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排序方式: 共有416条查询结果,搜索用时 15 毫秒
81.
Marcela L. Martínez María A. Marín Camila M. Salgado Faller Juliana Revol María C. Penci Pablo D. Ribotta 《LWT》2012,47(1):78-82
The processing parameters related with chia oil extraction employing screw press have not been studied yet. A Box–Behnken experimental design was used to study the optimization process by response surface analysis. The independent variables considered were seed moisture content, restriction die, screw press speed and barrel temperature, while the response variables measured were oil yield, fines content in oil and oil quality (acidity, peroxide index, K232, K270, values, antioxidant activity and total tocopherol content). Since chemical quality data of chia seeds oil pressed at different conditions was not affected, the response was optimize to maximize oil yield. The results suggested that 0.113 g/g dry solids (0.101 g/g seed), 6 mm restriction die, 20 rpm screw press speed and 30 °C barrel temperature were the best processing combination to maximize oil yield. 相似文献
82.
Viviane?L.?Pardo Cássia?A.?M.?Fagundes Sergiane?S.?Caldas Márcia?H.?Kurz Rosilene?M.?Clementin Marcelo?G.?M.?D’Oca Ednei?G.?PrimelEmail author 《Journal of the American Oil Chemists' Society》2012,89(4):631-637
The aim of this study was to develop and validate a method for the analysis of fatty acid methyl ester (FAMEs) content in
tung biodiesel and blends with soybean biodiesel. The limits of detection (LOD) and quantification (LOQ), linearity, robustness,
accuracy and precision were evaluated by using gas chromatography with mass spectrometry detection and impact electron ionization.
The analytical curves showed correlation coefficients values higher than 0.99. The LOD and LOQ were 0.78 and 2.5 mg L−1 for all FAMEs, respectively. The values of accuracy were between 86 and 117%, with relative standard deviation lower than
8%. The method was applied to tung biodiesel and tung and soybean biodiesel blends in the following proportions: 15:85, 20:80,
25:75 (%v/v). All of them showed good performance. Since the method was also applied to soybean biodiesel, the efficiency
of the method for the analysis of both pure tung biodiesel and blends with different raw materials was confirmed and the robustness
of the method was evidenced. 相似文献
83.
Fernanda Montenegro Barbosa Camila Valdejane Silva de Souza Ellane Sabryna Ribeiro Paulo Roberto Medeiros de Azevedo Karla Suzanne Florentino da Silva Chaves Damasceno Larissa Mont'Alverne Juc Seabra 《Journal of Food Safety》2021,41(1):e12869
The aim of the study was to evaluate the overall hygienic–sanitary conditions of university hospitals foodservices and assess food safety knowledge and self‐reported practices of food handlers. A self‐administered questionnaire based on sanitary standards for foodservices was given to 123 food handlers from three public hospitals. Microbiological analysis of food handling surfaces and food hygiene inspections were also performed. Food handlers' self‐reported knowledge and practices reached satisfactory levels (77.2% and 78.1%, respectively), and showed a significant positive intercorrelation (p < .05). Food hygiene inspections in the hospitals foodservices presented a 60.9% average of adequacy and microbiological analysis results showed that 66.7% of the evaluated surfaces presented significant contamination by mesophilic bacteria. The presence of coliforms at 45°C above the safety limit was identified in 47.9% of the surfaces. The results showed a need for motivating hospital food handlers to practice the safe handling knowledge that they have demonstrated in theory. 相似文献
84.
Wender H Feil AF Diaz LB Ribeiro CS Machado GJ Migowski P Weibel DE Dupont J Teixeira SR 《ACS applied materials & interfaces》2011,3(4):1359-1365
Self-organized TiO(2) nanotube (NT) arrays were produced by anodization in ethylene glycol (EG) electrolytes containing 1-n-butyl-3-methyl-imidazolium tetrafluoroborate (BMI.BF(4)) ionic liquid and water. The morphology of the as-formed NTs was considerably affected by changing the anodization time, voltage, and water and ionic liquid electrolyte concentrations. In general, a nanoporous layer was formed on the top surface of the TiO(2) NTs, except for anodization at 100 V with 1 vol % of BMI.BF(4), where the NT's mouth was revealed. The length and bottom diameter of the NTs as well as the pore diameter of the top layer showed a linear relationship with increased anodization voltage. These TiO(2) NTs were tested as photocatalysts for methyl orange photodegradation and hydrogen evolution from water/methanol solutions by UV light irradiation. The results show that the TiO(2) NTs obtained by anodization in EG/H(2)O/BMI.BF(4) electrolytes are active and efficient for both applications. 相似文献
85.
Inhibitory action of aqueous coffee ground extracts on the corrosion of carbon steel in HCl solution 总被引:1,自引:0,他引:1
Vanessa Vasconcelos Torres Roberto Salgado Amado Camila Faia de Sá Tatiana Lopez Fernandez Carlos Alberto da Silva Riehl Alexandre Guedes Torres Eliane D’Elia 《Corrosion Science》2011,(7):2385-2392
The effects of aqueous extracts of spent coffee grounds on the corrosion of carbon steel in a 1 mol L−1 HCl were examined. Two methods of extraction were studied: decoction and infusion. The inhibition efficiency of C-steel in 1 mol L−1 HCl increased as the extract concentration and temperature increased. The coffee extracts acted as a mixed-type inhibitor with predominant cathodic effectiveness. In this study, the adsorption process of components of spent coffee grounds extracts obeyed the Langmuir adsorption isotherm. The chlorogenic acids isolated do not seem to explain the corrosion inhibition observed during the use of the coffee extracts. 相似文献
86.
Park JH Dias CA Lee SB Valentini SR Sokabe M Fraser CS Park MH 《Protein engineering, design & selection : PEDS》2011,24(3):301-309
Eukaryotic translation initiation factor 5A (eIF5A) is the only cellular protein that contains the polyamine-modified lysine, hypusine [N(ε)-(4-amino-2-hydroxybutyl)lysine]. Hypusine occurs only in eukaryotes and certain archaea, but not in eubacteria. It is formed post-translationally by two consecutive enzymatic reactions catalyzed by deoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase (DOHH). Hypusine modification is essential for the activity of eIF5A and for eukaryotic cell proliferation. eIF5A binds to the ribosome and stimulates translation in a hypusine-dependent manner, but its mode of action in translation is not well understood. Since quantities of highly pure hypusine-modified eIF5A is desired for structural studies as well as for determination of its binding sites on the ribosome, we have used a polycistronic vector, pST39, to express eIF5A alone, or to co-express human eIF5A-1 with DHS or with both DHS and DOHH in Escherichia coli cells, to engineer recombinant proteins, unmodified eIF5A, deoxyhypusine- or hypusine-modified eIF5A. We have accomplished production of three different forms of recombinant eIF5A in high quantity and purity. The recombinant hypusine-modified eIF5A was as active in methionyl-puromycin synthesis as the native, eIF5A (hypusine form) purified from mammalian tissue. The recombinant eIF5A proteins will be useful tools in future structure/function and the mechanism studies in translation. 相似文献
87.
The globalization of the wine industry needs to be perceived as a challenge and an opportunity to innovate by traditional European producers’ countries, like Portugal, characterized by a terroir model, that is, an economic structure supported by a large number of grape growers, small and medium wine firms and high public regulation, to compete in international markets. Using a cluster approach, this article presents the case of the most important Portuguese wine region, the Demarcated Douro Region (DDR), which is a strong reference of terroir and known for producing Port wine. To increase its competitiveness in the world wine market, the DDR needs to evolve from an organized to an innovative cluster. 相似文献
88.
Maria Graças Andrade Korn Mauro Agildo Barbosa Guida José Tiago Pereira Barbosa Ednildo Andrade Torres Andréa Pires Fernandes Josué Carinhanha Caldas Santos Kelly das Graças Fernandes Dantas Joaquim Araújo Nóbrega 《Food Analytical Methods》2013,6(3):872-880
Propolis is a complex mixture of substances collected by honeybees from buds or exudates of plants, beeswax, and other constituents, as pollen and sugars. The main purpose of this study was to evaluate two digestion procedures for determination of major, minor, and trace elements (Ba, Ca, Cd, Cr, Co, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, and Zn) in natura propolis samples by inductively coupled plasma optical emission spectrometry (ICP OES). The first procedure studied was an open-vessel digestion using HNO3 + H2SO4 + H2O2 in a heating block and the second one was a microwave-assisted concentrated acid digestion using HNO3 + H2O2. Both digestion procedures led to similar results and quantitative recoveries. The residual carbon contents (RCCs) for propolis sample digests were 0.269?±?0.012 % when using the first procedure with conventional heating and 0.458?±?0.023 % by microwave-assisted closed vessel digestion, demonstrating high efficiency of both procedures. Accuracy of the results was demonstrated using a certified reference material and by comparison with a recommended official method. The t test (unpaired) at 95 % confidence level showed that there was no significant difference between determined and certified values of all analytes under investigation, except Ca concentration employing conventional procedure. The optimized microwave-assisted digestion procedure led to recoveries around 89–103 % and precision better than 5 % for most samples. The second procedure was faster, safer, and more accurate than the one based on conductive heating. Additionally, principal component analysis (PCA) was applied for checking if there was correlation between inorganic composition and source of propolis samples collected around Bahia State in the Northeast of Brazil. 相似文献
89.
Demétrius Paiva Arçari Juliana Carvalho Santos Alessandra Gambero Lucio Fábio Caldas Ferraz Marcelo Lima Ribeiro 《Molecular nutrition & food research》2013,57(10):1882-1885
The aim of this study was to evaluate the effects of yerba maté (YM) extract on the phosphatidylinositol 3‐kinase (PI3K)‐AKT signaling pathway in vivo. The mice were introduced to either standard‐ or high‐fat diet (HFD). After 8 weeks on an HFD, mice were randomly assigned to one of the two treatment conditions, water or yerba maté extract at 1.0 g/kg. After treatment, glucose blood level and hepatic insulin response were evaluated. Liver tissue was examined to determine the mRNA levels using the PI3K‐AKT PCR array. The nuclear translocation of forkhead box O1 (FOXO1) was determined by an electrophoretic mobility‐shift assay. Our data demonstrated that yerba maté extract significantly decreased the final body weight, glucose blood levels, and insulin resistance of mice. Molecular analysis demonstrated that an HFD downregulated Akt2, Irs1, Irs2, Pi3kca, Pi3kcg, and Pdk1; after yerba maté treatment, the levels of those genes returned to baseline. In addition, an HFD upregulated Pepck and G6pc and increased FOXO1 nuclear translocation. The intervention downregulated these genes by decreasing FOXO1 nuclear translocation. The results obtained demonstrate for the first time the specific action of yerba maté on the PI3K‐AKT pathway, which contributed to the observed improvement in hepatic insulin signaling. 相似文献
90.