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

From: Supercritical fluid extraction of polyphenols from lees: overall extraction curve, kinetic data and composition of the extracts

  Extraction methods
SFE Agitated bed Soxhlet
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
  Extracted polyphenols (mg/kg of lees)
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 derivativea 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 Ib 53.25 ± 0.01 31.1 ± 0.1 41 ± 1 54 ± 5
 10 Ferulic acid derivative IIb 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 Ic n.d. n.d. 24.6 ± 0.5 40 ± 6
 13 Quercetin derivative IIc 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
  1. aExpressed as milligrams of p-coumaric acid equivalents
  2. bExpressed as milligrams of ferulic acid equivalents
  3. cExpressed as milligrams of quercetin equivalents