The application of SNIF‐NMR and IRMS combined with C,H and O isotopes for detecting the geographical origin of Chinese wines

The regional origin of Chinese wines was investigated using two important complementary techniques, site‐specific natural isotopic fractionation nuclear magnetic resonance (SNIF‐NMR) and isotope ratio mass spectrometry (IRMS). Twenty samples from five different grape varieties were collected from north Xinjiang in 2009, along with 100 wine samples from five different regions during 2010–2013. The (D/H)_I and (D/H)_II in wine ethanol ranged from 95.10 to 102.86 ppm and from 115.99 to 126.39 ppm using SNIF‐NMR, respectively. The ¹³C/¹²C of wine ethanol and ¹⁸O/¹⁶O of wine water were detected using IRMS. The δ¹³C value (?23.36‰) in coastal regions was higher than that in continental regions (?27.75‰). The temperature is the key for δ¹³C value. The δ¹⁸O ranged from ?1.94 to 4.57‰. The δ¹⁸O values were only positive in north Xinjiang which had the arid climate and strong sunshine. No difference was found for isotope ratios for wines made from five different grape varieties in north Xinjiang. All data evaluated by principal component analysis and linear discriminant analysis showed that the best method to distinguish the regional wine origin correctly is a combination of (D/H)_I, (D/H)_II, R, δ¹³C and δ¹⁸O. Therefore, natural multi‐elemental isotope ratios are effective in contributing to wine quality control in the Chinese market.     

Progress in wine authentication: GC–C/P–IRMS measurements of glycerol and GC analysis of 2,3-butanediol stereoisomers

The determination of glycerol and 2,3-butanediol by photometric or enzymatic methods is well established. This paper reports on the direct assessment of glycerol and stereoselective analysis of 2,3-butanediol isomers in wine using capillary GC without any derivatisation. A “model wine” and commercially available wines, as well as wines of definite origin were investigated. The contents of glycerol and 2,3-butanediol and the ratio of (R,R)- and meso-2,3-butanediol were determined. Capillary GC has proved to be a reliable alternative in glycerol assessment from wine, thus a GC-IRMS method for authenticity assessment of glycerol was developed.δ¹³C_V‐PDB and δ¹⁸O_V‐SMOW multi-element IRMS-analysis of glycerol, an important by-product of wine fermentation, is reported. For that reason glycerol, extracted from a self-prepared “model wine”, from wines of definite origin, as well as commercially available wines, was investigated. Furthermore, the ¹⁸O/¹⁶O and ¹³C/¹²C isotope ratios of commercial glycerols from different origins were determined. In addition fermentation experiments with beet and cane sugar, and with grape juices were carried out. In order to check the influence of water on the oxygen isotope ratios, water from different places in Germany was used in the fermentation experiments with cane and beet sugar.     

氢、氧稳定同位素在植源性食品真实性鉴别中的应用

以国内外研究文献为基础,综述氢（H）、氧（O）稳定同位素在植源性食品真实性鉴别中的研究进展,阐明影响同位素分馏的环境气候因素和引起同位素分馏的物理、化学过程,为植源性食品真实性鉴别建立统计评估的数据库提供参考。H、O稳定同位素在多种植源性食品产地鉴别、掺假鉴别、有机鉴别中等均得到了广泛的应用, H、O稳定同位素可较直观的反映谷物、果蔬、葡萄酒、茶叶产地纬度、海拔及相关气候信息,在产地鉴别、种植模式鉴别中发挥重要作用。果汁、酒类可利用H、O稳定同位素实现外源水及酒精的掺假鉴别。在植源性食品真实性鉴别中,利用H、O稳定同位素进行产地真实性、食品掺假、种植模式鉴别中均取得较好成果。H、O稳定同位素可被认为是食品真实性鉴别的有效手段之一。     

Multivariate discrimination of wines with respect to their grape varieties and vintages

The primary focus of the European Union funded project entitled “Establishing a WINE Data Bank for analytical parameters for wines from Third Countries” (WINE-DB project, G6RD-CT-2001-00646-WINE-DB) was the discrimination of wine samples with respect to their geographical origin using only a few chemical parameters. Taking a step further, we have investigated the possibility of discriminating the wines in the data bank according to their harvesting seasons and grape varieties. Several chemometric methods were carefully selected and evaluated for this purpose. These were discriminant partial least squares, classification and regression trees, uninformative variable elimination discriminant partial least squares and neuro-fuzzy systems. With classification and regression trees, it was possible to identify a few chemical parameters including isotopic ratios (e.g. δ¹⁸O), biogenic amines and rare earth elements that discriminate between vintages and some grape varieties for wines produced in a particular country such as Czech Republic, Hungary, Romania or South Africa. These parameters can be used in evaluating the authenticity of wines.     

新、旧世界国家葡萄酒氧稳定同位素时空分布特征研究进展

氧稳定同位素是葡萄酒真实性检测的重要指标之一,其比值在自然因素(葡萄品种、地理环境、气候条件)和人为因素(栽培管理、酿酒工艺)影响下,在不同产地显示出不同时空分布特征。欧盟等旧世界国家已率先建立葡萄酒水中氧稳定同位素的测定方法及数据库,并将其应用于葡萄酒真实性检测中。然而,国内外在葡萄酒氧稳定同位素时空分布特征方面的研究较少,尚未形成统一数据平台,难以实现数据共享。本文总结了新世界(中国、美国、澳大利亚、智利等)和旧世界(西班牙、法国、意大利、奥地利等)国家葡萄酒中水的氧稳定同位素数据分布及鉴别应用,概述了影响该比值的因素,并阐述了目前存在问题和今后发展方向,目的在于明确氧稳定同位素比值在世界主要酿酒国家的分布特征,为我国建立葡萄酒氧同位素数据库及真伪鉴别提供数据支持。     

C、H、O同位素分析在葡萄酒产区鉴别中的应用

为有效鉴别产区葡萄酒,利用点特异性天然同位素分馏核磁共振技术和同位素比质谱仪技术对葡萄酒中C、H和O同位素进行研究。通过收集2010-2012年河北昌黎、山东烟台蓬莱、宁夏贺兰山东麓和河北沙城四大产区的60 个样品,发现（D/H）i、（D/H）ii、R、δ13C、δ18O、酒精体积分数的范围分别为95.68×10－6～99.15×10－6、115.99×10－6～126.39×10－6、2.38～2.59、－28.35‰～－23.00‰、－1.94‰～－0.05‰和11.3%～12.9%,总体上含量范围分布广泛,但同一地区较为集中。研究发现,单一使用任何一种元素都只能区分环境差异很大的地区,当结合3 种元素,采用线性判别分析能100%有效鉴别四大产区葡萄酒。基于沙城产区的数据库和酒精体积分数,结合t检验法,分3 步可判定出产区酒的真实性。待测的5 个盲样中只有1 个样品属于沙城产区的真实葡萄酒。     

In vitro antioxidant activity of red grape skins

Phenolic antioxidants seem to be partly responsible for the protective effects against cardiovascular diseases attributed to moderate wine consumption. Grape skins greatly contribute to the phenolic composition of red wine. In this paper, the in vitro antioxidant activity of red grape (Vitis vinifera) skins is determined. We show that the radical scavenging activity (C ₅₀ values) against 2,2-diphenyl-1-picrylhydrazyl (DPPH^·) of grape skin extracts is relatively high (3.2–11.1 mg dried skin/mg DPPH^·) in relation to other foodstuffs and, as expected, is influenced by grape variety, stage of grape ripening and vintage. The antioxidant potential of grape skins seems to be transferred into wine since grape varieties with skins exhibiting high antioxidant potential also resulted in wines with high antioxidant activity. Statistically significant correlations were found between antioxidant activity and phenolic content (total polyphenols, proanthocyanins, catechins and anthocyanins) for both grape skins and wines.     

Characterization of wines from grape varieties through multivariate statistical analysis of H NMR spectroscopic data

¹H NMR spectroscopic analysis coupled with multivariate statistical data was used to characterize wines vinified from four grape varieties: Muscat Bailey A (Vitis labrusca), Campbell Early (V. labrusca B.), Kyoho (V. labrusca L.) and Meoru (Vitis coignetiae). Pattern recognition methods, such as principal component analysis (PCA) and orthogonal projection to latent structure discriminant analysis (OPLS-DA), showed clear differentiation between wines made from these grape varieties. Metabolites responsible for the differentiation were identified as 2,3-butanediol, glycerol, malate, citrate, tartrate, succinate, lactate, proline, alanine, choline and trigonelline. The PCA score plot of quantitative analysis of targeted profiling data also showed clear separation between the wines. The highest levels of glycerol, 2,3-butanediol, succinate and alcohol were found in Kyoho wines, suggesting higher sugar content in the Kyoho grape berry compared to other grape varieties. Higher contents of citrate and trigonelline in Muscat Bailey A wines, alanine in Campbell Early wines and proline, malate and choline in Meoru wines demonstrated that the metabolites of the wines vary with the grape variety. This study provides insight into the relationship between grape variety and its wine through global and targeted analysis of ¹H NMR spectral data.     

Elemental Profile and <Superscript>87</Superscript>Sr/<Superscript>86</Superscript>Sr Isotope Ratio as Fingerprints for Geographical Traceability of Wines: an Approach on Romanian Wines

Wine geographical traceability is an important topic in the context of wine authentication and for that, many researchers worldwide have addressed this subject by developing different methodologies based on multivariate analysis of natural chemical composition data (inorganic or organic parameters) and isotopic signature. The goal of this work was to assess the potential of elemental composition and strontium isotope ratio (⁸⁷Sr/⁸⁶Sr) of wines from important wine-producing regions in Romania, located in relatively small geographical areas, in order to highlight reliable markers for wine geographical origin discrimination. Elemental profile determinations were performed by ICP-MS, GFAAS, and FAAS techniques after microwave acid digestion of the wine samples. The ⁸⁷Sr/⁸⁶Sr isotope ratio of the resulted extracts was determined by quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS), after separating strontium and rubidium using cation-exchange chromatography with Dowex 50W-X8 resin and the complexation ability of the carboxylic acid EDTA. The variation of elemental composition (Ga, Sr, and Al), Ca/Sr ratio, and the ⁸⁷Sr/⁸⁶Sr ratio of the investigated wine clearly demonstrated that these variables are suitable tracers for wine geographic origin determination. The proposed methodology allowed a 100 % successful classification of wines according to the region of provenance.     

Optimisation of the Amido Black assay for determination of the protein content of grape juices and wines

While the heat/chill stability of white wines cannot be predicted from the total protein concentration, this information is useful in assessing the effectiveness of fining treatments. We have adapted the Amido Black assay for use in grape juice and wine. The response of bovine serum albumin (BSA) was similar in water, model wine and model juice. The linear range of the assay (<100 mg l^?1) extends beyond protein concentrations typically found in grape juices and wines. The limit of quantification was 11.1 mg l^?1 for BSA in model wine and 7.6 mg l^?1 in model juice, while the limit of detection was found to be less than 3 mg l^?1 in either solution. In contrast to other methods of protein determination, this assay is not affected by common wine phenolic and pectic compounds or by glutathione. The mean response of BSA was similar in model juice and red and white grape juices. The mean response of BSA in red wine was lower than in white wine and model wine (p < 0.001), and there was considerable variation in response among wines. Protein concentrations determined using this method were reproducible (CV < 10%). This optimised assay can be used to monitor protein levels in grape juices and wines. © 2001 Society of Chemical Industry     

Differentiation of Greek red wines on the basis of grape variety using attenuated total reflectance Fourier transform infrared spectroscopy

Mid-infrared spectroscopy combined with appropriate software was used in an attempt to differentiate Greek red wines of different varietals origin, including the cultivars Agiorgitiko (Nemea-Peloponnesus), Xinomavro (Naousa-Central Macedonia) and Merlot from Greece. Extract of wine phenolic components were investigated by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The wine extracts were obtained by solid-phase extraction with C-18 columns and elution by methanol containing 0.01% hydrochloric acid. Libraries of spectra were created using sample from each wine variety. Spectra of unknown wine extracts were recorded and compared with those of the wine libraries and the rate of affinity (the match value) was measured automatically using the appropriate software (OMNIC ver. 7.3). The spectral region 1800–900 cm⁻¹ was used to ‘fingerprint’ wine on the basis of grape variety. This simple and fast method of analysis showed that wines from different grape varieties can be differentiated between them.     

Detection of ochratoxin A in tropical wine and grape juice from Brazil

BACKGROUND: Ochratoxin A (OTA) is the main mycotoxin found in grapes, wines and grape juices and is considered one of the most harmful contaminants to human health. In this study, samples of tropical wines and grape juices from different grape varieties grown in Brazil were analysed for their OTA content by high‐performance liquid chromatography. RESULTS: The detection and quantification limits for OTA were 0.01 and 0.03 µg L^?1 respectively. OTA was detected in 13 (38.24%) of the samples analysed, with concentrations ranging from < 0.03 to 0.62 µg L^?1. OTA was not detected in any of the grape juice samples. Most of the red wine samples proved to be contaminated with OTA (75%), while only one white wine sample was contaminated. However, the OTA levels detected in all samples were well below the maximum tolerable limit (2 µg L^?1) in wine and grape juice established by the European Community and Brazilian legislature. CONCLUSION: The results of this study indicate a low risk of exposure to OTA by consumption of tropical wines and grape juices from Brazil. © 2012 Society of Chemical Industry     

Evaluation of methods for DNA extraction from must and wine

The quality of wine depends on many factors. One of the most important is the selection of appropriate and defined grape varieties. The analysis of phenolic compounds, amino acids, trace elements and isotopes of wines, used for the identification of grapes varieties, is not sufficient and requires a lengthy analysis period. The development of molecular techniques such as restriction fragment length polymorphism, random amplified polymorphic DNA and microsatellites provides opportunities for the differentiation of grape varieties. In this regard, the use of DNA extracted from must and wine appears to be a good marker for the identification of grape varieties used in wine production. In this study, DNA was extracted from grape, leaf, must and wine samples of Vitis vinifera L. cv. Cabernet Sauvignon, Merlot and Sauvignon Blanc origin and examined using different extraction methods. Of the DNA extraction methods tested, the method using absorption at 260/280 nm (with values of 0.19 and 1.92) was considered the method of choice. Copyright © 2014 The Institute of Brewing & Distilling     

Phenolic profile and free radical‐scavenging activity of Cabernet Sauvignon wines of different geographical origins from the Balkan region

BACKGROUND: The phenolic profile, determined by the relative proportions of different phenolic compounds, is characteristic for each grape variety and its corresponding wine. The aim of this study was to determine the phenolic and hydroxycinnamate acid, flavan‐3‐ol and flavonol contents and free radical‐scavenging activity of single‐cultivar (Cabernet Sauvignon) wines from selected Balkan vineyard regions by spectrophotometric methods and high‐performance liquid chromatography with photodiode array and fluorescence detection. RESULTS: The contents of phenolic compounds varied depending on the agroclimatic factors and oenological practices of the vineyard region. The antioxidant activity of wine samples was estimated by their ability to scavenge the stable 2,2′‐diphenyl‐1‐picrylhydrazyl free radical (DPPH). All wines showed high DPPH‐scavenging activity (70.03–83.53%, mean 73.76%). Significant correlations between catechin (R² = 0.8504) and quercetin (R² = 0.8488) concentrations and DPPH‐scavenging ability of the wines were found. CONCLUSION: The concentrations of the main components catechin and quercetin can be used as biochemical markers for the authentication of red grape cultivars and their corresponding single‐cultivar wines. Copyright © 2010 Society of Chemical Industry     

Free radical scavenging capacity of selected red,rosé and white wines

The free radical scavenging capacity of selected red, rosé and white Spanish wines from different grape varieties was determined by the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH^·) method using a new methodology developed at our laboratory. The amount of sample necessary to decrease by 50% the initial DPPH^· concentration (EC₅₀), the time needed to reach the steady state at EC₅₀ concentration (T_EC50) and the antiradical efficiency (AE = 1/EC₅₀T_EC50) were determined in the wine samples. Some differences between rosé wines made with Garnacha and Tempranillo grape varieties were observed in the UV‐vis spectra and in the free radical scavenging parameters, those from Garnacha variety having the highest antioxidant activity. The antiradical efficiency of the wines followed a decreasing order: red wines (22.44 × 10⁻⁶) > rosé wines (4.90 × 10⁻⁶) > white wines (1.88 × 10⁻⁶). There was a correlation between antiradical efficiency and total polyphenol (TP): AE = −3.33135 + 0.0180535TP; the correlation coefficient was r = 0.951454. © 1999 Society of Chemical Industry     

Characterisation and determination of the geographical origin of wines. Part I: overview

One of the most challenging analytical issues in terms of wine authenticity is the control of geographical origin. This question becomes more and more important in the current context of a global wine market. Single parameters are often not sufficient on their own to determine the product identity with respect to the wine labelling. Recent developments have shown that control is improved by application of multivariate statistical methods to a combination of composition and isotopic data. In the past years, the official European wine control bodies have been confronted with wines that have had to be judged as suspicious in terms of their sophisticated authenticity, falsifications which are not readily identifiable, especially as it regards the grape variety, and particularly highlighted here the geographical origin. To improve the measures of authenticity control, a project with the title “Establishing of a WINE Data Bank for analytical parameters for wines from Third countries (WINE-DB project, G6RD-CT-2001-00646-WINE-DB)” was initiated in 2002, funded by the European Commission within the fifth framework “Competitive and Sustainable Growth”. The project consortium of this multinational project was composed of official and private laboratories from the European Union, from new European member states and a group of university partners for the statistical evaluation. Within the framework of the WINE-DB project, commercial and authentic wines originating from new European member states (Czech Republic, Hungary and Romania) and from overseas countries (South Africa and Australia) are collected and analysed. More than 1,800 wines from three vintages were analysed. First, a sampling plan for each wine-producing country was developed for the authentic samples taking into account, the surface and the grape variety of wine in the respective country. This sampling plan was used for the commercial samples accordingly. A series of three publications was prepared covering the statistical approaches and the results obtained for authentication of wine. The actual one—Part I—provides an overview on the structure of the project, the developing of the sampling plan, the strategy of sample collection and the analytical scheme.     

Characterization of Swiss vineyards using isotopic data in combination with trace elements and classical parameters

The objective of this work was to study methods to check the geographical origin of Swiss wines. Authentic grape samples from the vintages 2000 and 2001 were collected in representative locations, and the wines produced from these samples were subjected to isotopic (²H/¹H_ethanol; ¹⁸O/¹⁶O_{wine water}), elemental (Mn, Al, B, Ba, Ca, Fe, Mg, Na, Rb, Sr, Zn) and FT-IR (ethanol, pH, total acidity, volatile acidity, malic acid, fructose, tartaric acid, lactic acid, succinate, citric acid, glycerol, 2,3-butandiol, dry matter and relative density (d₂₀)) analyses. The results showed that the variables ¹⁸O/¹⁶O_{wine water}, strontium, rubidium, and ethanol%, when considered in a monovariate approach, allowed the best discrimination of the geographical origins of Swiss wines. By using a combination of all variables (multivariate approach), Switzerland was divided in four main production zones with a separation power that has never before been achieved. These zones were defined as Tessin, Valais, Romandie and Alemanique. A fifth zone (Graubünden) could be evidenced in vintage 2001.     

干红树葡萄酒与干红葡萄酒功能成分及其抗氧化活性对比

分别测定干红树葡萄酒与2种干红葡萄酒(法国干红葡萄酒、国产干红葡萄酒)中的总多酚、总黄酮、白藜芦醇、单宁、酚酸、维生素、花青素及矿物质等功能性成分,采用DPPH法、ABTS法、邻二氮菲法和FRAP法分析3种酒的抗氧化能力,并对其差异进行分析比较。结果表明:干红树葡萄酒与2种干红葡萄酒功能成分种类及含量各有特点和优势。干红树葡萄酒中没食子酸、VA、VC、Mn与Zn含量均极显著高于国产干红葡萄酒和法国干红葡萄酒;法国干红葡萄酒中总多酚、总黄酮、白藜芦醇、儿茶素、咖啡酸、香豆酸、阿魏酸、矢车菊色素及Fe含量均极显著高于国产干红葡萄酒和干红树葡萄酒;国产干红葡萄酒中单宁、VD、飞燕草色素、矮牵牛色素、天竺葵色素、芍药色素、锦葵色素、Ca和Mg含量均极显著高于法国干红葡萄酒和干红树葡萄酒。3种酒抗氧化活性亦各具特色,树葡萄红酒对DPPH·的清除能力最强,法国干红葡萄酒对·OH的清除能力最强,国产干红葡萄酒对ABTS~+的清除能力及对铁离子的还原能力最强。     

基于元素含量和稳定同位素比值的宁夏贺兰山东麓地区有机葡萄酒甄别

对贺兰山东麓产区生产的有机和非有机葡萄酒的元素含量和稳定C、N同位素比值分布特征进行分析,并利用此数据对宁夏贺兰山东麓地区有机与非有机葡萄酒进行甄别。结果表明,有机与非有机葡萄酒在一些金属元素如Na、Mg、K、Al和Cu的含量上具有显著差异,而且有机葡萄酒的乙醇和丙三醇的δ~(13)C值显著低于非有机葡萄酒,但δ~(15)N显著高于非有机葡萄酒。利用C、N稳定同位素和一些金属元素含量,结合主成分分析,可对贺兰山东麓地区有机和非有机葡萄酒进行有效区分,为我国有机葡萄酒掺假检测以及该地区的葡萄酒产业发展提供技术支撑,具有重要的应用前景。