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Search Results: 1 - 10 of 77616 matches for " Maria Alice Zarur Coelho "
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Obten??o de extratos de guaraná ricos em cafeína por processo enzimático e adsor??o de taninos
Ribeiro, Bernardo Dias;Coelho, Maria Alice Zarur;Barreto, Daniel Weingart;
Brazilian Journal of Food Technology , 2012, DOI: 10.1590/S1981-67232012005000020
Abstract: guarana-flavoured beverages are very popular in brazil and have shown an excellent sales potential on foreign markets. according to brazilian law, each 100 ml of guarana-flavoured beverages must contain between 0.02 g and 0.2 g of guarana seed or its equivalent. these levels are normally obtained by adding a concentrated hydroalcoholic extract or sugar syrup containing guarana extract, directly to the beverage. however, the use of more concentrated extracts is limited by the presence of tannins, which imparts astringency and a dark colour to the final product. in this work the development of an enzymatic process to obtain non-alcoholic guarana extracts with low tannin concentrations and high caffeine contents was studied using an experimental design and adsorption processes. by way of a fractional factorial design the quantities of 0.25% (v/v) pectinase and 0.1% (v/v) glucoamylase were determined, which were maintained in the central composite design, obtaining as the optimal conditions: 0.23% (v/v) cellulase, 0.86% (v/v) hemicellulase, 1% (v/v) alpha-amylase, 5.5 h extraction time, 200 rpm and 50 °c, producing a caffeine/tannin ratio of 1.65. using a magnesium oxide adsorption process at 10% (w/v), a caffeine/tannin ratio of 7.3 was obtained.
Enzyme-Enhanced Extraction of Phenolic Compounds and Proteins from Flaxseed Meal
Bernardo Dias Ribeiro,Daniel Weingart Barreto,Maria Alice Zarur Coelho
ISRN Biotechnology , 2013, DOI: 10.5402/2013/521067
Abstract:
Obten o de extratos de guaraná ricos em cafeína por processo enzimático e adsor o de taninos Production of caffeine-rich guarana extracts using an enzymatic process and tannin adsorption
Bernardo Dias Ribeiro,Maria Alice Zarur Coelho,Daniel Weingart Barreto
Brazilian Journal of Food Technology , 2012,
Abstract: As bebidas sabor guaraná s o muito populares no Brasil e têm apresentado um excelente potencial de vendas no mercado externo. De acordo com as leis brasileiras, bebidas sabor guaraná devem conter entre 0,02 g a 0,2 g de semente de guaraná ou equivalente, para cada 100 mL de produto. Tais teores s o usualmente obtidos pela adi o de um extrato concentrado hidroalcoólico ou xarope de a úcar contendo extrato de guaraná diretamente à bebida. A utiliza o desses extratos em concentra es mais elevadas, entretanto, é limitada pela presen a dos taninos, que conferem adstringência e colora o escura ao produto final. Neste trabalho, foi estudado o desenvolvimento de um processo enzimático para obten o de extratos n o alcoólicos de guaraná, de forma a produzir um extrato contendo baixas concentra es de taninos e teores elevados de cafeína, utilizando-se planejamento experimental e processos de adsor o. Por meio de um planejamento fatorial fracionário, foram determinadas as quantidades de 0,25% (v/v) de pectinase e 0,1% (v/v) de glucoamilase, sendo mantidas no planejamento composto central, que obteve como condi es ótimas: 0,23% (v/v) de celulase, 0,86% (v/v) de hemicelulase e 1% (v/v) de alfa-amilase durante 5,5 h de extra o a 200 rpm e 50 °C, obtendo-se uma rela o cafeína/tanino de 1,65. Com o processo de adsor o com óxido de magnésio a 10% (p/v), foi alcan ada uma rela o de cafeína-tanino de 7,3. Guarana-flavoured beverages are very popular in Brazil and have shown an excellent sales potential on foreign markets. According to Brazilian law, each 100 mL of guarana-flavoured beverages must contain between 0.02 g and 0.2 g of guarana seed or its equivalent. These levels are normally obtained by adding a concentrated hydroalcoholic extract or sugar syrup containing guarana extract, directly to the beverage. However, the use of more concentrated extracts is limited by the presence of tannins, which imparts astringency and a dark colour to the final product. In this work the development of an enzymatic process to obtain non-alcoholic guarana extracts with low tannin concentrations and high caffeine contents was studied using an experimental design and adsorption processes. By way of a fractional factorial design the quantities of 0.25% (v/v) pectinase and 0.1% (v/v) glucoamylase were determined, which were maintained in the central composite design, obtaining as the optimal conditions: 0.23% (v/v) cellulase, 0.86% (v/v) hemicellulase, 1% (v/v) alpha-amylase, 5.5 h extraction time, 200 rpm and 50 °C, producing a caffeine/tannin ratio of 1.65. Using a magnesiu
Enzyme-Enhanced Extraction of Phenolic Compounds and Proteins from Flaxseed Meal
Bernardo Dias Ribeiro,Daniel Weingart Barreto,Maria Alice Zarur Coelho
ISRN Biotechnology , 2013, DOI: 10.5402/2013/521067
Abstract: Flaxseed (Linum usitatissimum) meal, the main byproduct of the flaxseed oil extraction process, is composed mainly of proteins, mucilage, and phenolic compounds. The extraction methods of phenolics either commonly employed the use of mixed solvents (dioxane/ethanol, water/acetone, water/methanol, and water/ethanol) or are done with the aid of alkaline, acid, or enzymatic hydrolysis. This work aimed at the study of optimal conditions for a clean process, using renewable solvents and enzymes, for the extraction of phenolics and proteins from flaxseed meal. After a screening of the most promising commercial preparations based on different carbohydrases and proteases, a central composite rotatable design and a mixture design were applied, achieving as optimal results a solution containing 6.6 and 152?g of phenolics and proteins, respectively. The statistical approach used in the present study for the enzyme-enhanced extraction of phenolics and proteins from the major flaxseed byproduct was effective. By means of the sequential experimental design methodology, the extraction of such compounds was increased 10-fold and 14-fold, when compared to a conventional nonenzymatic extraction. 1. Introduction Flaxseed (Linum usitatissimum) meal is the main byproduct from the flaxseed oil extraction process, being primarily used as a ruminant feed. The meal is composed of three important fractions: proteins (over 300?g?kg?1), which are rich in arginine and glutamine; amino acids that are very important in the prevention and treatment of heart diseases and in supporting the immune system; mucilage (approximate content of 80?g?kg?1), which is a mixture of neutral arabinoxylans and rhamnogalacturonans, with good water-holding capacities and high viscosity; phenolic compounds, such as p-coumaric and ferulic acids, lignan secoisolariciresinol, which is presented glycosylated (Figure 1) and/or esterified with 3-hydroxy-3-methylglutaric acid to form oligomers. The content of secoisolariciresinol diglucoside in flaxseed is 2-3?g?kg?1, and about 10–40?g?kg?1 in defatted flaxseed powder [1–5]. Figure 1: Lignan secoisolariciresinol diglucoside. In humans and animals, secoisolariciresinol is transformed by the anaerobic intestinal microflora into the mammalian lignans, enterolactone, and enterodiol, which are capable of binding at low levels to estrogen receptors. Additionally, these lignans have antioxidant, hypocholesterolemic, and antiatherosclerotic activities and inhibit the development of type 1 and type 2 diabetes, and mammary, prostatic, and colonic tumors [3, 6–9]. Lignans
Production and Use of Lipases in Bioenergy: A Review from the Feedstocks to Biodiesel Production
Bernardo Dias Ribeiro,Aline Machado de Castro,Maria Alice Zarur Coelho,Denise Maria Guimar?es Freire
Enzyme Research , 2011, DOI: 10.4061/2011/615803
Abstract: Lipases represent one of the most reported groups of enzymes for the production of biofuels. They are used for the processing of glycerides and fatty acids for biodiesel (fatty acid alkyl esters) production. This paper presents the main topics of the enzyme-based production of biodiesel, from the feedstocks to the production of enzymes and their application in esterification and transesterification reactions. Growing technologies, such as the use of whole cells as catalysts, are addressed, and as concluding remarks, the advantages, concerns, and future prospects of enzymatic biodiesel are presented. 1. Lipid Feedstocks The main feedstocks which present paramount importance for the application of lipases are fats and oils. Such materials are primarily composed of triglycerides, which are glycerol esters with saturated and unsaturated fatty acids, from vegetable, animal, or microbial origins. One of the distinguishable characteristics between fats and oils is the occurrence of unsaturated and saturated fatty acids in the triglycerides: higher saturated fatty acids content (as examples in Figure 1), higher melting point, and the presence of remaining solids at room temperature are characteristics of a fat; on the other hand, oils usually present higher occurrence of unsaturated fatty acids, remaining in liquid state at room temperature. In addition to triglycerides, vegetable oils can present di- and monoglycerides, free fatty acids (FFAs), phosphatides, and unsaponifiable matter, such as carotenoids, phytosterols, tocochromanols, chlorophyll, triterpenic alcohols, and hydrocarbons [1–4]. Figure 1: Schematic representation of a triglyceride with saturated fatty acids. The role of fats and oils in plants is related to energy reserve, regarding their occurrence in seeds, and protection against water loss (by wax formation) and against mechanical injuries (by hormone generation), when such components appear in the leaves and fruits [2, 5]. Worldwide production of fats and oils was estimated in 174.6 million tons for the season 2010/2011. From that, 86% represent vegetable oils (Table 1), with soybean, palm, rapeseed, and sunflower seed as the major resources [6, http://lipidlibrary.aocs.org/, 2011]. In Brazil, some oilcrops, such as castor bean (Ricinus communis), jatropha (Jatropha curcas), crambe (Crambe abyssinica), macaw palm (Acrocomia aculeata), and oiticica (Licania rigida), have been explored as alternatives for biodiesel production due to their high tolerance to drought and frost, higher productivity on low-fertility soils, and great potential for
Factorial Design to Optimize Biosurfactant Production by Yarrowia lipolytica
Gizele Cardoso Fontes,Priscilla Filomena Fonseca Amaral,Marcio Nele,Maria Alice Zarur Coelho
Journal of Biomedicine and Biotechnology , 2010, DOI: 10.1155/2010/821306
Abstract: In order to improve biosurfactant production by Yarrowia lipolytica IMUFRJ 50682, a factorial design was carried out. A 24 full factorial design was used to investigate the effects of nitrogen sources (urea, ammonium sulfate, yeast extract, and peptone) on maximum variation of surface tension (ΔST) and emulsification index (EI). The best results (67.7% of EI and 20.9 mN m?1 of ΔST) were obtained in a medium composed of 10 g 1?1 of ammonium sulfate and 0.5 g 1?1 of yeast extract. Then, the effects of carbon sources (glycerol, hexadecane, olive oil, and glucose) were evaluated. The most favorable medium for biosurfactant production was composed of both glucose (4% w/v) and glycerol (2% w/v), which provided an EI of 81.3% and a ΔST of 19.5 mN m?1. The experimental design optimization enhanced ΔEI by 110.7% and ΔST by 108.1% in relation to the standard process.
Extra??o e fracionamento simultaneo do óleo da castanha-do-Brasil com etanol
Freitas, Suely Pereira;Freitas-Silva, Otniel;Miranda, Iara Concei??o de;Coelho, Maria Alice Zarur;
Ciência e Tecnologia de Alimentos , 2007, DOI: 10.1590/S0101-20612007000500002
Abstract: in this work, the extraction and simultaneous separation of lipids from brazil nuts (bertholletia excelsa h.b.k.) with ethanol were investigated. brazil nuts were dried and triturated prior to oil extraction. the process was carried out at a rate of 4:1 solvent to substrate (v.w -1). the raw material and ethanol were placed in an erlenmeyer flask and maintained in a temperature-controlled bath at 65 °c and 30 rpm. after 1 hour, the mixture was filtered under a vacuum and the resultant miscella was maintained at 10 °c and centrifuged for phase separation. a rich miscella containing 75% oil and 25% ethanol was obtained presenting a gel consistency while a poor miscella, containing 2.4% oil and 97.6% ethanol, was liquid. the rich miscella presented an important potential to partially replace hydrogenate fats in the food industry. scientific studies indicated that the consumption of trans fatty acids promote serious health effects. furthermore, the proposed technology can be extended to different commercial oleaginous by eliminating the use of n-hexane in vegetable oils extraction.
Produ??o de biossurfactante por levedura
Fontes, Gizele Cardoso;Amaral, Priscilla Filomena Fonseca;Coelho, Maria Alice Zarur;
Química Nova , 2008, DOI: 10.1590/S0100-40422008000800033
Abstract: biosurfactants are molecules extracellularly produced by bacteria, yeast and fungi that have significant interfacial activity properties. this review focuses on relevant parameters that influence biosurfactant production by yeasts. many works have investigated the optimization of yeast biosurfactant production, mainly within the last decade, revealing that the potential of such microorganisms is not well explored in the industrial field. the main points to increase the process viability lays on the reduction of the production costs and enhancement of biosynthesis efficiency through optimization the culture conditions (carbon and nitrogen source, ph, aeration, speed agitation) and the selection of inexpensive medium components.
An ethanol-based process to simultaneously extract and fractionate carotenoids from Mauritia flexuosa L. Pulp
Ribeiro, Bernardo Dias;Nascimento, Rafaella Ferreira;Barreto, Daniel Weingart;Coelho, Maria Alice Zarur;Freitas, Suely Pereira;
Revista Brasileira de Fruticultura , 2010, DOI: 10.1590/S0100-29452010005000099
Abstract: mauritia vinifera (buriti) is a palm tree that grows wild in different areas of brazil, particularly in the amazonian region. the buriti oil is rich in carotenoids, especially in β-carotene. the growing interest in other natural sources of β-carotene has stimulated the industrial use of buriti as a raw material for pulp oil extraction. most processes are based on the conventional technologies, involving drying and pressing the pulp for oil recovery and further separation of carotenoids in a liquid phase using organics solvents. in the present work, the ethanol-based process was evaluated for simultaneous carotenoids recovering and fractionating from buriti pulp. the raw material and ethanol, 1:4 ratio, were placed in an erlenmeyer flask and maintained at 30rpm for 1 hour in a temperature-controlled bath at 65oc. the mixture was filtered under vacuum and cooling at 10oc to allow for the separation of the solvent in two phases. carotenoids composition, determined by hplc, has indicated a β-carotene concentration about 12 times greater in the lower phase than in the upper phase. the profile of the carotenoids in the denser phase is quite similar to that of raw buriti oil, and the concentration of total carotenoids is 40% higher than that of the original raw oil, making the ethanol-based process particularly attractive for industrial applications.
Remo o de cor de efluentes têxteis com cogumelos Agaricus bispora = Decolorization of textile effluent with mushroom Agaricus bispora
Renata Lopes Landeira Silva,Maria Alice Zarur Coelho,Magali Christe Cammarota
Acta Scientiarum : Technology , 2010,
Abstract: O emprego direto de cogumelos Agaricus bispora foi avaliado para a remo o de cor de uma mistura sintética de corantes reativos. Avaliou-se o efeito da granulometria das partículas (cubos de 0,5 ou 1,0 cm e cogumelos moídos), da massa de cogumelos (10, 20, 40, 60 ou 80 g em 250 mL de solu o) e de diferentes formas de tratamento do cogumelo sobre a remo o de cor de uma solu o sintética dos corantes Reactive Yellow 37, Reactive Black 5 e Reactive Red na concentra o de 13,3 mg L-1 cada corante. Os melhores resultados foram obtidos para maiores áreas superficiais de contato do cogumelo (cogumelo moído) com o efluente colorido e sob aera o contínua. A adi o de acetona durante o processo de moagem, seguido de congelamento, contribuiu para o aumento da remo o de cor, obtendo-se os melhoresresultados: 73% após 6h, com 20 g de biocatalisador 250 mL-1 de efluente. A utiliza o de diferentes lotes e marcas de cogumelo levou à obten o de diferentes atividades enzimáticas, mas percentuais similares de remo o de cor, indicando que a remo o de cor n o possuirela o direta com a atividade enzimática. The direct application of Agaricus bispora mushroom was evaluated for decolorization of a synthetic mixture of reactive dyes. The effects of particle size (0.5 or 1.0 cm cubes and triturated mushroom), mushroom mass (10, 20, 40, 60 or 80 g in 250 mL of solution) and different mushroom tissue treatments were analyzed regarding color removal efficiency of dyes Reactive Yellow 37, Reactive Black 5 and Reactive Red in a synthetic solution of 13.3 mg L-1 concentrationof each dye. The best results were found with larger superficial contact area between mushroom particle (triturated mushroom) and colored effluent under continuous aeration. Acetone addition during mushroom trituration process followed by a freezing step contributed to decolorization improvement, leading to best results: 73% after 6h, with 20 g of biocatalyst 250 mL-1 of effluent. The use of different mushroom batches and brands resulted in different enzymatic activities and similar levels of color removal, such result confirmed that decolorization does not have any direct relation with enzyme activity.
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