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991.
Luciano Hocevar Vitória R. B. Soares Fábio S. Oliveira Maria Graças A. Korn Leonardo S. G. Teixeira 《Journal of the American Oil Chemists' Society》2012,89(5):781-786
Mid-infrared spectroscopy, in association with multivariate chemometric techniques, was employed for pattern recognition and
the determination of the composition of waste frying oils (WFO); data are presented in terms of the percentage of soybean
oil, palm oil and hydrogenated vegetable fat in frying oil blends. Principal component analysis (PCA) was performed using
spectral data (3,000–600 cm−1) to discriminate between the samples containing 100% soybean oil, 100% palm oil, 100% hydrogenated vegetable fat groups and
their blends. Additionally, the results indicated that partial least squares (PLS) models based on mid-infrared spectra were
suitable as practical analytical methods for predicting the oil contents in WFO blends. PLS models were validated by a representative
prediction set, and the root mean square errors of prediction (RMSEP) were 2.8, 4.7 and 5.5% for palm oil, soybean oil and
hydrogenated vegetable fat, respectively. The proposed methodology can be very useful for the rapid and low cost determination
of waste frying oil composition while also aiding in decisions regarding the management of oil pretreatment and production
routes for biodiesel production. 相似文献
992.
Santos MP França SA Santos JT Buzelle SL Bertolini GL Garófalo MA Kettelhut IC Frasson D Chaves VE Kawashita NH 《Lipids》2012,47(3):279-289
A low-protein, high-carbohydrate (LPHC) diet for 15 days increased the lipid content in the carcass and adipose tissues of
rats. The aim of this work was to investigate the mechanisms of this lipid increase in the retroperitoneal white adipose tissue
(RWAT) of these animals. The LPHC diet induced an approximately two- and tenfold increase in serum corticosterone and TNF-α,
respectively. The rate of de novo fatty acid (FA) synthesis in vivo was reduced (50%) in LPHC rats, and the lipoprotein lipase
activity increased (100%). In addition, glycerokinase activity increased (60%), and the phosphoenolpyruvate carboxykinase
content decreased (27%). Basal [U-14C]-glucose incorporation into glycerol-triacylglycerol did not differ between the groups; however, in the presence of insulin,
[U-14C]-glucose incorporation increased by 124% in adipocytes from only control rats. The reductions in IRS1 and AKT content as
well as AKT phosphorylation in the RWAT from LPHC rats and the absence of an insulin response suggest that these adipocytes
have reduced insulin sensitivity. The increase in NE turnover by 45% and the lack of a lipolytic response to NE in adipocytes
from LPHC rats imply catecholamine resistance. The data reveal that the increase in fat storage in the RWAT of LPHC rats results
from an increase in FA uptake from circulating lipoproteins and glycerol phosphorylation, which is accompanied by an impaired
lipolysis that is activated by NE. 相似文献
993.
The objective of this work was to promote the formation of the aragonite polymorph of calcium carbonate, which has some valuable applications in industry, via the mineral carbonation route. The combination of ultrasound with magnesium ions promoted the formation of pure aragonite crystals at optimum conditions. It was possible to synthesize high purity aragonite precipitates at temperatures ranging from 24 °C to 70 °C, with the resulting powders possessing varying particle size distributions (from sub-micron up to 20 μm) and crystal morphologies (from acicular needles to novel hubbard squash-like particles). Several process parameters were found to influence the produced calcium carbonate polymorph ratios (aragonite over calcite). Higher values of magnesium-to-calcium ratio, intermediate ultrasound amplitude (60%), continuous ultrasound application (100% cycle), introduction of ultrasound pre-breakage, lowering of the CO2 flow rate, and increase in the relative concentration (g/L Ca(OH)2), all promoted aragonite formation. A potential route for industrial production of this material has been identified via a fed-batch process, which effectively reutilizes magnesium chloride while maintaining high aragonite yield. The results presented herein are significantly superior to aragonite formation using only single promoting techniques, typically found in literature, and go beyond by focusing on pure (>99%) aragonite formation. 相似文献
994.
A new and expeditious automated procedure for the determination of ethanol content in alcoholic beverages (distilled liquors and wine) by using a single interface flow analysis (SIFA) system with spectrophotometric detection is presented. The developed approach was simply based on refractive index gradient measurements, known as Schlieren effect, produced when acidified beverages samples were introduced in a single-line SIFA system that used deionized water as carrier (trailing) stream and a computer-controlled spectrophotometer as detector. In the implemented SIFA system, no chromogenic reagent is used, being the refractive index gradient a consequence of the mutual interdispersion of sample and carrier zones at the formed single interface, and no predefined volumes of both sample and carrier are required, which greatly simplifies system operation and optimization. The proposed methodology allowed the determination of ethanol concentrations between 4% and 24% (v/v) with good precision (RSD < 5.2%, n = 3) and a sampling frequency of about 58 h−1 with consumption of 400 μl of sulfuric acid 0.5 mol l−1 and 400 μl of sample per measurement. The developed procedure was applied to whisky, gin, rum, vodka, the sugar cane-based beverage “cacha?a,” and white wine, and the obtained results were in a good agreement with those provided by the reference method (RD < 5.0%). Recovery values acquired in the analysis of spiked ethanol samples (between 90.0% and 111.0% of the added amount) were also satisfactory. 相似文献
995.
Alberto Angioni Luciano Porcu Marco Secci Pierantonio Addis 《Food Analytical Methods》2012,5(5):1131-1136
Sea urchin roe (Paracentrotus lividus) is an excellent biomarker, and it has been used as a test for toxicology study of chemical pollution of restricted marine
areas; in fact, unlike mussels which filter water, it feeds mainly on micro- and macroalgae. Therefore, it is not influenced
by the sea tide and meets better the situation of local pollution. A modified Quick Easy Cheap Effective Rugged Safe extraction
method coupled with gas chromatography ion trap mass spectrometry analysis has been used to set up a method for the determination
of 17 polycyclic aromatic hydrocarbons (PAHs) in P. lividus sea urchin roe. A method validation was performed, and the following parameters have been determined: instrument limit of
detection (LOD) and of quantification (LOQ), precision, recovery, and linearity. The method carried out showed good LOD under
1.5 μg/kg and LOQ under 5 μg/kg for all PAHs studied, and these values were in close agreement with quality criteria described
in the Commission Regulation (EC) no. 333/2007 concerning the PAH benzo[a]pyrene in foodstuffs. Precision and linearity were in accordance with EC SANCO/10684/2009 values. For all PAHs, recoveries
ranged from 72% to 119%, with RSD ranging from 3% to 17% in the most unfavorable case. 相似文献
996.
Zinc Oxide Nanoparticles: Synthesis,Antimicrobial Activity and Food Packaging Applications 总被引:2,自引:0,他引:2
Paula Judith Perez Espitia Nilda de Fátima Ferreira Soares Jane Sélia dos Reis Coimbra Nélio José de Andrade Renato Souza Cruz Eber Antonio Alves Medeiros 《Food and Bioprocess Technology》2012,5(5):1447-1464
Zinc oxide (ZnO) is an inorganic compound widely used in everyday applications. ZnO is currently listed as a generally recognized
as safe (GRAS) material by the Food and Drug Administration and is used as food additive. The advent of nanotechnology has
led the development of materials with new properties for use as antimicrobial agents. Thus, ZnO in nanoscale has shown antimicrobial
properties and potential applications in food preservation. ZnO nanoparticles have been incorporated in polymeric matrices
in order to provide antimicrobial activity to the packaging material and improve packaging properties. This review presents
the main synthesis methods of ZnO nanoparticles, principal characteristics and mechanisms of antimicrobial action as well
as the effect of their incorporation in polymeric matrices. Safety issues such as exposure routes and migration studies are
also discussed. 相似文献
997.
Cunha AL Silva PF Souza EA Júnior JR Santos FA Vargas EA 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2012,29(4):571-576
The increasing use of antimicrobial agents such as sulfonamides by the pig industry is of concern, since residues in both pork and its by-products, when derived from animals treated improperly, can endanger human health. The aim of this study was to establish the production conditions and to evaluate the homogeneity and the stability of sulfamethazine in porcine liver quality control material, produced 'in-house' for use in ring tests of the laboratory network of residues and contaminants of the Ministry of Agriculture, Livestock and Food Supply, Brazil. In the process of preparing the material, a FOSS blender was used, where the samples were ground to obtain a homogeneous mass, which was packed in polypropylene bottles. The material resulting from this process of homogenisation was sampled and analysed by LC/MS/MS. The analytical results were statistically evaluated by one-way ANOVA. According to statistical evaluation, the material produced was considered homogeneous, with 95% confidence. Stability tests were performed with the bottles stored under the specified storage conditions. They were randomly selected and analysed in duplicate by the same analytical method as the homogeneity study. The analytical results were statistically evaluated by the procedures for a stability check described in ISO 13528:2005, indicating that the material was unstable under the conditions of storage. 相似文献
998.
Gasperin BG Ferreira R Rovani MT Santos JT Buratini J Price CA Gonçalves PB 《Reproduction (Cambridge, England)》2012,143(6):815-823
Fibroblast growth factors (FGFs) are involved in paracrine control of follicle development. It was previously demonstrated that FGF10 decreases estradiol (E(2)) secretion in granulosa cell culture and that theca cell FGF10 mRNA expression is decreased in healthy follicles from abattoir ovaries. The main objectives of this study were to evaluate FGF10 and FGFR2b mRNA expression during follicular development in vivo, to evaluate the effect of FGF10 on follicle growth using Bos taurus taurus cows as a model, and to gain more insight into the mechanisms through which FGF10 inhibits steroidogenesis. Messenger RNA encoding both FGF10 and FGFR2b (main FGF10 receptor) was significantly more expressed in subordinate follicles (SFs) than in dominant follicles (DFs). The intrafollicular injection of FGF10 into the largest growing follicle at 7-8?mm in diameter interrupted the DF growth in a dose-dependent manner (11±0.4, 8.3±1 and 5.9±0.3?mm for 0, 0.1, and 1?μg/ml FGF10, respectively, at 72?h after treatment; P<0.05). In a third experiment, follicles were obtained 24?h after FGF10 (1?μg/ml) or PBS treatment through ovariectomy. In theca cells, FGF10 treatment did not affect mRNA encoding steroidogenic enzymes, LHCGR and IGFBPs, but significantly upregulated FGF10 mRNA expression. The expression of CYP19A1 mRNA in granulosa cells was downregulated by FGF10 treatment, which was accompanied by a 50-fold decrease in E(2) production, and decreased cyclin D2 mRNA. These results have shown that FGF10 and its receptor FGFR2b are more expressed in SFs and provide solid in vivo evidence that FGF10 acts as an important regulator of follicular growth in cattle. 相似文献
999.
J. C. Vazquez V. Champac A. M. ZiesemerJr. R. Reis I. C. Teixeira M. B. Santos J. P. Teixeira 《Analog Integrated Circuits and Signal Processing》2012,70(2):249-263
The impact of parametric variations on digital circuit performance is increasing in nanometer Integrated Circuits (IC), namely
of Process, power supply Voltage and Temperature (PVT) variations. Moreover, circuit aging also impacts circuit performance,
especially due to Negative Bias Temperature Instability (NBTI) effect. A growing number of physical defects manifest themselves
as delay faults (at production, or during product lifetime). On-chip, on-line delay monitoring, as a circuit failure prediction
technique, can be an attractive solution to guarantee correct operation in safety–critical applications. Safe operation can
be monitored, by predictive delay fault detection. A delay monitoring methodology and a novel delay sensor (to be selectively
inserted in key locations in the design and to be activated according to user’s requirements) is proposed, and a 65 nm design
is presented. The proposed sensor is programmable, allowing delay monitoring for a wide range of delay values, and has been
optimized to exhibit low sensitivity to PVT and aging-induced variations. Two MOSFET models—BPTM and ST—have been used. As
abnormal delays can be monitored, regardless of their origin, both parametric variations and physical defects impact on circuit
performance can be identified. Simulation results show that the sensor is effective in identifying such abnormal delays, due
to NBTI-induced aging and to resistive open defects. 相似文献
1000.
Effect of Different Thawing Conditions on the Concentration of Bioactive Substances in Broccoli (Brassica oleracea var. Avenger)
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