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SNIF-NMR—Part 4: Applications in an EconomicContext: The Example of Wines, Spirits, and Juices

Eric Jamin and Gerard J. MartinEurofins Scientific, BP 42301, 44323 Nantes, France

Introduction

The direct access to site-specific natural isotope fraction-ation opened by the SNIF-NMR method [1,2] was im-mediately recognized, not only as a source of diversifiedinformation in a context of basic research, but also asa powerful technique for controlling the origin of com-mercial products. The method provides a unique tool fordetecting whether a given main component of a foodor beverage has been substituted or diluted by additionof a substance with the same molecular formula butfrom a different chemical, botanical, geographical origin(Part 3, Sections “Natural or Synthetic Origin of Prod-ucts,” “Characterization of Chemical Processes,” “Iden-tification of Plant Precursors,” and “Climatic Effectsand Geographical Origin”). In this respect, it has al-ready largely contributed to establish the notion of au-thenticity of food products on rigorous bases. In or-der to illustrate the methodologies and performance ofSNIF-NMR applied in official and industrial contexts, wehave selected two examples of economically importantproducts—wines and juices.

The world wine market has changed drastically in thelast 10 years. In Europe—the largest production area—wine production is continually decreasing. Depending onthe climatic conditions of the year, the production of the15 countries of the EU has fallen from nearly 180 millionto 155 million hectoliters. It is expected that in 2004 theadmission in the EU of six countries whose wine produc-tion rose to 6 million hectoliters will just compensate thedecrease of production of the 15 former state members.The cause is manifold but, roughly speaking, consumptionswitches from quantity to quality: for example, the shareof quality wines produced in specific regions (QWPSR)which look like the French “Vins d’Appelation d’OrigineControlee” (AOC), overall production increases signifi-cantly. In France, Italy, and Spain, 46%, 23%, and 31%of the production is made up of QWPSR. However,in emerging Asian markets consumption is growingrapidly, mainly to the advantage of table wines, gener-ally produced locally or imported from neighboring coun-tries. Consequently, there is a greater pressure on the

sensory and analytical properties of relatively expensivewines.

Insofar as fruit juices are concerned, the trend towardsmore quality and less quantity follows that observed forwines. Pure juices are frequently preferred to juices madefrom concentrates and to nectars, mainly based on the ideathat fruit juice is “health in bottle,” and in the EU and US,fruit juice markets are of a multi-billion ˚ magnitude.Orange juices represent more than 60% of the market.

Taking into account this economic context, it is ofprime importance to be able to authenticate the originof marketed products and to detect and estimate possibleadulteration.

Current Regulations About Wines and Juices

In order to guarantee the quality of marketed products,very drastic requirements tend to be legally imposed.However, regulations are efficient only inasmuch as rigor-ous control methods can be implemented [3]. In the caseof wines, spirits, and juices, important problems—stillchallenging in 1980s—are concerned with origin recog-nition of chemically identical molecules. By offering thispossibility, the SNIF-NMR method has entered the fieldof official regulation and control.

Wines

The Commission of the EU subjects the common marketof wines and wine products to very careful attention. Theregulation of 1999 [4] resumes and completes regulationsof 1987 and 1990 [5]. The principles behind the regula-tion may be explained in terms of three main vine growingzones A, B, and C (zone C being split into CI, CII, andCIlI) rigorously defined according to the minimum alco-holic content of the natural must, t% min, the maximumenrichment, c% max, and the maximum alcoholic content,t% max, of the enriched wine (Table 1).

Men have always had an overactive imagination fortransforming grapes into a number of beverages and food.Grape juice can be used as it stands, partly fermented,

C

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Table 1: Conditions limiting the enrichment of musts indifferent regions A, B, and C. t% and c% are expressedin v/v of ethanol in wine and values into bracketscorrespond to red wines. For example, zone A includesthe 15 State Members but France, Greece, Portugal, andSpain, zone B is composed of the Northern and CentralFrance, Austria, and the Baden region in Germany, andzones C include Southern France, Greece, Portugal,and Spain

Area A B CIa Clb CII CIII

t% min 5 6 7.5 8 8.5 9c% max 3.5 (4.5) 2.5 (3.5) 0 (2) 0 (2) 0 0t% max 11.5 (12) 12 (12.5) 12.5 12.5 13 13.5

concentrated, rectified (grape sugar), caramelized, andso on. Fermented musts give table wines, quality wines,quality wines “psr” (provenance from specified region),liqueur wines, sparkling wines (aerated, semi-sparkling,etc.), wines lees, grape marc, piquette, wine vinegar, wineof overripe grapes, etc. The authorized oenological prac-tices fill 12 A4 pages, printed in small characters, of the1999 regulation but insofar as we are concerned withSNIF-NMR, only practices which can be enforced withthe help of this technique will be discussed now. Firstof all, the problem of controlling wine enrichment wasof great concern to the EU since the illegal increase ofthe alcoholic grade of wines by cheapest means, such asaddition of sucrose into the fermenting must, is a heavyburden to the European budget. The surplus of wine pro-duced by illegal enrichment should indeed be bought bythe European Commission at a price that is significantlyhigher than that of the corresponding sugar. A secondproblem, less drastic for the European Treasury but se-vere for the consumer and the honest wine maker, isthe fraud in quality wines “psr”: The geographical ori-gin and the year of production of high priced wines (andspirits) should be ascertained in order not to entail theloss of confidence of the buyer. In the case of sparklingwines, the origin of the carbonic anhydride must becontrolled.

Juices

In the European community, the Council directive2001/112/EC defines several categories of fruit juicesand the technology which can be used to produce them.The European industry, within the AIJN code of practice(http://www.aijn.org), provides more detailed guidelinesof the expected composition of the most widely consumedfruit juices, including some isotopic parameters. At theworld level, common definitions and guideline values of

the main parameters are defined by the Codex commit-tee for fruit juices (http://www.codexalimentarius.net). Afruit juice is defined as the fermentable but unfermentedproduct obtained from the edible part of sound and ripefruits using mechanical or physical means only. Two maincategories are defined as follows:

� fruit juice: obtained directly from the fruit (only flavor,pulp, and cells lost during processing may be restoredif necessary);

� fruit juice made from concentrate: obtained by replac-ing in a concentrated fruit juice the water extracted dur-ing concentration (plus flavor, pulp, and cells lost duringprocessing).

The addition of sugars to fruit juices (for correcting thesugar/acid ratio) is authorized (except for grape and pearjuice) up to 15 g/l, but this must be declared in the ingre-dients list. The addition of more sugar (up to a maximumof 150 g/l) implies labeling the product as “sweetened”(or “nectar,” when water is also added). The addition oflemon juice is also permitted up to 3 g citric acid per liter,but once again must be mentioned in the ingredients list.Moreover, the addition of both sugar and lemon juice isprohibited. No other ingredient not coming directly fromfruit of the same kind is allowed. Especially, the restoredflavor, pulp, and cells must be recovered during fruit juiceprocessing.

Ethanol: A Reliable Isotopic NMR Probe forCharacterizing Wines, Spirits, and Juicesin an Industrial Context

Thanks to its favorable relaxation properties and its well-resolved signals, the ethanol molecule is well adaptedto quantitative 2H NMR (Part 2, Section “Elaborationof SNIF-NMR Probes—From Carbohydrates to Ethanoland Glycerol”) and high levels of repeatability and repro-ducibility are reached in standardized experimental pro-cedures [6].

It is generally not obvious to consider that ethanol is agood probe for authenticating wines and still less evidentfor juices. In this last case, it is tempting to directly investi-gate carbohydrate molecules present in the juice. Unfortu-nately, the 2H NMR spectra of polymeric and even simplecarbohydrates are not suitable for estimating site-specificisotope ratios. Although the carbon-bound hydrogen pa-rameters of glucose and fructose are accessible throughappropriate chemical derivatizations [7], it is at the priceof time-consuming experiments and degraded accuracyincompatible with analytical procedures applicable in aneconomic context. In contrast, ethanol obtained by fer-menting sugars in strictly standardized conditions, pro-vides an attractive probe that enables carbohydrates with

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Table 2: Ranges of mean values exhibited by theisotopic ratios of ethanol samples obtained byfermenting different plant sugars, including grape, beet,and cane sugars. The carbon-13 deviation, δ13C (%)(Part 1, Equation 5) has been measured by IRMS.(D/H )I (in ppm) is the isotope ratio of the methyl siteof ethanol

Plant (D/H )I δ13C

Beet 92.7 −26.6Potato 96.7 −26.5Red fruits 97.2 −26.6Barley 98.2 −24.8Wheat 99.7 −25.8Apple 100.9 −25.0Grape 101.8 −26.3Citrus 105.0 −26.6Pineapple 108.9 −14.5Maize 110.7 −10.4Cane 112.0 −12.2

different molecular structures, including polymers, to beeasily compared in very accurate and precise conditions[8].

As discussed in Part 2 (Section “Elaboration of SNIF-NMR Probes—From Carbohydrates to Ethanol and Glyc-erol”), model fermentation experiments have establishedthe quantitative scheme of site-specific connectivity be-tween glucose and water reactants on one hand andethanol and water products on the other hand. On thisbasis, it is concluded that the isotope ratio of the methylsite of ethanol, (D/H )I (and the overall carbon isotoperatio), reflects properties of sugars and, to a lesser extent,water whereas the methylene isotope ratio, (D/H )II, ismainly representative of the aqueous medium. Since thenatural abundance isotope ratios of the non-exchangeablehydrogen atoms of sugars depend on metabolic and phys-iological characteristics of the plant and on the environ-mental conditions of the photosynthesis [7,9], the iso-topic distribution in the alcoholic fermentation productsmay reflect the origin of the carbohydrate precursors interms of both plant species and geographical area of pro-duction (Part 3, Sections “Identification of Plant Precur-sors” and “Climatic Effects and Geographical Origin”).Table 2 illustrates several ranges of isotopic values exhib-ited by ethanol samples obtained through fermentation, inidentical conditions, of sugars naturally present in fruit orpossibly added to the juice.

Obviously, isotopic values measured on differentethanol samples may be safely interpreted in terms ofproperties of the sugar precursors only on conditionthat all mechanistic aspects of the fermentation reaction

remain constant. In the case of wines, the fermentationparameters may significantly vary with the type of grapesand with oenological practices. Possible influence of thetype of yeast strains and of changes in the composi-tion of the medium had therefore to be investigated [10–12]. Only minor changes were observed in the percent-ages of intra- and inter-molecular transfer of hydrogento the methyl site of ethanol as a function of the natureof the yeasts. More generally, a remarkable stability ofthe (D/H )I parameter was demonstrated. However, sev-eral factors responsible for marginal perturbations of theisotopic results were identified, providing helpful criteriafor interpreting apparent anomalies observed in certainsamples.

Origin Authentication and Data Banks

Aside from the illegal enrichment of must with sucrose,which has a considerable economic importance, otherfrauds only burden the wine market. For example, usurpa-tion and abuse of origin affect wines from more or lessprestigious estates. Apart from some renowned connois-seurs, very few people are able to precisely identify soiland vintage of a given wine and the consumer is forcedto rely on the label. In such cases, isotopic analysesare very efficient tools to authenticate the origin of awine.

According to the general principles described in Part 3(Section “Climatic Effects and Geographical Origin”), theisotopic parameters of both water and ethanol are relatedto the humidity and temperature of the growing region ofthe plant. Therefore, consideration of meteorological dataof the region and of the year helps to make a diagnosis.In the case of wine and fruits, the isotopic parametersof ethanol have been shown to respond even to subtleenvironmental variations and they efficiently characterizethe region of production [13,14].

In practice, many types of wines have been investi-gated [15–21] and private and official data banks havebeen constructed in order to provide reference values. Inthe case of European wines, it was decided in 1991 tobuild an isotopic data bank concerning wines of all theMember States producing wine. At this time, the officiallaboratories of these States supply the data bank that ismaintained in the Joint Research Centre of Ispra (Italy).The files contain several thousand entries for Austrian,French, German, Greek, Italian, Portuguese, Spanish, andeven British and Luxembourg wines [22].

No official data are available for fruit juices, but manykinds of juices have now been isotopically characterized[23,24]. Producers organizations and private companiesinvolved in food and beverage controls have collected au-thentic samples and built up specific data banks [25]. Since1987, Eurofins laboratories have gathered data on several

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thousands of fruit samples. These have contributed inestablishing some statistically defined confidence rangesfor authentic fruits and guideline values for individualfruits included in the AIJN code of practice.

NMR Methodologies in an Officialand Economic Context

Analytical requirements are very different for experi-ments carried out on limited numbers of samples in a re-search laboratory, and for measurements performed rou-tinely in an economic context. In the second situation,the need for analyzing several thousands of samples ayear and combining a variety of instrumental techniquesappeals to rather sophisticated laboratory managementsystems. Moreover, conditions are placed on long-termreproducibility, reliability of the whole analytical chain,rapidity and minimum cost of the determination, and fa-cility of interpretation.

In order to render the NMR method applicable at anindustrial scale, much effort has been devoted to the elab-oration of appropriate technological environments. Thus,through continuous collaboration between the Bruker firmand Eurofins laboratories in France, dedicated equipmentsand computerized programs were elaborated, commer-cialized, and maintained (SNIF-NMR Concept r©). In par-ticular, optimized NMR spectrometers have been fittedwith specific probes and with fluorine locking devices,since the deuterium canal is used for observation. All pa-rameters of signal adjustment have been released fromany operator intervention through the development of arigorous theoretical algorithm [26] which enables quan-titative determinations to be fully automatized (Part 1,Section “Quantitative Deuterium NMR”).

Wines, juices, and even spirits cannot be directly stud-ied as they stand and it is necessary to carry out a series ofpreliminary treatments. Since the measurements are donewith ethanol and water, juices should be fermented in afirst step and the resulting fruit wines must then be dis-tilled. As a result of thermodynamic and kinetic isotopeeffects associated with phase transitions (Part 2, Sections“Simultaneous Determination of Site-specific Thermody-namic Isotope Effects” and “Determination of Kinetic Iso-tope Effects”), incomplete isolation of ethanol may induceisotopic fractionation of a few tenths of ppm for a yieldof about 90%. The most critical point is therefore to ex-tract ethanol from the product investigated with as highyield as possible and with the greatest alcoholic grade.For wines and spirits, a single distillation is sufficient butin any case, isotopic perturbations due to the process mustbe eliminated. Integrating the NMR detection into an in-formation system, which routinely manages preparationof samples, NMR acquisition procedures, data handling,

and diagnosis, optimizes the efficiency of the method.Moreover, detailed protocols have been defined and col-laborative studies organized in order to check the accuracyperformances.

Determination of Illegal Enrichments

According to the definitions given in Part 1, the isotopiccomposition of a mixture is a weighted mean of the pa-rameters of the components. It is therefore required toknow or to measure the isotopic ratios of the pure com-ponents in order to be able to compute the composition ofthe mixture. The first experimental description of the de-tection of chaptalization in wines appeared in 1983 [27].It was published 4 years later as an official method of the“Office International de la Vigne et du Vin” (OIV) [28]and in 1990 it was included in the EU regulation concern-ing the control of wines [29,30]. If using only SNIF-NMRcan determine wine chaptalization, the detection of otherfrauds is improved when the 2H and 18O isotopic ratiosof the water contained in the product are measured. Inthis respect, although SNIF-NMR can be safely appliedin determining the D/H of water, isotope ratio mass spec-trometry (IRMS) is routinely preferred for this purpose.The precautions for eliminating adverse isotopic effectshave been reviewed [21,29,31].

In the case of fruit juices, the SNIF-NMR and 13CIRMS methods based on the isotopic analysis of ethanolresulting from fermentation have been officially recog-nized after international collaborative studies (AOAC Of-ficial Methods 995.17 and 2004.01, respectively).

The composition of a chaptalized wine or of an en-riched juice is easily computed from the isotopic NMRratio of site I of ethanol, providing that reference data areavailable. The molar fraction x of a mixture M containingtwo components A and B is given by Equation (1):

x = [(D/H )A

I − (D/H )MI

]/ [(D/H )A

I − (D/H )BI

](1)

M may be either an unknown chaptalized wine or afermented sugared orange juice for instance. A is the ref-erence wine or juice and B is the sugar (beet or canesucrose) added to the product [32]. Some more refinedfraudsters use a mixture of beet and cane sucrose withthe idea of circumventing SNIF-NMR, since it has beenshown that an addition of beet sucrose in a must de-creases the isotope ratio, (D/H )I, of the methyl site ofwine ethanol, whereas addition of cane sucrose increasesthis parameter (Table 2). However, since two indepen-dent parameters can identify a ternary mixture containinggrape, beet, and cane ethanol, combining 13C IRMS deter-minations soon deterred this practice. To solve this systemof equations, the knowledge of the isotopic parameters of

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authentic wines or juices is required. Geographical andannual variations may be taken into account by resortingto the up-to-date databases of authentic samples describedin Section “Origin Authentication and Data Banks” [32].On this basis, authenticity limits are defined as statisti-cal confidence ranges of isotopic parameters, using eitherunivariate or multivariate approaches.

Isotopic Characterization ofConcentrated Juices

Commercial fruit juices are often made from concentrate.Similarly, concentrated grape juice may be used in wineproduction. Since the concentrated juices are preparedthrough low-temperature evaporation processes, the iso-topic data of the final products, commercial juices andwines, depend not only on the botanical and geograph-ical parameters but also on the fractionation factors as-sociated with the physical transformation. Consequently,when isotopic analysis is used for sample authentication,the influence of the technological treatment must be es-timated in order to isolate useful information about theoriginal product. Model experiments of low-temperatureevaporation processes have been carried out and analyzed[33], according to the principles discussed in Part 2 (Sec-tion “Simultaneous Determination of Site-specific Ther-modynamic Isotope Effects”), on the basis of Equation(2):

RC/RS = NC/N (βeff−1)S (2)

where RS and RC are the hydrogen (or oxygen) isotoperatio of water in the starting juice and in the remainingconcentrate respectively, and NC/NS is the molar ratioof residual water. βeff is the effective fractionation fac-tor which fits the kinetic contribution of the evaporationprocess. This parameter has been determined for 2H and18O in experiments involving different sugar solutionsand juices. At a temperature of 18 ◦C, the following val-ues have been determined: βeff(

2H) = 0.923(±0.003) andβeff(18O) = 0.991(±0.002). These results can be appliedin two complementary ways. Firstly, in the case of orangeconcentrates suspected of containing sucrose, it is possi-ble to infer the δ2H (or δ18O) value of the natural juicewater before concentration from both the Brix value andthe δ2H (or δ18O) value measured on water of the con-centrate. The computed isotope contents of the originaljuice water are then used for evaluating the (D/H )I valueof ethanol which would result from fermentation of thepure juice. These estimated parameters provide improvedreferences for computing the amount of sucrose additionin concentrate and they significantly increase the sensitiv-ity of detection of this practice. Conversely, when RS is

known, Equation (2) may be exploited for estimating theconcentration rate. This procedure was successfully ap-plied to the detection of added concentrated must in wine.The values of δ2H and δ8O of the wine water are thencompared to the values of the same parameters measuredin pure grape musts or natural wines from the same regionand year.

Multi-component and Multi-isotope Strategiesin the Detection of Adulterations

With the combined use of SNIF-NMR and 13C IRMS,most of the economically profitable forms of adulteration,which are concerned with the addition of sugar from cheapsources such as beet, cane, or maize, can be detected.In some instances, however (e.g. when the geographicalorigin is unknown), it can be difficult to prove adulter-ation with certainty, and the use of other componentsas isotopic internal references is a way of improving thedetection limits of adulterations. Such multi-componentmulti-isotope patterns may involve individual sugars [34],sugars and acids [35], or sugars and water [36]. Finally,some fractions like proteins can also be used as “absolute”internal references as they are not concerned by economicadulteration [37].

Thanks to the recent development of preparative HPLCprocedures, organic acids can be routinely isolated fromany kind of fruit juices and wine. Obviously, this requirescomplete recovery of each component at all stages ofthe purification to avoid any isotopic fractionation. Basedon numerous results from a wide database of authenticfruits collected around the world, systematic isotopic cor-relations between individual organic acids or betweenorganic acids and other components have been estab-lished. Reproducible relationships are observed for anygiven fruit species, which can be solely attributed to themetabolism of the fruit and remain independent fromits geographical origin. The use of internal referencingbased on such multi-component patterns significantly en-hances the sensitivity of both NMR and IRMS isotopicmethods for the detection of sophisticated adulterations[37–42].

To illustrate the increasing complexity of some prob-lems, it should be mentioned that refined adulterationpractices have been specially developed to bypass theisotopic methods based on sugar analysis via fermentedethanol. Thus, when addition of specifically designedsugar syrups, derived from starch or inulin from C3 plantsis suspected, the only way to detect low levels of sugaraddition is to use GC analysis of oligosaccharides pro-files, which reveal the presence of marker peaks of theseindustrial syrups. Conversely, this method does not detectraw sucrose addition. Therefore, in order to fully control

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the absence of sophisticated adulteration of a fruit juice,it may be necessary to combine isotopic and conventionalanalyses.

Detection of Exogeneous Minor Components

In certain cases, adulteration by exogeneous minor com-ponents may also be suspected. Frequently this prac-tice aims to mask illegal dilution or enrichment of theproduct.

The most abundant acids of fruit products (citric, l-malic, and l-tartaric acids) are solids that are insolublein most organic solvents, which makes their SNIF-NMRanalysis more difficult. Nevertheless, suitable derivativessuch as esters provide access to the D/H ratios of non-exchangeable hydrogen atoms. For example the 2H NMRspectrum of triethyl citrate enables the two original methy-lene sites of citric acid to be conveniently quantified.Looking at the affiliations of carbon and hydrogen atomsalong the glycolysis pathway and in the Krebs cycle,it appears that citric acid carbon atoms derive from allglucose carbon atoms and that at least two-thirds of thenon-exchangeable methylenic hydrogen atoms come fromwater of the medium. Since the industrial productionof citric acid uses various cheap sugar sources, the 13Cdeviations cover the whole range of values character-izing C3 and C4 plants. On the other hand, the deu-terium enrichment in plant water versus ground waterresults in a significant shift of the deuterium contentof fruit citric acid as compared to its artificial coun-terpart. Then, the combined use of global 13C/12C andsite-specific 2H/1H ratios satisfactorily discriminates cit-ric acid from fruits such as lemon from all commercialsources.

As a final example, we may consider the case of glyc-erol, usually produced in significant amounts (3–5%) infermentation reactions. Its presence in wine has a no-ticeable influence on the sensory parameters. Forbiddenaddition of exogeneous glycerol is easily detected bySNIF-NMR since the isotopic profile of glycerol natu-rally present in wines can be differentiated from that ofsynthetic glycerol and also from that of glycerol derivedfrom other plants [43,44].

References

1. Martin, G. J. and Martin, M.L., Tetrahedron Lett. 1981;22:3525–8.

2. Martin GJ, Martin ML. Brevet France: 1981;81-22710:1–24.3. Simpkins W, Harrison M. Trends Food Sci. Technol. 1995;

6:321–8.4. Commission of the European Communities. Off. J. Eur. Com-

mun. 1999;1–84.

5. Commission of the European Communities. Off. J. Eur. Com-mun. 1987;822:87 and 1990;2676:90.

6. Martin GG, Guillou C, Martin YL. Fruit Process. 1995;4:246–54.

7. Zhang BL, Billault I, Li X, Mabon F, Remaud G, Martin ML.J. Agric. Food Chem. 2002;50:1574–80.

8. Martin GG, Martin YL. Fruit Process. 1996;5:186–94.9. Martin GJ, Danho D, Vallet C. J. Sci. Food Agric.

1991;56:419–34.10. Vallet C, Said R, Rabiller C, Martin ML. Bioorg. Chem.

1996;24:319–30.11. Zhang BL, Yunianta, Vallet C, Martin YL, Martin ML. Bioorg.

Chem. 1997;25:117–29.12. Fauhl C, Wittkowski R. J. Agric. Food Chem. 2000;48:3979–

84.13. Martin GJ, Guillou C, Martin ML, Cabanis MT, Tep Y, Aerny

J. J. Agric. Food Chem. 1988;36:316–22.14. Martin GJ, Martin ML. In: HF Linskens and JF Jackson (Eds).

Modern Methods of Plant Analysis, Springer-Verlag, Berlin,1988;6:258–75.

15. Monetti A, Reniero F, Versini GZ. Lebensm. Unters. Forsch.1994;311–6.

16. Versini G, Monetti A, Reniero F. Wine: Nutritional and Ther-apeutic Benefits. In: TR Watkins (Ed). ACS Symposium Se-ries 661. Washington, Amer. Chem. Soc. 1997, pp 113–30.

17. Gimenez-Miralles JE, Salazar DM, Solana I. J. Agric. FoodChem. 1999;47:2645–52.

18. Ogrinc N, Kosir IJ, Kocjancic M, Kidric J. J. Agric. FoodChem. 2001;49:1432–40.

19. Martin GJ, Mazure M, Jouitteau C, Martin YL, Aguile L,Allain P. Am. J. Enol. Vitic. 1999;50:409–17.

20. Christoph N, Rossmann A, Voerkelius S. Mitt.Klosterneuburg 2003;53:23–40.

21. Ogrinc N, Kosir IJ, Spangenberg JE, Kidric J. Anal. Bioanal.Chem. 2003;376:424–30.

22. Official Journal of the European Communities. Off. J. Eur.Commun. 1991;L214:39–43.

23. Pupin AM, Dennis MJ, Parker I, Kelly S, Bigwood T, ToledoMCF. J. Agric. Food Chem. 1998;46:1369–73.

24. Simpkins WA, Patel G, Collins P, Harrison M, Goldberg D.J. Agric. Food Chem. 1999;47:2606–12.

25. Guillou C, Jamin E, Martin GJ, Reniero F, Wittkowski R,Wood R. Bulletin OIV. 2001;74:26–36.

26. Martin YL. J. Magn. Res. Ser. A. 1994;111:1–10.27. Martin GJ, Martin ML. J. Chim. Phys. 1983;80:293–7.28. Martin GJ, Brun S. Methodes d’Analyse de l’OIV. 1987;1–

15.29. Zhang BL, Fourel F, Naulet N, Martin GJ. Feuillet vert OIV.

1992 (1954/220792).30. Martin GJ. Endeavour. 1990;14:137–43.31. Martin GG, Wood R, Martin GJ. J. AOAC Int. 1996;79:917–

28.32. Martin GG, Hanote V, Lees M, Martin YL. J. AOAC Int.

1996;79:62–72.33. Yunianta (∗), Zhang BL, Lees M, Martin GJ. J. Agric. Food

Chem. 1995;43:2411–7.34. Day MP, Correia P, Hammond DA. J. AOAC Int. 2001;3:957–

63.35. Gonzalez J, Remaud G, Jamin E, Naulet N, Martin GG. J.

Agric. Food Chem. 1998;46:2316–21.

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36. Jamin E, Guerin R, Retif M, Lees L, Martin GJ. J. Agric.Food Chem. 2003;51:5202–6.

37. Jamin E, Gonzalez J, Bengoechea I, Kerneur G, Remaud G,Iriondo C, Martin GG. J. Agric. Food Chem. 1998;46:5118–23.

38. Jamin E, Gonzalez J, Remaud G, Naulet N, Martin GG. J.Agric. Food Chem. 1997;45:3961–7.

39. Jamin E, Gonzalez J, Remaud G, Naulet N, Martin GG,Weber D, Rossmann A, Schmidt HL. Anal. Chim. Acta.1997;347:359–68.

40. Jamin E, Gonzalez J, Bengoechea I, Kerneur G, Remaud G,Naulet N, Martin GG. J. AOAC Int. 1998;81:604–9.

41. Gonzalez J, Jamin E, Remaud G, Martin YL, Martin GG,Martin ML. J. Agric. Food Chem. 1998;46: 2200–5.

42. Weber D, Rossmann A, Schwarz S, Schmidt HL. Z. Lebensm.Unters. Forsch. 1997;205:158–64.

43. Zhang BL, Buddrus S, Trierweiler M, Martin GJ. J. Agric.Food Chem. 1998;46:1374–80.

44. Weber D, Kexel H, Schmidt H. J. Agric. Food Chem.1997;45:2042–6.

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