|
Table
1 –
Physical
properties, constitutive monomers and average content of the
main cork components, following Guillemonat and
Pereira.
|
Component
|
Properties
|
Monomers
|
Average
content %
(Guillemonat)
|
Average
content %
(
Pereira)
|
|
Suberin
|
Resilience
Impermeability
|
Fatty
acids
Alcohols
|
45
|
39
|
|
Lignin
|
Resistance
to compression
|
Aromatic
alcohols
|
27
|
22
|
|
Poly-saccharides
|
Resistance
to elongation
|
Monosaccharides
|
12
|
20
|
|
Tannins
|
|
Ellagic
acid
Proanthocyanidins
|
6
|
15
(*)
|
|
Waxes
|
Impermeability
|
Phenols
Fatty
acids
|
7
|
|
(*)
Extractable fraction including waxes, tannins etc
Table
2 –
Volatiles
identified in the cork and able to influence wines. Odours are
grouped following the classification proposed in the Quercus
Project.
|
Volatile
components
|
Odour
|
Flavour
threshold in wine or in water*
|
|
|
Conifer
|
|
|
a-pinene
|
Resin
|
|
|
b-pinene
|
Resin
|
10
ppb*
|
|
Isoborneol
|
Camphor
|
|
|
Camphor
|
Balsamic
|
|
|
|
Chemical
|
|
|
1-butanol
|
Pharmaceutic
|
5
ppm
|
|
1-octanol
|
Candle
|
|
|
3-methylbutanoic
acid
|
Rancid
|
0,7
ppm
|
|
Octanoic
acid
|
Candle,
pharmaceutic
|
15
ppm
|
|
|
Vegetal
|
|
|
3-methyl-1-butanol
|
Spicy
|
300
ppm
|
|
1-hexanol
|
Herbaceous
|
5
ppm
|
|
Limonene
|
Aromatic,
fruity
|
60
ppb*
|
|
Benzyl
alcohol
|
Aromatic,
fruity
|
50
ppm
|
|
Linalol
|
Aromatic,
floral
|
100
ppb*
|
|
Borneol
|
Pepper
|
|
|
b-phellandrene
|
Aromatic,
mint
|
|
|
Hexanal
|
Herbaceous
|
|
|
2-hexenal
|
Herbaceous
|
|
|
Benzaldehyde
|
Bitter
almond
|
3
ppm
|
|
Vanillin
|
Vanilla
|
0,1
ppm *
|
|
2-butanone
|
Aromatic
|
|
|
Acetophenone
|
Aromatic,
floral
|
|
|
a-terpineol
|
Aromatic,
floral
|
280
ppb*
|
|
Furfural
|
Almond
|
65
ppm
|
|
Furfuryl
alcohol
|
Hay
|
52
ppm
|
|
5-methylfurfural
|
Grilled
almond
|
35
ppm
|
Table
3 –
Phenolics extractable by the cork in hydroalcoholic solution.
Average contents are calculated
on 40 samples.
|
Phenolic
compounds
|
Average
content
(mg/stopper)
*
|
Flavour
threshold
in
water (mg/l)
|
|
Phenolic
acids
|
|
|
|
3,4-dihydroxybenzoic
|
50
|
30
|
|
4-hydroxybenzoic
|
6
(23)
|
40
|
|
Vanillic
|
66,4
|
30
|
|
Caffeic
|
160,4
|
90
|
|
Syringic
|
1,2
(9)
|
240
|
|
p-coumaric
|
5,2
(31)
|
40
|
|
Ferulic
|
92,4
|
90
|
|
Aldehydes
|
|
|
|
Vanillin
|
103,6
|
0,1
|
|
Syringaldehyde
|
5,2
|
50
|
|
Acetovanillone
|
2,8
|
3
|
(*)
Within brackets the number of samples where the compound was
identified.
Table
4 –
Substances responsible for tainted cork and some precursors.
|
|
Odour
|
Flavour
threshold
In
wine (ng/l)
|
|
2,4,6-trichloroanisole
|
Musty
|
4
|
|
2,3,4,6-tetrachloroanisole
|
Musty
|
4-11
|
|
Pentachloroanisole
|
|