Table 3.
Concentrations (μg/kg) of volatile compounds under cluster thinning and girdling in the pulp juice of ‘Jumeigui’ grape at harvest.
| Compounds | Treatment | |||
|---|---|---|---|---|
| CK | G | CT | CTG | |
| C6 compounds | ||||
| Hexanal | 1656 ± 48a | 1860 ± 48b | 2049 ± 30c | 2084 ± 39c |
| (Z)-3-Hexenal | 7.9 ± 2.0a | 8.6 ± 2.3ab | 10.9 ± 2.5ab | 13.3 ± 3.1b |
| (E)-2-Hexenal | 682 ± 23a | 815 ± 31b | 1095 ± 41c | 1198 ± 50d |
| Hexanol | 441 ± 30a | 405 ± 45a | 643 ± 61b | 828 ± 40c |
| (Z)-3-Hexenol | 11.9 ± 0.2a | 16.2 ± 0.8b | 15.0 ± 0.7b | 14.8 ± 0.9b |
| (E)-2-Hexenol | 134 ± 12a | 217 ± 54b | 189 ± 16ab | 229 ± 53b |
| Subtotal | 2933 ± 59a | 3322 ± 91b | 4001 ± 68c | 4367 ± 92d |
| Alcohols | ||||
| 1-Octen-3-ol | 3.28 ± 0.16a | 3.14 ± 0.12a | 4.84 ± 0.29b | 7.29 ± 0.32c |
| Heptanol | 3.58 ± 0.26b | 3.04 ± 0.11a | 2.87 ± 0.19a | 4.08 ± 0.31c |
| 2-Ethyl hexanol* | 1.63 ± 0.05a | 1.37 ± 0.18a | 1.27 ± 0.36a | 1.60 ± 0.10a |
| Octanol | 0.83 ± 0.11b | 0.57 ± 0.07a | 1.10 ± 0.11c | 1.52 ± 0.18d |
| Phenylethyl alcohol | 0.83 ± 0.24a | 1.20 ± 0.13b | 1.70 ± 0.02c | 1.53 ± 0.11c |
| Subtotal | 10.2 ± 0.4a | 9.3 ± 0.5a | 11.8 ± 0.2b | 16.0 ± 0.8c |
| Esters | ||||
| Ethyl acetate | 2275 ± 197a | 3343 ± 88b | 5159 ± 113d | 4885 ± 134c |
| Ethyl propionate* | 3.47 ± 0.23a | 4.85 ± 0.21b | 5.14 ± 0.64b | 8.64 ± 0.98c |
| Ethyl isobutyrate | nd | 15.1 ± 8.7a | 27.2 ± 6.8a | 55. 9 ± 7.0b |
| Ethyl butyrate | 79.2 ± 10.5a | 256 ± 6b | 318 ± 21c | 376. ± 32d |
| Ethyl 2-methylbutanoate* | 2.26 ± 0.42a | 8.95 ± 0.44b | 12.2 ± 4.9b | 13.1 ± 4.6b |
| Ethyl pentanoate | 31.4 ± 3.3a | 110 ± 3c | 76.1 ± 10.1b | 33.7 ± 4.5a |
| Ethyl hexanoate | 29.7 ± 5.0a | 62.9 ± 5.7bc | 68.1 ± 7.0c | 56.5 ± 4.4b |
| Hexyl acetate | 1.18 ± 0.11a | 1.96 ± 0.84ab | 2.32 ± 0.35ab | 3.31 ± 1.09b |
| 2-Hexenoic acid ethyl ester* | 3.24 ± 0.29a | 5.55 ± 0.51b | 11.0 ± 1.4c | 14.6 ± 0.5d |
| Ethyl octanoate* | 2.93 ± 2.10a | 4.60 ± 0.16ab | 6.49 ± 1.77b | 6.02 ± 1.56ab |
| Ethyl 3-hydroxybutyrate* | 1.84 ± 0.95a | 4.49 ± 0.29b | 6.11 ± 0.66c | 9.23 ± 0.95d |
| Subtotal | 2430 ± 212a | 3817 ± 88b | 5691 ± 126c | 5462 ± 172c |
| Aldehydes | ||||
| Pentanal | 4.96 ± 0.94ab | 4.46 ± 0.61a | 6.17 ± 0.46c | 6.02 ± 0.83bc |
| Heptanal* | 12.7 ± 3.6a | 13.0 ± 2.3a | 13.6 ± 2.8a | 13.5 ± 1.7a |
| Octanal | 6.82 ± 0.52a | 6.76 ± 1.01a | 8.90 ± 0.86b | 8.13 ± 0.81ab |
| Nonanal | 59.7 ± 15.1a | 48.4 ± 3.2a | 64.7 ± 8.1a | 53.5 ± 7.1a |
| Benzaldehyde | 17.3 ± 3.1a | 16.3 ± 2.6a | 17.8 ± 4.4a | 17.0 ± 6.5a |
| Phenylacetaldehyde* | 4.68 ± 0.21b | 2.77 ± 0.62a | 3.24 ± 0.25a | 3.47 ± 0.17a |
| Subtotal | 106 ± 17a | 91.7 ± 10.0a | 114 ± 16a | 102 ± 10a |
| Terpenes | ||||
| Subtotal | 659 ± 11a | 722 ± 24b | 906 ± 12c | 999 ± 13d |
| Total | 6138 ± 298a | 7962 ± 149b | 10725 ± 192c | 10945 ± 231d |
CK, the control treatment (unthinned and ungirdled); G, trunk girdled one week before véraison; CT, 50% clusters thinned one week before véraison; CTG, 50% clusters thinned and trunk girdled one week before véraison. Different letters within rows indicate statistically different values (p < 0.05) according to Duncan’s test. *Indicated the semi-quantitative determinations with the internal standards.