Wine chemistry

Wine is a complex mixture of chemical compounds in a hydro-alcoholic solution with a pH around 3.

Types of natural molecules present in wine

Acids in wine
Phenolic compounds in wine
Proteins in wine
Sugars in wine
Yeast assimilable nitrogen
Minerals
Dissolved gas (CO₂)
Monoterpenes^[1] and sesquiterpenes^[2] such as linalool and α-terpineol^[3]
Glutathione (reduced and oxidized)^[4]^[5]

Volatiles

Methoxypyrazines
Esters : Ethyl acetate is the most common ester in wine, being the product of the most common volatile organic acid — acetic acid, and the ethyl alcohol generated during the fermentation.
Norisoprenoids, such as C13-norisoprenoids found in grape (Vitis vinifera)^[6] or wine,^[7] can be produced by fungal peroxidases^[8] or glycosidases.^[9]

Other molecules found in wine

Conservatives

Ascorbic acid is used during wine making
Sulfur dioxide (SO₂), a preservative often added to wine

Fining agents

Gum arabic has been used in the past as fining agent.^[10]

List of additives permitted for use in the production of wine under EU law:

Type or purpose of addition	Permitted additives
Acidification	tartaric acid
Clarification	calcium alginate potassium alginate potassium caseinate casein isinglass silicon dioxide edible gelatine acacia (gum arabic) milk/lactalbumin proteins of plant origin ovalbumin (egg white) alumino silicates ferrous sulfate
Decolourants	polyvinyl-polypyr-rolidone (PVPP) activated charcoal
Deacidification	lactic bacteria neutral potassium tartrate potassium bicarbonate calcium carbonate
Deodorant	copper sulfate
Elaboration	oak chips metatartaric acid water
Enrichment	concentrated grape must rectified concentrated grape must saccharose tannin oxygen
Enzymes	betaglucanase pectolytics urease
Fermentation	fresh lees ammonium bisulphite thiamine hydrochloride yeast cell walls yeasts for wine production diammonium phosphate ammonium sulphate ammonium sulphite
Sequestrants	fresh lees potassium ferrocyanide calcium phytate citric acid
Stabilisation	calcium tartrate potassium bitartrate yeast mannoproteins Preservatives sorbic acid sulphur dioxide argon nitrogen potassium bisulphite dimethyl dicarbonate (DMDC) carbon dioxide potassium metabisulphite/disulfite allyl isothiocyanate lysozyme potassium sorbate ascorbic acid

Others

Melatonin^[11]
Wine lactone
Anthocyanone A, a degradation product of malvidin under acidic conditions

Wine faults

2,4,6-trichloroanisole, the chemical primarily responsible for cork taint in wines.

4-Ethylphenol is produced from the precursor p-coumaric acid. Brettanomyces converts this to 4-vinylphenol via the enzyme cinnamate decarboxylase.^[12] 4-Vinylphenol is further reduced to 4-ethylphenol by the enzyme vinyl phenol reductase. Coumaric acid is sometimes added to microbiological media, enabling the positive identification of Brettanomyces by smell.

Geraniol is a by-product of the metabolism of sorbate and, thus, is a very unpleasant contaminant of wine if bacteria are allowed to grow in wine.

Fusel alcohols are a mixture of several alcohols (chiefly amyl alcohol) produced as a by-product of alcoholic fermentation.

Notes

^ Monoterpenes in grape juice and wines. M. Jiménez, Journal of Chromatography A, Volume 881, Issues 1–2, 9 June 2000, Pages 557–567, doi:10.1016/S0021-9673(99)01342-4
^ Terpenes in the aroma of grapes and wines: A review. J. Marais, S. Afr. J. Enol. Vitic., 1983, volume 4, number 2, pages 49-58 (article)
^ Inhibition of the decline of linalool and α-terpineol in muscat wines by glutathione and N-acetyl-cysteine. Papadopoulou D. and Roussis I. G., Italian journal of food science, 2001, vol. 13, no4, pages 413-419, INIST 13441184
^ Using LC-MSMS To Assess Glutathione Levels in South African White Grape Juices and Wines Made with Different Levels of Oxygen. Wessel Johannes Du Toit, Klemen Lisjak, Maria Stander and Dersiree Prevoo, J. Agric. Food Chem., 2007, Vol. 55, No. 8, doi:10.1021/jf062804p
^ Straightforward Method To Quantify GSH, GSSG, GRP, and Hydroxycinnamic Acids in Wines by UPLC-MRM-MS. Anna Vallverdú-Queralt, Arnaud Verbaere, Emmanuelle Meudec, Veronique Cheynier and Nicolas Sommerer, J. Agric. Food Chem. 2015, 63, 142−149, doi:10.1021/jf504383g
^ Günata, Ziya; Wirth, Jérémie L.; Guo, Wenfei; Baumes, Raymond L. (2001). "Carotenoid-Derived Aroma Compounds". ACS Symposium Series. 802: 255. doi:10.1021/bk-2002-0802.ch018. ISBN 0-8412-3729-8. {{cite journal}}: |chapter= ignored (help); Cite journal requires |journal= (help)
^ P. Winterhalter, M. A. Sefton and P. J. Williams (1990). "Volatile C13-Norisoprenoid Compounds in Riesling Wine Are Generated From Multiple Precursors". Am. J. Enol. Vitic. 41 (4): 277–283.
^ Zelena, Kateryna; Hardebusch, Björn; Hülsdau, BäRbel; Berger, Ralf G.; Zorn, Holger (2009). "Generation of Norisoprenoid Flavors from Carotenoids by Fungal Peroxidases". Journal of Agricultural and Food Chemistry. 57 (21): 9951–5. doi:10.1021/jf901438m. PMID 19817422.
^ Cabaroglu, Turgut; Selli, Serkan; Canbas, Ahmet; Lepoutre, Jean-Paul; Günata, Ziya (2003). "Wine flavor enhancement through the use of exogenous fungal glycosidases". Enzyme and Microbial Technology. 33 (5): 581. doi:10.1016/S0141-0229(03)00179-0.
^ Vivas N, Vivas de Gaulejac N, Nonier M.F and Nedjma M (2001). "Incidence de la gomme arabique sur l'astringence des vins et leurs stabilites colloidales". Progres Agricole et Viticole (in French). 118 (8): 175–176. {{cite journal}}: Unknown parameter |trans_title= ignored (|trans-title= suggested) (help)CS1 maint: multiple names: authors list (link)
^ Lamont, Kim T.; Somers, Sarin; Lacerda, Lydia; Opie, Lionel H.; Lecour, Sandrine (2011). "Is red wine a SAFE sip away from cardioprotection? Mechanisms involved in resveratrol- and melatonin-induced cardioprotection". Journal of Pineal Research. 50 (4): 374–80. doi:10.1111/j.1600-079X.2010.00853.x. PMID 21342247.
^ Brettanomyces Monitoring by Analysis of 4-ethylphenol and 4-ethylguaiacol at etslabs.com

References

Comprehensive Natural Products II — Chemistry and Biology, chapter 3.26 – Chemistry of Wine, volume 3, pages 1119–1172. Véronique Cheynier, Rémi Schneider, Jean-Michel Salmon and Hélène Fulcrand, doi:10.1016/B978-008045382-8.00088-5

External links

[1] Monoterpenes in grape juice and wines. M. Jiménez, Journal of Chromatography A, Volume 881, Issues 1–2, 9 June 2000, Pages 557–567, doi:10.1016/S0021-9673(99)01342-4

[2] Terpenes in the aroma of grapes and wines: A review. J. Marais, S. Afr. J. Enol. Vitic., 1983, volume 4, number 2, pages 49-58 (article)

[3] Inhibition of the decline of linalool and α-terpineol in muscat wines by glutathione and N-acetyl-cysteine. Papadopoulou D. and Roussis I. G., Italian journal of food science, 2001, vol. 13, no4, pages 413-419, INIST 13441184

[4] Using LC-MSMS To Assess Glutathione Levels in South African White Grape Juices and Wines Made with Different Levels of Oxygen. Wessel Johannes Du Toit, Klemen Lisjak, Maria Stander and Dersiree Prevoo, J. Agric. Food Chem., 2007, Vol. 55, No. 8, doi:10.1021/jf062804p

[5] Straightforward Method To Quantify GSH, GSSG, GRP, and Hydroxycinnamic Acids in Wines by UPLC-MRM-MS. Anna Vallverdú-Queralt, Arnaud Verbaere, Emmanuelle Meudec, Veronique Cheynier and Nicolas Sommerer, J. Agric. Food Chem. 2015, 63, 142−149, doi:10.1021/jf504383g

[6] Günata, Ziya; Wirth, Jérémie L.; Guo, Wenfei; Baumes, Raymond L. (2001). "Carotenoid-Derived Aroma Compounds". ACS Symposium Series. 802: 255. doi:10.1021/bk-2002-0802.ch018. ISBN 0-8412-3729-8. {{cite journal}}: |chapter= ignored (help); Cite journal requires |journal= (help)

[7] P. Winterhalter, M. A. Sefton and P. J. Williams (1990). "Volatile C13-Norisoprenoid Compounds in Riesling Wine Are Generated From Multiple Precursors". Am. J. Enol. Vitic. 41 (4): 277–283.

[8] Zelena, Kateryna; Hardebusch, Björn; Hülsdau, BäRbel; Berger, Ralf G.; Zorn, Holger (2009). "Generation of Norisoprenoid Flavors from Carotenoids by Fungal Peroxidases". Journal of Agricultural and Food Chemistry. 57 (21): 9951–5. doi:10.1021/jf901438m. PMID 19817422.

[9] Cabaroglu, Turgut; Selli, Serkan; Canbas, Ahmet; Lepoutre, Jean-Paul; Günata, Ziya (2003). "Wine flavor enhancement through the use of exogenous fungal glycosidases". Enzyme and Microbial Technology. 33 (5): 581. doi:10.1016/S0141-0229(03)00179-0.

[10] Vivas N, Vivas de Gaulejac N, Nonier M.F and Nedjma M (2001). "Incidence de la gomme arabique sur l'astringence des vins et leurs stabilites colloidales". Progres Agricole et Viticole (in French). 118 (8): 175–176. {{cite journal}}: Unknown parameter |trans_title= ignored (|trans-title= suggested) (help)CS1 maint: multiple names: authors list (link)

[11] Lamont, Kim T.; Somers, Sarin; Lacerda, Lydia; Opie, Lionel H.; Lecour, Sandrine (2011). "Is red wine a SAFE sip away from cardioprotection? Mechanisms involved in resveratrol- and melatonin-induced cardioprotection". Journal of Pineal Research. 50 (4): 374–80. doi:10.1111/j.1600-079X.2010.00853.x. PMID 21342247.

[12] Brettanomyces Monitoring by Analysis of 4-ethylphenol and 4-ethylguaiacol at etslabs.com

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