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Statistical evalution of aroma and metal content in Tokay wines
Microchemical Journal 67 Ž2000. 91᎐96
Statistical evalution of aroma and metal content in Tokay wines Zoltan ´ Muranyi ´ U , Zsuzsanna Kovacs ´ K. Eszterhazy Teachers Training College, Eger, Hungary
Abstract Wine qualities are predominantly determined by the qualitative and quantitative composition of organic and inorganic components present, consequently elucidating them is one of the tasks of greatest significance facing wine analysis. It is, on the other hand, of unique importance from the economic viewpoint to make sure and keep a continuous check on whether wine qualities are satisfactory enough, taking the trend into consideration that nowadays among products for human consumption it is solely those that show a high likelihood to succeed on the market in the long run that manage to satisfy quality requirements of gradually increasing demands. Research into food analytic on the other hand, plays a considerably significant role in origin protection which is an issue of particular importance in the case of a wine-growing area of such long tradition. During the course of the investigation the answer was sought to the question of how qualitative and quantitative relations of volatile organic and metal components present in traditional wines produced in the wine-growing area depend on the vintage, the location on which it is grown, as well as the type of wine grape and to what extent these are characteristic of wines of given type and vintage. 䊚 2000 Elsevier Science B.V. All rights reserved. Keywords: Wine; Volatile compounds; Metal contents; SPME; GC-MS; ICP-AES; Statistical evaluation
1. Introduction Wine qualities are primarily determined by the qualitative and quantitative relations of organic and inorganic components contained in wines, therefore their analytical investigation is of indisputably great significance. Instrumental analytical investigations, on the
U
Corresponding author.
other hand, take a prominent part in examinations of origin and are nowadays indispensable in the case of wines of wine-growing areas of long traditions. Consumption of quality wines is gaining ground to an increasing extent; wine culture seems to obtain a rank it is worthy of in Hungary similar to traditional European wine-producing countries. The wine samples examined were from Tokay, one of the oldest and deservedly ᎏ perhaps ᎏ the most famous wine-growing areas.
0026-265Xr00r$ - see front matter 䊚 2000 Elsevier Science B.V. All rights reserved. PII: S 0 0 2 6 - 2 6 5 X Ž 0 0 . 0 0 1 0 3 - X
92
Z. Muranyi, ´ Z. Ko¨ ´acs r Microchemical Journal 67 (2000) 91᎐96
The Tokay wine-growing area is situated in the frontier zone of north-east Hungary in the agroecological area of the mountain ranges of Tokay᎐Zemplen ´ at a medium height of 500 m. The climate is of continental character with mild, sunny, misty, and slightly rainy autumns. This area has considerably diverse soils: in the Tokay region it is chiefly loess mixed with rubbles of rocks of volcanic origin. It is exclusively white wines that are produced in the wine-growing area of Tokay, particularly from varieties of grapes suitable for wine made from selected noble rot grapes Žaszu.. The principal aim of the current study was the investigation of volatile organic components and metal content of the wines from the area described above. The answer has been sought to the question of what sort of connections could be discovered between the qualitative and quantitative relations of aroma components and metal content in certain wines. Quantitative proportions of volatile components are characteristics of the wine types w1,2x. A great deal of significant information could be obtained concerning the origin of wines by processing the data, following the methods of multivariable statistics w3,4x. The aim of the current study was how to gain as much information as possible regarding the aroma and metal content of the given product by means of statistical assessment in the case of wines in a definite growing area ŽTokay.. A great deal of significant information could be obtained by processing the data.
Table 1 Wine samples analysed Type of wines
Muskotaly ´ Aszu ´ Szamorodni dry Szamorodni sweet Furmint
Wine growing area Tokaj
Mad ´
Tallya ´
Tarcal
Tolcsva
2 5 3 4 1
9 10 19 6 8
᎐ 14 12 13 11
᎐ 18 ᎐ 17 15
᎐ 20 ᎐ ᎐
new sample preparing method and is more and more widely used. The essence of the procedure is that a microextraction fibre, covered by an adsorbent polymer, sinks into the sample-solution or into its vapour space. Then, division takes place between liquid or vapour phase and extraction fibre. After adsorption equilibrium has set in Žin the case of headspace analysis it takes a few minutes, in solvent max. 1᎐2 h. and after placing the microextraction fibre into the GC injector, the adsorbed compounds get desorbed by heat. Contrarily to liquid᎐liquid extraction the SPME technique is cheap, fast, free of any solvents, easy to use, sensitive for same component, does not upset the sensitive balance system of wines, and can be reproduced quite easily w5,6x. During SPME sample preparation, after having poured 200 ml of the wine sample into an Erlenmeyer flask, the extraction fibre was placed into the liquid. Extraction took place for 5 min and the sample was stirred continuously by a magnetic stirrer. Desorption took place after 2 min in the temperature of the injector. During this operation a 100-m PDMS coated extraction fibre was used.
2. Materials and methods 2.1. Sample taking and sample preparation The numbers of samples analysed are found in Table 1. 2.1.1. Sample preparation for measuring of organic compounds We used solid phase microextraction ŽSPME. during our experiments. SPME, elaborated by Pawliszyn and his research workers is a relatively
2.1.2. Sample preparation for measurement of metal contents A significant problem arises as to how the constancy of the sample can be maintained during the course of the period between sample taking and measuring. It is especially advantageous in this case, that the complex-forming reagent applied for measuring could be observed to ‘preserve’ ironŽII., to put it another way, after the addition of 2,2⬘-dipirydin, ironŽII. concentration does not decrease w7,8x.
Z. Muranyi, ´ Z. Ko¨ ´acs r Microchemical Journal 67 (2000) 91᎐96
Samples were taken from a depth of 100 mm under the surface of the liquid through a pipe made of silicone into two plastic dishes. Ten millilitres of wine was put into one of the dishes and 1 ml of 1% 2,2⬘-dipirydin-solution with abs. alcohol was added to it. The wine having been placed into the other dish was not treated on the premises. ŽThe second fraction was essential for the determination of the total iron, and the other metal concentrations as well as for producing the reference applied at the photometric measuring.. Before further treatments both sample fractions were filtrated. To determine the metal content of the wines, 25 ml of the sample was evaporated to dryness then treated with a mixture of 4 ml pa. cc. nitric acid and 2 ml 30% pa. hydrogen peroxide solution; it was then evaporated to dryness three times. Next the dry residues were dissolved and their volume was set to 25 ml in 0.1 M nitric acid solution. Filtrations and the above mentioned treatment were carried out using 25-ml aliquots of distilled water, that is how we obtained blank samples w7,9x.
93
value to 3 and the alcohol content of solutions to 10%. The metal content of the pre-treated samples was determined by a low flow torch inductively coupled plasma atomic emission spectrometer ŽARL 3410.. The operating conditions are the following: power, 650 W; plasmagas ŽAr., 7.5 lrmin; auxiliary gas ŽAr., 0.7 lrmin; nebulizer gas ŽAr., 0.75 lrmin; nebulizer: Meinhard type. The measurement parameters are shown in Table 2. 2.3. Statistical e¨ aluation We have investigated the behaviour of different components in space and in the different types of wines by using the dates of metal concentration and relatative aroma concentrations w10x Mathematical analysis was performed using the Factor Analysis module of SPSS for Windows ’95 Software. We have investigated the influences of the growing area and the type of the grapes on the distribution of metal contents and aroma components. The extraction method used was principal component analysis.
2.2. Instrumentation 3. Results 2.2.1. Measuring conditions for organic compounds GCrMS: Injector: Column: Carrier gas:
FINNIGAN GCQ ion-trap split, 250⬚C, split ratio: 1:100 DB-5-MS 30 m = 0.32 mm Hydrogen, 1 mlrmin
Temperature program: 45⬚C: 3 min isotherm, 45᎐100⬚C 5⬚Crmin, 100⬚C: 1 min isotherm 100᎐160⬚C: 4⬚Crmin, 160⬚C: 1 min isotherm, 160᎐240⬚C: 10⬚Crmin, 240⬚C 1 min isotherm
2.2.2. Measuring conditions for metal contents Determination of ironŽII. concentration was carried out by means of a photometer, Jasco V-530 UVrVIS at a wavelength of 522 nm. The reference solution was produced by the addition of 1 ml abs. alcohol to 10 ml of wine. Calibration solutions Ž1 mgrl᎐25 mgrl. were produced from freshly made ironŽII. solution by setting the pH
The identified organic compounds are shown in Table 3. On the basis of measuring it might be concluded, in connection with volatile components, that the occurrence of main components are unambiguously determined by the types of both the growing area and the wine as well as the character of the wine Žsweet or dry.. There is a similar distribution in the identified volatile components in Szamorodni wines of the same type taken from different growing areas ŽFig. 1.. It could also be ascertained, at the same time, that in the case of wines of different types taken from the same growing area, the distribution of volatile components shows considerable similarities in wines similar in character. This is examplified in the chart representing the distribution of main volatile components in different types of wines from Mad ´ ŽFig. 2.. The fact that the growing area undoubtedly influences the aroma content, could be seen in
Z. Muranyi, ´ Z. Ko¨ ´acs r Microchemical Journal 67 (2000) 91᎐96
94
Table 2 Measurement parameters for metals Element
Al
Pb
Cd
Fe
Mn
Cu
Ca
Analytical lines Žnm. Concentration rangea Žgrml. Relative standard deviation Ž%. Limit of detection Žgrml.
167.081 0.01᎐1.5 1.0᎐3.5 0.002
220.353 0.02᎐0.2 7.0᎐12.0 0.01
228.802 0.01᎐0.1 1.0᎐3.5 0.002
259.940 0.2᎐50 0.6᎐1.5 0.002
257.940 0.1᎐5.0 1.0᎐3.5 0.001
324.754 0.01᎐1.0 1.0᎐3.5 0.002
422.673 0.2᎐50 0.5᎐1.5 0.001
a
Calibrating solutions were made from nitrates of metals.
Table 3 Identified organic compounds Number
Identified compounds
1 2 3 4 5 6 7 8 9 10 11 12 13
Ethyl-decanoate 3 Hexene-1-ol 2-Phenyl-ethanol Ethyl-hexanoate Phenetyl-acetate Hexanol Linalil-acetate Terpineol Dibuthyl,-dimethyl-succinate Ethyl-dodedaconate Methyl-␣-chetopalmitate Citronellol 3-Methyl,buthyl-octanoate Fig. 2. Concentration of volatile components in wines from Mad. ´
the case of wines of the same type Že.g. aszus. ŽFig. 3.. It might be established, on the other hand, examining the distribution of volatile components from the point of view of their types, that the distribution of components belonging to the
Fig. 1. Concentration of volatile components in Szamorodni wines.
same compound type in different wines are rather close to one another ŽFig. 4... The following facts could be pointed out in connection with the metal components investigated: The explanation of the different behaviour
Fig. 3. Concentration of volatile components in aszu wines.
Z. Muranyi, ´ Z. Ko¨ ´acs r Microchemical Journal 67 (2000) 91᎐96
95
Fig. 4. Main aroma components in the wines investigated.
Fig. 5. Metal contents of wines investigated.
certain metals ŽFig. 5. show is considerably difficult to find, since there are a great number of influencing factors. The intense difference of lead as well as the iron ᎐manganese and the iron᎐ironŽII. similarities are striking. The former is caused by the similarity in the migration of the metals mentioned, while the reason for the latter is that the way in which wines are treated unambiguously determines the proportion of irons in a lower state of oxidation of the total iron content. From investigations on the metal content chiefly entering the wines in the form of contamination ŽFig. 6., it might be ascertained that there has been one type of wine ŽFurmint from Tarcal. affected by a contamination to an incongruous extent Žin relation to the normal.. The extent to which wines are contaminated depends rather on their growing area. In the case of metals, migrating into the wine through the grape from the soil ŽFig. 7., surprisingly, it is not the area in which they are grown but the type of the wine which is the dominant factor. It is also interesting to observe that there are greater differences within
one type, in the case of young wines Žfurmint, muscatel., in addition to the differences from wines of older vintages.
4. Discussion In summary it could be established that the growing area, the type and the character of wines
Fig. 6. Cd, Cu, Pb content of wines from the wine growing area of Tokay.
Fig. 7. Al, Ca, Fe and Mn content of wines from the wine growing area of Tokay.
96
Z. Muranyi, ´ Z. Ko¨ ´acs r Microchemical Journal 67 (2000) 91᎐96
play a dominant role with a view to the metal content and the aroma content of the wines. Methods of multi-variable statistics seem to be indisputably suitable for discovering this role. References w1x R.F. Simpson, Vitis 17 Ž1978. 274᎐287. w2x R.F. Simpson, Vitis 18 Ž1979. 148᎐154. w3x L. Jakob, H.R. Eschnauer, Deut Weinbaujahrbuch 41 Ž1990. 215᎐222. ¨ ¨ w4x H.R. Eschnauer, Zur Onologie und Okologie anorganischer Wein-Inhaltsstoffe. In Analytiker-Taschenbuch, 17. Berlin, Heidelberhg, New York, 1998, pp. 294᎐315.
w5x J. Pawliszyn, Anal. Chem. 62 Ž1990. 2145᎐2148. w6x J. Pawliszyn, SPME Method Development. Solid Phase Microextarction, Wiley-VCH, Toronto, 1997, pp. 97᎐139. w7x H.R. Eschnauer, R. Neeb, Micro element analysis in wine and grapes, in: H. Linskens, J.F. Jackson ŽEds.., Wine Analysis, Academic Press, New York, 1988, pp. 67᎐89. w8x Z. Muranyi, L. Papp, 40th Hungarian Conference on ´ Spectrochemistry, 1997. w9x Z. Muranyi, L. Papp, ACH Models Chem. 134 Ž4. Ž1997. ´ 529᎐537. w10x M. Otto, Chemometrie-Statistik und Computereinsatz in der Analytik, Weinheim, 1997.
Statistical evalution of aroma and metal content in Tokay wines Zoltan ´ Muranyi ´ U , Zsuzsanna Kovacs ´ K. Eszterhazy Teachers Training College, Eger, Hungary
Abstract Wine qualities are predominantly determined by the qualitative and quantitative composition of organic and inorganic components present, consequently elucidating them is one of the tasks of greatest significance facing wine analysis. It is, on the other hand, of unique importance from the economic viewpoint to make sure and keep a continuous check on whether wine qualities are satisfactory enough, taking the trend into consideration that nowadays among products for human consumption it is solely those that show a high likelihood to succeed on the market in the long run that manage to satisfy quality requirements of gradually increasing demands. Research into food analytic on the other hand, plays a considerably significant role in origin protection which is an issue of particular importance in the case of a wine-growing area of such long tradition. During the course of the investigation the answer was sought to the question of how qualitative and quantitative relations of volatile organic and metal components present in traditional wines produced in the wine-growing area depend on the vintage, the location on which it is grown, as well as the type of wine grape and to what extent these are characteristic of wines of given type and vintage. 䊚 2000 Elsevier Science B.V. All rights reserved. Keywords: Wine; Volatile compounds; Metal contents; SPME; GC-MS; ICP-AES; Statistical evaluation
1. Introduction Wine qualities are primarily determined by the qualitative and quantitative relations of organic and inorganic components contained in wines, therefore their analytical investigation is of indisputably great significance. Instrumental analytical investigations, on the
U
Corresponding author.
other hand, take a prominent part in examinations of origin and are nowadays indispensable in the case of wines of wine-growing areas of long traditions. Consumption of quality wines is gaining ground to an increasing extent; wine culture seems to obtain a rank it is worthy of in Hungary similar to traditional European wine-producing countries. The wine samples examined were from Tokay, one of the oldest and deservedly ᎏ perhaps ᎏ the most famous wine-growing areas.
0026-265Xr00r$ - see front matter 䊚 2000 Elsevier Science B.V. All rights reserved. PII: S 0 0 2 6 - 2 6 5 X Ž 0 0 . 0 0 1 0 3 - X
92
Z. Muranyi, ´ Z. Ko¨ ´acs r Microchemical Journal 67 (2000) 91᎐96
The Tokay wine-growing area is situated in the frontier zone of north-east Hungary in the agroecological area of the mountain ranges of Tokay᎐Zemplen ´ at a medium height of 500 m. The climate is of continental character with mild, sunny, misty, and slightly rainy autumns. This area has considerably diverse soils: in the Tokay region it is chiefly loess mixed with rubbles of rocks of volcanic origin. It is exclusively white wines that are produced in the wine-growing area of Tokay, particularly from varieties of grapes suitable for wine made from selected noble rot grapes Žaszu.. The principal aim of the current study was the investigation of volatile organic components and metal content of the wines from the area described above. The answer has been sought to the question of what sort of connections could be discovered between the qualitative and quantitative relations of aroma components and metal content in certain wines. Quantitative proportions of volatile components are characteristics of the wine types w1,2x. A great deal of significant information could be obtained concerning the origin of wines by processing the data, following the methods of multivariable statistics w3,4x. The aim of the current study was how to gain as much information as possible regarding the aroma and metal content of the given product by means of statistical assessment in the case of wines in a definite growing area ŽTokay.. A great deal of significant information could be obtained by processing the data.
Table 1 Wine samples analysed Type of wines
Muskotaly ´ Aszu ´ Szamorodni dry Szamorodni sweet Furmint
Wine growing area Tokaj
Mad ´
Tallya ´
Tarcal
Tolcsva
2 5 3 4 1
9 10 19 6 8
᎐ 14 12 13 11
᎐ 18 ᎐ 17 15
᎐ 20 ᎐ ᎐
new sample preparing method and is more and more widely used. The essence of the procedure is that a microextraction fibre, covered by an adsorbent polymer, sinks into the sample-solution or into its vapour space. Then, division takes place between liquid or vapour phase and extraction fibre. After adsorption equilibrium has set in Žin the case of headspace analysis it takes a few minutes, in solvent max. 1᎐2 h. and after placing the microextraction fibre into the GC injector, the adsorbed compounds get desorbed by heat. Contrarily to liquid᎐liquid extraction the SPME technique is cheap, fast, free of any solvents, easy to use, sensitive for same component, does not upset the sensitive balance system of wines, and can be reproduced quite easily w5,6x. During SPME sample preparation, after having poured 200 ml of the wine sample into an Erlenmeyer flask, the extraction fibre was placed into the liquid. Extraction took place for 5 min and the sample was stirred continuously by a magnetic stirrer. Desorption took place after 2 min in the temperature of the injector. During this operation a 100-m PDMS coated extraction fibre was used.
2. Materials and methods 2.1. Sample taking and sample preparation The numbers of samples analysed are found in Table 1. 2.1.1. Sample preparation for measuring of organic compounds We used solid phase microextraction ŽSPME. during our experiments. SPME, elaborated by Pawliszyn and his research workers is a relatively
2.1.2. Sample preparation for measurement of metal contents A significant problem arises as to how the constancy of the sample can be maintained during the course of the period between sample taking and measuring. It is especially advantageous in this case, that the complex-forming reagent applied for measuring could be observed to ‘preserve’ ironŽII., to put it another way, after the addition of 2,2⬘-dipirydin, ironŽII. concentration does not decrease w7,8x.
Z. Muranyi, ´ Z. Ko¨ ´acs r Microchemical Journal 67 (2000) 91᎐96
Samples were taken from a depth of 100 mm under the surface of the liquid through a pipe made of silicone into two plastic dishes. Ten millilitres of wine was put into one of the dishes and 1 ml of 1% 2,2⬘-dipirydin-solution with abs. alcohol was added to it. The wine having been placed into the other dish was not treated on the premises. ŽThe second fraction was essential for the determination of the total iron, and the other metal concentrations as well as for producing the reference applied at the photometric measuring.. Before further treatments both sample fractions were filtrated. To determine the metal content of the wines, 25 ml of the sample was evaporated to dryness then treated with a mixture of 4 ml pa. cc. nitric acid and 2 ml 30% pa. hydrogen peroxide solution; it was then evaporated to dryness three times. Next the dry residues were dissolved and their volume was set to 25 ml in 0.1 M nitric acid solution. Filtrations and the above mentioned treatment were carried out using 25-ml aliquots of distilled water, that is how we obtained blank samples w7,9x.
93
value to 3 and the alcohol content of solutions to 10%. The metal content of the pre-treated samples was determined by a low flow torch inductively coupled plasma atomic emission spectrometer ŽARL 3410.. The operating conditions are the following: power, 650 W; plasmagas ŽAr., 7.5 lrmin; auxiliary gas ŽAr., 0.7 lrmin; nebulizer gas ŽAr., 0.75 lrmin; nebulizer: Meinhard type. The measurement parameters are shown in Table 2. 2.3. Statistical e¨ aluation We have investigated the behaviour of different components in space and in the different types of wines by using the dates of metal concentration and relatative aroma concentrations w10x Mathematical analysis was performed using the Factor Analysis module of SPSS for Windows ’95 Software. We have investigated the influences of the growing area and the type of the grapes on the distribution of metal contents and aroma components. The extraction method used was principal component analysis.
2.2. Instrumentation 3. Results 2.2.1. Measuring conditions for organic compounds GCrMS: Injector: Column: Carrier gas:
FINNIGAN GCQ ion-trap split, 250⬚C, split ratio: 1:100 DB-5-MS 30 m = 0.32 mm Hydrogen, 1 mlrmin
Temperature program: 45⬚C: 3 min isotherm, 45᎐100⬚C 5⬚Crmin, 100⬚C: 1 min isotherm 100᎐160⬚C: 4⬚Crmin, 160⬚C: 1 min isotherm, 160᎐240⬚C: 10⬚Crmin, 240⬚C 1 min isotherm
2.2.2. Measuring conditions for metal contents Determination of ironŽII. concentration was carried out by means of a photometer, Jasco V-530 UVrVIS at a wavelength of 522 nm. The reference solution was produced by the addition of 1 ml abs. alcohol to 10 ml of wine. Calibration solutions Ž1 mgrl᎐25 mgrl. were produced from freshly made ironŽII. solution by setting the pH
The identified organic compounds are shown in Table 3. On the basis of measuring it might be concluded, in connection with volatile components, that the occurrence of main components are unambiguously determined by the types of both the growing area and the wine as well as the character of the wine Žsweet or dry.. There is a similar distribution in the identified volatile components in Szamorodni wines of the same type taken from different growing areas ŽFig. 1.. It could also be ascertained, at the same time, that in the case of wines of different types taken from the same growing area, the distribution of volatile components shows considerable similarities in wines similar in character. This is examplified in the chart representing the distribution of main volatile components in different types of wines from Mad ´ ŽFig. 2.. The fact that the growing area undoubtedly influences the aroma content, could be seen in
Z. Muranyi, ´ Z. Ko¨ ´acs r Microchemical Journal 67 (2000) 91᎐96
94
Table 2 Measurement parameters for metals Element
Al
Pb
Cd
Fe
Mn
Cu
Ca
Analytical lines Žnm. Concentration rangea Žgrml. Relative standard deviation Ž%. Limit of detection Žgrml.
167.081 0.01᎐1.5 1.0᎐3.5 0.002
220.353 0.02᎐0.2 7.0᎐12.0 0.01
228.802 0.01᎐0.1 1.0᎐3.5 0.002
259.940 0.2᎐50 0.6᎐1.5 0.002
257.940 0.1᎐5.0 1.0᎐3.5 0.001
324.754 0.01᎐1.0 1.0᎐3.5 0.002
422.673 0.2᎐50 0.5᎐1.5 0.001
a
Calibrating solutions were made from nitrates of metals.
Table 3 Identified organic compounds Number
Identified compounds
1 2 3 4 5 6 7 8 9 10 11 12 13
Ethyl-decanoate 3 Hexene-1-ol 2-Phenyl-ethanol Ethyl-hexanoate Phenetyl-acetate Hexanol Linalil-acetate Terpineol Dibuthyl,-dimethyl-succinate Ethyl-dodedaconate Methyl-␣-chetopalmitate Citronellol 3-Methyl,buthyl-octanoate Fig. 2. Concentration of volatile components in wines from Mad. ´
the case of wines of the same type Že.g. aszus. ŽFig. 3.. It might be established, on the other hand, examining the distribution of volatile components from the point of view of their types, that the distribution of components belonging to the
Fig. 1. Concentration of volatile components in Szamorodni wines.
same compound type in different wines are rather close to one another ŽFig. 4... The following facts could be pointed out in connection with the metal components investigated: The explanation of the different behaviour
Fig. 3. Concentration of volatile components in aszu wines.
Z. Muranyi, ´ Z. Ko¨ ´acs r Microchemical Journal 67 (2000) 91᎐96
95
Fig. 4. Main aroma components in the wines investigated.
Fig. 5. Metal contents of wines investigated.
certain metals ŽFig. 5. show is considerably difficult to find, since there are a great number of influencing factors. The intense difference of lead as well as the iron ᎐manganese and the iron᎐ironŽII. similarities are striking. The former is caused by the similarity in the migration of the metals mentioned, while the reason for the latter is that the way in which wines are treated unambiguously determines the proportion of irons in a lower state of oxidation of the total iron content. From investigations on the metal content chiefly entering the wines in the form of contamination ŽFig. 6., it might be ascertained that there has been one type of wine ŽFurmint from Tarcal. affected by a contamination to an incongruous extent Žin relation to the normal.. The extent to which wines are contaminated depends rather on their growing area. In the case of metals, migrating into the wine through the grape from the soil ŽFig. 7., surprisingly, it is not the area in which they are grown but the type of the wine which is the dominant factor. It is also interesting to observe that there are greater differences within
one type, in the case of young wines Žfurmint, muscatel., in addition to the differences from wines of older vintages.
4. Discussion In summary it could be established that the growing area, the type and the character of wines
Fig. 6. Cd, Cu, Pb content of wines from the wine growing area of Tokay.
Fig. 7. Al, Ca, Fe and Mn content of wines from the wine growing area of Tokay.
96
Z. Muranyi, ´ Z. Ko¨ ´acs r Microchemical Journal 67 (2000) 91᎐96
play a dominant role with a view to the metal content and the aroma content of the wines. Methods of multi-variable statistics seem to be indisputably suitable for discovering this role. References w1x R.F. Simpson, Vitis 17 Ž1978. 274᎐287. w2x R.F. Simpson, Vitis 18 Ž1979. 148᎐154. w3x L. Jakob, H.R. Eschnauer, Deut Weinbaujahrbuch 41 Ž1990. 215᎐222. ¨ ¨ w4x H.R. Eschnauer, Zur Onologie und Okologie anorganischer Wein-Inhaltsstoffe. In Analytiker-Taschenbuch, 17. Berlin, Heidelberhg, New York, 1998, pp. 294᎐315.
w5x J. Pawliszyn, Anal. Chem. 62 Ž1990. 2145᎐2148. w6x J. Pawliszyn, SPME Method Development. Solid Phase Microextarction, Wiley-VCH, Toronto, 1997, pp. 97᎐139. w7x H.R. Eschnauer, R. Neeb, Micro element analysis in wine and grapes, in: H. Linskens, J.F. Jackson ŽEds.., Wine Analysis, Academic Press, New York, 1988, pp. 67᎐89. w8x Z. Muranyi, L. Papp, 40th Hungarian Conference on ´ Spectrochemistry, 1997. w9x Z. Muranyi, L. Papp, ACH Models Chem. 134 Ž4. Ž1997. ´ 529᎐537. w10x M. Otto, Chemometrie-Statistik und Computereinsatz in der Analytik, Weinheim, 1997.