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VEN124 Section VI. Wine Aroma and Flavor: Putting It All Together. Lecture 19:. The Flavor and Aroma Compounds of Wine. Distribution of Aroma Compounds in White Wines. “Canadian Muscat”. Muscats. Traminer. Fruity (Terpenes). Rieslings. Chardonnay Sauvignon blanc.
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VEN124 Section VI Wine Aroma and Flavor: Putting It All Together
Lecture 19: The Flavor and Aroma Compounds of Wine
Distribution of Aroma Compounds in White Wines “Canadian Muscat” Muscats Traminer Fruity (Terpenes) Rieslings Chardonnay Sauvignon blanc Chenin blanc Fr. Columbard Vegetal
Classes of Flavor/Aroma Compounds • Pyrazines
Pyrazines R = -CH2-CH-CH3 -CH2-CH3 -CH3 N R CH3 Bell pepper Potato N O-CH3 Peanut
Pyrazines • Derived from grape • Not microbial in origin • Vegetal characters • Bell pepper • Chili • Bean • Carrot • Potato • Peanut • Roasted Barley
Classes of Flavor/Aroma Compounds • Pyrazines • Terpenes
Terpenes • 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
Terpenes Formed from isoprene units 1 C 2 C 3 C 4 5 C C The double bond can occur anywhere in the 5-member structure
Terpenes • Monoterpenes: C10 • Higher terpenes: C10
Terpenes Can occur as: hydrocarbons alcohols aldehydes ketones esters
Monoterpene Hydrocarbons 4 CH3 3 5 2 1 1 2 C 3 CH3 CH2 4 5 Limonene
Monoterpene Alcohols CH3 CH3 CH2OH OH H CH2 C C CH3 CH3 CH3 CH3 Geraniol Linalool
Monoterpene Aldehydes CH3 CH3 H CHO H CHO C C CH3 CH3 CH3 CH3 Geranial Neral
Higher Terpenes • Includes napthalene derivatives • From plants • Fruit characters • Fuel characters
Higher Terpenes O CH2 C CH3 Grapefruit
Higher Terpenes CH3 CH3 CH3 Trimethyl Dihydronapthalene “Kerosene”
Classes of Flavor/Aroma Compounds • Pyrazines • Terpenes • Shikimic acid derivatives
Shikimic Acid Derivatives • Derived from aromatic amino acid metabolism • Produced by plants, microbes, oak extraction
Shikimic Acid Derivatives H O C OCH3 OH Vanillin
Classes of Flavor/Aroma Compounds • Pyrazines • Terpenes • Shikimic acid derivatives • Lactones
Lactones • Oxygen-containing 5-member ring compound • From grapes, microbes, oak extraction • Typical characters: cotton candy, generic candy, generic fruit, coconut, buttery
Lactones O CH2OH O O C4H9 CH3 Furfuryl Alcohol Methyl Lactone
Classes of Flavor/Aroma Compounds • Pyrazines • Terpenes • Shikimic acid derivatives • Lactones • Esters
Esters • From reaction of an alcohol and an acyl-CoA molecule • Formed mainly by microbes, but can come from plant • Readily hydrolyzed at wine pH
Esters O R1-OH R2-CCoA O R1-O-C-R2
Esters Alcohol: ethanol or alcohol from amino acid, purine, pyrimidine degradation Acid: acetic acid or acid from amino acid degradation, fatty acid biosynthesis
Esters • Ethyl acetate: nail polish remover/glue • Ethyl laurate: soap • Isoamyl acetate: banana • Phenethyl acetate: rose oil
Esters • Short chain: fruity, floral • Long chain: perfume,soap • Lower concentration: fruity, floral • Higher concentrations: perfume
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
Classes of Flavor/Aroma Compounds • Pyrazines • Terpenes • Shikimic acid derivatives • Lactones • Esters • Higher alcohols
Higher Alcohols • Made mostly by microbes, can be made by plants • From amino acid degradation/ biosynthesis Fusel oils Aromatic amino acid derivatives
The Fusel Oils • 3-Methylbutanol • 2-Methylbutanol • Isobutanol • Propanol
Classes of Flavor/Aroma Compounds • Pyrazines • Terpenes • Shikimic acid derivatives • Lactones • Esters • Higher alcohols • Acids
Acids • From plant or microbes • Sourness • Other characters: • Rancid (butyric acid) • Pungent (acetic acid)
Acids Most Sour Least Sour Citrate Fumarate Malate Lactate Succinate Tartrate
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
Classes of Flavor/Aroma Compounds • Pyrazines • Terpenes • Shikimic acid derivatives • Lactones • Esters • Higher alcohols • Acids • Phenolic compounds
Phenolic Compounds • Bitterness • Astringency • Produced by plant • Can be converted into vinyl phenols by microbes (spoilage characters)
Bitterness Flavanols OH OH HO O OH OH Catechin
Astringency Flavanols and Non-flavinoids OH OH HO OH OH CH HC C=O O HOOC-CH-CH-COOH COOH Gallic acid Caftaric acid OH
Classes of Flavor/Aroma Compounds • Pyrazines • Terpenes • Shikimic acid derivatives • Lactones • Esters • Higher alcohols • Acids • Phenolic compounds • Sulfur-containing compounds
Sulfur-Containing Compounds • Low thresholds of detection • Generally produced by microbes • Degradation of sulfur containing amino acids • Spontaneous reactions from microbially-derived sulfides
Sulfur-Containing Compounds • Sulfides • Thiols • Sulfoxides
Sulfides • H2S (hydrogen sulfide): rotten egg • CH3-S-CH3 (dimethyl sulfide): cabbage, canned corn • CH3-S-S-CH3 (dimethyl disulfide): clam
Sulfur-Containing Compounds • Sulfides • Thiols • Sulfoxides
Thiols • CH3-SH (methanethiol): rubber • CH3-CH2-SH (ethanethiol): onion, rubber, skunk
Sulfur-Containing Compounds • Sulfides • Thiols • Sulfoxides
Sulfoxides • CH3-SO-CH3 (dimethyl sulfoxide): plastic, rubber hose
Sulfur-Containing Compounds • Sulfides • Thiols • Sulfoxides • Thio alcohols