1. VEN124 Section VI Wine Aroma and Flavor: Putting It All Together

2. Lecture 19: The Flavor and Aroma Compounds of Wine

3. Distribution of Aroma Compounds in White Wines Vegetal Fruity (Terpenes) Muscats Chenin blanc Fr. Columbard Chardonnay Sauvignon blanc “Canadian Muscat” Rieslings Traminer

4. Classes of Flavor/Aroma Compounds Pyrazines

5. N N R O-CH 3 R = -CH 2 -CH-CH 3 -CH 2 -CH 3 -CH 3 CH 3 Bell pepper Potato Peanut

6. Pyrazines Derived from grape Not microbial in origin Vegetal characters –Bell pepper –Chili –Bean –Carrot –Potato –Peanut –Roasted Barley

7. Classes of Flavor/Aroma Compounds Pyrazines Terpenes

8. Fruity fruit/floral aromas from grapes Can be produced by some yeasts and molds (but not by Saccharomyces) Derived from isoprene units May be unbound or bound (as glycosides) Only unbound terpenes can be detected

9. Terpenes Formed from isoprene units C C C C 1 2 3 45 The double bond can occur anywhere in the 5-member structure

10. Terpenes Monoterpenes: C10 Higher terpenes:  C10

11. Terpenes Can occur as: hydrocarbons alcohols aldehydes ketones esters

12. Monoterpene Hydrocarbons CH 3 C CH 3 CH 2 4 5 3 2 1 5 4 3 2 1 Limonene

13. Monoterpene Alcohols C CH 3 CH 2 OH H CH 3 OH CH 2 C CH 3 Geraniol Linalool

14. Monoterpene Aldehydes CH 3 CHO H H CC CH 3 Geranial Neral

15. Higher Terpenes Includes napthalene derivatives From plants Fruit characters Fuel characters

16. Higher Terpenes C CH 3 CH 2 O Grapefruit

17. Higher Terpenes CH 3 Trimethyl Dihydronapthalene “Kerosene”

18. Classes of Flavor/Aroma Compounds Pyrazines Terpenes Shikimic acid derivatives

19. Shikimic Acid Derivatives Derived from aromatic amino acid metabolism Produced by plants, microbes, oak extraction

20. Shikimic Acid Derivatives C O H OCH 3 OH Vanillin

21. Classes of Flavor/Aroma Compounds Pyrazines Terpenes Shikimic acid derivatives Lactones

22. Oxygen-containing 5-member ring compound From grapes, microbes, oak extraction Typical characters: cotton candy, generic candy, generic fruit, coconut, buttery

23. Lactones O CH 2 OHO C4H9C4H9 O CH 3 Furfuryl Alcohol Methyl Lactone

24. Classes of Flavor/Aroma Compounds Pyrazines Terpenes Shikimic acid derivatives Lactones Esters

25. From reaction of an alcohol and an acyl- CoA molecule Formed mainly by microbes, but can come from plant Readily hydrolyzed at wine pH

26. Esters R 1 -OH R 2 -C  CoA O R 1 -O-C-R 2 O

27. Esters Alcohol: ethanol or alcohol from amino acid, purine, pyrimidine degradation Acid: acetic acid or acid from amino acid degradation, fatty acid biosynthesis

28. Esters Ethyl acetate: nail polish remover/glue Ethyl laurate: soap Isoamyl acetate: banana Phenethyl acetate: rose oil

29. Esters Short chain: fruity, floral Long chain: perfume, soap Lower concentration: fruity, floral Higher concentrations: perfume

30. Ester Formation Influenced By: Temperature –Higher temperature: increased loss Volatilization Hydrolysis Oxygen exposure –Stimulate fatty acid biosynthesis Nitrogen source availability –Precursor availability Strain/genetic background –As much as 10-fold difference in level of production

31. Classes of Flavor/Aroma Compounds Pyrazines Terpenes Shikimic acid derivatives Lactones Esters Higher alcohols

32. Higher Alcohols Made mostly by microbes, can be made by plants From amino acid degradation/ biosynthesis Fusel oils Aromatic amino acid derivatives

33. The Fusel Oils 3-Methylbutanol 2-Methylbutanol Isobutanol Propanol

34. Classes of Flavor/Aroma Compounds Pyrazines Terpenes Shikimic acid derivatives Lactones Esters Higher alcohols Acids

35. From plant or microbes Sourness Other characters: –Rancid (butyric acid) –Pungent (acetic acid)

36. Acids Least Sour Most Sour Citrate Fumarate Malate Lactate Succinate Tartrate

37. Acetic Acid Legal Limits: US CA OIV White: 1.2 g/L 1.1g/L 0.98g/L Red: 1.4 g/L 1.2g/L 0.98g/L Threshold of Detection:  1 g/L

38. Classes of Flavor/Aroma Compounds Pyrazines Terpenes Shikimic acid derivatives Lactones Esters Higher alcohols Acids Phenolic compounds

39. Phenolic Compounds Bitterness Astringency Produced by plant Can be converted into vinyl phenols by microbes (spoilage characters)

40. Bitterness Flavanols OH HO OH O Catechin

41. Astringency Flavanols and Non-flavinoids OH HO COOH OH CH HC C=O O HOOC-CH-CH-COOH OH Gallic acid Caftaric acid

42. Classes of Flavor/Aroma Compounds Pyrazines Terpenes Shikimic acid derivatives Lactones Esters Higher alcohols Acids Phenolic compounds Sulfur-containing compounds

43. Sulfur-Containing Compounds Low thresholds of detection Generally produced by microbes –Degradation of sulfur containing amino acids –Spontaneous reactions from microbially- derived sulfides

44. Sulfur-Containing Compounds Sulfides Thiols Sulfoxides

45. Sulfides H 2 S (hydrogen sulfide): rotten egg CH 3 -S-CH 3 (dimethyl sulfide): cabbage, canned corn CH 3 -S-S-CH 3 (dimethyl disulfide): clam

46. Sulfur-Containing Compounds Sulfides Thiols Sulfoxides

47. Thiols CH 3 -SH (methanethiol): rubber CH 3 -CH 2 -SH (ethanethiol): onion, rubber, skunk

48. Sulfur-Containing Compounds Sulfides Thiols Sulfoxides

49. CH 3 -SO-CH 3 (dimethyl sulfoxide): plastic, rubber hose

50. Sulfur-Containing Compounds Sulfides Thiols Sulfoxides Thio alcohols

51. Thio Alcohols HS-CH 2 -CH 2 -OH (mercaptoethanol): barnyard CH 3 -S-(CH 2 ) 4 -OH (thiomethylbutanol): garlic, chive CH 3 -S-(CH 2 ) 3 -OH (methionol): raw potato, soy

52. Classes of Flavor/Aroma Compounds Pyrazines Terpenes Shikimic acid derivatives Lactones Esters Higher alcohols Acids Phenolic compounds Sulfur-containing compounds Amino acid derivatives

53. Amino Acid Derivatives Several other types of compounds can be formed from amino acids by yeast and bacteria Appearance depends upon which microbes are present and what nitrogen/carbon sources are present

54. Amino Acid Derivatives: Mousiness N N C-CH 3 O H O 2-Acetyl-tetrahydro-pyridine Metabolite of lysine made by Lactic Acid Bacteria and Brettanomyces

55. Classes of Flavor/Aroma Compounds Pyrazines Terpenes Shikimic acid derivatives Lactones Esters Higher alcohols Acids Phenolic compounds Sulfur-containing compounds Amino acid derivatives Specific compounds

56. Specific Compounds Other plant compounds associated with aroma Not well characterized

57. Specific Compounds: Methyl Anthranilate Concord Grape Character: “Foxy” NH 2 C-O-CH 3 O