Modified CUPRAC spectrophotometric quantification of total polyphenol content in beer samples using Cu(II)/neocuproine complexes

Cu(II)/neocuproine (2,9-dimethyl-1,10-phenanthroline) complexes were utilized for spectrophotometric determination of total polyphenol content in beers. This procedure is based on the reduction of Cu(II) by polyphenols in hydroethanolic medium (pH 7.0) in the presence of neocuproine, yielding Cu(I)/complexes with maximum absorption at 454 nm. The sensitivity of the proposed method was compared with the AOAC method using tannic and gallic acid as standards. The average apparent molar absorptivity, in L cm(-1) mol(-1), of tannic acid (3.50 +/- 0.20) x 10(5) and gallic acid (5.12 +/- 0.21) x 10(4), was twice as high for the proposed method. A lower limit of detection (LOD) (2.9 x 10(-1) mg L-1) was found when tannic acid was used in the proposed method. Additionally, less interference from the most common additives in beers was noticed. Total content of polyphenols was analyzed in 17 Brazilian samples. Results ranged from 35.5 to 556 mg L-1 of tannic acid, with higher values for recovery rates (45.4-118%, mean 85.0%) than for gallic acid. Although tannic acid is a mixture of polygalloyl glucoses, the total polyphenol content found in the samples suggests that tannic acid should be used as a standard. This is the first attempt to use this particular copper complex to quantify total polyphenol content in beer samples. (C) 2012 Elsevier Inc. All rights reserved.

Evaluation and measurement of chromium in sea water in order to remove it with mineral absorbent kaolin for desalination

Today, the use of heavy metals and chemical products industry expanded. The presence of significant amounts of, pollutants in industrial waste water can lead to serious risks to the environment and human health have heavy metals like chromium is one example of the future of salmon knock pond environment. Chromium is an essential element in the diet, but high doses of this element is very dangerous. Hence the use of chemical methods as a tool for the removal of metals from waste water pond be used. The aim of this study was to investigate the mineral kaolin adsorbents for the removal of chromium is water. Thus, the effect of different concentrations of absorbent micro amounts of chromium absorption and variable temperature, pH and electrolytes were studied. During the investigation of spectroscopic instrument (Varian) UV-VIS are used. Comparison of the absorption mechanism of chromium adsorption by the adsorbent with nano-absorbent kaolin kaolin was investigated. According to the studies done in the same conditions of temperature, pH and shaking rate of chromium absorption by nano kaolin kaolin is much more attractive. Therefore, its use as an adsorbent abundant, cheap, accessible, efficient and effective is proposed.

Estudio preliminar sobre la determinación de elementos traza en cervezas venezolanas por ICP-OES

The levels of several chemical elements were determined simultaneously in ten different beers of the Venezuelan market by ICP-OES. With the exception of chromium, beer does not provide important amounts of nutritional oligoelements. The average chromium content found (33 µg/L) is higher than one reported for USA's beer (10 µg/L) but smaller than another reported for Brazilian beer (66 µg/L). The average percentage of chromium RDA by beer consumption found for Venezuela (6.3%) is similar to that reported for Belgium (5%). Regarding toxic elements, one of the samples contained an elevated amount of aluminium, probably dissolved from the aluminium can.

Proteins influencing foam formation in wine and beer: the role of yeast

This review focuses on the role of proteins in the production and maintenance of foam in both sparkling wines and beer. The quality of the foam in beer but especially in sparkling wines depends, among other factors, on the presence of mannoproteins released from the yeast cell walls during autolysis. These proteins are hydrophobic, highly glycosylated, and their molecular masses range from 10 to 200 kDa characteristics that allow mannoproteins to surround and thus stabilize the gas bubbles of the foam. Both the production and stabilization of foam also depend on other proteins. In wine, these include grape-derived proteins such as vacuolar invertase; in beer, barley-derived proteins, such as LTP1, protein Z, and hordein-derived polypeptides, are even more important in this respect than mannoproteins

Chromium mass balance in sodium chlorate process

Kuudenarvoista kromia käytetään natriumkloraatin valmistuksessa prosessin tuotantotehokkuuden ja turvallisuuden parantamiseksi. Kromia kuitenkin poistuu prosessista muutamaa reittiä pitkin. Koska kuuudenarvoisella kromilla on syöpää aiheuttavia, mutageenisiä sekä lisääntymiselle myrkyllisiä ominaisuuksia, olisi tärkeää ymmärtää, miten kromi kulkeutuu prosessin eri osiin, ja kuinka paljon sitä poistuu prosessista. Tämä on tärkeää, jotta osataan hallita kromin käytöstä aiheutuvat riskit, sekä toisaalta myös tehostaa kromin käyttöä prosessissa. Työn tarkoituksena oli tuottaa tietoa kromin käytöstä natriumkloraattiprosessissa. Työssä tutkittiin kromitasetta prosessin keskeisimmissä yksikköoperaatioissa. Myös kromin saostumista katodien pinnalle arvioitiin määrällisesti. Eri prosessinäytteistä tutkittiin lisäksi kromin hapetusasteita. Edellä mainittuja tutkimuskohteita varten määritettiin prosessinäytteiden kromipitoisuus. Eri prosessioperaatioille suoritettiin lisäksi taselaskelmat. Työn tuloksena esitettiin kromitase sekä yksikköoperaatioille että koko prosessille. Erinäisten epätarkkuustekijöiden vuoksi tasetta ei kuitenkaan pystytty määrittämään halutulla tarkkuudella, ja siksi työssä esitettyä tasetta voidaan pitää vain suuntaa antavana laskelmana. Katodien pinnalle saostunutta kromin määrää pidettiin kuitenkin oikean suuruusluokan tuloksena. Prosessinäytteiden hapetusasteita ei voitu arvioida, sillä saadut kokonaiskromitulokset eivät olleet täysin luotettavia. Huolimatta tulosten epätarkkuudesta, työ tuotti tärkeää tietoa prosessin toiminnasta kromin suhteen. Työtä voidaan hyödyntää jatkossa monin tavoin prosessin kromitaseen seurannassa.

Assessment of chromium contamination in the Monte Alegre stream: a case study

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

Paper electrophoretic studies of radioactive chromium salts in blood /

"Published with the approval of the Director of the University of Tennessee Agricultural Experiment Station."--Page iii.

In situ transmission electron microscopy ion irradiations of model iron-chromium alloys

Iron-chromium alloys are used as a model to study the microstructural evolution of defects in irradiated structural steel components of a nuclear reactor. We examine the effects of temperature and chromium concentration on the defect evolution and segregation behavior in the early stages of damage. In situ irradiations are conducted in a transmission electron microscope (TEM) at 300°C and 450°C with 150keV iron ions in single crystal Fe14Cr and Fe19Cr bicrystal to doses of 2E15 ions/cm^2. The microstructures resulting from annealing and irradiation of the alloy are characterized by analysis of TEM micrographs and diffraction patterns and compared with those of irradiated pure iron. We found the irradiation temperature to have little effect on the microstructural development. We also found that the presence of chromium in the sample leads to defect populations with small average loop size and no extended or nested loop structures, in contrast to the populations of large extended loops seen in irradiated pure iron. A very weak dependence was found on the specific chromium content of the alloy. Chromium was shown to suppress defect growth by inhibiting defect mobility in the alloy. While defects in pure iron are highly mobile and able to grow, those in the FeCr alloys remained small and relatively motionless due to the pinning effect of the chromium.

Nephrotoxicity effects of the wood preservative chromium copper arsenate on mice: histopathological and quantitative approaches

Chromium copper arsenate(CCA)was used for the protection of wood building material suntil the restriction by EPA in2002. During a short period of time 14–24h,a comparative nephrotoxicity study was performed regarding the effects of CCA and its compounds per se. Histopathological and histochemical features were correlated with the concentration of the total arsenic and chromium in mice kidney. Animals were subcutaneously injected with CCA(7.2mg/kg arsenic and 10.2mg/kg chromium per body weight), CrO3 (10.2 mg/kg),As2O5 (7.2 mg/kg)andNaCl(0.9%) per se. The histopathological examination of the renal sections evidenced acute tubular necrosis in the groups of animals exposed to CCA(in both periods of time). Although the same contents of pentavalent arsenic and hexavalent chromium were injected in treated animals with CCA and with the prepared solutions of As2O5 and CrO3, the arsenic concentration on kidneys of CCA-exposed animals was much higher than those in animals exposed to As2O5 (32- and28-fold higher at 14 and 24h,respectively). However,the elimination of chromium seems to occur similarly in the kidneys of animals treated with CCA and CrO3 per se. Interactions among the components of CCA result in a marked decrease of the ability of kidney to eliminate simultaneously both analytes.The nephrotoxicity of CCA was higher than its components per se, evidencing a possible synergetic effect.

Trends in self-reported past alcoholic beverage consumption and ethanol intake from 1950 to 1995 observed in eight European countries participating in the European Investigation into Cancer and Nutrition (EPIC).

OBJECTIVE To describe the trends of self-reported past consumption of alcoholic beverages and ethanol intake from 1950 to 1995 within the European Prospective Investigation into Cancer and Nutrition (EPIC). DESIGN Data on consumption of beer/cider, wine and liqueur/spirits were obtained retrospectively at age 20, 30 and 40 years to calculate average consumption and ethanol intake for the time periods 1950-1975 (at age 20), 1960-1985 (at age 30) and 1970-1995 (at age 40). Regression analysis was conducted with the time period data to assess trends in past alcoholic beverage consumption and ethanol intake with time. SETTING The EPIC project. SUBJECTS In total, 392 064 EPIC participants (275 249 women and 116 815 men) from 21 study centres in eight European countries. RESULTS Generally, increases in beer/cider consumption were observed for most EPIC centres for 1950-1975, 1960-1985 and 1970-1995. Trends in wine consumption differed according to geographical location: downward trends with time were observed for men in southern European EPIC centres, upward trends for those in middle/northern European study centres. For women, similar but less pronounced trends were observed. Because wine consumption was the major contributor to ethanol intake for both men and women in most study centres, time trends for ethanol intake showed a similar geographical pattern to that of wine consumption. CONCLUSION The different trends in alcoholic beverage consumption and ethanol intake suggest that information depicting lifetime history of ethanol intake should be included in analyses of the relationship between ethanol and chronic diseases, particularly in multi-centre studies such as EPIC.

The role of potassium in the corrosion of superheater materials in boilers firing biomass

Inhibition of global warming has become one of the major goals for the coming decades. A key strategy is to replace fossil fuels with more sustainable fuels, which has generated growing interest in the use of waste-derived fuels and of biomass fuels. However, from the chemical point of view, biomass is an inhomogeneous fuel, usually with a high concentration of water and considerable amounts of potassium and chlorine, all of which are known to affect the durability of superheater tubes. To slow down or reduce corrosion, power plants using biomass as fuel have been forced to operate at lower steam temperatures as compared to fossil fuel power plants. This reduces power production efficiency: every 10°C rise in the steam temperature results in an approximate increase of 2% in power production efficiency. More efficient ways to prevent corrosion are needed so that power plants using biomass and waste-derived fuels can operate at higher steam temperatures. The aim of this work was to shed more light on the alkali-induced corrosion of superheater steels at elevated temperatures, focusing on potassium chloride, the alkali salt most frequently encountered in biomass combustion, and on potassium carbonate, another potassium salt occasionally found in fly ash. The mechanisms of the reactions between various corrosive compounds and steels were investigated. Based on the results, the potassium-induced accelerated oxidation of chromia protected steels appears to occur in two consecutive stages. In the first, the protective chromium oxide layer is destroyed through a reaction with potassium leading to the formation of intermediates such as potassium chromate (K2CrO4) and depleting the chromium in the protective oxide layer. As the chromium is depleted, chromium from the bulk steel diffuses into the oxide layer to replenish it. In this stage, the ability of the material to withstand corrosion depends on the chromium content (which affects how long it takes the chromium in the oxide layer to be depleted) and on external factors such as temperature (which affects how fast the chromium diffuses into the protective oxide from the bulk steel). For accelerated oxidation to continue, the presence of chloride appears to be essential.

(E)-2-Nonenal determination in brazilian beers using headspace solid-phase microextraction and gas chromatographic coupled mass spectrometry (HS-SPME-GC-MS)

(E)-2-nonenal is considered an important off-flavor of beer, related to the flavor of beer staling. In this study, a new method for determination of (E)-2-nonenal in beer using headspace solid-phase microextraction and gas chromatographic coupled mass spectrometry (HS-SPME-GC-MS) was developed and applied in Brazilian beer samples. The extractions were carried out in CAR-PDMS (carboxen-polydimethylsiloxane) fiber and the best results were found with 15 minutes of equilibrium and 90 minutes of extraction at 50 °C. The method was linear in the range from 0.02 to 4.0 μg.L-1 with correlation coefficient of 0.9994. The limits of detection and quantification were 0.01 and 0.02 μg.L-1, respectively. 96.5% of recovery and 4% precision (RSD) were obtained in the fortification of beer samples with 2.0 μg.L-1 of (E)-2-nonenal. The developed method proved to be simple, efficient and highly sensitive to the determination of this analyte being easily applied in the quality control of the brewery. (E)-2-nonenal was found in all beer samples analyzed with levels between 0.17 and 0.42 μg.L-1.

A comparison of the anticancer properties of isoxanthohumol and 8-prenylnaringenin using in vitro models of colon cancer

The hops plant (Humulus lupulus L.) is an essential ingredient in beer and contains a number of potentially bioactive prenylflavonoids, the predominant being the weakly estrogenic isoxanthohumol (Ix), which can be converted to the more strongly estrogenic 8-PN by the colonic microbiota. The aim of this study was to investigate the biological activity of 8-PN and Ix using in vitro models representing key stages of colorectal carcinogenesis, namely cell growth and viability (MTT assay), cell-cycle progression (DNA content assay), DNA damage (Comet assay), and invasion (Matrigel assay). A significant decrease in Caco-2 cell viability was noted after both 8-PN and Ix treatments at the higher doses (40 and 50 μM, respectively) although the impact on cell cycle differed between the two compounds. The decreased cell viability observed after Ix treatment was associated with a concentration-dependent increase in G2/M and an increased sub-G1 cell-cycle fraction, whereas treatment with 8-PN was associated with an elevated G0/G1 and an increased sub-G1 cell-cycle fraction. Significant antigenotoxic activity was noted at all 8-PN concentrations tested (5-40 μM). Although significant antigenotoxic activity was also noted with Ix treatment at ≤25 μM, at a higher dose, Ix itself exerted genotoxic activity. In a dose-dependent manner, both compounds inhibited HT115 cell invasion with reductions up to 52 and 46% for Ix and 8-PN, respectively, in comparison to untreated cells. This study demonstrated that both Ix and its gut microbial metabolite 8-PN exert anticancer effects on models of key stages of colon tumourigenesis.