Table 2.
Content of phenolic compounds, α-tocopherol, and antioxidant capacity after 12 months of storage under different conditions.
| Phenolic Compound (mg/kg) | Fresh EVOO (Month 0) |
C1 | C2 | C3 | C4 | C5 |
|---|---|---|---|---|---|---|
| Elenolic acid | 76.5 ± 1.8 a | 73.1 ± 3.6 a | 107.9 ± 0.4 c | 107.4 ± 4.9 c | 113.6 ± 5.4 c | 98.5 ± 3.5 b |
| Hydroxytyrosol | 3.1 ± 3.0 a | 3.2 ± 0.1 a | 6.0 ± 0.3 c | 5.1 ± 0.1 b | 6.9 ± 0.1 d | 8.8 ± 0.3 e |
| Tyrosol | 5.1 ± 0.3 a | 5.0 ± 0.2 a | 6.0 ± 0.3 c | 5.4 ± 0.2 ab | 5.7 ± 0.1 bc | 6.5 ± 0.1 d |
| Vanillic acid | 0.4 ± 0.0 b | 0.3 ± 0.0 a | 0.3 ± 0.0 ab | 0.3 ± 0.0 a | 0.3 ± 0.0 a | 0.3 ± 0.0 a |
| p-Coumaric acid | 1.8 ± 0.1 c | 0.9 ± 0.1 b | 0.7 ± 0.0 a | 0.8 ± 0.0 ab | 0.8 ± 0.0 a | 0.8 ± 0.0 ab |
| 3,4-DHPEA-EDA | 74.7 ± 3.3 e | 64.9 ± 1.6 d | 42.7 ± 0.9 b | 52.2 ± 0.7 c | 40.4 ± 0.8 b | 25.3 ± 1.9 a |
| 3,4-DHPEA-EDA, oxidized form | 2.7 ± 0.3 a | 2.4 ± 0.2 a | 15.8 ± 1.3 d | 6.8 ± 0.4 b | 14.1 ± 0.3 c | 25.3 ± 0.7 e |
| 3,4-DHPEA-EDA-DOA | 3.5 ± 1.0 b | 1.5 ± 0.2 a | 0.6 ± 0.1 a | 0.7 ± 0.0 a | 0.5 ± 0.1 a | 0.4 ± 0.1 a |
| p-HPEA-EDA | 34.7 ± 2.7 e | 29.1 ± 0.7 d | 21.8 ± 0.9 b | 24.9 ± 1.0 c | 21.0 ± 0.5 b | 12.7 ± 0.5 a |
| p-HPEA-EDA, oxidized form | 2.3 ± 0.2 a | 1.8 ± 0.0 a | 8.3 ± 0.9 c | 4.6 ± 0.3 b | 9.4 ± 0.3 d | 17.2 ± 0.3 e |
| Pinoresinol a | 15.8 ± 1.2 c | 15.1 ± 0.8 bc | 14.2 ± 0.5 abc | 13.7 ± 0.3 ab | 12.8 ± 0.2 a | 12.7 ± 1.1 a |
| p-HPEA-EDA-DLA | 4.3 ± 0.4 ab | 4.6 ± 0.3 b | 4.0 ± 0.3 ab | 3.7 ± 0.1 ab | 3.5 ± 0.3 a | 4.2 ± 0.8 ab |
| 3,4-DHPEA-EA-AH, oxidized form | 9.6 ± 0.7 a | 10.8 ± 0.4 ab | 13.9 ± 0.8 c | 11.0 ± 0.6 b | 15.5 ± 0.5 d | 20.3 ± 0.9 e |
| 3,4-DHPEA-EA-AH | 27.8 ± 2.9 b | 30.2 ± 0.3 bc | 33.3 ± 0.7 c | 38.7 ± 1.4 d | 30.3 ± 1.2 bc | 23.5 ± 0.6 a |
| Luteolin | 7.7 ±0.7 d | 8.3 ± 0.2 d | 6.1 ± 0.2 bc | 6.6 ± 0.2 c | 5.4 ± 0.1 ab | 5.2 ± 0.2 a |
| Apigenin | 2.4 ± 0.3 a | 2.8 ± 0.2 b | 2.4 ± 0.1 a | 2.4 ± 0.1 ab | 2.3 ± 0.0 a | 2.3 ± 0.1 a |
| Methyl luteolin | 1.3 ± 0.2 a | 1.5 ± 0.1 b | 1.3 ± 0.1 a | 1.3 ± 0.0 ab | 1.2 ± 0.0 a | 1.2 ± 0.0 a |
| Total phenols | 273.5 ± 8.2 bc | 255.7 ± 5.1 a | 285.3 ± 4.1 c | 285.6 ± 6.2 c | 283.5 ± 7.8 c | 265.2 ± 7.1 ab |
| non-oxidized phenols | 259.0 ± 7.5 cd | 240.6 ± 4.9 b | 247.3 ± 1.8 bc | 263.3 ± 5.8 d | 244.5 ± 7.7 b | 202.5 ± 5. 6 a |
| Oxidized phenols | 14.5 ± 0.9 a | 15.0 ± 0.5 a | 38.0 ± 2.8 c | 22.3 ± 0.9 b | 39.0 ± 0.3 c | 62.8 ± 1.8 d |
| α-Tocopherol (mg/kg) | 180.2 ± 2.4 d | 144.0 ± 10.6 c | 80.3 ± 4.0 a | 128.8 ± 2.6 bc | 124.3 ± 0.6 b | 117.3 ± 1.2 b |
| ORAC (μmol TE/g) | 5.5 ± 0.2 b | 3.7 ± 0.3 a | 3.6 ± 0.2 a | 4.1 ± 0.4 a | 3.9 ± 0.3 a | 3.9 ± 0.4 a |
Note: Different letters in the same row indicate significant differences between storage conditions (p < 0.05; HSD Tukey). Values are mean ± SD (n = 3). a: Mixed with 1-acetoxy-pinoresinol. Abbreviations: 3,4-DHPEA-EDA, dialdehydic form of decarboxymethyl oleuropein aglycon. 3,4-DHPEA-EDA-DOA, dialdehydic form of oleouropein aglycon. p-HPEA-EDA, dialdehydic form of decarboxymethyl ligstroside aglycon. p-HPEA-EDA-DLA, dialdehydic form of ligstroside aglycon. 3,4-DHPEA-EA-AH, aldehyde, and hydroxylic form of oleuropein aglycone.