Table 5.
Phenolic compound content of olive pomace extracts by pressurized liquid extraction in optimal conditions (OP-PLE) and olive pomace extract by conventional extraction (OP).
| Compound Names | OP (d.w.) | OP-PLE (d.w.) | ||
|---|---|---|---|---|
| (mg/kg) | (%) | (mg/kg) | (%) | |
| Quinic acid | 40.2 ± 0.2 a | 14.1 ± 0.9 a | 223 ± 20 b | 13.6 ± 0.4 a |
| Oxidized hydroxytyrosol | - a | - a | 638 ± 16 b | 38.5 ± 0.2 b |
| Oleoside/secologanoside or isomer 1 | 4.8 ± 0.3 a | 1.7 ± 0.1 a | 33.9 ± 0.2 b | 2.1 ± 0.0 b |
| Hydroxytyrosol | - a | - a | 67 ± 2 b | 4.0 ± 0.1 b |
| Secoiridoid derived | 47.6 ± 2.0 b | 16.9 ± 0.9 b | 9.7 ± 0.4 a | 0.6 ± 0.0 a |
| Decarboxylated form of hydroxyl elenolic acid | 2.9 ± 0.4 a | 1.1 ± 0.1 a | 60 ± 1 b | 3.6 ± 0.1 b |
| Hydroxylated product of decarboxymethyl elenolic acid | - a | - a | 17.2 ± 0.3 b | 1.1 ± 0.1 b |
| Demethyl oleuropein | 2.9 ± 0.4 b | 0.8 ± 0.1 b | UDL a | UDL a |
| Elenolic acid glucoside or isomer 1 | 0.7 ± 0.2 a | 0.3 ± 0.1 a | 33.4 ± 0.5 b | 2.0 ± 0.1 b |
| Oleoside/secologanoside or isomer 2 | 15 ± 2 a | 5.7 ± 0.5 b | 45.5 ± 0.4 b | 2.8 ± 0.1 a |
| Hydroxy oleuropein | - a | - a | 100 ± 1 b | 5.9 ± 0.2 b |
| Aldehydic form of decarboxymethyl elenolic acid | 13 ± 1 b | 4.7 ± 0.3 b | UDL a | UDL a |
| Luteolin-7-O-rutinoside | - a | - a | 2.3 ± 0.1 b | 0.1 ± 0.0 b |
| Luteolin-7-O-glucoside | 2.5 ± 0.2 a | 0.9 ± 0.0 a | 21 ± 2 b | 1.3 ± 0.1 b |
| Oleuropein | 22 ± 3 a | 7.7 ± 0.9 b | 94 ± 1 b | 5.6 ± 0.0 a |
| Ligstroside | 20 ± 2 a | 7.0 ± 0.6 b | 16.5 ± 0.8 a | 1.0 ± 0.1 a |
| Pinoresinol | 4.7 ± 0.3 b | 1.7 ± 0.1 b | 2.9 ± 0.3 a | 0.2 ± 0.0 a |
| Acetoxypinoresinol | 18 ± 1 b | 6.5 ± 0.3 a | 14.8 ± 0.4 a | 0.9 ± 0.0 a |
| Luteolin | 50 ± 1 a | 17.7 ± 0.4 | 221 ± 4 b | 13.2 ± 0.2 |
| Apigenin | 12.4 ± 0.5 a | 4.4 ± 0.2 | 29.8 ± 0.1 b | 1.9 ± 0.1 |
| Total phenolic compounds | 282 ± 12 a | 100 a | 1659 ± 31 b | 100 a |
| Secoiridoids | 154 ± 9 a | 55 ± 1 b | 435 ± 10 b | 26.4 ± 0.3 a |
| Phenolic alcohols | - a | - a | 702 ± 14 b | 42.5 ± 0.2 b |
| Flavonoids | 65 ± 2 a | 23.0 ± 0.5 b | 271 ± 7 b | 16.4 ± 0.1 a |
| Lignans | 23 ± 2 b | 8.1 ± 0.3 b | 17.6 ± 0.6 a | 1.1 ± 0.0 a |
OP: Olive pomace; PLE: Pressurized liquid extraction; d.w.: Dry weight; UDL: Under detection level. All the variables were tested in three independent cultures for each experiment. Values are means ± SD. Different letters represent level of significance: p < 0.05.