994 resultados para Over modified malt
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Gluten sensitive consumers and people suffering from coeliac disease account for up to 6% of the general population (Catassi et al., 2013). These consumers must avoid foods which contain gluten and related proteins found in wheat, rye or barley. Beer is produced from barley malt and therefore contains hordeins, (gluten like proteins). Beers labelled as gluten-free must contain below 10 mg/kg hordeins (10 mg/kg hordeins = 20 mg/kg gluten under current regulations) to be considered safe for gluten sensitive consumers. Currently there are a limited number of methods available for reducing beer hordeins, the studies outlined in this thesis provide a range of tools for the beverage industry to reduce the hordein content of beer It is well known, that during malting and brewing hordeins are reduced, but they still remain in beer at levels above 10 mg/kg. During malting, hordeins are broken down to form new proteins in the growing plant. Model malting and brewing systems were developed and used to test, how the modification of the malting process could be used to reduce beer hordeins. It was shown, that by using a controlled malting and brewing regime, a range of barley cultivars produced beer with significant differences in levels of hordeins. Beer hordeins ranged from 10 mg/kg to 60 mg/kg. Another study revealed that when malting was prolonged, to maximise breakdown of proteins, beer hordeins can be reduced by up to 44%. The natural breakdown of hordein during malting enhanced in a further study, when a protease was added to support the hordein degradation during steeping and germination. The enzyme addition resulted in a 46% reduction in beer hordeins 2 when compared to the control. All of the malt treatments had little or no impact on malt quality. The hordein levels can also be reduced during the beer stabilisation process. Levels of beer hordein were tested after stabilisation using two different concentrations of silica gel and tannic acid. Silica gel was very effective in reducing beer hordeins, 90% of beer hordeins were removed compared to the control beer. Beer hordeins could be reduced to below 10 mg/kg and the beer qualities such as foam, colour and flavour were not affected. Tannic acid also reduced beer hordein by up to 90%, but it reduced foam stability and affected beer flavours. A further study described treatment of beer with microbial transglutaminase (mTG), to create bonds between hordein proteins, which increased particle size and allowed removal during filtration. The addition of the mTG led to a reduction of the beer hordein by up to 96% in beer, and the impact on the resulting beer quality was minimal. These studies provide the industry with a toolbox of methods leading to the reduction of hordein in the final beer without negatively affecting beer quality.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Biodiesel production by methanolysis of semi-refined rapeseed oil was studied over lime based catalysts. In order to improve the catalysts basicity a commercial CaO material was impregnated with aqueous solution of lithium nitrate (Li/Ca = 03 atomic ratio). The catalysts were calcined at 575 degrees C and 800 degrees C, for 5 h, to remove nitrate ions before reaction. The XRD patterns of the fresh catalysts, including the bare CaO, showed lines ascribable to CaO and Ca(OH)(2). The absence of XRD lines belonging to Li phases confirms the efficient dispersion of Li over CaO. In the tested condition (W-cat/W-oil = 5%; CH3OH/oil = 12 molar ratio) all the fresh catalysts provided similar biodiesel yields (FAME >93% after 4 h) but the bare CaO catalyst was more stable. The activity decay of the Li modified samples can be related to the enhanced, by the higher basicity, calcium diglyceroxide formation during methanolysis which promotes calcium leaching. The calcination temperature for Li modified catalysts plays an important role since encourages the crystals sinterization which appears to improve the catalyst stability. (C) 2013 Elsevier B.V. All rights reserved.
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Bio-ethanol has been used as a fuel additive in modern society aimed at reducing CO2-emissions and dependence on oil. However, ethanol is unsuitable as fuel supplement in higher proportions due to its physico-chemical properties. One option to counteract the negative effects is to upgrade ethanol in a continuous fixed bed reactor to more valuable C4 products such as 1-butanol providing chemical similarity with traditional gasoline components. Bio-ethanol based valorization products also have other end-uses than just fuel additives. E.g. 1-butanol and ethyl acetate are well characterised industrial solvents and platform chemicals providing greener alternatives. The modern approach is to apply heterogeneous catalysts in the investigated reactions. The research was concentrated on aluminium oxide (Al2O3) and zeolites that were used as catalysts and catalyst supports. The metals supported (Cu, Ni, Co) gave very different product profiles and, thus, a profound view of different catalyst preparation methods and characterisation techniques was necessary. Additionally, acidity and basicity of the catalyst surface have an important role in determining the product profile. It was observed that ordinary determination of acid strength was not enough to explain all the phenomena e.g. the reaction mechanism. One of the main findings of the thesis is based on the catalytically active site which originates from crystallite structure. As a consequence, the overall evaluation of different by-products and intermediates was carried out by combining the information. Further kinetic analysis was carried out on metal (Cu, Ni, Co) supported self-prepared alumina catalysts. The thesis gives information for further catalyst developments aimed to scale-up towards industrially feasible operations.
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Lanthana modified sol-gel titania is prepared through particulate sol-gel route and the physico-chemical characterizations of the prepared systems were done using X-Ray diffration, EDX, BET surface area-pore volume measurements and TG-DTG analysis. Benzophenone was observed to be the sole product in the TiO2 photocatalyzed oxidation of benzhydrol in oxygen purged acetonitrile. The influence of various parameters, like irradiation time, amount of catalyst, concentration of the catalyst and other factors on the photocatalytic oxidation has been investigated. The proposed mechanism envisages the involvement of a superoxide radical anion.
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We have reported earlier that modification of commercial graphite Pt-supported catalysts with Teflon fluorinated polymeric coating of a very strong hydrophobic nature can significantly improve catalytic activity for aerial oxidation of water-insoluble alcohols such as anthracene methanol in supercritical carbon dioxide (scCO(2)). Thus, this paper presents some further characterization of these new catalyst materials and the working fluid phase during the catalysis. Using the same Teflon-modified metal catalysts, this paper addresses the oxidation of another water-insoluble alcohol molecule, m-hydrobenzoin in scCO(2). It is found that conversion and product distribution of this diol oxidation critically depend on the temperature and pressure of the scCO(2) used, which suggest the remarkable solvent properties of the scCO(2) under these unconventional oxidation conditions. (C) 2004 Elsevier Inc. All rights reserved.
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The immobilization of gold nanoparticles (Au NPs) on silica is made possible by the functionalization of the silica surfaces with organosilanes. Au NPs could only be stabilized and firmly attached to silica-support surfaces that were previously modified with amino groups. Au NPs could not be stabilized on bare silica surfaces and most of the NPs were then found in the solution. The metal-support interactions before and after the Au NP formation, observed by X-ray absorption fine structure spectroscopy (XAFS), indicate a stronger interaction of gold-(III) ions with amino-modified silica surfaces than with the silanol groups in bare silica. An amino-modified, silica-based, magnetic support was used to prepare an active Au NP catalyst for the chemoselective oxidation of alcohols, a reaction of great interest for the fine chemical industry.
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PURPOSE: Describe a modified technique to increase nostril cross-sectional area using rib and septal cartilage graft over alar nasal cartilages. METHODS: A modified surgical technique was used to obtain, carve and insert cartilage grafts over alar nasal cartilages. This study used standardized pictures and measured 90 cadaveric nostril cross-sectional area using Autocad (c); 30 were taken before any procedure and 60 were taken after grafts over lateral crura (30 using costal cartilage and 30 using septal cartilage). Statistical analysis were assessed using a model for repeated measures and ANOVA (Analysis of Variance) for the variable "area". RESULTS: There's statistical evidence that rib cartilage graft is more effective than septal cartilage graft. The mean area after the insertion of septal cartilage graft is smaller than the mean area under rib graft treatment (no confidence interval for mean difference contains the zero value and all P-values are below the significance level of 5%). CONCLUSIONS: The technique presented is applicable to increase nostril cross section area in cadavers. This modified technique revealed to enhance more nostril cross section area with costal cartilage graft over lateral crura rather than by septal graft.
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The Advanced Very High Resolution Radiometer (AVHRR) carried on board the National Oceanic and Atmospheric Administration (NOAA) and the Meteorological Operational Satellite (MetOp) polar orbiting satellites is the only instrument offering more than 25 years of satellite data to analyse aerosols on a daily basis. The present study assessed a modified AVHRR aerosol optical depth τa retrieval over land for Europe. The algorithm might also be applied to other parts of the world with similar surface characteristics like Europe, only the aerosol properties would have to be adapted to a new region. The initial approach used a relationship between Sun photometer measurements from the Aerosol Robotic Network (AERONET) and the satellite data to post-process the retrieved τa. Herein a quasi-stand-alone procedure, which is more suitable for the pre-AERONET era, is presented. In addition, the estimation of surface reflectance, the aerosol model, and other processing steps have been adapted. The method's cross-platform applicability was tested by validating τa from NOAA-17 and NOAA-18 AVHRR at 15 AERONET sites in Central Europe (40.5° N–50° N, 0° E–17° E) from August 2005 to December 2007. Furthermore, the accuracy of the AVHRR retrieval was related to products from two newer instruments, the Medium Resolution Imaging Spectrometer (MERIS) on board the Environmental Satellite (ENVISAT) and the Moderate Resolution Imaging Spectroradiometer (MODIS) on board Aqua/Terra. Considering the linear correlation coefficient R, the AVHRR results were similar to those of MERIS with even lower root mean square error RMSE. Not surprisingly, MODIS, with its high spectral coverage, gave the highest R and lowest RMSE. Regarding monthly averaged τa, the results were ambiguous. Focusing on small-scale structures, R was reduced for all sensors, whereas the RMSE solely for MERIS substantially increased. Regarding larger areas like Central Europe, the error statistics were similar to the individual match-ups. This was mainly explained with sampling issues. With the successful validation of AVHRR we are now able to concentrate on our large data archive dating back to 1985. This is a unique opportunity for both climate and air pollution studies over land surfaces.
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Mode of access: Internet.
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Peer reviewed
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Captures with black and white Shannon traps were undertaken to identify aspects of the behavior of the two cryptic and sympatric species implicated as vectors of cutaneous leishmaniasis, Nyssomyia intermedia (Lutz & Neiva, 1912) and Nyssomyia neivai (Pinto, 1926). The traps were installed side by side, monthly, from July 2001 to June 2002, from 18 to 07 hours, in a peridomicile of Iporanga municipality, state of São Paulo, Brazil. A total of 2,142 specimens were captured, Ny. intermedia (47.4%) and Ny. neivai (50.5%). The white trap was more attractive to both sexes of both species. Males of Ny. neivai predominated (70%) over those of Ny. intermedia on the two traps; on the black trap, the females of Ny. intermedia predominated (63.3%) over those of Ny. neivai (36.7%). Seventy percent of the specimens of both species were captured between 18 and 24 h. Females of Ny. intermedia presented the highest peak at 19-20 h, and those of Ny. neivai at 20-21 h. The highest hourly average for females of Ny. intermedia on the black trap occurred in the winter and that for males in the summer. For Ny. neivai, both sexes predominated in the summer. The two species probably transmit the cutaneous leishmaniasis in the area due to their great predominance.
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The uptake of ascorbate by neuroblastoma cells using a ruthenium oxide hexacyanoferrate (RuOHCF)-modified carbon fiber disc (CFD) microelectrode (r = 14.5 mu m) was investigated. By use of the proposed electrochemical sensor the amperometric determination of ascorbate was performed at 0.0 V in minimum essential medium (MEM, pH = 7.2) with a limit of detection of 25 mu mol L(-1). Under the optimum experimental conditions, no interference from MEM constituents and reduced glutathione (used to prevent the oxidation of ascorbate during the experiments) was noticed. The stability of the RuOHCF-modified electrode response was studied by measuring the sensitivity over an extended period of time (120 h), a decrease of around 10% being noticed at the end of the experiment. The rate of ascorbate uptake by control human neuroblastoma SH-SY5Y cells, and cells transfected with wild-type Cu,Zn-superoxide dismutase (SOD WT) or with a mutant typical of familial amyotrophic lateral sclerosis (SOD G93A), was in agreement with the level of oxidative stress in these cells. The usefulness of the RuOHCF-modified microelectrode for in vivo monitoring of ascorbate inside neuroblastoma cells was also demonstrated.