Table 5 Extraction conditions and extracted polyphenols from lees of pisco-making

Pressure (MPa)

20

35

0.1

0.1

Temperature (K)

313

313

313

352

Solvent

CO₂ + ethanol

CO₂ + ethanol

Ethanol

Ethanol

Total S/F (d.b.)

242 ± 1

137

10

20

Global yield (g/100 g of lees in dry basis)

10.5 ± 0.2

5.73

16.8 ± 0.2

27.6 ± 0.4

Phenolic acids

 1

Gallic acid

7.37 ± 0.03

3.017 ± 0.003

78 ± 4

112 ± 13

 2

Protocatechuic acid

12.1 ± 0.1

4.56 ± 0.04

27 ± 2

40 ± 4

 3

p-Hydroxybenzoic acid

n.d.

n.d.

n.d.

n.d.

 4

Vanillic acid

61.8 ± 0.2

25.7 ± 0.4

76 ± 3

104 ± 14

 5

Syringic acid

59.3 ± 0.1

23 ± 1

87 ± 2

118 ± 12

 6

p-Coumaric acid

n.d.

n.d.

n.d.

n.d.

 7

p-Coumaric acid derivative^a

53.0 ± 0.1

44.6 ± 0.1

n.d.

n.d.

 8

Ferulic acid

n.d.

n.d.

n.d.

n.d.

 9

Ferulic acid derivative I^b

53.25 ± 0.01

31.1 ± 0.1

41 ± 1

54 ± 5

 10

Ferulic acid derivative II^b

2.5 ± 0.1

2.78 ± 0.02

n.d.

n.d.

Flavonoids

 11

Quercetin

15.6 ± 0.1

5.8 ± 0.1

121 ± 2

183 ± 22

 12

Quercetin derivative I^c

n.d.

n.d.

24.6 ± 0.5

40 ± 6

 13

Quercetin derivative II^c

8.7 ± 0.1

3.40 ± 0.01

n.d.

30 ± 3

 14

Catechin

n.d.

n.d.

n.d.

n.d.

Stilbenes

 15

Resveratrol

n.d.

n.d.

n.d.

n.d.

Total extracted polyphenols

274 ± 1

144 ± 1

455 ± 15

682 ± 80