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At least 271 records · Page 15Linked to original sources
PubMed2006

Commercial dietary ingredients from Vitis vinifera L. leaves and grape skins: antioxidant and chemical characterization.

This paper reports an attempt to functionally and chemically characterize commercial ingredients from Vitis vinifera L. grape skins, grape pomace, and leaves, which are used in the formulation of dietary antioxidant supplements. The antioxidant capacity of these ingredients was assessed for the first time by the oxygen radical absorbance capacity (ORAC) methodology. Ingredients from grape skins and pomace (n = 17) showed ORAC values from 1.38 to 21.4 mumol Trolox equivalents/mg whereas ingredients from leaves (n = 4) showed ORAC values from 1.52 to 2.55 mumol Trolox equivalents/mg. The high-performance liquid chromatography-diode array detection/electrospray ionization-mass sprectrometry analysis of anthocyanins and flavonols revealed the authenticity of the ingredients as derived from V. vinifera L. and confirmed large differences in their phenolic content and distribution. A progressive decline in both antioxidant capacity and total anthocyanin content of a grape skin ingredient (43 and 40% decrease, respectively) was observed over a 60 day storage period (45 degrees C and 75% relative humidity), demonstrating its poor stability under these conditions.

Anthocyanins↗
PubMed2005

1H NMR and chemometrics to characterize mature grape berries in four wine-growing areas in Bordeaux, France.

The biochemical composition of grape berries depends on the cultivar genome and is influenced by environmental conditions and growing practices, which vary according to origin and "terroir" (French word accounting for the factors of climate, soil, and cultural practices on grape and wine quality). The components currently measured to determine the potential quality of grapes for wine-making at harvest are sugars, acidity, pH, and total phenolics, referred to as "classic analysis". The aim of this work was to establish metabolic profiles using both conventional physicochemical analyses and 1H NMR spectrometry of the skin and pulp of mature berry extracts in order in four appellations situated in different locations in southern-western France (Bordeaux). Principal component analysis was applied to the physiochemical and 1H NMR data to investigate the variability of the grape composition and to characterize groups of samples. A significant clustering of the metabolic profile of pulps or skins in relation to their terroir was observed. Physicochemical analyses were more discriminant than 1H NMR data, but NMR spectroscopy allowed metabolic finger-printings using identified metabolites and some still nonattributed resonances.

Chemical Phenomena↗
PubMed2006

Validation of an electrothermal atomization atomic absorption spectrometry method for the determination of aluminum, copper, and lead in grapes.

An electrothermal atomization atomic absorption spectrometry method was validated to quantify aluminum, copper, and lead in grapes. The limits of detection were 1.11, 0.19, and 0.35 micro g/L for Al, Cu, and Pb, respectively. The linearity ranges under optimized conditions were 1.11-50.0, 0.19-25, and 0.35-50.0 micro g/L for Al, Cu, and Pb, respectively. The limits of quantification were 74.0, 12.5, and 11.6 ng/g of dry weight for Al, Cu, and Pb, respectively. For all of the metals, the precision for the instrumental method was lower than 5.4% and for the analytical method, lower than 10%. The accuracy of the method was evaluated by the standard additions method, the recoveries being higher than 90% for all of the concentrations added. An interference study was also carried out in a simulated matrix, and it was verified that the deviations from the expected values were lower than 3.4% for all of the metals. The method was applied to the monitoring of the metals referred to above in 35 samples of grapes obtained in marketplaces and at farmhouses. The metals were quantified in the whole grapes, washed or not, and in the peel and pulp of unwashed grapes.

Aluminum↗
PubMed1999

Changes in the free amino acid composition with maturity of the noble cultivar of Vitis rotundifolia Michx. grape.

The changes in amino acid composition that occur with maturity of the Noble cultivar of the Vitis rotundifolia Michx. (muscadine) grape were determined by HPLC. Eighteen amino acids were identified. Histidine was the most prominent amino acid followed by alanine. The concentrations of most of the major amino acids (alanine, glycine, histidine, valine, isoleucine, aspartic acid, and serine) were highest at verasion. Glutamine and threonine contents dropped sharply after fruit set, while those of arginine and proline increased gradually with maturity and ripening. Tyrosine content increased gradually with maturity and ripening following a slight drop after fruit set. In ripe grapes, seeds contained most of the amino acids in mature grapes (50%) followed by the pulp (23%), the juice (15%), and the skin (11%). Alanine, histidine, and arginine were the principal amino acids identified in the juice. Alanine, histidine, arginine, valine, glutamine, aspartic acid, proline, serine, and threonine accounted for about 90% of the amino acids in the pulp. In seeds, alanine, proline, asparagine, and histidine accounted for over 55% of the amino acids, while alanine and histidine were found to be the predominant free amino acids in the skin. The profile indicates some differences in the changes in amino acid composition with berry maturity and relative amounts of amino acids present in muscadine compared to those in nonmuscadine grape species.

Amino Acids↗
PubMed2000

Decay of methidathion on Greek soultanina grapes during storage and on the vines.

Decomposition of the pesticide methidathion on and in soultanina (Thomson seedless) grapes was studied. Vines, uncovered and covered were sprayed with the pesticide. Samples were collected and analyzed in regular time intervals. Two lots were collected, the first of them, 2 h after spraying and the second 20 days later, and were stored in a commercial refrigerated room. Degradation of the pesticide was studied for about 50 days for the grapes on the vines and 130 days for the grapes stored in the refrigerated room. The half-life of the pesticide methidathion was found to be 5 days for the uncovered vines, 7 days for the covered vines and 64 days for the grapes stored in the refrigerator.

Chromatography, Gas↗
PubMed2001

Allergy to grape: a case report.

We report a case of a 5-year-old child who suffered an oral allergy syndrome and lip angiedema after eating grapes. We obtained a positive prick test with commercial grape extract and a positive prick-by-prick test with pulp and peel of fresh white grape (Moscatel variety) and pulp and peel of blue grape. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis followed by immunoblotting revealed specific immunoglobulin E (IgE) antibodies in the patient's serum against a 94,000 molecular-weight antigenic band. Lip open challenge was positive.

Angioedema↗
PubMed2001

Role of botrytized grape micro-organisms in SO2 binding phenomena.

AIMS: The purpose of this work was to study the involvement of micro-organisms, which develop together with Botrytis cinerea on grapes, in the SO2 binding power of musts. METHODS AND RESULTS: Yeasts and bacteria were involved. Most bacteria were acetic acid bacteria, mainly of the Gluconobacter genus. Unlike oxidative yeasts, Gluconobacter produce gluconic acid (in balance with delta-gluconolactone) from glucose, 5-oxofructose from fructose and dihydroxyacetone from glycerol. Production of carbonyl compounds from other sugars and polyols was not detected or was very weak. CONCLUSION: Acetic acid bacteria are responsible for the increases in SO2 binding power of musts from botrytized grapes by oxidizing the three main sugars of these grapes. SIGNIFICANCE AND IMPACT OF THE STUDY: Up to 80% of the SO2 binds with products of Gluconobacter which easily grow on 'botrytized' grapes. Depending on climatic conditions, some vintages are particularly difficult to stabilize.

Acetic Acid↗
PubMed2006

Grape variety affects larval performance and also female reproductive performance of the European grapevine moth Lobesia botrana (Lepidoptera: Tortricidae).

For insect herbivores, the quality of the larval host plant is a key determinant of fitness. Therefore, insect populations are supposed to be positively correlated with the nutritional quality of their host plant. This study aimed to determine if and how different varieties of grapes (including the wild grape Lambrusque) affect both larval and adult performance of the polyphagous European grapevine moth Lobesia botrana (Denis & Schiffermüller). Significant differences were found in larval development time, but not in pupal mass, adult emergence rate, or sex ratio. Although the fecundity of females is not different among varieties, females fed on some varieties produced eggs of different sizes which are correlated to their fertility. Thus, females adapt resource allocation to eggs depending on their diet as larvae. Using a fitness index, the average reproductive output was found to be highest for females reared on cv. Chardonnay. Females reared on wild grape produced a fitness index identical to the cultivated grapes. However, Lambrusque and Gewurztraminer separate themselves from the cultivated varieties according to our discriminant analyses. It is emphasized, through this study, that cultivars fed on by larvae should be considered in the population dynamics of L. botrana and that egg number is insufficient to determine host plant quality.

Analysis of Variance↗
PubMed2000

The determination of total SO2 in grape juice. A comparison among five methods.

The EC official method of total SO2 analysis in grape juice was modified in 1990. The main improvements concerned the amount and concentration of H3PO4 used during the distillation to recover the combined SO2 and the standardization of the distillation time at 15 min. This comparative study evaluated the total SO2 level of 12 grape juices determined by five methods, including distillation, iodimetric and enzymatic-based methods. Attention was focused on the total SO2 legal limit of 10 mg/l fixed in Europe for grape juice. Analysis of variance disclosed a significant difference among the total SO2 content in grape juices determined by five methods. Each analytical method showed limits in relation of their ability to release the combined SO2. In particular, the SO2 bonded to phenolic compounds is partially released at low pH in the acidified juice leading to higher results.

Analysis of Variance↗
PubMed2001

Fenhexamid residues in grapes and wine.

The behaviour of the fungicide, fenhexamid, on grapes, and during wine-making, as well as its effect on the microflora of alcoholic and malolactic fermentation has been studied. After treatment, the residue on grapes decreased rapidly to one-third of the initial level after the first week, while it remained constant during the following two weeks. At harvest, in the wine obtained by vinification without skins, the fungicide residue decreased on average by 49%, while in the wine obtained by vinification with skins, the decrease was on average 62%. The presence of this fungicide on grapes and in the wine did not affect alcoholic and malolactic fermentation, nor did fermentation cause any degradation of the fungicide. A simple and rapid gas chromatograhic method (GC-NPD) for the determination of fenhexamid residues in grapes, must and wine is described.

Aminophenols↗
PubMed2004

Occurrence of ochratoxin A in wine and grape juice marketed in Rio de Janeiro, Brazil.

Ochratoxin A (OA) is receiving attention world-wide because of the hazard it poses to human health. The aim was to test the distribution of OA in grape juice, pulps of frozen grapes, and national and imported table wine obtained from markets in Rio de Janeiro, Brazil. Analytical methodology using immunoaffinity column for OA extraction and clean-up with a final separation on a reversed-phase (C(18)) column and fluorescence detection in high-performance liquid chromatography showed a detection limit of 21 ng l(-1). The mean recovery was 91% for red wines and 82% for white wines; while the mean recoveries for juices and pulps of frozen grapes were 91.6 and 88%, respectively. Of 64 samples of grape juice and frozen pulps, 25% were positive for OA, being the mean content of 37 ng l(-1) with a maximum concentration of 100 ng l(-1). In wines, the mean concentration detected in 80 samples analysed was 34.4 ng l(-1) with 28.75% of positive samples. Red wines showed the highest percentages and levels of contaminated samples: 38% and 37 ng l(-1), respectively. The white wine contained levels above 26 ng l(-1) in 17.75% of the analysed samples. The levels of contamination detected in red wine sold in Río de Janeiro were not enough to surpass the virtually safe dose established as 5 n g kg(-1) body weight of daily intake.

Beverages↗
PubMedDate not supplied

Ochratoxin A in table wine and grape-juice: occurrence and risk assessment.

The concentrations of ochratoxin A (OA) and C (ethyl ester of OA, OC) have been measured in table wine from the Swiss retail market. The overall median concentrations of OA in white, rose and red table wine were (number of samples; range) < 3 pg/ml (24; < 3-178 pg/ml), 19 pg/ml (15; < 3-123 pg/ml) and 13 pg/ml (79; < 3-388 pg/ml)), respectively. For dessert wines (Malaga, Marsala) a median of 337 pg/ml (5; 44-451 pg/ml) resulted. Concentrations of OC were about 10% of those of OA. OA has been detected in red grape-juices for the first time with median concentrations amounting to 235 pg/ml (8; < 3-311 pg/ml). White grape-juices (3) as well as other fruit juices (2 apple, 6 orange, 2 others) did not contain OA (< 5 pg/ml). The analytical method used was not appropriate for grapefruit-juices because of an interfering substance. The results indicate that OA is formed prior to the alcoholic fermentation. It also appears that the more southerly in Europe is the origin of the samples the higher is the frequency of occurrence and the concentration of OA in red wines and red grape-juices. Although the estimated mean daily OA intake of 0-7 ng/kg body mass (men) can easily be more than doubled by moderate wine consumption, an additional health risk by OA is not to be expected. On the other hand the consumption of red grape-juices among infants and children may result in intakes high enough to justify a reduction of the OA concentrations in these juices to less than 100 pg/ml.

Beverages↗
PubMed2007

Black grape and garlic extracts protect against cyclosporine a nephrotoxicity.

The aim of this study was to determine if the natural antioxidant foods, dried black grape and garlic, protect against cyclosporine nephrotoxicity. Forty-two Sprague-Dawley rats were given Cyclosporine A (CsA) orally for 10 days, with the antioxidant food supplementation begun 3 days before CsA treatment and continued during the study period (totaling 13 days). In each group (control, CsA alone, CsA plus black grape, CsA plus aqueous garlic extract, aqueous garlic extract alone and black grape alone), there were 7 animals. At the end of the study period, the animals were sacrificed; their kidneys were removed and prepared for biochemical and histopathological investigations. Oxidant (xanthine oxidase enzyme and malondialdehyde) and antioxidant (superoxide dismutase, glutathione peroxidase and catalase enzymes) parameters were measured in the kidney tissues of the groups. Histopathological examinations of the tissues were also performed. It has been found that CsA creates oxidant load to the kidneys through both xanthine oxidase activation and impaired antioxidant defense system, which accelerates oxidation reactions in the kidney tissue. Supplementation with either dried black grape or aqueous garlic extract led to reduced malondialdehyde level in the kidney tissue possibly, by preventing oxidant reactions. In conclusion, the results suggest that impaired oxidant/antioxidant balance may play part in the CsA-induced nephrotoxicity, and some foods with high antioxidant power may ameliorate this toxicity, in agreement with studies with antioxidant vitamins.

Animals↗
PubMedDate not supplied

Quercetin is bioavailable from a single ingestion of grape juice.

The in vivo bioactivity of polyphenols will depend on their bioavailability. Grape juice is an important source of dietary phenolics. This paper reports results that prove that quercetin (3,3',4',5,7-pentahydroxyflavone) is bioavailable after a single ingestion of red grape juice by healthy volunteers. Blood plasma samples were collected before and after 2 h of ingestion of 100 ml of concentrated grape juice (n = 14), and of a placebo solution (n =6). Significant differences in the variation of the total plasma quercetin content (before and after ingestion) between the grape juice ingestion group (3.1 microg/l increase, as a mean) and the placebo group (6.0 microg/l decrease, as a mean) were found. This relatively low increase in comparison with that obtained after 2 h of ingestion of onions (201 microg/l, as a mean) and with those reported in the literature for other foods/beverages was attributed to differences in the amount of quercetin ingested, in the form in which quercetin is present, and in the food matrix.

Adult↗
PubMed2002

Grape seed proanthocyanidins improved cardiac recovery during reperfusion after ischemia in isolated rat hearts.

BACKGROUND: Increasing evidence shows that red wine consumption has cardioprotective effects. These effects have been attributed to the polyphenolic compounds in grapes. OBJECTIVE: We studied the effects of red grape seed proanthocyanidins on the recovery of postischemic function in isolated rat hearts. DESIGN: Two groups of rats were fed different doses of proanthocyanidin-rich extract for 3 wk and another group was untreated and served as controls. The animals were then anesthetized and the hearts were isolated and subjected to 30 min of ischemia followed by 2 h of reperfusion. Coronary effluents were collected during the third minute of reperfusion for measurement of oxygen free radicals by using electron spin resonance spectroscopy. RESULTS: In rats treated with 50 and 100 mg grape seed proanthocyanidins/kg, the incidence of reperfusion-induced ventricular fibrillation was reduced from its control value of 92% to 42% and 25%, respectively (P < 0.05 for both). The incidence of ventricular tachycardia showed the same pattern. In rats treated with 100 mg proanthocyanidins/kg, the recovery of coronary flow, aortic flow, and developed pressure after 60 min of reperfusion was improved by 32% +/- 8%, 98% +/- 8%, and 37% +/- 3%, respectively (P < 0.05 for all) compared with untreated control rats. Electron spin resonance studies indicated that proanthocyanidins significantly inhibited the formation of oxygen free radicals. In rats treated with 100 mg proanthocyanidins/kg, free radical intensity was reduced by 75% +/- 7% (P < 0.05) compared with the control rats. CONCLUSION: Grape seed proanthocyanidins have cardioprotective effects against reperfusion-induced injury via their ability to reduce or remove, directly or indirectly, free radicals in myocardium that is reperfused after ischemia.

Animals↗
PubMed2002

Carbaryl resistance in populations of grape berry moth (Lepidoptera: Tortricidae) in New York and Pennsylvania.

We collected grape berry moth, Endopiza viteana (Clemens) (from cultivated and wild Vitis along Lake Erie in Pennsylvania and New York), and measured carbaryl susceptibility in first instars. A model of susceptibility was based on the concentration-mortality curve of laboratory-maintained colonies originating from wild Vitis with no prior history of carbaryl exposure, and a noncommercial vineyard with modest previous exposure to carbaryl. We estimated LC50 and LC90 for susceptible grape berry moth larvae at 45.4 and 2319 microg/ml, respectively. Bioassays on field-collected larvae from commercial vineyards in both states, where grape growers were abiding by current pest management guidelines for carbaryl use, revealed carbaryl resistance ratios from 7 to 71 at the LC50 level. With the loss or restriction of alternative chemical control tactics in the Food Quality Protection Act era, resistance management programs for grape berry moth should be immediately developed and implemented to regain the efficacy of this once effective insecticide and other related chemical compounds.

Animals↗
PubMed2005

Functional xylem in the post-veraison grape berry.

A number of studies have shown a transition from a primarily xylem to a primarily phloem flow of water as fleshy fruits develop, and the current hypothesis to explain this transition, particularly in grape (Vitis vinifera L.) berries, is that the vascular tissue (tracheids) become non-functional as a result of post-veraison berry growth. In most studies, pedicels have been dipped in a vial containing an apoplastic dye, which was taken up into the entire peripheral and axial xylem vasculature of pre-veraison, but not post-veraison berries. The pressure plate/pressure membrane apparatus that is commonly used to study soil moisture characteristics was adapted and the pre- to post-veraison change in xylem functionality in grape berries was re-evaluated by establishing a hydrostatic (tension) gradient between the pedicel and a cut surface at the stylar end of the berry. Under the influence of this applied hydrostatic gradient, movement of the apoplastic tracer dye, basic fuchsin, was found in the pedicel and throughout the axial and peripheral xylem of the berry mesocarp. A similar movement of dye could be obtained by simply adjoining the stylar cut surface to a dry, hydrophilic wicking material. Since both pre- and post-veraison berries hydrate when the pedicel is dipped in water, it is hypothesized that the absence of dye movement into the vasculature of post-veraison berries indicates not a loss of xylem function, but rather the loss of an appropriate driving force (hydrostatic gradient) in the berry apoplast. Based on this hypothesis, and the substantial decrease in xylem flows that occur in intact grape berries at veraison, it is suggested that there may be significant changes in the pattern of solute partitioning between the fruit symplast and apoplast at veraison. It is further suggested that diurnal patterns in symplast/apoplast solute partitioning in grapes and other fleshy fruit, may explain the observed minimal xylem contribution to the water budgets of these fruits.

Biological Transport, Active↗
PubMed2006

Pathways of glucose regulation of monosaccharide transport in grape cells.

Grape (Vitis vinifera) heterotrophic suspension-cultured cells were used as a model system to study glucose (Glc) transport and its regulation. Cells transported D-[14C]Glc according to simple Michaelis-Menten kinetics superimposed on first-order kinetics. The saturating component is a high-affinity, broad-specificity H+ -dependent transport system (Km = 0.05 mm). Glc concentration in the medium tightly regulated the transcription of VvHT1 (Vitis vinifera hexose transporter 1), a monosaccharide transporter previously characterized in grape berry, as well as VvHT1 protein amount and monosaccharide transport activity. All the remaining putative monosaccharide transporters identified so far in grape were poorly expressed and responded weakly to Glc. VvHT1 transcription was strongly repressed by Glc and 2-deoxy-D-Glc, but not by 3-O-methyl-D-Glc or Glc plus mannoheptulose, indicating the involvement of a hexokinase-dependent repression. 3-O-Methyl-D-Glc, which cannot be phosphorylated, and Glc plus mannoheptulose induced a decrease of transport activity caused by the reduction of VvHT1 protein in the plasma membrane without affecting VvHT1 transcript levels. This demonstrates hexokinase-independent posttranscriptional regulation. High Glc down-regulated VvHT1 transcription and Glc uptake, whereas low Glc increased those parameters. Present data provide an example showing control of plant sugar transporters by their own substrate both at transcriptional and posttranscriptional levels. VvHT1 protein has an important role in the massive import of monosaccharides into mesocarp cells of young grape berries because it was localized in plasma membranes of the early developing fruit. Protein amount decreased abruptly throughout fruit development as sugar content increases, consistent with the regulating role of Glc on VvHT1 expression found in suspension-cultured cells.

Biological Transport↗