Characterization and quantification of grape variety by means of shikimic acid concentration and protein fingerprint in still white wines

Protein profiles, obtained by high-performance capillary electrophoresis (HPCE) on white wines previously dialyzed, combined with shikimic acid concentration and multivariate analysis, were used for the determination of grape variety composition of a still white wine. Six varieties were studied through monovarietal wines elaborated in the laboratory: Chardonnay (24 samples), Chenin (24), Petit Manseng (7), Sauvignon (37), Semillon (24), and Ugni Blanc (9). Homemade mixtures were elaborated from authentic monovarietal wines according to a Plackett-Burman sampling plan. After protein peak area normalization, a matrix was elaborated containing protein results of wines (mixtures and monovarietal). Partial least-squares processing was applied to this matrix allowing the elaboration of a model that provided a varietal quantification precision of around 20% for most of the grape varieties studied. The model was applied to commercial samples from various geographical origins, providing encouraging results for control purposes.

Stir bar sorptive extraction combined with GC-MS analysis and chemometric methods for the classification of South African Wines according to the volatile composition

A simple method for the analysis of major wine volatiles and semivolatiles by stir bar sorptive extraction in combination with thermal desorption and gas chromatography-mass spectrometry (SBSE-TD-GC-MS) was developed. Significant experimental parameters such as extraction time, temperature, salt addition, pH, and thermal desorption parameters were optimized to provide a sensitive and robust analytical method. The method provided good repeatability (%RSD < 10%) for 38 major wine volatile compounds, including alcohols, acids, esters, phenols, aldehydes, ketones, and lactones. Quantitative data for 62 South African red and white wines were used to study the suitability of major volatile data for the differentiation of wine samples according to grape variety or cultivar. Principal component analysis (PCA) and cluster analysis (CA) showed that most of the variation in volatile composition between wine samples could be ascribed to differences in wine age, wood contact, and fermentation practices. Despite the contribution of these factors, discriminant analysis (DA) was successfully applied to the classification of red and white wine samples according to cultivar.

Prediction of enological parameters and discrimination of rice wine age using least-squares support vector machines and near infrared spectroscopy

The use of least-squares support vector machines (LS-SVM) combined with near-infrared (NIR) spectra for prediction of enological parameters and discrimination of rice wine age is proposed. The scores of the first ten principal components (PCs) derived from PC analysis (PCA) and radial basis function (RBF) were used as input feature subset and kernel function of LS-SVM models, respectively. The optimal parameters, the relative weight of the regression error gamma and the kernel parameter sigma 2, were found from grid search and leave-one-out cross-validation. As compared to partial least-squares (PLS) regression, the performance of LS-SVM was slightly better, with higher determination coefficients for validation ( Rval2) and lower root-mean-square error of validation (RMSEP) for alcohol content, titratable acidity, and pH, respectively. When used to discriminate rice wine age, LS-SVM gave better results than discriminant analysis (DA). On the basis of the results, it was concluded that LS-SVM together with NIR spectroscopy was a reliable and accurate method for rice wine quality estimation.

Comparative study of wine tannin classification using Fourier transform mid-infrared spectrometry and sensory analysis

Wine tannins are fundamental to the determination of wine quality. However, the chemical and sensorial analysis of these compounds is not straightforward and a simple and rapid technique is necessary. We analyzed the mid-infrared spectra of white, red, and model wines spiked with known amounts of skin or seed tannins, collected using Fourier transform mid-infrared (FT-MIR) transmission spectroscopy (400-4000 cm(-1)). The spectral data were classified according to their tannin source, skin or seed, and tannin concentration by means of discriminant analysis (DA) and soft independent modeling of class analogy (SIMCA) to obtain a probabilistic classification. Wines were also classified sensorially by a trained panel and compared with FT-MIR. SIMCA models gave the most accurate classification (over 97%) and prediction (over 60%) among the wine samples. The prediction was increased (over 73%) using the leave-one-out cross-validation technique. Sensory classification of the wines was less accurate than that obtained with FT-MIR and SIMCA. Overall, these results show the potential of FT-MIR spectroscopy, in combination with adequate statistical tools, to discriminate wines with different tannin levels.

Use of solid-supported liquid-liquid extraction in the analysis of polyphenols in wine

Solid-supported liquid-liquid extraction (SS-LLE) was compared to liquid-liquid extraction (LLE) for the analysis of phenolic compounds in wine. Diatomaceous earth commercial cartridges were evaluated together with "in-house" made cartridges for the wine phenolic extraction. Statistical treatment, analysis of variance ANOVA-single factor, was used to compare the extraction yields obtained by these methods, and for the majority of the studied compounds, significantly higher yields were obtained by the SS-LLE methodology using the "in-house" prepared cartridges. This is an environmentally friendly low-cost sample preparation method which proved to be reproducible (RSD<5% for the most compounds) and yielding high recoveries (80-100%) for the compounds studied.

Classification of wines produced in specific regions by UV-visible spectroscopy combined with support vector machines

Discriminating wines according to their denomination of origin using cost-effective techniques is something that attracts the attention of different industrial sectors. In search of simplicity, direct UV-visible spectrophotometric techniques and different multivariate statistical techniques are used with admissible results to characterize wine produced in specific regions. However, most of the reported classification methods do not exploit all of the statistical relations in the investigated dataset and are inherently affected by the presence of outliers. The aim of this paper is to test novel classification methods such as support vector machines as a means of improving the classification rate when UV-visible spectrophotometric methods are used to discriminate wines. The advantages of such a discrimination tool are demonstrated when classification rates are compared for a large number of Spanish red and white wines and classification rates above 96% are achieved. The proposed methodology also enables the selection of the most relevant wavelengths for sample discrimination. The proposed methodology also enables the selection of the most relevant wavelengths for sample discrimination.

Geography and vintage predicted by a novel GIS model of wine delta18O

Wine hydrogen and oxygen stable isotopes record the climatic conditions experienced by the grape vine and the isotopic composition of the vine's source water during berry development. As such, stable isotopes have been explored extensively for use in detecting wine adulteration or for independently verifying claims of origin. We present the results of a study designed to evaluate the relationships between wine water delta18O and spatial climate and precipitation delta18O patterns across the winegrape-growing regions of Washington, Oregon, and California. Retail wines produced from typically small vineyards across these regions were obtained from the 2002 vintage, and the delta18O of wine water was analyzed using a CO2 equilibration method. Significant correlations were observed between the measured wine water delta18O from 2002 and the long-term average precipitation delta18O and late season 2002 climate, based on a spatial join with continuous geographic information system (GIS) maps of these drivers. We then developed a regression model that was implemented spatially in a GIS. The GIS model is the first of its kind and allows spatially explicit predictions of wine delta18O across the region. Because high spatial resolution monthly climate layers are now available for many years, wine delta18O could be modeled for previous years. We therefore tested the model by executing it for specific years and comparing the model predictions with previously published results for wine delta18O from seven vintages from Napa and Livermore Valleys, California. With the exception of one year, an anomaly potentially related to the effects of El Niño on precipitation isotopic composition, the model predicted well the wine delta18O for both locations for all vintages and generally reflected the consistent enrichment of wine from Napa relative to Livermore. Our results suggest that wine water delta18O records both source water delta18O and climate during the late stages of winegrape ripening and that GIS models of wine water delta18O are useful tools for independently verifying claims of regional origin and vintage.

Analysis of non-anthocyanin phenolic compounds in wine samples using high performance liquid chromatography with ultraviolet and fluorescence detection

A simple and rapid HPLC method with UV and fluorescence detection (FLD) for the separation of ten phenolic compounds including gallic acid, catechin, epicatechin, caffeic acid, coumaric, trans-piceid, cis-piceid, trans-resveratrol, cis-resveratrol and quercetin is reported. The UV and fluorescence detector in series provided a high selectivity for the determination of these compounds. Precisions, recoveries and LODs achieved for all the analytes were satisfactory. The proposed method was applied to the determination of these compounds in commercially available red wines.

Rapid fingerprinting of red wines by MALDI mass spectrometry

Here we report a simple and fast method for wine fingerprinting based on direct matrix-assisted laser desorption/ionization (MALDI) mass spectrometry analysis of different red wine samples, useful for batch-to-batch analysis and for the detection of key compounds even in trace amounts which may vary from vintage to vintage, and from one treatment to another one. A series of 20 samples from different wines were subjected to MALDI mass spectrometry. We found that 2,5-dihydroxybenzoic acid is far superior with respect to all the matrices tested To the best of our knowledge this is the first application of an effective wine profiling not limited to detection of anthocyanins. More than 80 molecular species were detected. Moreover, qualitative and quantitative differences were observed, owing to the nature and relative abundance of different chemical compounds among the wines.

Yeast systems biology: modelling the winemaker's art

Yeast research represents an important nexus between fundamental and applied research. Just as fundamental yeast research transitioned from classical, reductionist strategies to whole-genome techniques, whole-genome studies are advancing to the next level of biological research, referred to as systems biology. Industries that rely on high-performing yeast, such as the wine industry, are therefore poised to reap the many benefits that systems biology can provide. This includes the promise of strain development at speeds and costs which are unobtainable using current techniques. This article reviews the current state of whole-genome techniques available to yeast researchers and outlines how these processes can be used to obtain 'systems-level' information to provide insights into winemaking.

Characterization of Vitis vinifera L. Cv. Carménère grape and wine proanthocyanidins

A formal compositional study of the proanthocyanidins of Vitis vinifera L. cv. Carménère was conducted in this work. We first characterized the polymeric proanthocyanidins of Carménère skins, seeds, and wines. In addition, the wine astringency was analyzed and compared with Cabernet Sauvignon. Although Carménère wines had a higher proanthocyanidin concentration and mean degree of polymerization than Cabernet Sauvignon wines, the former wines were perceived as less astringent. The low seed/skin proportion in Carménère wines as compared to other varieties, as evidenced by the reduced number of seeds per berry and the higher amount of epigallocatechin subunits of Carménère wine proanthocyanidins, could explain this apparent paradox.

White grapes arose through the mutation of two similar and adjacent regulatory genes

Most of the thousands of grapevine cultivars (Vitis vinifera L.) can be divided into two groups, red and white, based on the presence or absence of anthocyanin in the berry skin, which has been found from genetic experiments to be controlled by a single locus. A regulatory gene, VvMYBA1, which could activate anthocyanin biosynthesis in a transient assay, was recently shown not to be transcribed in white berries due to the presence of a retrotransposon in the promoter. We have found that the berry colour locus comprises two very similar genes, VvMYBA1 and VvMYBA2, located on a single bacterial artificial chromosome. Either gene can regulate colour in the grape berry. The white berry allele of VvMYBA2 is inactivated by two non-conservative mutations, one leads to an amino acid substitution and the other to a frame shift resulting in a smaller protein. Transient assays showed that either mutation removed the ability of the regulator to switch on anthocyanin biosynthesis. VvMYBA2 sequence analyses, together with marker information, confirmed that 55 white cultivars all contain the white berry allele, but not red berry alleles. These results suggest that all extant white cultivars of grape vines have a common origin. We conclude that rare mutational events occurring in two adjacent genes were essential for the genesis of the white grapes used to produce the white wines and white table grapes we enjoy today.

White grapes arose through the mutation of two similar and adjacent regulatory genes

Most of the thousands of grapevine cultivars (Vitis vinifera L.) can be divided into two groups, red and white, based on the presence or absence of anthocyanin in the berry skin, which has been found from genetic experiments to be controlled by a single locus. A regulatory gene, VvMYBA1, which could activate anthocyanin biosynthesis in a transient assay, was recently shown not to be transcribed in white berries due to the presence of a retrotransposon in the promoter. We have found that the berry colour locus comprises two very similar genes, VvMYBA1 and VvMYBA2, located on a single bacterial artificial chromosome. Either gene can regulate colour in the grape berry. The white berry allele of VvMYBA2 is inactivated by two non-conservative mutations, one leads to an amino acid substitution and the other to a frame shift resulting in a smaller protein. Transient assays showed that either mutation removed the ability of the regulator to switch on anthocyanin biosynthesis. VvMYBA2 sequence analyses, together with marker information, confirmed that 55 white cultivars all contain the white berry allele, but not red berry alleles. These results suggest that all extant white cultivars of grape vines have a common origin. We conclude that rare mutational events occurring in two adjacent genes were essential for the genesis of the white grapes used to produce the white wines and white table grapes we enjoy today.

Activation of endothelial nitric oxide synthase by red wine polyphenols: impact of grape cultivars, growing area and the vinification process

OBJECTIVE

Accumulating data document protective effects of red wine in cardiovascular disease by improved nitric oxide bioavailability. Not all wines, however, seem to be equally effective. The aim of the present study was to elucidate the impact of grape cultivars, growing area and the vinification/fermentation process on the ability of red wine polyphenol extracts to increase human endothelial nitric oxide synthase (eNOS) promotor and enzyme activity.

METHODS

We produced polyphenol extracts from a variety of red wines from all over the world and tested their influence on eNOS promotor activity by a luciferase reporter gene assay. Selected extracts were subjected to the L-arginine-L-citrulline conversion assay to confirm that enhanced eNOS transcription results in enhanced enzyme activity.

RESULTS

We show that polyphenol extracts from wines of specific origin and grape cultivars vary strongly in their individual activity. However, when averaged, the activity could not be attributed to a specific grape cultivar or growing area. Resveratrol alone significantly enhanced eNOS promotor and enzyme activity, although at concentrations higher than those available in effective concentrations of red wine polyphenol extracts. Extracts of grape juice showed activity as well.

CONCLUSIONS

The biological activity of red wines on eNOS transcription depends neither on grape cultivars nor on growing area in general. Resveratrol may be the most promising ingredient in red wine polyphenol extracts, but does not account for the complete effect. A large part of the active components are genuine grape compounds, since extracts of grape juice that did not undergo a fermentation process also showed activity.

Internal standardization--atomic spectrometry and geographical pattern recognition techniques for the multielement analysis and classification of Catalonian red wines

Major and minor (K, P, Ca, Mg, Na, Fe, Mn, Zn, and Sr) and trace (Ba, Ni, Pb, V, Co, Cd, and Sb) elements from wine samples from the Denomination of Origin (DO) Empordà-Costa Brava (Catalonia, Spain) were analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES) and mass spectrometry (ICP-MS) respectively. Previously, a comparison of different calibration methodologies and sample digestion treatments had been carried out using ANOVA statistical tool. The obtained results demonstrated that internal standardization provides reliable results with the advantage that no further manipulation of the sample is needed. A principal component analysis of the concentration data was performed to differentiate the samples of DO Empordà-Costa Brava from wine samples from other wine-producing regions in Spain (i.e., Penedès, Somontano, and Rioja). It was found that Sr and Ba contents discriminate the two DO groups. Moreover, a discriminant analysis function involving both variables distinguishes the two groups with a 100% classification rate. At the level of the leave-one-out cross-validation, all of the Empordà-Costa Brava samples were well classified, whereas the other DOs presented two borderline misclassifications.

Analysis of some stilbenes in Italian wines by liquid chromatography/tandem mass spectrometry

Stilbenes from grapes and wines play a central role in the human diet because of their antioxidant, antimutagenic and anticarcinogenic properties. We describe a method for the direct determination of some stilbenes (cis- and trans-resveratrol, cis- and trans-resveratrol glucoside, cis- and trans-piceatannol, and cis- and trans-piceatannol glucoside) in wine by high-performance liquid chromatography/mass spectrometry using a triple quadrupole (QqQ) mass spectrometer, in multiple reaction monitoring (MRM) mode, acquiring two diagnostic product ions from the chosen precursor. All the target analytes were separated on a C-18 column using gradient elution, in a single run. Electrospray ionization (ESI) in negative ion mode gives higher sensitivity for all the target compounds than atmospheric pressure chemical ionization (APCI). For the identification of piceatannol glucoside (astringin), because of the lack of a suitable standard, an HPLC/TOFMS method was used. The method permits direct injection of samples and it is time-saving, removing the need for sample pre-treatment. The detection limits were 48.0 ng mL(-1) for cis- and trans-resveratrol and for cis- and trans-resveratrol glucoside, and 50.0 ng mL(-1) for cis- and trans-piceatannol. The procedure proved to be simple and suitable for routine and confirmatory purposes. A total of 19 red and 3 white Italian wines were analyzed and differences in the stilbene composition were found among these samples.

Development of a rapid "fingerprinting" system for wine authenticity by mid-infrared spectroscopy

This paper reports on the development of a rapid and simple method for red wine authenticity confirmation during transport and processing; namely, a wine "fingerprinting" system. When wine is transported between two sites, a sample is taken and a mid-infrared (MIR) spectrum is obtained. One hundred sixty-one (n = 161) samples of three main red wine varieties grown in Australia, Shiraz, Cabernet Sauvignon, and Merlot, were collected from six commercial wineries across Australia and scanned in transmission on two MIR spectrophotometers located at The Hardy Wine Company's main site at Reynella, South Australia (Foss WineScan FT 120) (926-5012 cm-1). A similarity index (SI) method was used as a tool to classify wine samples on the basis of their spectral data. The results showed that high rates of classification were obtained when wine samples scanned in different instruments were analyzed. The SI has been proven to provide an acceptable measurement for authentication of red wine integrity during transportation. In five of the six winery data sets, the SI correctly classified 98% of the wines. It was also observed that less than 1% of wines were misclassified between the different wineries investigated. Further studies are needed in order to test the applicability of the SI in a commercial situation and to evaluate its potential as a rapid quality control tool for routine use to authenticate wine samples during transport.

Geographic classification of spanish and Australian tempranillo red wines by visible and near-infrared spectroscopy combined with multivariate analysis

Visible (vis) and near-infrared (NIR) spectroscopy combined with multivariate analysis was used to classify the geographical origin of commercial Tempranillo wines from Australia and Spain. Wines (n = 63) were scanned in the vis and NIR regions (400-2500 nm) in a monochromator instrument in transmission. Principal component analysis (PCA), discriminant partial least-squares discriminant analysis (PLS-DA) and linear discriminant analysis (LDA) based on PCA scores were used to classify Tempranillo wines according to their geographical origin. Full cross-validation (leave-one-out) was used as validation method when PCA and LDA classification models were developed. PLS-DA models correctly classified 100% and 84.7% of the Australian and Spanish Tempranillo wine samples, respectively. LDA calibration models correctly classified 72% of the Australian wines and 85% of the Spanish wines. These results demonstrate the potential use of vis and NIR spectroscopy, combined with chemometrics as a rapid method to classify Tempranillo wines accordingly to their geographical origin.

Discrimination of Portuguese grapevines based on microsatellite markers

A set of 46 grapevine denominations was genotyped at 11 microsatellite loci in order to discriminate them. Ninety four alleles with a mean number of 8.55 alleles per locus were observed in a total of 37 detected unique genotypes. Previously assumed synonyms were confirmed and several cases of homonymy resolved. Comparison of the data obtained in this study with data of 32 genotypes previously reported enabled the detection of three parent offspring relationships, and identified other putative parent/progeny relationships. These data allowed understanding the origin of some Portuguese cultivars. The integration of the obtained data with ampelographic data would be very important for the accurate identification of the Portuguese cultivars and can become a significant tool for the certification of quality wines produced in specific regions.

Classifying wine according to geographical origin via quadrupole-based ICP–mass spectrometry measurements of boron isotope ratios

The potential of quadrupole-based ICP-MS as a tool for B-isotopic analysis of wines and its usefulness in provenance determinations were assessed. A precision of 0.1-0.25% RSD (corresponding to a relative standard deviation of the mean of three replicate measurements of 0.06-0.12%) was sufficient to establish small differences in the B isotope ratios in wines from different geographical origins. Each sample measurement was bracketed by measurements of a standard and mass bias drift correction made by interpolation. Sample preparation was kept to a minimum to avoid possible fractionation. Dilution of the wine samples by a factor of 100 with 0.65% HNO3 was found to reduce matrix-induced mass discrimination substantially. Wines from three wine-producing regions, Stellenbosch, Robertson, and Swartland, in the Western Cape Province of South Africa, and wines from specific regions in France (Bergerac) and Italy (Valpolicella) were analyzed by ICP-QMS for their B-isotopic compositions. It was concluded that the 11B/10B ratios can be used to characterize wines from different geographical origins. Average 11B/10B ratios in red wines from South Africa (Stellenbosch), France (Bergerac), and Italy (Valpolicella) were found to differ by between 0.5 and 1.5%.

Analysis of polyphenols in wines: Correlation between total polyphenolic content and antioxidant potential from photometric measurements

The polyphenols (some of them are also called phytoalexins, flavonols, flavanons, flavanonols, flavons, flavanols, and anthocyanines) are usually marked as potent antioxidants or radical scavengers which assist the body cells against oxidation. Polyphenols in wine are also considered to explain so called French paradox (long life aging and low number of coronary diseases despite of high alcohol and fat consumption). The total polyphenolic content (TPC) and total antioxidant potential (TAP) were determined by photometry and found strongly correlated. This finding suggests that the determination of TAP can be replaced by a more simple procedure of TPC determination. Capillary zone electrophoresis (CZE) with preconcentration by solid phase extraction (SPE) was applied for some polyphenols determination and for obtaining electropherograms of the SPE extracts (fingerprints). From mathematical evaluation of the fingerprints, prediction of cultivars and vintage using artificial neural networks (ANN) was done with more than 90% correct prediction. The study was performed on a set of 47 samples of young wines (vintage 1999-2002) from south Moravia (Czech Republic) and New South Wales (Australia).

Multi-element analysis of South African wines by ICP-MS and their classification according to geographical origin

Wines from three important wine-producing regions, Stellenbosch, Robertson, and Swartland, in the Western Cape Province of South Africa, were analyzed by ICP-MS and the elemental composition used in multivariate statistical analysis to classify the wines according to geographical origin. The method is based on the assumption that the provenance soil is an important contributor to the trace element composition of a wine. A total of 40 elements were determined in 40 wines. Of these, 20 elements: Li, B, Mg, Al, Si, Cl, Sc, Mn, Ni, Ga, Se, Rb, Sr, Nb, Cs, Ba, La, W, Tl, and U showed differences in their means across the three areas. In a stepwise discriminant analysis procedure, functions based on linear combinations of the log-transformed element concentrations of Al, Mn, Rb, Ba, W, and Tl were generated to correctly classify wines from each region. In an alternative approach, a pairwise discriminant analysis procedure, not previously used in wine provenance studies, was tested. In this procedure, the classification was done in three steps, with each step classifying a wine as coming from a certain region or not. The combination of elements characterizing wines from a particular region was different in each region. The discriminant functions were based on the following elements: Al, Mn, Rb, Ba, and W for Stellenbosch; Se, Rb, Cs, and Tl for Robertson; and Al, Mn, Rb, Sr, Ba, and Tl for Swartland. After this procedure, the classification of the wines into one of the groups was 100% successful.

Application of a headspace mass spectrometry system to the differentiation and classification of wines according to their origin, variety and ageing

The system based on coupling a headspace sampler to a mass spectrometer (HS-MS), considered a kind of electronic nose (e-nose), is an emerging technique in the field of food aroma analysis. The global mass spectrum this system provides is a fingerprint of each sample analysed that contains the information related to volatile composition of the sample. The use of chemometric techniques allows to compare the spectra of the samples and then, to classify them according to different properties. In this paper, we present the development of a method for wine analysis using a HS-MS system and multivariate analysis techniques. The method was successfully applied to differentiate and classify wines according to its origin, variety and ageing. The main advantages of the proposed methodology are the minimum sample preparation required and the speed of analysis (10 min/sample).

Biogenic amines in wines from three Spanish regions

One hundred and sixty-three wines from La Rioja, Utiel-Requena, and Tarragona were analyzed to determine if there were any differences in the concentrations of six biogenic amines that are found in these three regions. The influence of grape variety, type of vinification, wine pH, malolactic fermentation, and storage in bottle on biogenic amine concentrations was studied. Results show important differences in putrescine and histamine concentrations among regions, varieties of grape, and type of wine; differences were less appreciable for the remaining biogenic amines studied. Low pH prevented biogenic amine formation. Malolactic fermentation and short storage periods in bottle (3-6 months) showed increases in histamine concentration, whereas longer periods of storage led to a general decrease in histamine. Several strains of lactic acid bacteria were isolated in this work, and their ability to form biogenic amines was assayed in synthetic media, grape must, and wine. Grape varieties, different types of winemaking, pH, and lactic acid bacteria may be responsible for the differences observed in the biogenic amine concentrations of the wines analyzed.