of viruses. While clarification, sand filtration and disinfection did not remove or inactivate viruses equally, the entire treatment chain is still essential. This is because even if a barrier does not directly remove viruses it ensures that subsequent processes can function effectively. Overall the treatment processes should not be considered as discrete barriers but rather an integrated system that must function throughout to avoid a risk to customers.

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