Table 2.
Phenolic compound content in experimental design by olive pomace extracts obtained under different PLE extraction conditions.
| Tentative Identification | T1 | T2 | T3 | T4 | T5 | T6 | T7 | T8 | T9 | T10 | T11 | T12 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 108 °C 50% EtOH | 108 °C 50% EtOH | 108 °C 100% EtOH | 164 °C 10% EtOH | 176 °C 50% EtOH | 51 °C 90% EtOH | 108 °C 50% EtOH | 40 °C 50% EtOH | 164 °C 90% EtOH | 108 °C 50% EtOH | 51 °C 10% EtOH | 108 °C 0% EtOH | |
| (mg/kg d.w.) | ||||||||||||
| Quinic acid | 127.5 ± 6.9 | 137.2 ± 3.4 | 145.8 ± 0.9 | 217.8 ± 11.5 | 231.6 ± 1.3 | 71.4 ± 1.1 | 118.7 ± 0.9 | 56.3 ± 1.4 | 215.5 ± 10.9 | 107.3 ± 0.0 | 68.4 ± 0.8 | 89.2 ± 2.8 |
| Oxidized hydroxytyrosol | 94 ± 9 | 100 ± 7 | - | 458 ± 27 | 148.4 ± 0.5 | - | 176 ± 4 | - | - | 131.3 ± 0.0 | 10.3 ± 0.7 | 363 ± 12 |
| Oleoside/secologanoside or isomer 1 | 61 ± 1 | 60 ± 2 | 44.5 ± 0.6 | 12.6 ± 0.4 | 32.1 ± 0.5 | 28.6 ± 0.9 | 61.7 ± 0.8 | 10.2 ± 0.1 | 77.9 ± 0.6 | 49.1 ± 0.0 | 32 ± 1 | 44 ± 2 |
| Loganic acid | - | - | 8.3 ± 0.3 | 9.0 ± 0.4 | 6.9 ± 0.2 | 11.1 ± 0.2 | - | 8.4 ± 0.2 | 6 ± 1 | - | 12.8 ± 0.4 | 8.6 ± 0.6 |
| Hydroxytyrosol | 28 ± 2 | 24 ± 1 | 51 ± 2 | 218 ± 1 | 258 ± 5 | - | 23 ± 1 | - | 55 ± 3 | 22.4 ± 0.0 | - | 6.9 ± 0.0 |
| Secoiridoid derived | 98.9 ± 0.5 | 95 ± 1 | 67 ± 1 | 119 ± 3 | 143 ± 4 | 74.2 ± 0.3 | 100 ± 2 | 62.0 ± 0.2 | 84 ± 3 | 97 ± 4 | 83.3 ± 0.2 | 73 ± 2 |
| D-OH-EA | 2.9 ± 0.2 | 2.6 ± 0.1 | 1.7 ± 0.0 | - | - | 6.8 ± 0.5 | 2.7 ± 0.2 | - | - | 0.6 ± 0.0 | 1.7 ± 0.2 | - |
| Hydroxy D-oleuropein aglycone | 70 ± 1 | 70 ± 2 | 12.1 ± 0.2 | - | - | 3.8 ± 0.1 | 73 ± 2 | 1.1 ± 0.0 | 9.9 ± 0.5 | 61 ± 2 | 3.3 ± 0.4 | 66 ± 3 |
| Hydroxy oleuropein | 123 ± 2 | 125 ± 4 | 22.3 ± 0.7 | 25.5 ± 0.9 | 62 ± 3 | 2.3 ± 0.3 | 105 ± 2 | 0.4 ± 0.0 | 33.6 ± 0.3 | 101.6 ± 0.1 | 6.6 ± 0.5 | 133 ± 1 |
| Demethyl oleuropein | 19.7 ± 0.6 | 19.5 ± 0.8 | 21.6 ± 0.9 | - | - | - | 15.3 ± 0.5 | - | 20.9 ± 0.5 | 10.9 ± 0.1 | - | 5.0 ± 0.5 |
| Aldehydic form of decarboxymethyl elenolic acid | 9.4 ± 0.7 | 9.5 ± 0.8 | 3.2 ± 0.2 | - | - | - | - | 5.1 ± 0.1 | - | 7.6 ± 0.0 | 8.8 ± 0.1 | 3.0 ± 0.1 |
| Luteolin-7-glucoside | 19.2 ± 0.6 | 10.0 ± 0.9 | 21.0 ± 0.3 | - | - | 2.6 ± 0.3 | 8.3 ± 0.3 | - | 35 ± 1 | 37.5 ± 0.0 | - | - |
| Decarboxymethyl oleuropein aglycon | 19.1 ± 0.8 | 18.1 ± 0.7 | 10 ± 1 | - | - | 0.5 ± 0.0 | 13.9 ± 0.6 | - | 4.9 ± 0.1 | 12 ± 3 | - | 4.8 ± 0.3 |
| Oleuropein | 80.0 ± 0.3 | 81 ± 5 | 79 ± 1 | 15 ± 1 | 63.2 ± 0.9 | 15.2 ± 0.3 | 67.5 ± 0.7 | 6.0 ± 0.3 | 113 ± 3 | 60.0 ± 0.3 | 3.7 ± 0.2 | 56 ± 2 |
| Pinoresinol | 11.4 ± 0.5 | 10.9 ± 0.3 | 10.7 ± 0.8 | 3.7 ± 0.3 | - | 7.8 ± 0.2 | 8.3 ± 0.4 | 4.6 ± 0.0 | 10.9 ± 0.0 | 6.9 ± 0.0 | - | 1.4 ± 0.0 |
| Acetoxypinoresinol | 33.6 ± 0.5 | 37.8 ± 0.8 | 30.1 ± 0.5 | 28.9 ± 0.2 | 17.6 ± 0.2 | 33.7 ± 0.8 | 28.0 ± 0.4 | 29.3 ± 0.4 | 27.5 ± 0.3 | 25 ± 1 | 17.8 ± 0.4 | 23 ± 1 |
| Ligstroside | 32 ± 1 | 31 ± 1 | 29.4 ± 0.5 | - | 8.5 ± 0.4 | 19.8 ± 0.4 | 24.4 ± 0.1 | 10.2 ± 0.3 | 24.0 ± 0.4 | 22.1 ± 0.3 | - | 19.4 ± 0.5 |
| Luteolin | 66 ± 1 | 68 ± 2 | 127.5 ± 0.8 | 34 ± 1 | 67.4 ± 0.7 | 71 ± 1 | 74.0 ± 0.5 | 41.0 ± 0.6 | 158 ± 1 | 67.9 ± 0.0 | 3.1 ± 0.0 | 12.7 ± 0.1 |
| Apigenin | - | - | - | - | - | 17.4 ± 0.2 | - | 6.5 ± 0.2 | 6.9 ± 0.3 | 0.5 ± 0.0 | - | - |
| Secoiridoids (mg/kg) | 517 ± 1 | 511 ± 10 | 299 ± 2 | 182 ± 5 | 315.7 ± 0.5 | 162 ± 3 | 463.1 ± 0.4 | 103 ± 1 | 375 ± 3 | 422.5 ± 0.1 | 153 ± 1 | 413 ± 6 |
| (%) | 57.6 ± 0.2 | 56.8 ± 0.9 | 43.7 ± 0.4 | 15.9 ± 0.4 | 30.4 ± 0.0 | 44.3 ± 0.7 | 51.5 ± 0.0 | 42.9 ± 0.5 | 42.4 ± 0.4 | 51.4 ± 0.0 | 60.5 ± 0.5 | 45.4 ± 0.7 |
| Phenolic alcohols (mg/kg) | 122 ± 4 | 124 ± 1 | 51.1 ± 0.5 | 676 ± 11 | 407 ± 7 | - | 199 ± 2 | - | 55 ± 3 | 153.7 ± 0.0 | 10.3 ± 0.8 | 370 ± 3 |
| (%) | 13.6 ± 0.5 | 13.8 ± 0.6 | 7.5 ± 0.1 | 59 ± 1 | 39.1 ± 0.6 | - | 22.2 ± 0.2 | - | 6.3 ± 0.4 | 18.7 ± 0.0 | 4.1 ± 0.3 | 40.7 ± 0.3 |
| Flavonoids (mg/kg) | 85.7 ± 0.5 | 78 ± 2 | 148 ± 2 | 34 ± 1 | 67.4 ± 0.7 | 91.3 ± 0.1 | 82.3 ± 0.9 | 47.5 ± 0.3 | 199.9 ± 0.0 | 105.9 ± 0.0 | 3.1 ± 0.0 | 12.7 ± 0.1 |
| (%) | 9.6 ± 0.1 | 8.7 ± 0.1 | 21.7 ± 0.3 | 3.0 ± 0.1 | 6.5 ± 0.1 | 24.9 ± 0.0 | 9.1 ± 0.1 | 19.7 ± 0.1 | 22.6 ± 0.0 | 12.9 ± 0.0 | 1.2 ± 0.0 | 1.4 ± 0.0 |
| Lignans (mg/kg) | 45 ± 2 | 49 ± 1 | 41 ± 1 | 33 ± 2 | 17.6 ± 0.2 | 41.5 ± 0.9 | 36.3 ± 0.8 | 33.9 ± 0.4 | 38.4 ± 0.1 | 32 ± 1 | 17.8 ± 0.3 | 25 ± 1 |
| (%) | 5.0 ± 0.2 | 5.4 ± 0.1 | 6.0 ± 0.2 | 2.9 ± 0.2 | 1.7 ± 0.0 | 11.3 ± 0.2 | 4.0 ± 0.1 | 14.1 ± 0.2 | 4.3 ± 0.0 | 3.9 ± 0.2 | 7.1 ± 0.1 | 2.7 ± 0.1 |
| Total phenolic compounds (mg/kg) | 897 ± 3 | 890 ± 12 | 685 ± 9 | 1141 ± 10 | 1039 ± 11 | 366 ± 2 | 900 ± 18 | 241 ± 7 | 885 ± 9 | 821.0 ± 0.1 | 252 ± 3 | 910 ± 2 |
| (%) | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
EtOH: Ethanol; d.w.: Dry weight.