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At least 253 records · Page 14Linked to original sources
PubMed1996

Gastric emptying of beer in Mexican-Americans compared with non-Hispanic whites.

Gastric emptying studies were performed on 11 nondiabetic Mexican-Americans and 11 nondiabetic non-Hispanic whites following ingestion of 450 mL beer. Plasma glucose, serum insulin, and serum alcohol levels were measured in the fasting state and at 7, 15, 30, 45, and 60 minutes following ingestion of the beer. The area under the gastric emptying curve was significantly larger for non-Hispanic whites compared with Mexican-Americans (P = .0492), indicating that Mexican-Americans had faster stomach emptying. Partial correlation coefficients (adjusted for ethnicity, gender, age, and body mass index [BMI]) showed the gastric half-emptying time was inversely related to the incremental levels of glucose (r = -.709, P = .0010) and alcohol (r = -.650, P = .0035). The faster the rate of gastric emptying of beer, the higher the glucose and alcohol levels. There were no significant correlations between insulin and the rate of gastric emptying. The caloric emptying rate for the beer was much more rapid than previously reported for other liquid meals.

Adult↗
PubMed1998

Occurrence of fumonisins in Spanish beers analyzed by an enzyme-linked immunosorbent assay method.

This study describes the occurrence of fumonisin in a survey of 32 Spanish beers, including some non-alcoholic beers. The analysis was conducted using an enzyme-linked immunosorbent assay (ELISA) method and, in the range assayed (0-100 ng fumonisin B1/ml spiked-beer), recovery rates were about 81%, with variation coefficients that did not exceed 4.2%. The detection limit with this method was 3 ng fumonisins/ml beer. Results for the fourteen positive samples (43.8% of total samples) showed that the lowest amount of fumonisins found in a positive sample was 4.76 ng/ml and the highest was 85.53 ng/ml.

Beer↗
PubMed1998

Detection of beer spoilage bacteria Megasphaera and Pectinatus by polymerase chain reaction and colorimetric microplate hybridization.

Anaerobic bacteria of the genera Megasphaera and Pectinatus cause beer spoilage by producing off flavours and turbidity. Detection of these organisms is complicated by the strict anaerobic conditions and lengthy incubation times required for their cultivation, consequently there is a need for more rapid detection methods. A polymerase chain reaction (PCR) method and a colorimetric microplate hybridization assay were developed for the rapid and specific detection of Megasphaera cerevisiae and Pectinatus spp. A biotinylated primer pair was designed for the amplification of a 403 base pair (bp) fragment of the M. cerevisiae 16S rRNA gene and a primer pair from literature was used for the amplification of an 816 bp fragment of Pectinatus 16S rRNA gene. Amplified PCR products were analyzed by the colorimetric microplate hybridization method in which a biotinylated PCR product was captured by streptavidin and hybridized with a digoxigenin-labelled oligonucleotide probe. In the final step an enzyme-linked antibody and a colorimetric reaction were utilized. A simple and rapid sample treatment was set up for the PCR detection of contaminants in beer. Detection of M. cerevisiae (> or = 5 x 10(3) colony forming units [cfu]/100 ml) and Pectinatus frisingensis (> or = 5 x 10(5) cfu/100 ml) in beer was successful, but the sensitivity of the assay still needs to be improved for direct detection of the small amounts of bacteria present in beer.

Beer↗
PubMed1999

Beer drinker's hyponatraemia: a case report.

Beer drinker's hyponatraemia, also called beer potomania, is a syndrome of hyponatraemia in patients who consume excessive amounts of beer and have a poor dietary intake. We describe a patient with chronic asymptomatic hyponatraemia due to beer potomania. The pathophysiology of this syndrome, the treatment and prevention are reviewed.

Aged↗
PubMed2002

The influence of additives on beer stability investigated by EPR spectroscopy.

In thermally-accelerated aging followed by EPR spectroscopy of beer samples of various stabilities, free radical 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPOL) was shown to be an effective indicator of the breakdown of a sample's stability, comparable to the commonly used spin trapping agent alpha-phenyl-N-tert-butylnitrone (PBN). Both indicators were then employed to investigate the influence of additives on beer stability. The addition of L-ascorbic acid (ASC) to the beer samples accelerated the radical processes and a lower stability was found. DL-alpha-tocopherol (alpha-TOC) did not influence beer stability significantly (probably due to its limited solubility). Na2SO3, described as a very effective stabilizer in experiments with the PBN spin trap, was found not to be effective using the TEMPOL indicator. This is probably due to inhibition in the formation of spin adducts or their degradation by Na2SO3.

Ascorbic Acid↗
PubMedDate not supplied

Continuous beer fermentation using immobilized yeast cell bioreactor systems.

Traditional beer fermentation and maturation processes use open fermentation and lager tanks. Although these vessels had previously been considered indispensable, during the past decades they were in many breweries replaced by large production units (cylindroconical tanks). These have proved to be successful, both providing operating advantages and ensuring the quality of the final beer. Another promising contemporary technology, namely, continuous beer fermentation using immobilized brewing yeast, by contrast, has found only a limited number of industrial applications. Continuous fermentation systems based on immobilized cell technology, albeit initially successful, were condemned to failure for several reasons. These include engineering problems (excess biomass and problems with CO(2) removal, optimization of operating conditions, clogging and channeling of the reactor), unbalanced beer flavor (altered cell physiology, cell aging), and unrealized cost advantages (carrier price, complex and unstable operation). However, recent development in reactor design and understanding of immobilized cell physiology, together with application of novel carrier materials, could provide a new stimulus to both research and application of this promising technology.

Beer↗
PubMed2001

N(delta)-(5-hydroxy-4,6-dimethylpyrimidine-2-yl)-l-ornithine, a novel methylglyoxal-arginine modification in beer.

N(delta)-(5-Hydroxy-4,6-dimethylpyrimidine-2-yl)-L-ornithine, or Argpyrimidine, was identified and quantified in beer by high-performance liquid chromatography (HPLC) and coupled gas chromatography-mass spectrometry (HRGC-MS). This novel fluorescent arginine Maillard modification represents the first amino acid modification reported in beer retaining the full backbone of the original amino acid. Two mechanisms of formation could be verified: the major pathway via methylglyoxal and the minor pathway via 5-deoxypentoses. Argpyrimidine concentrations, determined in 35 lager-type beer varieties, reached up to 27 nmol/L and could be positively correlated to beer color and wort content. Within this context, 5-deoxy-D-ribose was identified as a novel intermediate of the Maillard reaction of maltose by HRGC-MS and independent synthesis.

Acetone↗
PubMed2000

3-methylthiopropionaldehyde as precursor of dimethyl trisulfide in aged beers.

Hop S-methylcysteine sulfoxide has previously been postulated as the precursor of dimethyl trisulfide (DMTS) in beers. The present data point to 3-methylthiopropionaldehyde, the Strecker aldehyde issued from methionine, as another potential precursor in aged beers. Spiking either fresh beer or wort before boiling leads in all cases to higher levels of DMTS after storage. Moreover, special malts with a high level of 3-methylthiopropionaldehyde also favor polysulfide synthesis. A higher pH should increase this onion-like off-flavor, whereas a low pH is unfortunately known to enhance the cardboard flavor of aged beers. 3-methylthiopropanol, issued from yeast reducing activity, can be considered as an additional DMTS source during aging.

Aldehydes↗
PubMed2001

Beer consumption and changes in stability of human serum proteins.

The aim of this study was to evaluate the influence of beer consumption (BC) on the functional and structural properties of human serum proteins (HSP). Thirty-eight volunteers (after coronary bypass) were divided into two groups: experimental (EG) and control (CG). Nineteen volunteers of the EG consumed 330 mL per day of beer (about 20 g of alcohol) for 30 consecutive days. The CG volunteers consumed mineral water instead of beer. Blood samples were collected from EG and CG patients before and after the experiment. Albumin (Alb), globulin (Glo), and methanol-precipitable proteins (MPP) from human serum were denatured with 8 M urea. Fluorescence and electrophoresis were employed in order to elucidate urea-induced conformational changes and structural behavior of proteins. The measured fluorescence emission spectra were used to estimate the stability of native and denatured protein fractions before and after BC. It was found that before BC the fractions most stable to urea denaturation were Glo, Alb, and MPP fractions. After BC in most of the beer-consuming patients (EG) some changes in native and denatured protein fractions were detected: a tendency to lower stability and minor structural deviations. These qualitative changes were more profound in MPP than in Alb and Glo. Thus, Glo is more resistible to alcohol influence than Alb, which in turn is more resistible than MPP. No serum protein changes were detected in patients of CG.

Beer↗
PubMed2003

Voltammetric assay for the aging of beer.

A new method for the evaluation of beer aging, based on a voltammetric analysis of beer distillates, is described. By measuring the current of both acetaldehyde and sulfite voltammetric peaks it is possible to distinguish between fresh, naturally aged, and artificially aged beers. The results obtained for the ratio of acetaldehyde and SO(2) currents correlate well with those given by an expert sensory panel. The kinetics of the combining reaction of sulfite with acetaldehyde was followed for different acetaldehyde/SO(2) molar ratios by using a programmed voltammetric procedure. The formation of an acetaldehyde-sulfite adduct is rapid, and the reaction equilibrium is reached after 30 min, which is in accordance with the results previously obtained by other methods. This voltammetric-based approach seems to be a new attractive tool for detecting chemical equilibria of the addition of sulfite to carbonyls in beer model systems.

Acetaldehyde↗
PubMed2003

Determination of free phenolic acids in wort and beer by coulometric array detection.

The simultaneous determination of 19 phenolic compounds was performed directly in wort and beer by a combination of reverse-phase high-performance liquid chromatography coupled with coulometric array detection. Chromatographic separation was achieved with an appropriate gradient of flow and a binary solvent based on phosphate buffer, methanol, and acetonitrile in a 45-min run. Eight serial coulometric detectors were used for on-line generation of voltammetric data to resolve coeluting compounds. The method was reliable and sensitive, the regression coefficient of standard calibration curves is 0.972 < or = r < or = 1.000, and the standard deviation value ranges from 0.010 to 0.129 mg/L for wort and from 0.002 to 0.332 mg/L for beer. The mean concentrations of phenolic acids were 22.1 and 33.8 mg/L, respectively, in worts and beers produced in Italy. These amounts represent 5 and 10% of the non-tannic, non-flavonoid phenols in wort and beer, respectively.

Beer↗
PubMed2003

Quantitation of (R)- and (S)-linalool in beer using solid phase microextraction (SPME) in combination with a stable isotope dilution assay (SIDA).

A stable isotope dilution assay (SIDA) was developed for the quantitation of both linalool enantiomers using synthesized [2H(2)]R/S-linalool as the internal standard. For enrichment of the target compound from beer, a solid phase microextraction method (SPME) was developed. In comparison to the more time-consuming extraction/distillation cleanup of the beer samples, the results obtained by SPME/SIDA were very similar, even under nonequilibration conditions. Analysis of five different types of beer showed significant differences in the linalool concentrations, which were clearly correlated with the intensity of the hoppy aroma note as evaluated by a sensory panel. In addition, significant differences in the R/S ratios were measured in the beers. The SPME/SIDA yielded exact data independently from headspace sampling parameters, such as exposure time or ionic strength of the solution.

Acyclic Monoterpenes↗
PubMed2005

Identification based on quantitative measurements and aroma recombination of the character impact odorants in a Bavarian Pilsner-type beer.

Application of aroma extract dilution analysis on the volatiles isolated from a Bavarian Pilsner-type beer revealed 40 odor-active constituents in the flavor dilution (FD) factor range of 16-2048, among which ethyl octanoate, (E)-beta-damascenone, 2- and 3-methylbutanoic acid, and 4-hydroxy-2,5-dimethyl-3(2H)-furanone showed the highest FD factor of 2048. After quantitation of the 26 odorants showing FD factors > or =128 by stable isotope dilution analysis and determination of their odor thresholds in water, odor acitivity values (OAVs) were calculated. The results indicated ethanol, (E)-beta-damascenone, (R)-linalool, acetaldehyde, and ethyl butanoate with the highest OAVs, followed by ethyl 2-methylpropanoate and ethyl 4-methylpentanoate, which was previously unknown in beer. Finally, the overall aroma of the beer could be mimicked for the first time by recombining 22 reference odorants in the same concentrations as they occurred in the beer using ethanol/water as the matrix.

Acetaldehyde↗
PubMed2006

Effects of beer and hop on ionotropic gamma-aminobutyric acid receptors.

Beer induced the response of the ionotropic gamma-aminobutyric acid receptors (GABA(A) receptors) expressed in Xenopus oocytes, indicating the presence of gamma-aminobutyric acid (GABA)-like activity. Furthermore, the pentane extract of the beer, hop (Humulus lupulus L.) oil, and myrcenol potentiated the GABA(A) receptor response elicited by GABA. The GABA(A) receptor responses were also potentiated by the addition of aliphatic esters, most of which are reported to be present in beer flavor. Aliphatic esters showed the tendency to decrease in the potentiation of the GABA(A) receptor response with an increase in their carbon chain length. When myrcenol was injected to mice prior to intraperitoneal administration of pentobarbital, the pentobarbital-induced sleeping time of mice increased additionally. Therefore, the beer contained not only GABA-like activity but also the modulator(s) of the GABA(A) receptor response.

Acyclic Monoterpenes↗
PubMed2006

Ochratoxin a determination in beer by solid-phase microextraction coupled to liquid chromatography with fluorescence detection: a fast and sensitive method for assessment of noncompliance to legal limits.

A solid-phase microextraction-liquid chromatography-fluorescence detection (SPME-LC-FD) method for the determination of ochratoxin A (OTA) in commercial beer samples was developed for the first time using a 60 microm thick poly(dimethylsiloxane)/divinylbenzene (PDMS/DVB) fiber. The procedure required a very simple sample pretreatment, an isocratic elution, and provides a selective extraction. All of the factors influencing fiber adsorption (extraction time, temperature, pH, and salt addition) and desorption of the analyte (desorption and injection time and desorption solvent mixture composition) have been investigated. The linear range investigated in beer was 0.03-2 ng/mL; within-day and between-days relative standard deviation in beer were 4.3 and 5.9%, respectively. The limit of quantification in spiked beer was 53 pg mL(-)(1), well below all European regulatory levels.

Beer↗
PubMed2006

Composition of beer by 1H NMR spectroscopy: effects of brewing site and date of production.

A principal component analysis (PCA) of 1H NMR spectra of beers differing in production site (A, B, C) and date is described, to obtain information about composition variability. First, lactic and pyruvic acids contents were found to vary significantly between production sites, good reproducibility between dates being found for site A but not for sites B and C beers. Second, site B beers were clearly distinguished by the predominance of linear dextrins, while A and C beers were richer in branched dextrins. Carbohydrate reproducibility between dates is poorer for site C with dextrin branching degree varying significantly. Finally, all production sites were successfully distinguished by their contents in adenosine/inosine, uridine, tyrosine/tyrosol, and 2-phenylethanol, reproducibility between dates being again poorer for site C. Interpretation of the above compositional differences is discussed in terms of the biochemistry taking place during brewing, and possible applications of the method in brewing process control are envisaged.

Adenosine↗
PubMed2006

Use of beer bran as an adsorbent for the removal of organic compounds from wastewater.

Beer bran was found to effectively adsorb several organic compounds, such as dichloromethane, chloroform, trichloroethylene, benzene, pretilachlor, and esprocarb. Equilibrium adsorption isotherms conformed to the Freundlich isotherm (log-log linear). Adsorption of these organic compounds by beer bran was observed in the pH range of 1-11. At equilibrium, the adsorption efficiency of beer bran for benzene, chloroform, and dichiloromethane was higher than that of activated carbon. The removal of these organic compounds by beer bran was attributed to the uptake by intracellular particles called spherosomes. The object of this work was to investigate several adsorbents for the effective removal of organic compounds from wastewater.

Adsorption↗
PubMed1999

Analysis of organic acids and inorganic anions in different types of beer using capillary zone electrophoresis.

Two methods for the investigation of different types of beer by capillary zone electrophoresis are presented. The first separation system described in this work allows the quantitative analysis of beers with respect to their contents of low molecular mass anionic components using indirect ultraviolet detection as well as conductivity detection, providing relative standard deviation between 0.5 and 6.6% for the peak areas and excellent limits of detection (LOD) ranging from 0.02 mg L(-)(1) for chloride to 0.41 mg L(-)(1) for phosphate. The second method offers the possibility of fast determination of amino acids in beer samples without the necessity of any sample pretreatment. LODs obtained for the investigated solutes were found to be strongly dependent on their spectroscopical properties and in the range of 0.5-50 mg L(-)(1). Despite this restriction, this analytical method can be regarded as a suitable tool for the screening of beers with respect to their amino acid patterns.

Anions↗