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The influence of beer with different antioxidant potential on plasma lipids, plasma antioxidant capacity, and bile excretion of rats fed cholesterol-containing and cholesterol-free diets.

The aim of this investigation was to assess the influence of beers with different antioxidant potentials on plasma lipid metabolism, plasma antioxidant capacity, and bile excretion of rats fed cholesterol-containing and cholesterol-free diets. Four types of beers were investigated in vitro. Two of them (designated as BeerHigh and BeerLow) with the highest and lowest antioxidant potentials (34.5% and 21.4% and 2.07 mmol/L and 1.65 mmol/L according to beta-carotene assay and Trolox equivalent antioxidant coefficient, respectively), were chosen for the experiment on rats. A total of 60 male Wistar rats were divided into 6 dietary groups of 10 rats each; the groups were designated as Control, BeerA, BeerB, Chol, Chol/BeerA, and Chol/BeerB. The rats in the Control group were fed a basal diet (BD) only, which included wheat starch, casein, soybean oil, vitamin, and mineral mixtures. To the BD of the other five groups were added the following: BeerHigh (BeerA), BeerLow (BeerB), 1% of cholesterol (Chol), 1% of cholesterol and BeerHigh (Chol/BeerA), and 1% of cholesterol and BeerLow (Chol/BeerB). After 4 weeks of feeding, diets supplemented with BeerHigh and, to a lesser degree, with BeerLow (Chol/BeerA and Chol/BeerB groups) hindered a rise in plasma lipids and a decrease in plasma antioxidant capacity, and increased the bile excretion indices. Supplementation with BeerHigh and, to a lesser degree, with BeerLow in rats fed cholesterol-free diets increased their plasma antioxidant capacity. No significant changes in the plasma lipid levels, antioxidant capacity, and bile excretion indices were observed in the Control group. In conclusion, beer was found to have a positively effect on plasma lipid profile and plasma antioxidant capacity, and to increase the bile excretion indices in rats fed cholesterol-containing diets. The degree of this positive influence is directly connected to the contents of the bioactive components and the related antioxidant potential of beer. It is suggested that to achieve the best results, beer with the highest antioxidant potential must be consumed.

Animals↗

Red wine, white wine, liquor, beer, and risk for coronary artery disease hospitalization.

International comparison data suggest that wine may be more protective against coronary artery disease than beer or liquor. There are potentially protective antioxidants in wine, especially red wine. However, prospective population studies suggest that each beverage type may reduce coronary risk. The role of alcoholic beverage choice in coronary risk remains unresolved. We performed a prospective study of coronary disease hospitalizations among 128,934 adult members of a Northern California prepaid comprehensive health care program. Alcohol data were supplied at health examinations. Using Cox proportional-hazards models with 9 covariates, analyses were performed of the roles of each major beverage type (wine, beer, and liquor) and of drinking only table wine (red, white, or both). Generally, coronary risk traits were most favorable for wine drinkers and least favorable for liquor drinkers. Among 3,931 persons hospitalized for coronary disease, total alcohol drinking was inversely related to risk in both sexes. Uncontrolled for total alcohol, each beverage type showed evidence for coronary protection, weakest for liquor and strongest for beer in men and wine in women. Controlled for total alcohol, these relations were much reduced, and lost statistical significance except for beer in men and both red and white wine (combined) in all persons. We conclude that (1) drinking ethyl alcohol apparently protects against coronary disease, and (2) there may be minor additional benefits associated with drinking both beer and wine, but not especially red wine.

Adult↗

Determination of ochratoxin A in domestic and imported beers in italy by immunoaffinity clean-up and liquid chromatography.

A method first developed to quantify ochratoxin A in wine has been applied to the analysis of domestic and imported beers in Italy. The method uses commercial immunoaffinity columns for clean-up and high-performance liquid chromatography for quantification of the toxin. Beer was degassed, then diluted with a polyethylene glycol-sodium hydrogencarbonate solution and applied to an OchraTest immunoaffinity column. Ochratoxin A was eluted from the immunoaffinity column with methanol and quantified by reversed-phase HPLC with fluorometric detector. Average recoveries of ochratoxin A from blank beer spiked at levels from 0.04 to 1.0 ng/ml ranged from 93.8% to 100.4%, with relative standard deviations between 3.3% and 5.7%. The detection limit was 0.01 ng/ml based on a signal-to-noise ratio of 3:1. The analysis of 61 samples of domestic (10) and imported (51) beers showed ochratoxin A levels ranging from <0.01 to 0.135 ng/ml with an incidence of contamination of 50% and no substantial difference between strong and pale beers.

Beer↗

Identification of isoflavonoids in beer.

The isoflavonoids, genistein (4',5,7-trihydroxyisoflavone), biochanin A (5,7-dihydroxy-4'-methoxyisoflavone), daidzein (4',7-dihydroxyisoflavone), and formononetin (7-hydroxy-4'-methoxyisoflavone) are supposed to be health-promoting dietary factors of plant origin. They are particularly abundant in seeds and other parts of many plant species belonging to Leguminosae. The most popular source of isoflavonoids in human diet is soy. Here, evidence is presented that isoflavonoids are regularly found in beer. Diethyl ether extracts of beer were fractionated on thin-layer chromatography-silica, (straight phase) and rechromatographed using a reversed phase high-performance liquid chromatography octadecylsilica column. The fractions were analyzed by two recently developed radioimmunoassays, the first of them being specific for diadzein/formononetin and the second one specific for genistein/biochanin A. The immunoreactivity was found only in fractions with the mobility corresponding to the positions of standards on control chromatograms. Additionally, 26 samples of bottled beer were analyzed for isoflavonoid content using the combination of reversed phase high-performance liquid chromatography and radioimmunoassay. The sum of the four isoflavonoids ranged from 1.26 to 29 nmol/L in individual beers. Formononetin was the major isoflavonoid (0.19-14.99 nmol/L), whereas the concentration of daidzein was several times lower (0.08-2.5 nmol/L). Genistein and biochanin A concentrations were comparable, ranging from 0.169-6.74 nmol/L and from 0.820-4.84 nmol/L for genistein and biochanin A, respectively. It is concluded that beer contains significant amounts of biologically active isoflavonoid phytoestrogens.

Beer↗

Possible neural substrates of beer-craving in rats.

Rats voluntarily consumed beer in a distinctive environment during 30 min daily sessions over 21 days, ingesting a daily average of 0.96 g/kg of ethanol. On a final test day, rats in a 'craving' condition were denied access to the beer in the drinking environment. The expression of c-fos in the brain of 'craving' rats was compared with that in rats given free access on the test day ('beer' condition), and to rats which had been repeatedly placed in the drinking environment without ever having access to beer ('control' condition). Rats in the 'craving' condition showed significantly higher c-fos counts than either the 'beer' or 'control' rats in a variety of corticolimbic and brainstem structures, indicating that activation of these regions occurs when a desirable alcoholic beverage is expected but not received.

Alcoholism↗

Beta-pseudouridine, a beer component, reduces radiation-induced chromosome aberrations in human lymphocytes.

We previously found that drinking beer reduces chromosome aberrations in blood lymphocytes that were collect and irradiated in vitro. In this study, human whole-blood was in vitro exposed to 200kVp X-rays or 50keV/microm carbon ions in the presence or absence of beer, ethanol and beta-pseudouridine (one of the beer components). All three agents reduced the chromosome aberrations (dicentric) caused by either X-rays or carbon ions of 4Gy. The maximum protection for X-rays by ethanol, beer and beta-pseudouridine was 64, 26 and 34%, respectively, while the maximum protection for carbon-ion by ethanol, beer and beta-pseudouridine was 22, 26 and 32%, respectively. It is concluded that beta-pseudouridine, a nucleoside present in tRNA, is a potent protector against damage caused by radiation with direct and indirect actions.

Antimutagenic Agents↗

Determination of estrogenic activity in beer by biological and chemical means.

It has been suspected that beer drinking may change the hormonal status of men caused by phytoestrogens. Five different Austrian lager beers have been investigated for estrogenic activity by a yeast two-plasmid system harboring the human estrogen receptor alpha, after concentration by solid phase extraction. The beer concentrate was further fractionated by reversed phase HPLC, and then the fractions were characterized by the biological assay and GC-MS. The most potent fraction did not contain a known phytoestrogen. The total activity corresponded to an average of 43 ng of 17beta-estradiol/L of beer. It was concluded that the human health hazard of beer drinking originating from compounds activity on the estrogen receptor alpha is negligible.

Austria↗

Method development and fate determination of pesticide-treated hops and their subsequent usage in the production of beer.

The fate of residues of seven agrochemicals (chlorfenapyr, quinoxyfen, tebuconazole, fenarimol, pyridaben, and E- and Z-dimethomorph) from the treatment on hops to the brewing of beer was studied. First, a multi-residue analytical method was developed for the determination of pesticide residues in spent hops, trub, wort, and beer. Each matrix was validated over at least two levels of fortification, for all seven compounds, in the ranges 0.05-5.0, 0.001-1.0, 0.001-0.05, and 0.0005-1.0 ppm for spent hops, trub, wort, and beer, respectively. Recoveries ranged from 73 to 136%. Second, the matrixes prepared from hops, which were treated under commercial practices with each compound, were analyzed using the method developed. The use of treated hops resulted in the carryover of 0.001 ppm of tebuconazole, 0.008 Z-dimethomorph, and 0.005 ppm of E-dimethomorph into the wort. The bulk of the remaining residues of all seven compounds was found on the spent hops. Following fermentation, all compounds were found in levels less than 0.0005 ppm in beer, except Z- (0.006 ppm) and E-dimethomorph (0.004 ppm). Third, when all seven pesticides were spiked prior to the pitching of yeast into clean wort, most of the nonpolar compounds (chlorfenapyr, quinoxyfen, and pyridaben) partitioned into the organic material (trub) which settled to the bottom, while the more polar compounds (fenarimol, tebuconazole, and E- and Z-dimethomorph) were generally distributed evenly between the beer and the trub.

Beer↗

Structural changes in plasma circulating fibrinogen after moderate beer consumption as determined by electrophoresis and spectroscopy.

The effects of short-term moderate beer consumption (MBC) on plasma circulating fibrinogen (PCF) in patients suffering from coronary atherosclerosis were investigated by use of 2-dimensional electrophoresis (2-DE), circular dichroism (CD), and Fourier transform infrared spectroscopy (FT-IR). Forty-eight volunteers after coronary bypass surgery were divided into experimental (EG) and control (CG) groups, each of 24. Patients of the EG group consumed 330 mL of beer/day (about 20 g of alcohol) for 30 consecutive days, and CG volunteers drank mineral water instead of beer. Blood samples were collected before and after the experiment. In 21 out of 24 patients after beer consumption the plasma circulating fibrinogen was compromised: changes in its secondary structure were found. These changes were expressed in relatively low electrophoretic mobility and charge heterogeneity, decrease in alpha-helix and increase in beta-sheet, and in slight shift of amide I and II bands. Our findings indicate that one of the positive benefits of moderate beer consumption is to diminish the production of fibrinogen and its stability, which reduces the potential risk exerted by this protein. Thus, in most of beer-consuming patients some qualitative structural changes in plasma circulating fibrinogen were detected.

Aged↗

Evolution of chemical and sensory properties during aging of top-fermented beer.

The aging and consequent changes in flavor molecules of a top-fermented beer were studied. Different aging conditions were imposed on freshly bottled beer. After 6 months of aging, the concentration changes were recorded for acetate esters, ethyl esters, carbonyls, Maillard compounds, dioxolanes, and furanic ethers. For some flavor compounds, the changes with time of storage were monitored at different temperatures, either with CO(2) or with air in the headspace of the bottles. For some molecules a relationship was determined between concentration changes and sensory evaluation results. A decrease in volatile esters was responsible for a reduced fruity flavor during aging. On the contrary, various carbonyl compounds, some ethyl esters, Maillard compounds, dioxolanes, and furanic ethers showed a marked increase, due to oxidative and nonoxidative reactions. A very high increase was found for furfural, 2-furanmethanol, and especially the furanic ether, 2-furfuryl ethyl ether (FEE). For FEE a flavor threshold in beer of 6 mug/L was determined. In the aged top-fermented beer, FEE concentrations multiple times the flavor threshold were observed. This was associated with the appearance of a typical solvent-like flavor. As the FEE concentration increased with time at an almost constant rate, with or without air in the headspace, FEE (and probably other furanic ethers) is proposed as a good candidate to evaluate the thermal stress imposed on beer.

Beer↗

Use of nitroxide spin probes and electron paramagnetic resonance for assessing reducing power of beer. role of SH groups.

Intensity of EPR spectra of stable organic free radicals, nitroxides, is decreasing with time if the radicals are dissolved in beer. The process is determined by a chemical reaction of nitroxide reduction by components naturally present in beer. Kinetics can be described as a simple irreversible first order with respect to both nitroxide and one reducing agent. Effective concentration of the reducing agent and the corresponding reaction rate constant has been determined. It is demonstrated that the nitroxide reduction is sensitive to the presence of solvent-accessible SH groups of proteins present in beer. It is proposed that quantitative analysis of reduction kinetics of small water-soluble nitroxide radicals such as TEMPO and TEMPOL can be used to assess the reducing power of beer. The effect of accelerated aging of beer achieved at elevated temperatures on nitroxide reduction kinetics is demonstrated.

Beer↗

Fumonisin mycotoxins in traditional Xhosa maize beer in South Africa.

The production and consumption of home-brewed Xhosa maize beer is a widespread traditional practice in the former Transkei region of South Africa. HPLC determination of fumonisins B1 (FB1), B2 (FB2), and B3 (FB3) in maize beer samples collected in two magisterial areas, Centane and Bizana, showed a wide range of levels. All samples were positive for FB(1), with a mean level of 281 +/- 262 ng/mL and a range from 38 to 1066 ng/mL. Total fumonisins (FB1 + FB2 + FB3) ranged from 43 to 1329 ng/mL, with a mean of 369 +/- 345 ng/mL. Data on the consumption of home-brewed beer are not available. On the basis of published data for the consumption of commercial beer in South Africa, the fumonisin exposure in these districts among the consumers of maize beer was found to be well above the provisional maximum tolerable daily intake of 2 mug/kg of body weight/day set by the Joint FAO/WHO Expert Committee on Food Additives.

Beer↗

Colorimetric sensor arrays for the analysis of beers: a feasibility study.

Eighteen commercial beers have been analyzed in both liquid and gas phases using colorimetric sensor arrays made from selected chemically responsive dyes printed on a hydrophobic membrane. Digital imaging of the dye array before and after exposure to the complex analytes in either the liquid phase or the head-gas provides a color change profile as a unique fingerprint for the specific analyte. The digital data libraries generated were analyzed using statistical and chemometric methods, including principal component analysis (PCA) and hierarchical clustering analysis (HCA). In either liquid- or gas-phase experiments, facile identification of specific beers was achieved using comparison of the color change profiles; using HCA statistical analysis the error rate of identification was <3%. Differentiation between even very similar beers proved to be straightforward. In addition, differentiation of pristine beer from the effects of watering or decarbonation proved to be possible. These results suggest that colorimetric sensor arrays may prove to be useful for quality assurance/quality control applications of beers and perhaps other beverages.

Beer↗

Monoclonal antibody probe for assessing beer foam stabilizing proteins.

A monoclonal antibody (Mab; IFRN 1625) has been produced, which is specific for the most hydrophobic polypeptides responsible for foam stabilization. The binding characteristics of the Mab suggest that it is the conformation of certain hydrophobic polypeptides which is important for foam stabilization. An enzyme-linked immunosorbent assay (ELISA) for assessing the foam-positive form of the foam-stabilizing polypeptides in beer was developed using IFRN 1625. A good correlation was obtained between ELISA determination of foam-stabilizing polypeptides and an empirical means of determining foaming, that is, the Rudin head retention values, for a collection of beers of various foam qualities. Application of the ELISA to different stages of the brewing process showed that the amounts of foam-positive polypeptides increased during barley germination. During the brewing process the proportion of foam-positive polypeptides present after fermentation increased slightly, although a large amount was lost along with other beer proteins during subsequent steps, such as filtering. The present study demonstrates that the amounts of beer polypeptide present in a foam-positive form have a direct relationship with the foaming potential of beer, that their levels are altered by processing, and that there is potential for greater quality control.

Antibodies, Monoclonal↗

Determination of the hop-derived phytoestrogen, 8-prenylnaringenin, in beer by gas chromatography/mass spectrometry.

A method was developed to determine 8-prenylnaringenin, a novel hop-derived phytoestrogen, in beer. Matrix purification involved solid-phase extraction on octadecyl silica followed by liquid/liquid extraction on a ChemElut 1010 column connected to a Florisil adsorption/desorption cartridge. 8-Prenylnaringenin was eluted from the tandem columns using a 1:1 mixture of diethyl ether and ethyl acetate and subsequently determined as tris(trimethylsilyl) ether by GC/MS-SIM. The recovery of 8-prenylnaringenin in beer samples was between 61.1 +/- 6.6 and 82.2 +/- 8.8% for levels of 37 and 92.5 microg L(-1), respectively, and the detection limit was approximately 5 microg L(-1). Although most beers do not contain 8-prenylnaringenin in detectable quantities, the highest concentration found was 19.8 microg L(-1). The concentration of 8-prenylnaringenin in beers and, possibly, its absence depend on the selection of particular hop varieties, the hopping rate, or the type of hop product used in brewing. The efficiency of transfer of 8-prenylnaringenin from hops to beer is between 10 and 20%.

Beer↗

Beer-induced anaphylaxis: identification of allergens.

BACKGROUND: We report on a 21-year-old atopic woman who developed urticaria, angioedema of the face, and wheezy dyspnea shortly after drinking beer and after eating a corn-made snack. METHODS: Skin prick tests and specific IgE determinations to beer ingredients and cereal extracts were performed. Immunoblotting inhibition assays were carried out to investigate possible common allergens shared by barley and malt with corn. RESULTS: Skin prick tests and specific IgE measurements with beer, barley, malt, wheat, corn, rye, rice, and oat flour were positive. Ten pollen-allergic patients showed negative skin tests to beer. Double-blind, placebo-controlled, oral challenge tests with sodium metabisulfite and wheat flour were negative. Immunoblotting demonstrated several IgE-binding bands at 31-56 kDa in malt and barley extracts, and a major band at 38 kDa in the beer extract. Immunoblot inhibition assays showed that malt extract was able to inhibit most of the IgE-binding bands in wheat and corn extracts, whereas corn did not produce significant inhibition to barley and malt extracts. CONCLUSIONS: This patient developed type I hypersensitivity to barley/malt and corn. Although she also showed IgE reactivity to wheat and other cereals, no symptoms were elicited upon ingestion of these cereals, probably indicating latent sensitization to them.

Administration, Oral↗

Isolation and characterization of barley lipid transfer protein and protein Z as beer allergens.

Beer has recently been implicated as the causative agent of contact urticaria and severe IgE-mediated anaphylaxis. However, no allergen from beer has as yet been isolated and characterized. Two major components of 45 kd and 9 kd were detected in crude protein preparations from beer. Both components were purified; they were identified as barley protein Z(4) (45 kd) and lipid transfer protein 1 (LTP1; 9 kd). Protein Z(4) was recognized by the 4 individual sera tested but provoked weak positive responses to skin testing in 2 of 4 beer-allergic patients. Purified LTP1 showed reactivity with 3 of 4 individual sera and induced strong positive skin prick responses in all 4 patients tested. Barley LTP1 and protein Z(4) have been identified as the main beer allergens.

Adult↗

Moderate beer consumption and the risk of colorectal cancer.

The relationship between beer consumption and the risk of colon and rectal cancer was considered in a case-control study conducted in northern Italy. The study was based on 828 histologically confirmed incident cases of colon cancer, 498 of rectal cancer, and 2,024 controls in hospital for a wide spectrum of acute, nonneoplastic, nonalcohol-related diseases. Beer drinking was reported by 6% of colon cancer cases, 7% of rectal cancer cases, and 10% of controls; regular beer drinkers (> or = 1 drinks/day) made up 2.6% of colon cancer cases, 3.2% of rectal cancer cases, and 4.1% of controls. Thus the multivariate relative risks (RR) for irregular drinkers were 0.6 [95% confidence interval (CI) 0.4-1.0] for colon and 0.7 (95% CI 0.4-1.2) for rectum. Corresponding values for regular drinkers were 0.7 (95% CI 0.4-1.2) for colon and 0.9 (95% CI 0.5-1.5) for rectal cancer. Despite the low frequency of beer drinking in this study, and hence its limited statistical power, the originality of the population in terms of colorectal cancer incidence, patterns of risk factor exposure, and the large dataset provide interesting and useful confirmation that moderate beer drinking is not associated with elevated colon or rectal cancer risk.

Adult↗