Table 3.
Volatile compounds determined in Bobal wines.
| Odour Threshold (μg/L) | Season 1 | Season 2 | |||
|---|---|---|---|---|---|
| C1 | S1 | C2 | S2 | ||
| Acids (µg/L) | |||||
| Decanoic acid | 1000 [60] | 917.37 ± 117.18 a (0.92) | 629.89 ± 104.28 a (0.63) | 228.43 ± 18.20 a (0.23) | 222.59 ± 31.57 a (0.22) |
| Hexanoic acid | 420 [60] | 1838.54 ± 125.11 a (4.38) | 1774.81 ± 294.67 a (4.23) | 4361.65 ± 409.36 b (10.38) | 2853.99 ± 463.65 a (6.80) |
| Octanoic acid | 500 [60] | 2333.49 ± 378.19 a (4.67) | 1772.37 ± 308.77 a (3.54) | 1485.23 ± 78.56 b (2.97) | 1219.95 ± 201.24 a (2.44) |
| Σ Acids | 5089.40 ± 620.48 a | 4177.06 ± 707.72 a | 6075.31 ± 482.37 b | 4296.52 ± 688.78 a | |
| Alcohols (µg/L) | |||||
| Benzyl alcohol | 200,000 [61] | 213.37 ± 49.79 a (0.00) | 327.34 ± 48.39 b (0.00) | 206.03 ± 8.89 b (0.00) | 187.80 ± 8.51 a (0.00) |
| 1-Hexanol | 8000 [38] | 618.68 ± 105.73 a (0.08) | 551.16 ± 17.21 a (0.07) | 558.09 ± 44.06 b (0.07) | 438.82 ± 17.32 a (0.05) |
| 2 + 3-Methyl-1-butanol | 30,000 [38] | 14,048.87 ± 1,246.23 a (0.47) | 14,251.55 ± 1,621.15 a (0.48) | 228,945.84 ± 13,701.97 a (7.63) | 255,920.62 ± 9,419.51 b (8.53) |
| 2-Phenylethanol | 10,000 [38] | 7015.40 ± 1,014.62 a (0.70) | 7032.57 ± 877.96 a (0.70) | 41,080.13 ± 2,184.45 a (4.11) | 43,320.08 ± 3,807.34 a (4.33) |
| Σ Alcohols | 21,896.31 ± 2,366.51 a | 22,162.62 ± 2,477.21 a | 270,790.09 ± 15,650.77 a | 299,867.32 ± 10,858.72 b | |
| Acetates (µg/L) | |||||
| Ethyl acetate | 7500 [38] | 25,372.05 ± 867.02 a (3.38) | 26,918.12 ± 860.79 a (3.59) | 32,093.83 ± 4,866.11 a (4.28) | 24,808.05 ± 5,430.47 a (3.31) |
| Hexyl acetate | 1500 [61] | 6.63 ± 0.23 b (0.00) | 3.19 ± 0.06 a (0.00) | 1.53 ± 0.17 a (0.00) | 1.47 ± 0.25 a (0.00) |
| Isoamyl acetate | 30 [38] | 2032.55 ± 62.52 b (67.75) | 1382.58 ± 94.35 a (46.09) | 564.59 ± 60.81 b (18.82) | 426.73 ± 28.87 a (14.22) |
| Linalyl acetate | not found | nd | nd | 0.14 ± 0.00 a | 0.17 ± 0.01 b |
| 2-Phenylethyl acetate | 250 [38] | 143.19 ± 8.56 b (0.57) | 74.59 ± 19.68 a (0.30) | 19.82 ± 2.46 a (0.08) | 20.58 ± 3.37 a (0.08) |
| Σ Acetates | 27,554.41 ± 938.34 a | 28,378.49 ± 764.52 a | 32,679.91 ± 4,929.37 a | 25,257.01 ± 5,454.39 a | |
| Ethyl esters (µg/L) | |||||
| Diethyl succinate | 200,000 [61] | 152.76 ± 15.64 a (0.00) | 156.85 ± 6.27 a (0.00) | 353.20 ± 37.32 b (0.00) | 244.69 ± 24.37 a (0.00) |
| Ethyl butyrate | 20 [38] | 138.29 ± 1.97 a (6.91) | 144.60 ± 12.86 a (7.23) | 88.68 ± 9.84 b (4.43) | 59.13 ± 4.33 a (2.96) |
| Ethyl decanoate | 200 [60] | 71.14 ± 3.48 a (0.36) | 78.43 ± 10.95 a (0.39) | 68.10 ± 10.29 a (0.34) | 71.74 ± 22.77 a (0.36) |
| Ethyl dihydrocinnamate | 1.6 [60] | 0.31 ± 0.03 a (0.19) | 0.20 ± 0.05 a (0.12) | 0.31 ± 0.02 a (0.20) | 0.35 ± 0.04 a (0.22) |
| Ethyl hexanoate | 14 [60] | 247.99 ± 5.41 a (17.71) | 244.54 ± 30.88 a (17.47) | 348.64 ± 35.75 b (24.90) | 226.16 ± 20.35 a (16.15) |
| Ethyl lactate | 154,000 [61] | nd | nd | 8449.52 ± 442.07 a (0.05) | 10,202.75 ± 3,161.90 a (0.07) |
| Ethyl octanoate | 5 [60] | 172.95 ± 2.67 a (34.59) | 199.90 ± 25.55 a (39.98) | 454.57 ± 46.11 b (90.91) | 316.76 ± 69.58 a (63.35) |
| Ethyl vanillate | 990 [62] | 72.70 ± 13.56 a (0.07) | 108.54 ± 12.52 b (0.11) | 36.09 ± 3.24 a (0.04) | 42.31 ± 6.49 a (0.04) |
| Σ Ethyl esters | 856.13 ± 22.13 a | 933.05 ± 79.61 a | 9799.10 ± 415.70 a | 11,163.88 ± 3,244.40 a | |
| Terpenoids (µg/L) | |||||
| Citronellol | 100 [61] | 17.78 ± 3.07 a (0.18) | 21.62 ± 2.71 a (0.22) | 6.41 ± 0.22 a (0.06) | 7.14 ± 0.53 b (0.07) |
| β-Damascenone | 0.05 [38] | 0.35 ± 0.06 a (7.02) | 0.29 ± 0.04 a (5.77) | nd | nd |
| Farnesol | 1000 [63] | 112.01 ± 14.77 a (0.11) | 227.13 ± 26.84 b (0.23) | 17.30 ± 3.10 a (0.02) | 21.60 ± 3.70 a (0.02) |
| Geraniol | 30 [38] | 7.15 ± 0.23 b (0.24) | 5.50 ± 1.08 a (0.18) | 8.61 ± 0.45 b (0.29) | 6.76 ± 0.27 a (0.23) |
| Geranyl acetone | 60 [38] | 0.24 ± 0.02 a (0.00) | 0.22 ± 0.01 a (0.00) | 0.15 ± 0.01 a (0.00) | 0.15 ± 0.02 a (0.00) |
| β-Ionone | 0.09 [60] | 0.09 ± 0.02 a (0.99) | 0.11 ± 0.03 a (1.19) | 0.02 ± 0.00 a (0.22) | 0.02 ± 0.00 a (0.17) |
| Linalool | 25 [60] | 1.18 ± 0.09 a (0.05) | 1.32 ± 0.13 a (0.05) | 2.75 ± 0.12 a (0.11) | 3.04 ± 0.26 a (0.12) |
| Nerol | 15 [61] | 5.24 ± 1.20 a (0.35) | 6.08 ± 1.08 a (0.41) | nd | nd |
| Nerolidol | 15 [61] | 1.36 ± 0.12 a (0.09) | 2.77 ± 0.25 b (0.18) | 3.64 ± 0.45 a (0.24) | 5.43 ± 0.74 b (0.36) |
| Σ Terpenoids | 145.39 ± 17.62 a | 265.05 ± 24.39 b | 38.88 ± 4.16 a | 44.14 ± 5.33 a | |
| Volatile phenols (µg/L) | |||||
| Eugenol | 6 [60] | nd | nd | 1.19 ± 0.07 a (0.20) | 1.02 ± 0.13 a (0.17) |
| Guaiacol | 9.5 [60] | 17.21 ± 6.61 a (1.81) | 26.87 ± 9.06 a (2.83) | 53.95 ± 8.82 a (5.68) | 68.48 ± 15.08 a (7.21) |
| 4-Vinylguaiacol | 40 [38] | 13.17 ± 3.05 b (0.33) | 6.51 ± 0.59 a (0.16) | nd | nd |
| Σ Volatile phenols | 30.37 ± 9.28 a | 33.37 ± 7.88 a | 55.15 ± 8.81 a | 69.50 ± 15.20 a | |
| Others (µg/L) | |||||
| Acetovanillone | 1000 [62] | 74.66 ± 8.09 a (0.07) | 75.16 ± 5.65 a (0.08) | nd | nd |
| Phenylacetaldehyde | 1 [64] | nd | nd | 0.55 ± 0.05 a (0.55) | 0.65 ± 0.06 a (0.65) |
C1: control wine (from untreated grapevines); S1: wine from grapevines treated by spraying 1; C2: control wine (from untreated grapevines); S2: wine from grapevines treated by spraying 2. The mean values (n=2) are shown with their standard deviations. For each compound and season, different letters indicate significant differences according to the independent samples t-test (p < 0.05). nd: not detected. Odour activity values (OAV) are shown in parentheses for each compound and wine. Bold OAV values indicate the compounds with concentrations above their odour threshold. Reference numbers for the odour thresholds (in wine or synthetic wine) are shown in square brackets for each compound.