Determination of purine contents of alcoholic beverages using high performance liquid chromatography

The purine contents of alcoholic beverages were determined in order to utilize them in the dietary care of gout and hyperuricemia. In the management of these diseases, restriction of both alcohol and purine intake are important. The method employed in this study is a quantitative determination of purine contents by HPLC. Alcoholic beverages were hydrolyzed to corresponding purine bases, which were then separated by HPLC, and base peaks were identified using an enzymatic peak‐shift technique. This method is sufficiently accurate and reproducible to examine the purine contents of various alcoholic beverages that patients consume. Purine contents were as follows: spirits, 0.7–26.4 µmol/L; regular beer, 225.0–580.2 µmol/L; low‐malt beer, 193.4–267.9 µmol/L; low‐malt and low‐purine beer, 13.3 µmol/L; other liquors, 13.1–818.3 µmol/L. Some local and low‐alcohol beers were found to contain about 2.5 times more purines than regular beer. As some alcoholic beverages contain considerable amounts of purines, we recommend that excess consumption of these beverages be avoided. These data should be useful in the management of hyperuricemia and gout, not only for patients but also for physicians. Copyright © 2009 John Wiley & Sons, Ltd.     

Simultaneous quantification of urinary purines and creatinine by ultra high performance liquid chromatography with ultraviolet spectroscopy and quadrupole time‐of‐flight mass spectrometry: Method development,validation, and application to gout study

We present an ultra high performance liquid chromatography with ultraviolet spectroscopy and quadrupole time‐of‐flight mass spectrometry method for the simultaneous quantification of ten purines (adenine, hypoxanthine, guanine, xanthine, deoxyadenosine, adenosine, inosine, guanosine, xanthosine, and uric acid) and creatinine in human urine. After chromatographic separation on an ACE Excel 2 AQ column, high abundant creatinine and uric acid and the other low abundant purines were sequentially detected by ultraviolet and quadrupole time‐of‐flight mass spectrometry within a single run. Method validations including specificity (improved by accurate mass measurement), linearity (correlation coefficients ≥0.9944), limit of quantification (0.002–9.756 µg/mL), intra‐ and interday precision (relative standard deviations ≤9.1 and 14.0%, respectively), accuracy (relative errors ≤13.1%), extraction recovery (between 90.3 and 109.6%), matrix effect (between 85.3 and 110.5%), and stability (relative errors ≤14.3%) were fully evaluated. This approach was applied to characterize the disordered purine metabolism in acute and chronic gout as an example. Quantitative results (normalized by creatinine) showed that an overproduction of urinary purine precursors might be involved in the gout process. The developed method represents a useful tool to investigate the purine disturbances in gout and other relevant diseases.     

Microrobots in Brewery: Dual Magnetic/Light-Powered Hybrid Microrobots for Preventing Microbial Contamination in Beer

Yeasts play a key role in the production of alcoholic beverages by fermentation processes. However, because of their continuous growth, they commonly cause spoilage of the final product. Herein, we introduce dual magnetic/light-responsive self-propelled microrobots that can actively move in a beer sample and capture yeast cells. The presence of magnetic nanoparticles on the surface of the microrobots enables their magnetic actuation under fuel-free conditions. In addition, their photoactivity under visible-light irradiation leads to an overall enhancement of their swimming and yeast removal capabilities. It was found that after the application of the microrobots into a real unfiltered beer sample, these micromachines were able to remove almost 100 % of residual yeasts. In addition, these microrobots could also be added at the initial step of the fermentation process without altering the final beer properties, such as alcohol level, color, and pH. This work demonstrates the potential of using externally actuated microrobots as an innovative and low-cost solution for avoiding yeast spoilage in complex liquid environments, such as alcoholic beverages. Therefore, these autonomous self-propelled microrobots open new avenues for future applications in the food industry.     

Therapeutic Effects of Selaginella tamariscina on the Model of Acute Gout with Hyperuricemia in Rats Based on Metabolomics Analysis

Gout is a disease of purine metabolic disorders which results from long‐term hyperuricemia and the sodium urate deposition in and around the joints. Selaginella tamariscina (ST ) is an important traditional Chinese herbal medicine and is used for the treatment of gout and hyperuricemia. In this study, the rat model of acute gout with hyperuricemia was established by intraperitoneal injection of xanthine and oxonic acid potassium salt and articular injection monosodium urate (MSU ). The effect of ST in the treatment of gout was investigated by measuring joint swelling, the expression of IL ‐1β in serum and histological changes of joint by haematoxylin eosin (H&E) staining. Subsequently, urine metabolomics analysis for biomarkers discovery in acute gout with hyperuricemia rats was performed by the ultra‐performance liquid chromatography‐electrospray ionization quadruple time‐of‐flight mass spectrometry (UPLC‐ESI‐QTOF /MS ) combined with chemometric approach. Principal component analysis (PCA ) and orthogonal partial least squares‐discriminant analysis (OPLS‐DA ) were used to detect potential biomarkers. A total of 18 potential biomarkers were identified mainly including tryptophan metabolism; tyrosine metabolism; lysine methylation; pyrimidine metabolism; purine metabolism; TCA cycle and fatty acid metabolisms. This study indicates that ST could efficiently ameliorate the disease of acute gout with hyperuricemia in rats. The related metabolic biomarkers could provide useful information and the metabolic mechanism could be used for further study about the model of acute gout with hyperuricemia in rats.     

Banana as Adjunct in Beer Production: Applicability and Performance of Fermentative Parameters

Traditionally, the raw materials for beer production are barley, hops, water, and yeast, but most brewers use also different adjuncts. During the alcoholic fermentation, the contribution of aroma compounds from other ingredients to the final beer flavor depends on the wort composition, on the yeast strain, and mainly on the process conditions. In this context, banana can also be a raw material favorable to alcoholic fermentation being rich in carbohydrates and minerals and providing low acidity. In this work, the objective was to evaluate the performance of wort adjusted with banana juice in different concentrations. For this, static fermentations were conducted at 15 °C at pilot scale (140 L of medium). The addition of banana that changed the concentration of all-malt wort from 10 °P to 12 and 15 °P were evaluated (°P is the weight of the extract or the sugar equivalent in 100 g solution, at 20 °C). The results showed an increase in ethanol production, with approximately 0.4 g/g ethanol yield and 0.6 g/L h volumetric productivity after 84 h of processing when concentrated wort was used. Thus, it was concluded that banana can be used as an adjunct in brewing methods, helping in the development of new products as well as in obtaining concentrated worts.     

Beer: An Ancient Yet Modern Biotechnology

The brewing of beer is a complex process that draws on a diversity of sciences and technology, of which chemistry is but one. This paper focuses on the chemistry of the brewing process and of the finished product. It examines each of the main classes of molecule found in beer, considers their contribution to quality and their origins in the brewing process. The study of beer and its production provides an excellent illustrative example for teaching how raw materials and the manner by which they are processed determine the acceptability of a product. Beer, whilst 90%+ water, contains a wide range of chemical species which establish its properties. Apart from ethanol (the common denominator amongst all alcoholic beverages), beer contains substances that determine its flavor, foam, and color. The flavorsome components of beer include the bitter iso-a-acids and aromatic essential oils from hops, along with esters, acids, sulfur-containing compounds and vicinal diketones from yeast. The foaminess of beer depends on the presence of carbon dioxide but also of surface-active materials like amphipathic polypeptides from malt and the bitter substances from hops. The color is due to Maillard reaction products generated largely during the kilning of malt. The malting and brewing processes (which are briefly described) are designed to maximize the extraction and digestion of barley starch and protein, yielding highly fermentable wort. The processes are also designed to eliminate materials that can have an adverse effect on beer quality, such as the haze-forming polyphenol from barley and hops and the lipids and oxygen that, together, can cause beer to stale.     

A Systematic Review of Uric Acid Transporter 1(URAT1) Inhibitors for the Treatment of Hyperuricemia and Gout and an Insight into the Structure-activity Relationship(SAR)

Gout is caused by the deposition of uric acid as monosodium urate(MSU). Chronic hyperuricemia is the necessary condition for MSU deposition, which arises from over-production and/or under-excretion of uric acid. Renal under-excretion of uric acid accounts for greater than 90% of the patients with hyperuricemia, making URAT1 inhibitors, which act through uricosuric effect a promising class of urate-lowering therapy(ULT). This review aims at the summary and discussion of the latest development of URAT1 inhibitors for the treatment of hyperuricemia and gout and providing an insight into their structure-activity relationship(SAR), which will be helpful to the design of URAT1 inhibitors for both academic research and pharmaceutical industry. The current development pipeline of URAT1 inhibitors is promising and encouraging.     

Evaluation of headspace solid-phase microextraction for the analysis of volatile carbonyl compounds in spirits and alcoholic beverages

A method was developed for the determination of C1-C6 carbonyl compounds in alcoholic solutions using pentafluorobenzoxymation followed by headspace sampling solid-phase microextraction and subsequent analysis by GC with electron-capture detection. Experimental conditions-alcohol content, exposure time, temperature and sample agitation were optimised. In this method, a spirit or distilled alcoholic beverage is first adjusted to 20% (v/v) alcohol. Detection limits for particular aldehydes and ketone varied from 0.05 to 0.5 microg/l and relative standard deviation was between 2.3 and 20%. Generally, the method showed good linearity for the tested concentration range 8 microg/l-0.32 mg/l with regression coefficients ranging between 0.9434 and 0.9983. The method was applied to the analysis of real alcoholic beverages (vodkas).     

Yeast Fermentation at Low Temperatures: Adaptation to Changing Environmental Conditions and Formation of Volatile Compounds

Yeast plays a key role in the production of fermented foods and beverages, such as bread, wine, and other alcoholic beverages. They are able to produce and release from the fermentation environment large numbers of volatile organic compounds (VOCs). This is the reason for the great interest in the possibility of adapting these microorganisms to fermentation at reduced temperatures. By doing this, it would be possible to obtain better sensory profiles of the final products. It can reduce the addition of artificial flavors and enhancements to food products and influence other important factors of fermented food production. Here, we reviewed the genetic and physiological mechanisms by which yeasts adapt to low temperatures. Next, we discussed the importance of VOCs for the food industry, their biosynthesis, and the most common volatiles in fermented foods and described the beneficial impact of decreased temperature as a factor that contributes to improving the composition of the sensory profiles of fermented foods.     

Surface-enhanced Raman scattering for quantitative detection of ethyl carbamate in alcoholic beverages

Ethyl carbamate, a by-product of fermentation and storage with widespread occurrence in fermented food and alcoholic beverages, is a compound potentially toxic to humans. In this work, a new approach for quantitative detection of ethyl carbamate in alcoholic beverages, based on surface-enhanced Raman scattering (SERS), is reported. Individual silver-coated gold nanoparticle colloids are used as SERS amplifiers, yielding high Raman enhancement of ethyl carbamate in three kinds of alcoholic beverages (vodka, Obstler, and white rum). The characteristic band at 1,003 cm^-1, which is the strongest and best reproducible peak in the SERS spectra, was used for quantitative evaluation of ethyl carbamate. The limit of detection, which corresponds to a signal-to-noise ratio of 3, was 9.0?×?10^-9 M (0.8 μg?·?L^-1), 1.3?×?10^-7 M (11.6 μg?·?L^-1), and 7.8?×?10^-8 M (6.9 μg?·?L^-1), respectively. Surface-enhanced Raman spectroscopy offers great practical potential for the in situ assessment and identification of ethyl carbamate in the alcoholic beverage industry.     

Simple method for the simultaneous quantification of medium-chain fatty acids and ethyl hexanoate in alcoholic beverages by gas chromatography-flame ionization detector: development of a direct injection method

Free medium-chain fatty acids (MCFAs) can negatively influence the fermentation process and taste quality in alcoholic beverages. Ethyl hexanoate is important in providing a fruit-like flavour to drinks, particularly in Japanese sake. In this study, we developed a direct injection method for a gas chromatography-flame ionization detector following the semi-purification of chemical components, such as esters, alcohols and MCFAs in alcoholic beverages. Evaluation of MCFAs by this method gave a limit of detection on the order of sub-ppm and relative standard deviations less than 10% in standard solution. Good repeatability and recovery rates against MCFAs and ethyl hexanoate were also obtained in non-distilled real alcoholic beverages. Because this method enabled us to simultaneously quantify the concentrations of MCFAs and ethyl hexanoate, the proportion of ester against MCFAs was proposed as a quality control index. This method could be suitable for routine analysis in the alcohol beverage industry.     

Effect of Collagen Types,Bacterial Strains and Storage Duration on the Quality of Probiotic Fermented Sheep’s Milk

Collagen has become popular in dietary supplements, beverages and sports nutrition products. Therefore, the aim of this study was to evaluate the possibility of using various doses of collagen and collagen hydrolysate to produce probiotic sheep’s milk fermented with Lactobacillus acidophilus, Lacticaseibacillus casei, Lacticaseibacillus paracasei and Lacticaseibacillus rhamnosus. The effects of storage time, type and dose of collagen, and different probiotic bacteria on the physicochemical, organoleptic and microbiological properties of fermented sheep’s milk at 1 and 21 days of refrigerated storage were investigated. The addition of collagen to sheep’s milk increased the pH value after fermentation and reduced the lactic acid contents of fermented milk compared to control samples. After fermentation, the number of probiotic bacteria cells was higher than 8 log cfu g⁻¹. In sheep’s milk fermented by L. acidophilus and L. casei, good survival of bacteria during storage was observed, and there was no effect of collagen dose on the growth and survival of both strains. The addition of collagen, both in the form of hydrolysate and bovine collagen, resulted in darkening of the color of the milk and increased the sweet taste intensity of the fermented sheep’s milk. However, the addition of hydrolysate was effective in reducing syneresis in each milk sample compared to its control counterpart.     

Comparison of headspace and direct single-drop microextraction and headspace solid-phase microextraction for the measurement of volatile sulfur compounds in beer and beverage by gas chromatography with flame photometric detection

Three approaches based on headspace single-drop microextraction (HS-SDME), direct single-drop microextraction (Direct-SDME), and headspace solid-phase microextraction (HS-SPME), have been compared for analyzing volatile sulphur compounds (VSCs) in beer and beverage. Procedures and performance of the three methods have been contrasted through the determination of extraction efficiencies, precision, linearity and limits of detection. The overall process of HS-SDME and HS-SPME was applied to GC-FPD determination of five VSCs in beer and beverage.     

Urethanase of Bacillus licheniformis sp. isolated from mouse gastrointestine.

Trace levels of urethane, a cancer causing chemical, were detected in many kinds of wine, sherry, whisky, brandy and sake. Urethane formation from urea and ethanol in sake can be prevented by the treatment of acid urease, which is produced by Lactobacillus fermentum, but urethane, once formed, is very difficult to decompose. In order to keep the safety of alcoholic beverages, enzymatic removal of urethane has become an urgent problem. We found that Bacillus licheniformis sp., isolated from mouse gastrointestine, decomposed urethane to ethanol and ammonia. The enzyme showed higher urethanase activity at an acidic condition than at a neutral condition, and was resistant against ethyl alcohol of high concentrations. However, the enzyme had a low affinity to urethane for the industrial removal of the compound from alcoholic beverages.     

Determination of Cu in Tequila by Anodic Stripping Voltammetry

Abstract

Concentrations of metals such as copper in alcoholic beverages must be strictly regulated due to negative effects ranging from beverage spoilage and hazing, to sensorial and health consequences. In this paper, a voltammetric alternative is presented for the analysis of copper in tequila, a Mexican spirituous alcoholic beverage. Anodic Stripping Voltammetry is applied and the standard addition method is used to quantify copper in this beverage at concentrations commonly present in tequila (<10 ppm) without sample pretreatment. Copper can be reduced and then oxidized quantitatively and reproducibly. A comparison of Anodic Stripping Voltammetry with Atomic Absorption Spectrometry is presented.     

A novel strategy to verification of adulteration in alcoholic beverages based on Schlieren effect measurements and chemometric techniques

A novel strategy to evaluation of adulteration in alcoholic beverages based on the measurement of the Schlieren effect using an automated FIA system with photometric detection is proposed. The assay is based on the Schlieren effect produced when beverage samples are injected in a single-line FIA system that uses water as carrier stream and a light-emitting diode-phototransistor photometer controlled by microcomputer as detector. The flow system presents limited mixing conditions which make possible to create gradients of refractive index (Schlieren effect) in the injected sample zone. These gradients are reproducible, characteristic of each alcoholic beverage and undergo specific modifications when adulterations with water or ethanol are imposed. Schlieren effect data of brandies, cachaças, rums, whiskies and vodkas were treated by SIMCA to elaborate class models applied in the evaluation of alcoholic beverages adulteration. Samples of the original matrix of each sort of beverages were adulterated in laboratory by adding water, methanol and ethanol in levels of 5% and 10% (v/v). These samples were used as test set to validate SIMCA class models. The verification of authenticity using Schlieren effect measurements presented good results making possible to identify 100% of the beverages samples adulterated in laboratory and 93% of the actual adulterated alcoholic beverages with confidence levels of 95%. As principal advantage, the automated system does not use reagents to carry out the analysis.     

Supported Noble Metal Catalysts and Adsorbents with Soft Lewis Acid Functions

Heterogeneous noble metal catalysts exhibit various functions. Although their redox functions have been extensively studied, we focused on their soft Lewis acid functions. Supported Au, Pt, and Pd catalysts electrophilically attack the π-electrons of soft bases such as alkynes, alkenes, and aromatic compounds to perform addition and substitution reactions. Hydroamination, intramolecular cyclization of alkynyl carboxylic acids, isomerization of allylic esters, vinyl exchange reactions, Wacker oxidation, and oxidative homocoupling of aromatics are introduced based on a discussion of the active species and reaction mechanisms. Furthermore, the adsorption of sulfur compounds, which are soft bases, onto the supported AuNPs is discussed. The adsorption and removal of 1,3-dimethyltrisulfane (DMTS), which is the compound responsible for the stale odor of “hine-ka” in alcoholic beverages, particularly Japanese sake, is described.     

高效液相色谱法对牦牛血浆与尿中嘌呤衍生物及肌酐含量的测定

建立了牦牛血浆及尿中的嘌呤衍生物及肌酐含量测定的HPLC/UVD方法.在室温条件下,以乙酸铵为流动相,分别以Lichrospher RP-C18 Merck(4.6×250 mm,5 μm i.d.)和5C18-AR-Ⅲ Waters(4.6×250 mm)为色谱柱,检测波长220 nm,流速1 mL/min,对尿囊素、尿酸、肌酐、黄嘌呤和次黄嘌呤进行了检测.方法检出限(LOD)为0.2 ~0.4 μmol/L,血样和尿样的加标回收率分别为81% ~103%、83% ~104%.     

Investigation into the structural composition of hydroalcoholic solutions as basis for the development of multiple suppression pulse sequences for NMR measurement of alcoholic beverages

An eight‐fold suppression pulse sequence was recently developed to improve sensitivity in ¹H NMR measurements of alcoholic beverages [Magn. Res. Chem. 2011 (49): 734–739]. To ensure that only one combined hydroxyl peak from water and ethanol appears in the spectrum, adjustment to a certain range of ethanol concentrations was required. To explain this observation, the structure of water–ethanol solutions was studied. Hydroalcoholic solutions showed extreme behavior at 25% vol, 46% vol, and 83% vol ethanol according to ¹H NMR experiments. Near‐infrared spectroscopy confirmed the occurrence of four significant compounds (‘individual’ ethanol and water structures as well as two water–ethanol complexes of defined composition – 1 : 1 and 1 : 3). The successful multiple suppression can be achieved for every kind of alcoholic beverage with different alcoholic strengths, when the final ethanol concentration is adjusted to a range between 25% vol and 46% vol (e.g. using dilution or pure ethanol addition). In this optimum region, an individual ethanol peak was not detected, because the ‘individual’ water structure and the 1 : 1 ethanol–water complex predominate. The nature of molecular association in ethanol–water solutions is essential to elucidate NMR method development for measurement of alcoholic beverages. The presented approach can be used to optimize other NMR suppression protocols for binary water–organic solvent mixtures, where hydrogen bonding plays a dominant role. Copyright © 2014 John Wiley & Sons, Ltd.