Transcript VEN124 Section VI

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
Muscats
Muscat”
Traminer
Fruity
(Terpenes)
Rieslings
Chenin blanc
Chardonnay
Fr. Columbard
Vegetal
Sauvignon
blanc
Classes of Flavor/Aroma Compounds
• Pyrazines
Pyrazines
R=
N
N
R
O-CH3
CH3
-CH2-CH-CH3
Bell pepper
-CH2-CH3
Potato
-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
2
C
C
C
3
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
3
CH3
5
2
1
1
2
3
C
CH3 CH2
Limonene
4
5
Monoterpene Alcohols
CH3
CH3
CH2OH
OH
H
C
CH3 CH3
Geraniol
CH2
C
CH3 CH3
Linalool
Monoterpene Aldehydes
CH3
CH3
H
CHO
H
C
CHO
CH3 CH3
C
CH3 CH3
Geranial
Neral
Higher Terpenes
•
•
•
•
Includes napthalene derivatives
From plants
Fruit characters
Fuel characters
Higher Terpenes
O
C
CH2
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
O C H
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 acylCoA molecule
• Formed mainly by microbes, but can
come from plant
• Readily hydrolyzed at wine pH
Esters
R1-OH
O
R2-CCoA
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
Least
Most
Sour
Sour
Citrate
Fumarate
Malate
Succinate
Tartrate
Lactate
Acetic Acid
Legal Limits: US
White: 1.2 g/L
Red:
1.4 g/L
Threshold of Detection:
 1 g/L
CA
OIV
1.1g/L 0.98g/L
1.2g/L 0.98g/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
COOH
Gallic acid
Caftaric acid
HC
C=O
O
OH
HOOC-CH-CH-COOH
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 microbiallyderived 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
Thio Alcohols
• HS-CH2-CH2-OH (mercaptoethanol):
barnyard
• CH3-S-(CH2)4-OH (thiomethylbutanol):
garlic, chive
• CH3-S-(CH2)3-OH (methionol): raw
potato, soy
Classes of Flavor/Aroma Compounds
•
•
•
•
•
•
•
•
•
•
Pyrazines
Terpenes
Shikimic acid derivatives
Lactones
Esters
Higher alcohols
Acids
Phenolic compounds
Sulfur-containing compounds
Amino acid derivatives
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
Amino Acid Derivatives: Mousiness
O
N
H
C-CH3
O
N
C-CH3
2-Acetyl-tetrahydro-pyridine
Metabolite of lysine made by Lactic
Acid Bacteria and Brettanomyces
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
Specific Compounds
• Other plant compounds associated with
aroma
• Not well characterized
Specific Compounds: Methyl
Anthranilate
Concord Grape Character: “Foxy”
NH2
O
C-O-CH3