Table 4.
Concentration of tentatively identified volatile compounds in the virgin olive oil samples and in those flavored with orange, orange by-product, and orange by-product with black pepper, expressed in mg/kg. Letters of significance refer to ANOVA, Tukey’s HSD (p ≤ 0.05). TEST_1, TEST_2 = olive oil control samples; AR = co-milled olive oil produced by milling olives and entire oranges; ST_AR = co-milled olive oil produced by milling olives and orange pomace; ST_AR_P = co-milled olive oil produced by milling olives with orange pomace and black pepper. Roman numbers indicate different tentatively identified stereoisomers forms. LRI = Linear Retention Index (Kovats Indexes).
| Compound | TEST_1 mg/kg | TEST_2 mg/kg |
AR mg/kg |
ST_AR mg/kg |
ST_AR_P mg/kg |
LRI |
|---|---|---|---|---|---|---|
| 3-Ethyl-1,5-octadiene I | 0.08 ± 0.00 B | 0.29± 0.04 A | n.d. | n.d. | n.d. | 961 |
| 3-Ethyl-1,5-octadiene II | 1.51 ± 0.07 A | 1.23 ± 0.19 A | n.d. | n.d. | n.d. | 968 |
| 3-Ethyl-1,5-octadiene III | 1.32 ± 0.14 A | 1.26± 0.23 A | n.d. | n.d. | n.d. | 1012 |
| α-Pinene | n.d. | n.d. | 8.61 ± 0.59 B | 6.96 ± 0.64 B | 23.49 ± 0.79 A | 1022 |
| 3-Thujene | n.d. | n.d. | 0.79 ± 0.09 B | 0.63 ± 0.07 B | 4.58 ± 0.26 A | 1028 |
| 1-Penten-3-one | 1.58 ± 0.06 C | 0.90 ± 0.08 C | 1.52 ± 0.10 B | 2.05 ± 0.29 B | 3.36 ± 0.24 A | 1035 |
| Hexanal | 0.51 ± 0.02 C | 0.43 ± 0.04 C | 0.51 ± 0.06 B | 1.28 ± 0.06 A | n.d. | 1094 |
| β-Pinene II | n.d. | n.d. | n.d. | n.d. | 24.29 ± 1.27 | 1109 |
| Sabinene | n.d. | n.d. | 5.82 ± 0.60 B | 4.08 ± 0.34 B | 19.91 ± 2.14 A | 1125 |
| 3-Carene | n.d. | n.d. | 0.66 ± 0.06 B | 1.04 ± 0.08 B | 43.48 ± 1.39 A | 1154 |
| β-Myrcene | n.d. | n.d. | 108.43 ± 6.42 B | 89.52 ± 7.57 C | 138.66 ± 2.63 A | 1171 |
| 4-Carene | n.d. | n.d. | 0.70 ± 0.12 B | n.d. | 1.61 ± 0.12 A | 1186 |
| Limonene | 0.22 ± 0.01 D | 10.39 ± 1.24 C | 1336.32 ± 92.92 A | 1088.06 ± 83.82 B | 1475.72 ± 18.05 A | 1209 |
| β-Phellandrene | n.d. | n.d. | 6.45 ± 1.17 B | 5.12 ± 0.18 B | 11.04 ± 0.92 A | 1216 |
| (E)-2-Hexenal | 2.74 ± 0.4 C | 15.54 ± 1.35 B | 44.28 ± 6.99 A | 15.04 ± 2.40 B | 26.63 ± 0.29 B | 1237 |
| γ-Terpinene | n.d. | n.d. | n.d. | n.d. | 2.84 ± 0.13 | 1254 |
| α-Terpinene | n.d. | n.d. | 0.79 ± 0.10 A | 0.51 ± 0.04 B | n.d. | 1255 |
| (Z)-β-Ocimene | 0.59 ± 0.02 B | 0.52 ± 0.04 B | n.d. | n.d. | 2.83 ± 0.37 A | 1261 |
| (E)-β-Ocimene | n.d. | n.d. | 1.76 ± 0.11 A | 1.62 ± 0.09 A | n.d. | 1263 |
| m-Cymene | n.d. | n.d. | n.d. | 1.04 ± 0.18 | n.d. | 1282 |
| Terpinolene | n.d. | n.d. | 1.31 ± 0.04 B | n.d. | 3.34 ± 0.26 A | 1293 |
| Octanal | n.d. | n.d. | 6.35 ± 1.23 A | 4.33 ± 0.75 A | 1.61 ± 0.18 B | 1302 |
| Geranyl nitrile | n.d. | n.d. | 0.90 ± 0.10 A | 0.44 ± 0.04 B | 0.72 ± 0.13 A | 1315 |
| (Z)-2-Penten-1-ol | 0.36 ± 0.03 CD | 0.18 ± 0.01 D | 0.41 ± 0.02 C | 0.88 ± 0.10 B | 1.28 ± 0.11 A | 1333 |
| 1-Hexanol | 0.05 ± 0.01 C | 0.10 ± 0.01 C | 0.35 ± 0.06 B | 1.29 ± 0.20 A | 1.28 ± 0.04 A | 1364 |
| (Z)-3-Hexen-1-ol | n.d. | n.d. | n.d. | n.d. | 3.03 ± 0.33 | 1393 |
| (E)-3-Hexen-1-ol | 0.49 ± 0.00 C | 0.05 ± 0.00D | n.d. | 2.89 ± 0.07 A | 1.60 ± 0.11 B | 1398 |
| (E)-2-Hexen-1-ol | 0.05 ± 0.00 C | 0.56 ± 0.04 B | n.d. | 2.74 ± 0.16 A | n.d. | 1446 |
| (E,E)-2,4-Hexadienal | 0.13 ± 0.04 C | 0.10 ± 0.02 C | 0.59 ± 0.08 A | 0.25 ± 0.05 B | n.d. | 1460 |
| Citronellal | n.d. | n.d. | n.d. | 0.84 ± 0.02 B | 1.31 ± 0.02 A | 1489 |
| Copaene | n.d. | n.d. | n.d. | n.d. | 1.66 ± 0.12 | 1496 |
| Decanal | n.d. | n.d. | n.d. | 4.67 ± 0.81 A | 3.84 ± 0.72 A | 1511 |
| Linalool | n.d. | n.d. | 1.45 ± 0.00 B | 0.15 ± 0.05 B | 9.90 ± 0.77 A | 1556 |
| Linalyl formate | n.d. | n.d. | n.d. | 9.08 ± 1.34 | n.d. | 1587 |