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At least 991 records · Page 55Linked to original sources
PubMed2005

Gas chromatographic ion trap mass spectrometry determination of zoxamide residues in grape, grape processing, and in the fermentation process.

A gas chromatographic ion-trap mass spectrometry (GC-ITMS) method was developed for the determination of the fungicide zoxamide in grape, must, wine, and spirits. Samples were extracted with hexane and analyzed without any clean up. The gas chromatograph was fitted with a carbofrit inserted into the glass liner to allow large volume injections. Analyses were carried out both in EI and CI mode. Recoveries from fortified samples ranged between 86 and 114% at four different fortification levels (n=6 each), ranging between 0.05 and 2.00 mg/kg. The relative standard deviation was below 19%. Both in EI and CI mode the calculated limit of detection (LOD) and quantification (LOQ) were 0.01 and 0.05 mg/kg (0.08 mg/kg in CI), respectively. Moreover the influence of yeasts and bacteria fermentation was evaluated.

Alcohols↗
PubMed2005

Determination of volatile compounds in grape distillates by solid-phase extraction and gas chromatography.

Solid-phase extraction (SPE) procedure on octadecylsilica (C18) was developed for accumulation of volatile compounds from grape distillates. The procedure was optimised for final analysis by capillary gas chromatography. At mass concentrations in model solutions ranging from 0.1 to 50 mg/l solid-phase extraction recoveries of all analytes ranged from 69% for 2-phenylethanol to 102% for capric acid, with RSD values from 2 to 9%. SPE recoveries of internal standards to be added in the sample solution prior to extraction, higher alcohols 2-ethyl-1-hexanol and 1-undecanol, were 97 and 93%, respectively, with RSD values of 3%. Detection limits of analyzed compounds in model solutions ranged from 0.011 mg/l for isoamyl acetate to 0.037 mg/l for caproic acid. Method efficiency was tested in relation to acetic acid content, volume fraction of ethanol and possible matrix effects. A significant influence of matrix on SPE efficiency for geraniol, cis-2-hexen-1-ol and cis-3-hexen-1-ol was detected. For the same reason, 2-phenylethanol could not be determined by developed SPE method in samples of grape distillates. The developed solid-phase extraction method was successfully applied to determine the differences in volatile compound content in different grape distillates produced by the distillation of crushed, pressed and fermented grapes.

Adsorption↗
PubMed2006

A comparison of a gas chromatographic with electron-capture detection and a gas chromatographic with mass spectrometric detection screening methods for the analysis of famoxadone in grapes and wines.

Famoxadone is a recent oxazolidinedione fungicide widely used in viticulture and in Integrated Pest Management strategies. In this work, after a simple and fast liquid-liquid extraction (LLE), two new gas chromatographic methods were developed to analyze famoxadone residues in grapes and wines, one with electron-capture detection (GC-ECD) and the other with mass spectrometry (GC-MS). Global uncertainties for validation parameters of both methods were compared. Limits of detection (LODs) were 0.06 and 0.02 mg/L, precision was not above 11.7 and 6.8% and recoveries were, on average, 103%+/-12 and 96%+/-12, respectively, for the GC-ECD and GC-MS methods. Similar expanded uncertainties in the range from 0.25 to 1.00 mg/L were below 35%, with increasing values for lower levels of famoxadone. GC-MS method had a lower LOD and a lower uncertainty if compared with the GC-ECD method.

Chromatography, Gas↗
PubMed2006

Enantioselective analysis of monoterpenes in different grape varieties during berry ripening using stir bar sorptive extraction- and solid phase extraction-enantioselective-multidimensional gas chromatography-mass spectrometry.

The stereoisomeric ratios of various genuine metabolites of linalool (furanoid and pyranoid linalool oxides, hotrienol) and citronellol (cis- and trans-rose oxide) were determined in grape berries by means of enantioselective-multidimensional gas chromatography-mass spectrometry. Stereoisomers of the metabolites could be separated on a chiral column with a modified cyclodextrin as stationary phase. The detailed stereoselective analysis of the furanoid and pyranoid linalool oxides in the cv. Morio-Muskat during berry ripening is giving evidence that furanoid linalool oxides are generated via two different reaction pathways. Additionally, stereoselective analysis of rose oxide in different varieties that have attained commercial maturity has been performed demonstrating that cis-(2S,4R)-rose oxide is the main stereoisomer in all varieties. (3S)-Hotrienol was the main stereoisomer in all varieties with enantiomeric purities that were always higher than 90%.

Acyclic Monoterpenes↗
PubMed2006

Rapid analysis of stilbenes and derivatives from downy mildew-infected grapevine leaves by liquid chromatography-atmospheric pressure photoionisation mass spectrometry.

Resveratrol, trans-epsilon-viniferin and trans-delta-viniferin are the major stilbenes induced in downy mildew infected grapevine leaves. In addition, nine minor polyphenolic compounds, described as stilbenes derivatives, have been separated and detected among known stilbenes after a methanolic microextraction of small pieces (1-2 mg) from infected grapevine leaves with a rapid, qualitative and optimized HPLC method coupled to mass spectrometry using atmospheric pressure photoionisation (APPI-MS(n)). The characterization of unknown stilbenic derivatives as six resveratrol dimers, two dimethylated resveratrol dimers and a resveratrol trimer are reported. Therefore, structures have been proposed for the dimethylated resveratrol dimers. Use of an easy sample treatment and the LC-APPI-MS(n) method results in spectral data of these minor naturally occurring viniferin analogues.

Chromatography, Liquid↗
PubMed2006

Determination of trans-resveratrol in grapes by pressurised liquid extraction and fast high-performance liquid chromatography.

A study has been made of the extraction of trans-resveratrol from grapes using pressurised liquids (PLE); for this, the first stage was to determine the stability of this compound during extractions at different temperatures (50, 100, 150 degrees C), with quantitative recoveries being obtained up to 150 degrees C. By employing solid-phase extraction (SPE) it was possible to retain this compound and separate it from other interfering substances present in the grape. The method developed comprises a sequential extraction of the sample adsorbed (0.5g) on a polystyrene-divinylbenzene based sorbent in the extraction chamber, first with water at 40 degrees C and 40atm of pressure (three cycles of 5min), and then with methanol at 150 degrees C and 40atm (three cycles of 5min). The trans-resveratrol content of the methanolic extract is determined by means of liquid chromatography. A rapid (5min) chromatographic method employing a monolithic column, with fluorescence detection, has been developed; for this, the conditions for detection of the compound were optimised (excitation at 310nm and emission at 403nm). The analytical parameters of the method of chromatographic analysis developed have been calculated: linear range (0.11-2.75mg/L), detection limit (0.003mg/L), quantification limit (0.004mg/L). Using this method, three varieties of grape have been analysed and the concentration of trans-resveratrol in these has been determined.

Antineoplastic Agents, Phytogenic↗
PubMed2006

Optimization and evaluation of a procedure for the gas chromatographic-mass spectrometric analysis of the aromas generated by fast acid hydrolysis of flavor precursors extracted from grapes.

A procedure has been developed for the GC-MS analysis of the aromas released in fast acid hydrolysis of precursor fractions from grape musts and skins. Different sorbents for the extraction of the precursors were compared. The best results were obtained with LiChrolut EN polymeric resins which displayed two and six-fold more extraction capacity than Amberlite XAD-2 resins and C18 sorbents, respectively. C18 sorbents are more suitable for selective extraction of less polar precursors. The initial version of the method was imprecise and so the imprecision of the different steps was assessed. The maceration of the solid parts and the liquid-liquid extraction of the aromas released in the acid hydrolysis proved to be the critical steps. Greater crushing of the solid parts and solid-phase extraction (SPE) instead of liquid-liquid extraction (LLE) improved reproducibility. In the method finally proposed about 100 aromatic components belonging to four large groups (lipid derivatives, shikimic acid derivatives, norisoprenoids and terpenes) were determined with good reproducibility. Important aroma compounds, such as cis-rose oxide or wine lactone were detected in non-Muscat grapes.

Acids↗
PubMed2006

Comparison of micro-scale simultaneous distillation-extraction and stir bar sorptive extraction for the determination of volatile organic constituents of grape juice.

Traditional micro-scale simultaneous distillation-extraction (SDE) and stir bar sorptive extraction (SBSE) were compared for their effectiveness in the extraction of volatile organic compounds in a synthetic grape juice and a real grape juice (Huxelrebe, a variety of half Muscat ancestry) from an English vineyard. The novel immersion-mode SBSE method, using stir bars with PDMS sorbent, was optimised using the synthetic grape juice. Although mean percent relative recoveries and reproducibilities (%CV) of the SBSE method were inferior to SDE (28.4 and 8.5%, respectively, against 86.9 and 6.3%), the former method proved to be significantly more sensitive: 126 aroma compounds in Huxelrebe grape juice were identified using SBSE, against 98 using SDE. This allowed the identification of a number of volatile components that have not been reported previously in the juice or wine from the grapes of Muscat varieties.

Beverages↗
PubMed2006

Isolation of hydroxycinnamoyltartaric acids from grape pomace by high-speed counter-current chromatography.

A method for the isolation of caftaric, coutaric and fertaric acids from grape pomace by high-speed counter-current chromatography (HSCCC) was developed. Using a system of hexane/ethyl acetate/methanol/water 3:7:3:7 (v/v/v/v) and 0.5% trifluoroacetic acid (TFA) in the head-to-tail elution mode, the target compounds were separated from co-extracted polyphenolics and subsequently isolated in a second run (tert-butyl-methyl ether/acetonitrile/n-butanol/water, 2:2:1:5 (v/v/v/v) and 0.5% TFA; tail-to-head elution mode). The concomitant flavonoid quercetin 3-glucuronide was also isolated with the present method. The compounds were characterized by 1H NMR spectroscopy, by LC/electrospray ionization (ESI)-MS/MS in the negative ionization mode, and by UV spectroscopy. A purity of 97.0% (2.0% Z-isomer) for caftaric acid, 97.2% (4.8% Z-isomer) for coutaric acid, and 90.4% (13% Z-isomer) for fertaric acid was obtained from 10 g of grape pomace with yields of 62, 48 and 23%, respectively. Caftaric and coutaric acids may be used for in vitro and in vivo studies and as reference substances for analytical purposes.

Countercurrent Distribution↗
PubMed2006

Determination of the biogenic amines in musts and wines before and after malolactic fermentation using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate as the derivatizing agent.

An accurate, rapid and sensitive high-performance liquid chromatographic (HPLC) method is reported for the determination of four biogenic amines in red and white wine samples. The method involves derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) followed by liquid chromatography gradient elution analysis without any other sample pretreatment. The procedure developed permitted the determination of the four amines in 40 min. The relative standard deviation (RSD) values ranged from 3.1% to 6.1% in peak areas and the response was linear (R2>0.994) in a range from 0.1 to 4 mg/l. Leaving aside putrescine in Tempranillo wines, the malolactic fermentation did not exert any effect on the concentration of these compounds. On the contrary, the influence of the grape variety was important, and Tempranillo wines showed higher levels of tyramine and histamine and lesser of putrescine and cadaverine (p<0.05) than wines made with Cabernet Sauvignon.

Aminoquinolines↗
PubMed2006

Rapid gas chromatographic method for the determination of famoxadone, trifloxystrobin and fenhexamid residues in tomato, grape and wine samples.

Trifloxystrobin, fenhexamid and famoxadone belong to the generation of fungicides acting against a broad spectrum of fungi and widely used in Integrated Pest Management strategies in different agricultural crops but mainly in viticulture. In the present work, a gas chromatographic (GC) method for their determination was developed and validated on tomato, grape and wine matrices. The method was based on a simple one step liquid-liquid microextraction with cyclohexane/dichloromethane (9+1, v/v) and determination of fungicides by gas chromatography with nitrogen phosphorous (NP-) and electron capture (EC-) detection, and ion trap mass spectrometry (ITMS) for confirmation. The method was validated by recovery experiments, assessment of matrix effect and calculation of the associated uncertainty. Recoveries for GC-NPD and GC-ECD were found in the range of 81-102% with RSD <12%, while matrix-matched calibration solutions were imposed for quantification. LOQs ranged from 0.005 to 0.05 mg/kg and 0.01 to 0.10 mg/kg for the GC-ECD and GC-NPD, respectively, depending on the sensitivity of each compound with trifloxystrobin being the most sensitive. The expanded uncertainty, calculated for a sample concentration of 0.10 mg/kg, ranged from 4.8 to 13% for the GC-ECD and from 5.4 to 29% for the GC-NPD. The concentration levels for famoxadone residues found in tomato and grape samples from field experiments were clearly below the EU established MRL values, thus causing no problems in terms of food safety.

Acetates↗
PubMed2006

Determination of phenolic compounds in grape skin by capillary electrophoresis with simultaneous dual fluorescence and diode array absorption detection after dynamic superheated liquid leaching.

A fast method for the analysis of 10 of the characteristic compounds of the phenolic fraction in grape skin is proposed here. The method is based on a leaching step by superheated ethanol-water at 120 degrees C and 80bar, which enables to maintain the leachant in liquid state and wide the range of leachable compounds (polar, mid-polar and relatively non-polar compounds) by decrease of the dielectric constant; thus, allowing high leaching efficiencies to be achieved in 30min. After leaching, the target analytes were separated by capillary electrophoresis using a 50mM sodium tetraborate with 10% methanol (pH 8.4) solution as background electrolyte. Determination was performed by simultaneous dual diode array absorption and fluorescence detection, the combination of which increased the selectivity of the overall method, particularly interesting taking into account the complexity of the leachate as no additional concentration and/or clean-up steps were required prior to electrophoretic separation, which lasted only 10min. The short time of the electrophoretic step makes it useful as a screening tool of the target analytes in commercial and non-commercial extracts belonging to the pharmaceutical, cosmetic, nutraceutical or food fields.

Absorption↗
PubMed2006

Investigation on phenolic compounds stability during microwave-assisted extraction.

The stability of 22 phenolic compounds of different families (benzoic acids, benzoic aldehydes, cinnamic acids, catechins, coumarins, stilbens and flavonols) has been studied under conditions of microwave-assisted extraction. The influence on the stability affected by the working temperature between 50 and 175 degrees C has been evaluated, and it has been concluded that all the compounds studied are stable up to 100 degrees C, whereas at 125 degrees C there is significant degradation of epicatechin, resveratrol and myricetin. Conclusions have been drawn on the relationship between the chemical structure and the stability of the compounds; it has been found that those that have a greater number of hydroxyl-type substituents are more easily degraded under the extraction conditions.

Chemical Fractionation↗
PubMed2006

Interaction of flurbiprofen with cranberry juice, grape juice, tea, and fluconazole: in vitro and clinical studies.

OBJECTIVES: Recent anecdotal, unvalidated case reports have suggested potentiation of warfarin-induced anticoagulation by cranberry juice, possibly through inhibition of human cytochrome P450 (CYP) 2C9, the enzyme responsible for the clearance of the active S-enantiomer of warfarin. To address this question, the effect of cranberry juice and other beverages on CYP2C9 activity was evaluated in vitro and in vivo. METHODS: The effects of 4 beverages on CYP2C9 activity were studied in human liver microsomes, by use of flurbiprofen hydroxylation as the index reaction. In a clinical study 14 healthy volunteers received 100 mg flurbiprofen on 5 occasions in a crossover fashion, with at least 1 week separating the 5 trials. Flurbiprofen was preceded in random sequence by the following: (1) cranberry juice placebo (8 oz), (2) cranberry juice (8 oz), (3) brewed tea (8 oz), (4) grape juice (8 oz), and (5) fluconazole, a CYP2C9 inhibitor serving as a positive control, with 8 oz of water. RESULTS: Flubiprofen hydroxylation in vitro was reduced to 11% +/- 8% of control by 2.5% (vol/vol) brewed tea, to 10% +/- 7% of control by grape juice, to 56% +/- 16% of control by cranberry juice, to 85% +/- 5% of control by cranberry juice placebo, and to 21% +/- 6% of control by the index inhibitor sulfaphenazole (2.5 micromol/L) (P <.01 for all comparisons versus control). Flurbiprofen clearance (29-33 mL/min) and elimination half-life (3.3-3.4 hours) did not differ significantly among trials 1, 2, 3, and 4. However, clearance in the fluconazole treatment condition (trial 5) was significantly reduced compared with the placebo control (17 +/- 5 mL/min versus 31 +/- 8 mL/min, P <.05), and the half-life was prolonged (5.3 +/- 1.6 hours versus 3.3 +/- 0.8 hours, P <.05). Formation of 4-hydroxyflurbiprofen was correspondingly reduced by fluconazole (P <.05). CONCLUSIONS: Although grape juice and tea impaired CYP2C9 activity in vitro, none of the 3 beverages altered CYP2C9-mediated clearance of flurbiprofen in humans, making a pharmacokinetic interaction with warfarin highly unlikely.

Adult↗
PubMed2005

Influence of temperature and nutritional requirements for mycelial growth of Eutypa lata, a vineyard pathogenic fungus.

Eutypa dieback (dying arm disease, eutypiosis) is a very devastating disease in many grape-producing areas around the world. This vascular disease is induced by the ascomycete Eutypa lata Pers. Fr. Tul & C. Tul. invading the trunk by pruning wounds. The environmental factors and the nutritional requirements regulating fungus development are yet poorly known. This work shows that the isolated strain of E. lata was able to grow in a large temperature range (2-30 degrees C). However, a higher temperature (35 degrees C) presented inhibitory effects on mycelial growth. E. lata was able to use various osidic molecules (C5, C6, C12, C18, C24, and starch); showing thus a large adaptation to the carbon source supplied. As nitrogen source, it used salts and numerous natural amino acids. A significant result was obtained with cysteine presenting obvious antifungal properties. This effect can further be used with the aim of setting up a curative treatment of the disease.

Ascomycota↗
PubMed2005

[Dog-days, cold periods, grape-harvests (France, 15-19th centuries)].

Dog-days, cold periods, grape-harvests (France, 15-19th centuries). The climate history can be based on several kinds of data. In the present paper, French records of grape-harvest dates in Burgundy from 1370 to 1890 were used for evaluate the climates at these various period of time. These results reveal that temperatures as high as those reached in the 1990s have occurred several times in Burgundy since 1370. Correlations between temperatures and historic data are presented.

Agriculture↗
PubMed2004

Prevalence of the K469E polymorphism of intercellular adhesion molecule 1 gene in Italian patients with inflammatory bowel disease.

BACKGROUND: Intercellular adhesion molecule 1 plays an important role in the recruitment of leucocytes at sites of inflammation and is up-regulated in intestinal mucosa of inflammatory bowel disease. Intercellular adhesion molecule 1 gene lies on chromosome 19p13, implicated in determining susceptibility to inflammatory bowel disease. Recently, the polymorphism K469E of intercellular adhesion molecule 1 gene has been identified. AIM: To assess the potential association of this polymorphism with inflammatory bowel disease. PATIENTS: A total of 165 inflammatory bowel disease patients, 75 with Crohn's disease and 90 with ulcerative colitis, and 187 controls were studied. METHODS: The K469E polymorphism was detected by polymerase chain reaction and restriction enzyme analysis. Statistical analysis was performed by chi2-test. RESULTS: In inflammatory bowel disease, the distribution of intercellular adhesion molecule 1 genotypes was 24.9% E/E, 44.2% E/K and 30.9% K/K. In controls, 11.8% showed E/E genotype, 55.6% E/K and 32.6% K/K. The frequency of the E/E genotype was significantly higher in inflammatory bowel disease (Crohn's disease and ulcerative colitis) patients than in controls. Subgroup analysis showed that the frequency of the E469 allele was significantly increased only in Crohn's disease patients with ileocolonic location of disease and penetrating behaviour compared with controls. CONCLUSIONS: We found an association of inflammatory bowel disease with the E/E genotype of intercellular adhesion molecule 1 gene, while allele E469 was associated with a subgroup of Crohn's disease patients with more extensive location of disease and penetrating behaviour. However, further studies are needed to confirm our findings.

Adolescent↗
PubMed2005

The implications of copper fungicide usage in vineyards for earthworm activity and resulting sustainable soil quality.

To investigate the impact of copper-containing fungicides (copper oxychloride) on earthworms in South African vineyards, field inventories of earthworms in and between vine rows were carried out and compared to directly adjacent grassland. Also copper content, pH, organic matter content, and soil porosity were determined in these soils. This was combined with laboratory experiments to study the impact of vineyard soil characteristics on the burrowing and dispersal behavior of earthworms. Moreover, the direct toxic action of copper oxychloride on different endpoints of the earthworms (survival and growth) was studied. Copper oxychloride had a negative impact on these endpoints (decreased growth and survival related to increased copper body content) as well as on the behavioral aspect (decreased burrowing rate and avoidance of copper-containing soil). Moreover, there was an inverse relation between burrowing activity and soil bulk density that could also be related to the copper content. This may lead to a decrease in sustainable soil quality in vineyards.

Agriculture↗