20 resultados para Chemical quality

em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo


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CHEMICAL PROFILE COMPARISON OF SUGARCANE SPIRITS FROM THE SAME WINE DISTILLED IN ALEMBICS AND COLUMNS. Six wines were distilled in two different distillation apparatus (alembic and column) producing 24 distillates (6 for each alembic fraction - head, heart and tail; 6 column distillates). The chemical composition of distillates from the same wine was determined using chromatographic techniques. Analytical data were subjected to Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) allowing discrimination of four clusters according to chemical profiles. Both distillation processes influenced the sugarcane spirits chemical quality since two types of distillates with different quantitative chemical profiles were produced after the elimination of fermentation step influence.

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Six wines were distilled in two different distillation apparatus (alembic and column) producing 24 distillates (6 for each alembic fraction - head, heart and tail; 6 column distillates). The chemical composition of distillates from the same wine was determined using chromatographic techniques. Analytical data were subjected to Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) allowing discrimination of four clusters according to chemical profiles. Both distillation processes influenced the sugarcane spirits chemical quality since two types of distillates with different quantitative chemical profiles were produced after the elimination of fermentation step influence.

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We aimed to develop site-specific sediment quality guidelines (SQGs) for two estuarine and port zones in Southeastern Brazil (Santos Estuarine System and Paranagua Estuarine System) and three in Southern Spain (Ria of Huelva, Bay of Cadiz, and Bay of Algeciras), and compare these values against national and traditionally used international benchmark values. Site-specific SQGs were derived based on sediment physical-chemical, toxicological, and benthic community data integrated through multivariate analysis. This technique allowed the identification of chemicals of concern and the establishment of effects range correlatively to individual concentrations of contaminants for each site of study. The results revealed that sediments from Santos channel, as well as inner portions of the SES, are considered highly polluted (exceeding SQGs-high) by metals, PAHs and PCBs. High pollution by PAHs and some metals was found in Sao Vicente channel. In PES, sediments from inner portions (proximities of the Ponta do Mix port`s terminal and the Port of Paranagua) are highly polluted by metals and PAHs, including one zone inside the limits of an environmental protection area. In Gulf of Cadiz, SQGs exceedences were found in Ria of Huelva (all analysed metals and PAHs), in the surroundings of the Port of CAdiz (Bay of CAdiz) (metals), and in Bay of Algeciras (Ni and PAHs). The site-specific SQGs derived in this study are more restricted than national SQGs applied in Brazil and Spain, as well as international guidelines. This finding confirms the importance of the development of site-specific SQGs to support the characterisation of sediments and dredged material. The use of the same methodology to derive SQGs in Brazilian and Spanish port zones confirmed the applicability of this technique with an international scope and provided a harmonised methodology for site-specific SQGs derivation. (C) 2009 Elsevier B.V. All rights reserved.

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Sediment quality from Paranagua Estuarine System (PES), a highly important port and ecological zone, was evaluated by assessing three lines of evidence: (1) sediment physical-chemical characteristics; (2) sediment toxicity (elutriates, sediment-water interface, and whole sediment); and (3) benthic community structure. Results revealed a gradient of increasing degradation of sediments (i.e. higher concentrations of trace metals, higher toxicity, and impoverishment of benthic community structure) towards inner PES. Data integration by principal component analysis (PCA) showed positive correlation between some contaminants (mainly As, Cr, Ni, and Pb) and toxicity in samples collected from stations located in upper estuary and one station placed away from contamination sources. Benthic community structure seems to be affected by both pollution and natural fine characteristics of the sediments, which reinforces the importance of a weight-of-evidence approach to evaluate sediments of PES. (C) 2008 Elsevier Inc. All rights reserved.

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The development of an electroanalytical method for simultaneous determination of copper and lead ions in sugar cane spirit (cachaca) using carbon paste electrode modified with ascorbic acid and carbon nanotubes (CPE-AaCNT) is described. Squarewave voltammetry (SWV) with anodic stripping was employed, and this technique was optimized with respect to the following parameters: frequency (50 Hz), amplitude (100 mV) and scan increment (9 mV). The analytical curves were linear in the range from 0.0900 to 7.00 mg L-1 for lead and copper. The limits of detection were 48.5 and 23.9 mu g L-1 for lead and copper, respectively. The developed method was applied to the simultaneous determination of copper and lead in five commercial samples of sugar cane spirit. The results were in good agreement with those obtained by F AAS/GF AAS (flame atomic absorption spectrometry/graphite furnace atomic absorption spectrometry) and showed that CPE-AaCNT can be successfully employed in the simultaneous determination of these metals in real sugar cane spirit samples.

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Brazil nut richness has been widely studied aiming at finding transformation models that increase its yield, keep its quality, reduce costs, and increase its productivity. The objective of this study is to evaluate the spectroscopic profile and the chemical and thermal behavior of Brazil nut oil obtained by different extraction processes. Lipid soxhlet extractions with petroleum ether and hexane, and using hydraulic pressing and supercritical carbon dioxide (CO2) were performed. The physicochemical analyses showed an acidity index with significant differences between the samples obtained by hydraulic pressing and supercritical CO2. The peroxide index presented significant difference for the oil obtained by hydraulic pressing compared to that obtained by the other extraction processes. The fatty acid profiles showed a relevant presence of the omega series (w-3, w-6, and w-9) with significant differences for the extraction processes evaluated. The results of the thermogravimetric and differential analyses did not indicate changes in mass loss and presented predominantly exothermic behavior. The spectroscopic profiles indicate that the extraction processes do not change the spectral profile of the oils. (c) 2011 Elsevier Ltd. All rights reserved.

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The hydroponic cultivation of vegetables has increased markedly in recent years, however, little is known about its chemical composition, which is of extreme importance in view of changing food habits of a considerable fraction of the population seeking food quality. For this reason, cultivation of watercress, chicory, rocket and lettuce American (Lucy Brown) and smooth (cv. Regina) were grown in hydroponics, NFT system, aiming to evaluate the yield, nitrate content and chemical composition. The experiment was conducted in a greenhouse at the Universidade Federal de Santa Catarina, Florianopolis city in the Santa Catarina State (Brazil), from may to july 2004 under a completely randomized design with four replications. The spacing used was 25 x 25 cm for the crops of watercress, chicory and lettuce (cv. Lucy Brown and cv. Regina) and 5 x 5 cm to the rocket. The traits were: number of leaves, nitrate content and chemical composition of vegetables. The lettuce cv. Regina and chicory had higher number of leaves per plant. The watercress had lower water content and higher dry mass of shoots. The largest increase in fresh weight was obtained in chicory, lettuce, cv. Regina. Higher levels of lipids, protein, ash, carbohydrates, calories, fiber and nitrate were obtained from the watercress. The rocket had lower values for the variables fresh and dries the whole plant, shoot and root and leaf number per plant. All cultures showed good visual appearance, low calorie and nitrate levels suitable for human consumption.

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Araucaria angustifolia, commonly named Araucaria, is a Brazilian native species that is intensively exploited due to its timber quality. Therefore, Araucaria is on the list of species threatened by extinction. Despite the importance of soil for forest production, little is known about the soil properties of the highly fragmented Araucaria forests. This study was designed to investigate the use of chemical and biological properties as indicators of conservation and anthropogenic disturbance of Araucaria forests in different sampling periods. The research was carried out in two State parks of Sao Paulo: Parque Estadual Turistico do Alto do Ribeira and Parque Estadual de Campos de Jordao. The biochemical properties carbon and nitrogen in microbial biomass (MB-C and MB-N), basal respiration (BR), the metabolic quotient (qCO(2)) and the following enzyme activities: beta-glucosidase, urease, and fluorescein diacetate hydrolysis (FDA) were evaluated. The sampling period (dry or rainy season) influenced the results of mainly MB-C, MB-N, BR, and qCO(2). The chemical and biochemical properties, except K content, were sensitive indicators of differences in the conservation and anthropogenic disturbance stages of Araucaria forests. Although these forests differ in biochemical and chemical properties, they are efficient in energy use and conservation, which is shown by their low qCO(2), suggesting an advanced stage of succession.

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Florianopolis, a city located in the Santa Catarina State in southern Brazil, is the national leading producer of bivalve mollusks. The quality of bivalve mollusks is closely related to the sanitary conditions of surrounding waters where they are cultivated. Presently, cultivation areas receive large amounts of effluents derived mainly from treated and non-treated domestic, rural, and urban sewage. This contributes to the contamination of mollusks with trace metals, pesticides, other organic compounds, and human pathogens such as viruses, bacteria, and protozoan. The aim of this study was to perform a thorough diagnosis of the shellfish growing areas in Florianopolis, on the coast of Santa Catarina. The contamination levels of seawater, sediments, and oysters were evaluated for their microbiological, biochemical, and chemical parameters at five sea sites in Florianopolis, namely three regular oyster cultivation areas (Sites 1, 2, and oyster supplier), a polluted site (Site 3), and a heavily polluted site (Site 4). Samples were evaluated at day zero and after 14 days. Seawater and sediment samples were collected just once, at the end of the experiment. Antioxidant defenses, which may occur in contaminated environments in response to the increased production of reactive oxygen species (ROS) by organisms, were analyzed in oysters, as well as organic compounds (in oysters and sediment samples) and microbiological contamination (in oysters and seawater samples). The results showed the presence of the following contaminants: fecal coliforms in seawater samples (four sites), human adenovirus (all sites), human noroviruses GI and GII (two sites), Hepatitis A viruses (one site), JC Polyomavirus in an oyster sample from the oyster supplier, Giardia duodenalis cysts, and Cryptosporidium sp oocysts (one site). Among organochlorine pesticides, only DDT (dichlorodiphenyltrichloroethane) and HCH (hexachlorocyclohexane) were detected in some sediment and oysters samples in very low levels; site 4 had the highest concentrations of total aliphatic hydrocarbons. PAHs, and linear alkylbenzenes (LABs) found either in oysters or in sediment samples. The major concentration of fecal sterol coprostanol was found at site 4, followed by site 3. After 14 days of allocation in the four selected sites, there was a significant difference in the enzymes analyzed at the monitored spots. The detection of different contaminants in oysters, seawater, and sediment samples in the present study shows the impact untreated or inadequately treated effluents have on coastal areas. These results highlight the need for public investment in adequate wastewater treatment and adequate treatment of oysters, ensuring safe areas for shellfish production as well as healthier bivalve mollusks for consumption.

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An environmental impact study was conducted to determine the Piracicamirim's creek water quality in order to assess the influence of effluents from a sugar industry in this water body. For this, toxicity tests were performed with a water sample upstream and downstream the industry using the microcrustaceans Daphnia magna, Ceriodaphnia dubia and Ceriodaphnia silvestrii as test organisms, as well as physical and chemical analysis of water. Results showed that physical and chemical parameters did not change during the sampling period, except for the dissolved oxygen. No toxicity was observed for D. magna and reproduction of C. dubia and C. silvestrii in both sampling points. Thus, the industry was not negatively impacting the quality of this water body.

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Current methods for quality control of sugar cane are performed in extracted juice using several methodologies, often requiring appreciable time and chemicals (eventually toxic), making the methods not green and expensive. The present study proposes the use of X-ray spectrometry together with chemometric methods as an innovative and alternative technique for determining sugar cane quality parameters, specifically sucrose concentration, POL, and fiber content. Measurements in stem, leaf, and juice were performed, and those applied directly in stem provided the best results. Prediction models for sugar cane stem determinations with a single 60 s irradiation using portable X-ray fluorescence equipment allows estimating the % sucrose, % fiber, and POL simultaneously. Average relative deviations in the prediction step of around 8% are acceptable if considering that field measurements were done. These results may indicate the best period to cut a particular crop as well as for evaluating the quality of sugar cane for the sugar and alcohol industries.

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Brazil holds the second largest population of domestic dogs in the world, with 33 million dogs, only behind the United States. The annual consumption of dog food in the country is 1.75 million tons, corresponding to the World's sixth in trade turnover. Dog food is supposed to be a complete and balanced diet, formulated with high quality ingredients. All nutrients and minerals required for an adequate nutrition of dogs are added to the formulation to ensure longevity and welfare. In this context, the present study aimed at assessing the chemical composition of dry dog foods commercialized in Brazil. Thirty-four samples were acquired in the local market of Piracicaba and analyzed by instrumental neutron activation analysis (INAA) to determine the elements As, Br, Ca, Co, Cr, Cs, Fe, K, La, Na, Rb, Sb, Sc, Se, U, and Zn. In general, the concentrations of Ca, Fe, K, Na, and Zn complied with the values required by the Association of American Feed Control Officials (AAFCO). To evaluate the safety of dog food commercialized in Brazil, further investigation is necessary to better understand the presence of toxic elements found in this study, i.e. Sb and U. INAA was useful for the screening analysis of different types and brands of dry dog foods for the determination of both essential and toxic elements.

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Araucaria angustifolia, commonly named Araucaria, is a Brazilian native species that is intensively exploited due to its timber quality. Therefore, Araucaria is on the list of species threatened by extinction. Despite the importance of soil for forest production, little is known about the soil properties of the highly fragmented Araucaria forests. This study was designed to investigate the use of chemical and biological properties as indicators of conservation and anthropogenic disturbance of Araucaria forests in different sampling periods. The research was carried out in two State parks of São Paulo: Parque Estadual Turístico do Alto do Ribeira and Parque Estadual de Campos de Jordão. The biochemical properties carbon and nitrogen in microbial biomass (MB-C and MB-N), basal respiration (BR), the metabolic quotient (qCO2) and the following enzyme activities: β-glucosidase, urease, and fluorescein diacetate hydrolysis (FDA) were evaluated. The sampling period (dry or rainy season) influenced the results of mainly MB-C, MB-N, BR, and qCO2. The chemical and biochemical properties, except K content, were sensitive indicators of differences in the conservation and anthropogenic disturbance stages of Araucaria forests. Although these forests differ in biochemical and chemical properties, they are efficient in energy use and conservation, which is shown by their low qCO2, suggesting an advanced stage of succession.

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The aim of this study was to evaluate the physicochemical properties of avocado pulp of four different varieties (Avocado, Guatemala, Dickinson, and Butter pear) and to identify which has the greatest potential for oil extraction. Fresh avocado pulp was characterized by moisture, protein, fat, ash, carbohydrates and energy contents were determined. The carotenoids and chlorophyll contents were determined by the organic solvent extraction method. The results showed significant differences in the composition of the fruit when varieties are compared. However, the striking feature in all varieties is high lipid content; Avocado and Dickinson are the most suitable varieties for oil extraction, taking into account moisture content and the levels of lipids in the pulp. Moreover, it could be said that the variety Dickinson is the most affected by the parameters evaluated in terms of overall quality. Chlorophyll and carotenoids, fat-soluble pigments, showed a negative correlation with respect to lipids since it could be related to its function in the fruit. The varieties Avocado and Dickinson are an alternative to oil extraction having great commercial potential to be exploited thus avoiding waste and increasing farmers income.

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The development of an electroanalytical method for simultaneous determination of copper and lead ions in sugar cane spirit (cachaça) using carbon paste electrode modified with ascorbic acid and carbon nanotubes (CPE-AaCNT) is described. Squarewave voltammetry (SWV) with anodic stripping was employed, and this technique was optimized with respect to the following parameters: frequency (50 Hz), amplitude (100 mV) and scan increment (9 mV). The analytical curves were linear in the range from 0.0900 to 7.00 mg L- 1 for lead and copper. The limits of detection were 48.5 and 23.9 µg L- 1 for lead and copper, respectively. The developed method was applied to the simultaneous determination of copper and lead in five commercial samples of sugar cane spirit. The results were in good agreement with those obtained by F AAS/GF AAS (flame atomic absorption spectrometry/graphite furnace atomic absorption spectrometry) and showed that CPE-AaCNT can be successfully employed in the simultaneous determination of these metals in real sugar cane spirit samples.