819 resultados para Físico-química


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Agronomia (Energia na Agricultura) - FCA

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The present study had as objective contribute to the characterization of beekeeping in the Pernambuco State and evaluate the physical-chemical quality of the honeys produced in the region. For this, was applied a directed formulary to the representative organ of beekeeping class aboutthe productives and technicals aspects of beekeepers. Was obtained 14 samples of honey by Apis mellifera africanized, stored in sterile plastic vessels was sent to the Beekeeping Products Quality Control Laboratory (CEA-UNITAU). Was observed that the most of beekeepers have of 50 to 100 hives (57,14%), 28,57% of 100 to 200 hives and 14,28% more than 500 hives, being that 85,71% produce 30 to 50 kg honey/hives/flowering. All use the standard hive Langstroth and 85,71% obtain their swarm by capture. About the physical-chemical quality of the honey, was observed that moisture content varied from 18,2% to 22,0%, with mean value of 19,80±1,11; the water activity varied from 0,70 to 0,84 aw, with mean value of 0,79±0,05 aw; the total acidity was 24,91±8,99 meq/kg and the average index of hydroxymethylfurfural was 16,32±17,88 meq/kg. The results obtained are according to the quality limits established by the brazilian legislation, excepted the water activity that exceeded the maximum limit of 0,65 aw. The datasobtained in this paper shows the development of beekeeping in Pernambuco State and the honey presents nice quality.

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The biomass resulting from processing sugarcane bagasse has been considered a source of cellulose with the potential production of bio-fuels. This lignocellulose can be processed into ethanol since is hydrolyzed by chemical processes (acids) or biotechnology (enzymes) which generate sugars suit for fermentation. This study had the objective to utilize physical and chemical pre-treatment processes for prehydrolysis of sugarcane bagasse. The experimental treatment was adjusted at a factor of 4 X 2, by the combination of pre-hydrolysis timing (15, 30, 45 and 60 minutes) and sulfuric acid concentrations (7.0% and 9.0%) which was incubated at a temperature of 121° C in an autoclave. The treatment data was subjected to analysis of the variance and averages which were compared using the Tukey test with a probability of 5%. The results obtained showed that through pretreatment acid applied on the lignocellulose material, there was a significant break from the substrate fibers like cellulose, hemicellulose and lignin.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Cassava leaves can be considered an important nutritional source when compared to other commonly consumed vegetables leaves. Cassava leaves have high levels of protein, fiber and minerals, and arestill underexplored due to the lack of information regarding the use of them as afood product, as well as, their use as an industrial raw material. The consumption of cassava leaves in fresh form is impractical due to the presence of cyanide, thereby it is required a pretreatment to be performed to reduce this component. The objective of this study was to produce and characterize the four made with cassava leaves as its chemical composition, color, indices of absorption and water solubility, and pasting properties, aiming to provide information of interest for possible application as an ingredient in the food industry. Cassava leaf flour showed low moisture content (6.6 %)and significant amounts of fiber (30.68 %), protein (23.00 %), and total carbohydrate (22.27%). Drying and milling processes allowed to obtain a flour with a low content of total cyanide (0.3 mg 100g-1 ), and the presence of vitamin C (56.6 mg 100g-1 ) and β –carotene (38 mg 100g- 1 ). The color analysis of cassava leaf flour showed low lightness with, predominantly, green and yellow pigments. The cassava leaf flour presented good solubility (14.85 %) and water absorption (6.87 g gel. g-1 ). Pasting properties showed a low peak of viscosity and a higher final viscosity with a retrogradation tendency, indicating a low capacity of this flour to form gel. The flour of cassava leaves can be a good source of nutrition when used as a food ingredient in soups and pasta. However, it is not indicated to products that require high gel formation.

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This study aimed to characterize the physical and chemical composition of ten items of arracacha grown in the municipality of São Manuel for the 2009 harvest. In the roots of the clones BGH (4560, 5741, 5744, 5746, 5747, 6414, 6513, 6525 and 7609) and the cultivar Amarela de Senador Amaral the characteristics evaluated were: color (L *, a * and b *) and moisture, ash, crude fiber, raw grease, protein, reducing sugars, total sugars and starch. After obtaining the data, an analysis was performed for the variance of test F and comparisons between the means made by the Tukey test at 5% probability. There was no significant difference to the results of luminosity (L *) while BGH 6414 and BGH 5744 showed the highest values for chroma and * BGH 5741, BGH 6414, BGH 7609, 'Amarela de Senador Amaral' BGH 5747 presented the highest chroma values for b *. Clones BGH 7609 and BGH 6414 showed significantly higher levels of dry matter and with the potential yield of agro-industrial processes it would be best suited in the form of frying. The materials that showed significantly larger amounts of ash were BGH 6525, BGH 5747, 'Amarela de Senador Amaral ", BGH 4560, BGH 5746, BGH 6513. Regarding the contents of fatty matter BGH 6525, BGH 5741 and BGH 5744 showed the highest levels. The results of BGH 7609 showed crude fiber significantly higher than the other materials tested, it can be used in diets composed of fibers. BGH 4560 and cultivar had the highest crude protein. BGH 5741 showed the lowest reducing sugar content among the clones, but not significantly different from results found for the cultivar. All clones showed total sugar levels were higher in the cultivar, which may have more flavor. BGH 5741, BGH 5746, BGH 6525 and BGH 6513 showed significantly higher starch content than the cultivar Amarela de Senador Amaral. From these results we conclude that the clones have similar color characteristics, and are potentially a nutritionally adequate substitute for the cultivar.

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Mulberry (Morus nigra L.) is a fruit with a great potential for technological uses, which could be employed to manufacture of syrups, ice cream, candies, yoghurts, beverages, jam, etc. Only the leaf from mulberry trees is commercially used for silkworm feeding. This tree is cultivated on many agricultural environments such as small rural proprieties and settlements. Small farmers waste a great amount of their production for not knowing about mulberry technology. Thus, the objective of this work was to access extraction yield and physical-chemical properties of mulberry whole juice from ripe, green and a mixture of both by using press and depulper. Statistical analysis of results was carried by media and standard deviation calculations. 173 kg of mulberry were picked being 49.31% ripe and 50.68% green. Press delivered greater extraction yield of whole juice (80.50% to 81.60%) when compared to press (71.43% to 77.50%). Whole juice obtained from both equipments has shown the following values: soluble solids 7.45% - 12.11%, titrable acidity 0.45 – 1.23%, ratio 6.03 – 26.84, pH 3.69 – 4.35, total reducing sugar 4.05% – 9.96%, reducing sugar 3.95% - 9.15%, sucrose 0.00% - 0.04%, turbidity 221.25 NTU - >4,000 NTU. Whole juices obtained from both equipments has shown similar physical-chemical characteristics except turbidity. The authors concluded that press was the best extraction equipment due to its greater yield and whole juice quality regarding turbidity

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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[EN] Bioindicators have been used in urban and industrial areas to control the atmospheric pollution because it constitutes one of the most important environmental problems of human health. In this sense, mosses are able to reflect the chemical composition of surrounding atmosphere that together with the easy production techniques becomes mosses as one of the potential bioindicators in Europe. This study is part of the Mossclone project (FP-7) and quantifies the adsorption of heavy metals on 4 typical moss species in order to propose one of them to be used for environmental monitoring in the moss bag technique.

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Com o aumento dos tratamentos químicos e/ou físicos nos cabelos aos quais são realizados mediante o uso de dispositivos térmicos, há uma maior preocupação a respeito dos danos causados aos cabelos por estes tipos de tratamentos. O conhecimento dos efeitos, benefícios e/ou malefícios, de ingredientes cosméticos em cabelos torna-se necessário, pois facilita a busca por produtos baseada no tipo de cabelo. O principal objetivo do trabalho foi a caracterização físico-química, analítica e térmica de mechas de cabelo de diferentes etnias (caucasiano, oriental e afro-étnico virgem e brasileiro virgem e descolorido) antes e após o uso de ingredientes cosméticos seguido de um tratamento térmico (utilizando piastra) e intercalando com lavagens. O estudo das amostras de cabelo e de uma amostra de queratina animal envolveu a utilização das técnicas de TG/DTG, DSC, análise elementar, FTIR, MEV e técnicas de avaliação de eficácia, como tensão/deformação, penteabilidade e quebra por escovação. A partir da TG/DTG, foi possível avaliar as etapas de decomposição térmica das amostras de cabelo virgem e de queratina animal e estas apresentaram um comportamento térmico semelhante entre si. O estudo cinético não isotérmico por TG mostrou que, dos diferentes tipos de amostras de cabelo virgem, o afro-étnico apresentou menor estabilidade térmica e o oriental foi o mais estável termicamente. Os resultados de DSC corroboraram os obtidos por TG, demonstrando que a amostra de cabelo afro-étnico apresentou temperatura de desnaturação térmica das cadeias de α-queratina menor (TD = 223°C) do que as amostras dos outros tipos de cabelo (TD = 236°C). As mechas de cabelo virgem e clareadas foram tratadas com formulações cosméticas contendo silicones e avaliadas quanto a eficiência destes na proteção térmica dos cabelos. Algumas delas mostraram eficiência na proteção térmica das cadeias de α-queratina, diminuindo o seu grau de desnaturação. Foi possível observar que a associação do calor da piastra com as lavagens sucessivas causou danos tanto à cutícula (conforme resultados de FTIR e MEV), como também, ao córtex dos cabelos (conforme resultados de DSC). Em alguns casos, os danos causados foram tão graves que as camadas mais superficiais da cutícula sofreram descamações. O estudo mostrou, também, que a eficiência da proteção térmica nos cabelos depende do tipo da formulação cosmética em que estes protetores estão incorporados e do estado em que os cabelos se encontram. A DSC permitiu a avaliação da modificação termicamente induzida das cadeias de α-queratina e sua posterior desnaturação. O estudo envolvendo a associação das diferentes técnicas apresentou-se viável na avaliação tanto dos danos causados aos cabelos quanto na eficiência dos ingredientes cosméticos na proteção térmica dos mesmos.

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O óleo da amêndoa de pequi (Caryocar brasiliense Camb.) é considerado um coproduto do fruto, consumido na região do Cerrado, bioma brasileiro. Ele é fundamental para agregar valor e ampliar a utilização deste fruto regional a outros setores produtivos comerciais. Relatos na literatura apontam que o óleo possui capacidade antioxidante e efeitos benéficos sobre doenças inflamatórias, que estão associados à presença de ácidos graxos insaturados e fitoquímicos em sua composição química. Por outro lado, o tetracloreto de carbono (CCl4) é uma potente hepatotoxina, capaz de gerar radicais livres que levam ao estresse oxidativo e à inflamação. Nesse contexto, o objetivo do presente estudo foi caracterizar os óleos da amêndoa de pequi obtidos artesanalmente e por prensagem a frio e verificar o efeito de seus constituintes graxos e bioativos sobre parâmetros oxidativos e inflamatórios de ratos submetidos à toxicidade aguda induzida por tetracloreto de carbono. Inicialmente, foram investigados os parâmetros de qualidade dos óleos, bem como o perfil de ácidos graxos, teores de compostos bioativos, capacidade antioxidante e estabilidade termo-oxidativa. Os óleos da amêndoa de pequi apresentaram boa qualidade e resistência termo-oxidativa e mostraram-se ricos em ácido graxo oleico, além de possuírem compostos com propriedades antioxidantes, como fenólicos, carotenoides, tocoferóis e fitosteróis. Posteriormente, o efeito do tratamento por 22 dias com óleos da amêndoa de pequi artesanal ou prensado a frio (3 mL/kg) sobre a toxicidade aguda induzida pelo CCl4 em ratos \"Wistar\" machos foi avaliado. Para tal, foram determinados marcadores bioquímicos séricos, perfil lipídico, peroxidação lipídica, marcadores do sistema de defesa antioxidante e detoxificante, além de parâmetros inflamatórios do tecido hepático. De maneira geral, verificou-se que os óleos da amêndoa de pequi não minimizaram as alterações hepáticas induzidas pelo CCl4, evidenciadas pelas enzimas marcadoras do dano hepático e por parâmetros inflamatórios, no entanto os animais tratados com o óleo prensado a frio aumentaram sua capacidade antioxidante.