Table 3.
The content (µg/kg FW) of volatile compounds in ‘Orin’ apple peels at different ripening stages.
| Compounds | CAS | 60 DAFB | 90 DAFB | 120 DAFB | 150 DAFB | 180 DAFB |
|---|---|---|---|---|---|---|
| Esters | ||||||
| Ethyl butyrate | 105-54-4 | – | – | – | – | 71.66 |
| Ethyl 2-methylbutyrate | 7452-79-1 | – | – | – | – | 11.93 |
| Butyl acetate | 123-86-4 | – | – | – | 68.26 | 115.64 |
| 2-Methylbutyl acetate | 624-41-9 | – | – | – | 200.05 | 188.15 |
| Butyl propionate | 590-01-2 | – | – | – | – | 137.84 |
| Amyl acetate | 628-63-7 | – | – | – | 24.38 | 20.77 |
| Butyl butyrate | 109-21-7 | – | – | – | 190.18 | 972.18 |
| Butyl 2-methylbutyrate | 15706-73-7 | – | – | – | 406.10 | 992.24 |
| 2-Methylbutyl butyrate | 51115-64-1 | – | – | – | 18.88 | 78.49 |
| Hexyl acetate | 142-92-7 | 34.41 | 7.20 | 80.68 | 534.73 | 925.04 |
| 2-Methylbutyl 2-methylbutyrate | 2445-78-5 | – | – | – | 42.73 | 101.89 |
| Pentyl butyrate | 540-18-1 | – | – | – | 34.79 | 185.86 |
| Amyl 2-methylbutyrate | 68039-26-9 | – | – | – | 132.70 | 257.60 |
| 2-Hexenol acetate | 10094-40-3 | 41.09 | 11.89 | 8.08 | – | – |
| Hexyl propanoate | 2445-76-3 | – | – | – | 47.82 | 422.72 |
| Hexyl isobutyrate | 2349-07-7 | – | – | – | 141.75 | 477.96 |
| Butyl caproate | 626-82-4 | – | – | – | 356.84 | 1054.14 |
| Hexyl butyrate | 2639-63-6 | 7.69 | – | – | 931.06 | 5505.92 |
| Hexyl 2-methylbutyrate | 10032-15-2 | 8.83 | 12.02 | 13.46 | 7767.45 | 8164.16 |
| 2-Methylbutyl hexanoate | 2601-13-0 | – | – | – | 33.13 | 92.26 |
| Amyl caproate | 540-07-8 | – | – | – | 137.91 | – |
| Heptyl 2-methylbutyrate | 50862-12-9 | – | – | – | 118.31 | 271.34 |
| Hexyl hexanoate | 6378-65-0 | 11.77 | – | – | 2073.11 | 316.32 |
| Hexyl tiglate | 16930-96-4 | – | – | – | 143.10 | – |
| Hexyl caprylate | 1117-55-1 | – | – | – | 209.84 | 261.86 |
| Octyl hexanoate | 4887-30-3 | – | – | 11.27 | – | – |
| Butyl caprylate | 589-75-3 | – | – | – | 500.55 | – |
| 2-Pentyl octanoate | 55193-30-1 | – | – | – | 109.59 | – |
| Octyl heptanoate | 5132-75-2 | – | – | – | – | 90.43 |
| Alcohols | ||||||
| 2-Methyl-1-butanol | 137-32-6 | – | – | – | – | 52.35 |
| 2-Hexyn-1-ol | 764-60-3 | 76.98 | 53.97 | 27.67 | 58.26 | 20.66 |
| 1–Hexanol | 111-27-3 | – | – | – | 55.22 | 171.25 |
| Aldehydes | ||||||
| Hexanal | 66-25-1 | 431.02 | 454.14 | 159.33 | 127.30 | 158.79 |
| 2-Methyl-4-pentenal | 5187-71-3 | – | 10.19 | 6.00 | – | – |
| (E)-2-Hexenal | 505-57-7 | 5669.86 | 4122.50 | 1913.52 | 2210.68 | 2164.99 |
| 3-Hexenal | 4440-65-7 | 6.86 | 17.00 | 14.99 | – | – |
| Nonanal | 124-19-6 | – | – | 5.87 | – | – |
| (E,E)-2,4-Heptadienal | 4313-03-5 | 19.92 | 7.39 | 6.56 | – | – |
| Benzaldehyde | 100-52-7 | 80.79 | – | – | – | – |
| (E,E)-2,4-Hexadienal | 142-83-6 | 23.99 | 23.03 | 3.99 | – | – |
| Others | ||||||
| Dodecane | 112-40-3 | 24.82 | 19.70 | – | – | – |
| Tetradecane | 629-59-4 | 70.00 | 44.82 | 5.59 | – | 39.85 |
| Estragole | 140-67-0 | – | – | – | 26.40 | 456.98 |
| (E)-α-Bergamotene | 13474-59-4 | – | – | – | 466.54 | 1131.35 |
| α-Farnesene | 502-61-4 | 15.10 | 11.67 | 75.14 | 3805.96 | 4435.00 |
| Thujopsene | 470-40-6 | 31.89 | 17.01 | – | 49.71 | 77.05 |
| Copaene | 3856-25-5 | – | 6.19 | 9.51 | – | – |
Volatile compounds identified by the methods: MS—mass spectra comparison with published data and MS library (NIST14); RI—retention index agreed with the data reported in previous papers or a database on the web (http://www.odour.org.uk/lriindex.html). Data are means of three replications. DAFB indicates days after full bloom. – indicates not detected.