Quantitation of ochratoxin A in South African wines

The natural occurrence of the carcinogenic mycotoxin ochratoxin A (OTA) in wines sold in local retail outlets in South Africa and Italy was investigated by HPLC analysis with fluorescence detection following cleanup by immunoaffinity column. All 24 local South African wines tested (15 white and 9 red) were found to contain detectable levels (>0.01 microg/L) of OTA, with a mean of 0.16 microg/L in the white wines and a mean of 0.24 microg/L in the red wines. Results were subsequently confirmed by LC-MS analysis using positive ion electrospray ionization with collision-induced dissociation of the protonated molecular ion [M + H](+) at m/z 404 and selected reaction monitoring of the resultant product ions [M + H - H(2)O - CO](+) at m/z 358 and [M + H - H(2)O](+) at m/z 386. Comparison with the fluorescence method gave a significant correlation (r = 0.87; p < 0.01). Although OTA contamination was present in all of the South African samples analyzed, levels were well below the suggested European Union limit of 0.5 microg/kg. The highest level found in a locally purchased wine was 0.39 microg/L in a blend of local and imported Spanish red wine. Of the eight Italian wines analyzed, only two red wines were contaminated above the suggested maximum level.     

Automated on-line solid-phase extraction-liquid chromatography-electrospray tandem mass spectrometry method for the determination of ochratoxin A in wine and beer

An automated on-line solid-phase extraction-liquid chromatography-electrospray tandem mass spectrometry (SPE-LC-ESI-MS/MS) method was developed for the determination of ochratoxin A (OTA) in alcoholic beverages. Mean recoveries for wine and beer were, respectively, 75 and 82%. Detection was achieved in negative ionization with a Q TRAP mass spectrometer operating in multiple-reaction monitoring (MRM) mode or enhanced product ion (EPI) mode, using the third quadrupole as linear ion trap. The MRM mode turned out to be more sensitive; the method allowed accurate determination of OTA in the range of 0.01-25 ng mL(-1) using external calibration. Within-day and between-day relative standard deviation percentages were <6.2 and <9.1%, respectively. In EPI mode, fragmentation spectra at the limit of quantification (0.03 ng mL(-1)) and good linearity could be obtained. Application of the method (MRM mode) to the analysis of several wine and beer samples purchased in local stores revealed OTA levels in the ranges of 0.03-1.44 ng mL(-1) for wines and 0.02-0.14 ng mL(-1) for beers.     

Isotope ratios of lead in Italian wines by inductively coupled plasma mass spectrometry

Lead and its isotope ratios (IRs) in 83 Italian wines from 42 different administrative provinces produced on laboratory scale in 2000 were measured by inductively coupled plasma mass spectrometry. Lead had a median of 19.0 microg/L, ranging from 10.0 up to 149 microg/L and was higher in the samples from northwestern Italy. The values of the IRs were (mean +/- standard deviation) 1.171 +/- 0.011 for (206)Pb/(207)Pb, 2.071 +/- 0.017 for (208)Pb/(206)Pb, 2.425 +/- 0.014 for (208)Pb/(207)Pb, 17.84 +/- 0.32 for (206)Pb/(204)Pb, 15.24 +/- 0.31 for (207)Pb/(204)Pb, and 37.31 +/- 0.52 for (208)Pb/(204)Pb. These ratios agree with those in the literature for several European regions. (206)Pb/(207)Pb distinguished the northwestern from the northeastern and southern Italian wines, and the southern samples were distinguishable only from the northwestern ones. (208)Pb/(206)Pb distinguished the northwestern from the southern Italian samples. Nevertheless, the lead IRs do not seem to be a very effective tool for the origin authentication of wines from different Italian regions.     

Determination of stilbenes (delta-viniferin, trans-astringin, trans-piceid, cis- and trans-resveratrol, epsilon-viniferin) in Brazilian wines

Phenolics from grapes and wines can play a role against oxidation and development of atherosclerosis. Stilbenes have been shown to protect lipoproteins from oxidative damage and to have cancer chemopreventive activity. We describe a method for the direct determination of stilbenes in several red wines using high-performance liquid chromatography with UV detection. In a survey of 12 commercial wines from the south of Brazil (Rio Grande del Sul), levels of delta-viniferin are reported for the first time in different varieties of red wines. Brazilian red wine contains trans-astringin, trans-piceid, trans-resveratrol, cis-resveratrol (in high quantity: 5 times more than the trans form), epsilon-viniferin, and a compound isolated for the first time in wine, trans-delta-viniferin. Isolation and identification of delta-viniferin was achieved by NMR after extraction and fractionation of red wine phenolics. delta-Viniferin contributes, as well as cis-resveratrol and trans-piceid, to a significant proportion of stilbenes in wine dietary intake, particularly with Merlot varieties containing an average level of 10 mg/L for delta-viniferin, 15 mg/L for cis-resveratrol, and 13 mg/L for trans-piceid. The total stilbene intake from wine origin was estimated for the Brazilian population as 5.3 mg/day per person (on the basis of a regular wine consumption of 160 mL/day). delta-Viniferin can contribute to around 20% of total stilbenes in wine (average of 6.4 mg/L in red Brazilian wines). It would be important in the future to investigate the origins of the differences in wine stilbene levels in relation to the vine varieties, and the bioavailability of the newly extracted stilbene delta-viniferin in plasma after consumption of different types of wines.     

Characterization of wines by nuclear magnetic resonance: a work study on wines from the Basilicata region in Italy

We explored the possibility of differentiating Italian wines produced in different regions by means of nuclear magnetic resonance (NMR) techniques. Ten commercial red Aglianico wines were selected from different areas of the Basilicata region in the south of Italy. Some important components of these wines were identified by the assignments of their (1)H and (13)C resonances using one- and two-dimensional homonuclear and heteronuclear NMR experiments. These data were compared with those obtained from 10 Aglianico wines produced in Campania, another southern Italian region. Differences were found among the wines according to their geographical origin and vintage. A fine discrimination of Aglianico wines from Basilicata and Campania was obtained, suggesting that the selected NMR parameters may be a valuable tool for wine authenticity control.     

Method for the gas chromatographic assay with mass selective detection of trichloro compounds in corks and wines applied to elucidate the potential cause of cork taint

To investigate the role of trichloro compounds as a potential cause of "cork taint" in wine, an assay for trichloroanisole (TCA) and trichlorophenol (TCP) in corks and wine was developed utilizing solid phase extraction on a C(18) cartridge followed by gas chromatography with mass selective detection. Recovery and imprecision for TCA were 86-102 and 1.6-5.8%, respectively, and for TCP 82-103% and 1.7-3.9%, respectively. Limits of detection and quantitation were 0.1 and 2 ng/L, respectively, for TCA, and 0.7 and 4 ng/L, respectively for TCP. A survey of 2400 commercial wines revealed a higher incidence of cork taint in white wine than in red and in wines utilizing composite cork closures; wines from central Europe and Spain had higher overall rates of contamination and those from Canada and Italy the lowest. Significant but modest associations were found between the TCA and TCP contents of the wines and corks, but many wines exhibiting cork taint had low or undetectable concentrations of TCA. Over a 12-month period, experimentally bottled wines exhibited a slow increase in TCA and TCP content while cork closures manifested a decrease; most bottles showing cork taint contained low levels of TCA, and TCP concentrations were well below the sensory threshold. Neither compound was cytotoxic to human cell lines in culture up to final concentrations of 500 ng/mL. It was concluded that these two trichloro compounds are, at most, minor components of cork taint in commercial wines.     

Analysis of ochratoxin A in foods consumed by inhabitants from an area with balkan endemic nephropathy: a 1 month follow-up study

In the 1950s, a series of publications from Bulgaria, Yugoslavia, and Romania locally described a kidney disease called Balkan Endemic Nephropathy (BEN). In Bulgaria, the exposure of populations to ochratoxin A (OTA) was supported by analysis of individual food items demonstrating a higher prevalence and higher levels of OTA in food from the high-incidence areas of BEN. In this work, food consumption from a series of individuals from two villages of the BEN area during 1 month was followed using the duplicate diet method. Meals consumed by volunteers from both villages showed uneven OTA contents, spreading from below the limit of quantification (<0.07 microg/kg) to 2.6 microg/kg. The average weekly intake of OTA varies from 1.86 to 92.7 ng/kg of body weight. Some of these levels approach the provisional tolerable weekly intake (PTWI) established by the JECFA at 100 ng/kg of body weight. These results confirm previous studies performed in the same area and demonstrate the high exposure of this population to OTA, thus strengthening the hypothesis of the involvement of this mycotoxin in BEN etiology.     

Antioxidant capacities and phenolics levels of French wines from different varieties and vintages.

Phenolics from grapes and wines can play a role against oxidation and development of atherosclerosis. Levels of phenolics, major catechins [(+)-catechin, (-)-epicatechin, procyanidin dimers B1, B2, B3, and B4], phenolic acids (gallic acid and caffeic acid), caftaric acid, malvidin-3-glucoside, peonidin-3-glucoside, and cyanidin-3-glucoside were quantified by HPLC with UV detection for 54 French varietal commercial wines taken from southern France to study the antioxidant capacity and the daily dietary intake of these compounds for the French population. The highest antioxidant capacity was obtained with red wines and ranged from 12.8 mmol/L (Grenache) to 25.2 mmol/L (Pinot Noir). For white wines, Chardonnay enriched in phenolics by special wine-making was found to have an antioxidant capacity of 13.8 mmol/L, comparable to red wine values. For red wines classified by vintages (1996-1999) antioxidant capacities were approximately 20 mmol/L and then decreased to 13.4 mmol/L for vintages 1995-1991. Sweet white wines have 1.7 times more antioxidant capacity (3.2 mmol/L) than dry white wines (1.91 mmol/L). On the basis of a still significant French wine consumption of 180 mL/day/person, the current daily intake of catechins (monomers and dimers B1, B2, B3, and B4) averaged 5 (dry white wine), 4.36 (sweet white wines), 7.70 (rosé wines), 31.98 (red wines), and 66.94 (dry white wine enriched in phenolic) mg/day/resident for the French population. Red wine, and particularly Pinot Noir, Egiodola, Syrah, Cabernet Sauvignon, and Merlot varieties, or Chardonnay enriched in phenolics during wine-making for white varieties contribute to a very significant catechin dietary intake.     

Ochratoxin A in Korean food commodities: occurrence and safety evaluation

To evaluate the exposure of Koreans to ochratoxin A, we conducted a survey in 2003 for ochratoxin A in various domestic food commodities: 60 polished rices, 22 barleys, 35 wheat flours, 46 beers, and 14 unstrained rice wine (makkolli) samples. They were analyzed for ochratoxin A using immunoaffinity column and high-performance liquid chromatography (HPLC)-fluorescence detection, and the positive samples were confirmed using HPLC-tandem mass spectrometry. By combining results from different surveys on the levels of ochratoxin A in selected foods and the consumption patterns, we obtained the Korean probable daily intakes (PDI) of ochratoxin A. The polished rice commodity had the highest mean levels of ochratoxin A, which ranged from 0.2 (not detected, i.e., ND = 0) to 1.0 ng/g (ND = limit of detection, i.e., LOD). The estimated PDI for all Koreans fell into the range of 0.8-4.1 ng/kg bw/day, while for heavy consumers the estimates ranged from 1.7 to 9.1 ng/kg bw/day, which did not exceed the PTDI value (14 ng/kg bw/day). Staple rice is the major contributor (>90%) to the Korean dietary intake of ochratoxin A. On the basis of these estimates, it may be concluded that there is at present no considerable risk of ochratoxin A exposure for the average Korean consumer.     

Contribution of proanthocyanidins to the peroxy radical scavenging capacity of some Italian red wines

Highly reactive radicals, ROO(*), were generated from 2, 2'-azobis[2-(2-imidazolin-2-yl)propane] and linoleic acid. The ROO(*) scavenging capacity of some Italian red wines was evaluated following the changes in oxygen consumption. Under the experimental conditions the time course of oxygen consumption shows two typical behaviors: trolox-like (class I) and gallic acid-like (class II). Usually the time course of wine was similar to that of gallic acid. The rate of oxygen consumption was found to decrease exponentially with the amount of wine or gallic acid added to the test solution. On this basis the capacity of red wines to scavenge peroxy radicals was expressed as content of gallic acid (S(GA)). The S(GA) values were found to be correlated to the amount of total proanthocyanidins and total polyphenols of some Italian red wines (p < 0.01). The proanthocyanidins extracted from seeds were shown to make a major contribution to the peroxy radical scavenging capacity of red wines, whereas, interestingly, the chemical class of the low molecular weight tannins reactive to vanillin did not correlate with the S(GA) values.     

Anthocyanin and proanthocyanidin content in selected white and red wines. Oxygen radical absorbance capacity comparison with nontraditional wines obtained from highbush blueberry

Antioxidant capacity, as measured by oxygen radical absorbance capacity (ORAC(PE)), total phenolic, total and individual anthocyanins, and proanthocyanidin fraction contents were evaluated in red and white wines from grapes. A comparison in terms of antioxidant capacity is made with nontraditional wines made from highbush blueberry. Blueberries are among fruits that are best recognized for their potential health benefits. In red wines, total oligomeric proanthocyanidin content, including catechins, was substantially higher (177.18 +/- 96.06 mg/L) than that in white wines (8.75 +/- 4.53 mg/L). A relative high correlation in red wines was found between ORAC(PE) values and malvidin compounds (r = 0.75, P < 0.10), and proanthocyanidins (r = 0.87, P < 0.05). In white wines, a significant correlation was found between the trimeric proanthocyanidin fraction and peroxyl radical scavenging values (r = 0.86, P < 0.10). A moderate drink (1 drink per day, about 140 mL) of red wine, or white wine, or wine made from highbush blueberry corresponds to an intake of 2.04 +/- 0.81 mmol of TE, 0.47 +/- 0.15 mmol of TE, and 2.42 +/- 0.88 mmol of TE of ORAC(PE)/day, respectively.     

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.     

Positive correlation between high levels of ochratoxin A and resveratrol-related compounds in red wines

The natural occurrence of ochratoxin A in red wines has been widely reported by several authors, as well as a that of group of stilbenes including cis- and trans-resveratrols and related glucosylated forms. In the present study 112 samples of retail red wines were collected from northern (17), central (46), and southern (49) Italy and were analyzed for both ochratoxin A and resveratrol-related stilbenes. The mean levels of total resveratrols and total piceids were 3.14 and 5.80 mg/L, respectively, whereas the ochratoxin A mean level was 0.64 microg/L. The Merlot wines showed the highest mean value of total stilbenes, followed by Negroamaro and Negroamaro blend, Aglianico, and Syrah, all with mean levels of >10 mg/L. Ochratoxin A was detected in 70, 59, and 100% of wine samples from northern, central, and southern Italy, with mean levels of 0.12, 0.07, and 1.36 microg/L, respectively. The highest values of ochratoxin A were recorded in Negroamaro- and Primitivo-based wine samples from southern Italy, showing also the highest content of stilbenes. In wine samples from southern Italy, a positive correlation was obtained between levels of ochratoxin A and total stilbenes (r = 0.74) as well as between ochratoxin A and total resveratrols (r = 0.50) and between ochratoxin A and total piceids (r = 0.74). These results suggest that toxic levels of ochratoxin A in red wine may be, at some extent, counterbalanced by the beneficial effects of resveratrol derivatives. Further investigation should be warranted in this regard.     

Optimizing the process of making sweet wines to minimize the content of ochratoxin A

During the drying process of raisins, the grapes are subjected to climatic variations that can result in heavy infections of some fungal species that produce ochratoxin A (OTA), a powerful toxic metabolite, whose maximum permitted content is set by the European Union at 2.0 μg/L for grapes, wine and other drinks derived from the grape. The aim of this paper is to optimize the process of making sweet wines in order to minimize the content of ochratoxin A. The results reflect a reduction of the OTA content in grapes dried under controlled conditions in a climatic chamber up to 24% compared to those sunned in the traditional way. A decrease of the concentrations of OTA is also observed during the processes of vinification. Those wines with prefermentative maceration reached a higher OTA content than the wines without maceration, but unexpectedly were not those preferred from a sensorial point of view. In addition, the process of aging in oak casks has been shown to serve as a natural method for reducing the OTA content of these wines.     

Dietary wine phenolics catechin, quercetin, and resveratrol efficiently protect hypercholesterolemic hamsters against aortic fatty streak accumulation

The effects of the phenolic compounds catechin (Cat), quercetin (Qer), and resveratrol (Res) present in red wine on early atherosclerosis were studied in hamsters. Hamsters (n = 32) were divided into 4 groups of 8 and fed an atherogenic diet for 12 weeks. They received by force-feeding 7.14 mL/(kg of body wt.day) Cat, Qer, or Res in water [2.856 mg/(kg of body wt.day) for Cat and 0.1428 mg/(kg of body wt.dday) for Qer and Res], mimicking a moderate consumption of alcohol-free red wine (equivalent to that supplied by the consumption of about two glasses of red wine per meal for a 70 kg human), or water as control. Plasma cholesterol concentration was lower in groups that consumed phenolics than in controls. The increase in plasma apolipoprotein (Apo) A1 concentration was mainly due to Cat (26%) and Qer (22%) and to a lesser extent, but nonsignificantly, Res (19%). Apo-B was not affected. Plasma antioxidant capacity was not improved, and there was no sparing effect on plasma vitamins A and E. Plasma iron and copper concentrations were not modified nor were liver super oxide dismutase and catalase activities. A sparing effect of Qer on liver glutathione peroxidase activity appeared, whereas Cat and Res exhibited a smaller effect. Aortic fatty streak area was significantly reduced in the groups receiving Cat (84%) or Qer (80%) or Res (76%) in comparison with the controls. These findings demonstrate that catechin, quercetin, and resveratrol at nutritional doses prevent the development of atherosclerosis through several indirect mechanisms.     

Sensory and analytical study of rose sparkling wines manufactured by second fermentation in the bottle

The sensory and analytical characteristics of five rose sparkling wines manufactured by the traditional method have been determined. Moreover, the changes that take place in the nitrogen and volatile fraction of the wines during the second fermentation and the aging with the yeasts have been studied. Each of these wines was made from a single industrial rose base wine of the Garnacha Tinta variety, with five selected yeasts strains. The base wine had a low content in free amino acids, 16 mg/L, and the yeast consumed more peptides than free amino acids during second fermentation. From the application of the two-way analysis of variance, yeast strain, and aging time factors to the data of volatile compounds, it has been found that most of the differences between these sparkling wines are due to the aging time. It has been verified that these rose sparkling wines have foam of good quality and that the grape variety Garnacha Tinta is suitable for the production of rose sparkling wines.     

Removal of ochratoxin A in red wines by means of adsorption treatments with commercial fining agents

The presence in wine of the fungal metabolite, ochratoxin A (OTA), represents a serious risk for consumer health. A variety of fining agents, including activated carbon, silica gel, potassium caseinate, egg albumin, and gelatin, was evaluated in relation to their abilities to remove OTA in fortified wines. Freundlich adsorption isotherms were used to model the adsorption behavior between ochratoxin A and the fining agent. Potassium caseinate and activated carbon were found to be the best fining agents that could be used to remove OTA in wine. Potassium caseinate removed up to 82% of OTA when used at 150 g/hL, whereas activated carbon showed the highest specific adsorption capacity due to a high surface area per mass and low adsorption of total polyphenols.     

Multiwalled carbon nanotubes as sorbent for online solid-phase extraction of resveratrol in red wines prior to fused-core C18-based ultrahigh-performance liquid chromatography-tandem mass spectrometry quantification

An ultrafast analytical protocol based on online solid-phase extraction (SPE)/high-performance liquid chromatography-tandem mass spectrometry for the determination of resveratrol in red wines has been developed. In the present work, multiwalled carbon nanotubes (MWCNTs) were used as SPE sorbents for the analytes' online extraction and cleanup. The target analytes were separated on a fused-core C18-silica column (Halo, 50 mm × 2.1 mm i.d., 2.7 μm) and quantified by triple-quadrupole linear ion trap mass spectrometry in negative ion multiple-reaction monitoring (MRM) mode. The proposed analytical procedures were carefully optimized and validated. The calibration function is linear from 0.37 to 370 ng mL(-1) and from 0.13 to 130 ng mL(-1) for trans- and cis-resveratrol, respectively. The limits of quantification (LOQs) of trans- and cis-resveratrol obtained were 0.05 and 0.06 ng mL(-1), which means that the proposed method is suitable for trace analysis of resveratrol at low-level concentration. At the three fortified levels (low, medium, and high), recoveries of resveratrol ranging from 76.9 to 108.3% were obtained. Eight red wine samples from different regions of China were analyzed. The results indicated that the present online SPE-LC-MS/MS system significantly increased sample throughput and decreased solvent consumption, exhibiting great potential to be applied for analyzing resveratrol in red wines.     

Lead dietary intake in a Spanish population (Canary Islands)

For most people diet is the main route of exposure to trace metals, so information about dietary intake is also important to assess risks to human health for these elements. The purpose of this study was to determine the levels of Pb in the foods and drinks of highest consumption in the authors' our community to estimate daily intakes of Pb for each of the seven Canary Islands. Four hundred and twenty samples were analyzed using GFAAS. The total Pb intake of the Canarian population is 72.8 microg/day, 29.12% (for a person of 70 kg body weight) of the provisional tolerable weekly intake limit of 25 microg/kg fixed by the FAO/WHO. The island that presents the highest lead intake is La Gomera, followed by Lanzarote, Tenerife, and Gran Canaria islands. These four islands present a lead dietary intake over the mean Pb intake for the whole archipelago. The islands with lower Pb intakes are La Palma and Fuerteventura, with intakes under 70 microg/day. These results have also been compared with the values found for other national and international communities.     

A novel method for quantification of 2-methyl-3-furanthiol and 2-furanmethanethiol in wines made from Vitis vinifera grape varieties

A rapid, easy method has been developed for isolating and quantifying 2-methyl-3-furanthiol (2M3F) in wines. Until now, it was not possible to quantify this highly odoriferous compound, with a smell reminiscent of cooked meat, in wine. The original aspect of this method is the specific release of volatile thiols using a cysteamine solution applied in reverse flow to sample percolation on the basis of a p-hydroxymercuribenzoate (pHMB)-volatile thiol conjugate formed by the direct addition of pHMB to 50 mL of wine. Purification of volatile thiols in wines is much faster and easier than our previous method. This method may also be used to assay 2-furanmethanethiol in wine. This thiol's strong aroma of roasted coffee has been shown to contribute to the "roast coffee" aroma of certain wines. Assaying 2M3F by this method showed that it was present in the wines analyzed (red and white Bordeaux, Loire Valley Sauvignon blanc, white Burgundy, and Champagne) at concentrations up to 100 ng/L, i.e., significantly above the olfactory perception threshold for this compound in model dilute alcohol solution.