## 3 Results and Discussion
### Identification and Determination of Volatile Compounds in Forty Apple Cultivars
\begin{table}
\begin{tabular}{l c c c c c c} \hline
**Code \({}^{\ast}\)** & **Compounds** & **CAS No \({}^{\bullet}\)** & **Odour Description \({}^{\ast}\)** & **RT \({}^{\bullet}\)** & **RI \({}^{\ast}\)/RI \({}^{\ast}\)** & **Content (ug/kg FW)** \\ \hline Esters & & & & & & \\ E1 & Ethyl acetate & 141-78-6 & Pineapple, balsamic & 8.74 & 894/893 & 3.01 (0–73.34) \\ E2 & Ethyl propanoate & 105-37-3 & Banana, apple & 10.20 & 964/964 & 0.24 (0–9.53) \\ E3 & Proxyl acetate & 109-60-4 & Celery & 10.67 & 982/982 & 3.39 (0–52.92) \\ E4 & Ethyl butyrate & 105-54-4 & Pineapple, fruity & 12.33 & 1045/1048 & 8.52 (0–147.95) \\ E5 & Propy1 propionate & 106-36-5 & Fruity, sweet & 12.57 & 1050/1045 & 2.43 (0–22.76) \\ E6 & Ethyl-2 methylbutyrate & 7452-79-1 & Fruity, berry, fresh & 12.78 & 1062/1063 & 4.85 (0–74.61) \\ E7 & Burti acetate & 123-86-4 & Fruity, fine banana & 13.40 & 1074/1075 & 145.31 (0–1064.54) \\ E8 & 2-Methylbutyl acetate & 624-41-9 & Fruity, banana & 14.84 & 1126/1128 & 245.02 (0–1158.08) \\ E9 & Propy1 butyrate & 105-66-8 & Fruity & 14.88 & 1135/1153 & 1.37 (0–26.05) \\ E10 & Propy2-2 methylbutyrate & 37064-20-3 & Fruity, sweet & 15.29 & 1150/1150 & 13.66 (0–49.23) \\ E11 & Butyl propionate & 590-01-2 & Apple, fruity & 15.41 & 1157/1158 & 51.57 (0–343.31) \\ E12 & Amyl acetate & 628-63-7 & Pear, banana & 16.37 & 1178/1185 & 20.5 (0–99.25) \\ E13 & Amyl propionate & 624-54-4 & Fruity & 16.84 & 1159/1208 & 11.01 (0–103.27) \\ E14 & Butyl butyrate & 109-21-7 & Fruity, apple, pear & 17.69 & 1240/1240 & 103.51 (0–490.14) \\ E15 & Butyl 2-methylbutyrate & 15706-73-7 & Fruity & 18.08 & 1243/1241 & 204.79 (0–706.61) \\ E16 & 2-Methylbutyl butyrate & 51115-64-1 & Fruity & 19.06 & 1270/1270 & 11.87 (0–69.21) \\ E17 & Healy acetate & 142-92-7 & Sweet, flora, cherry & 19.28 & 1274/1276 & 492.44 (10–164.99) \\ E18 & Fenyl superlattice & 2173-55-0 & Fruity & 19.45 & 1283/1284 & 3.59 (0–13.61) \\ E19 & 2-Methylbutyl & 2445-78-5 & Fruity & 19.48 & 1286/1286 & 43.66 (0–268.76) \\ E20 & Fenyl butyrate & 540-18-1 & Fruity & 20.52 & 1321/1320 & 17.00 (0–81.93) \\ E21 & Propy1 hexanoate & 626-77-7 & Fruity, pineapple & 20.58 & 1324/1324 & 10.08 (0–81.98) \\ E22 & Amyl 2-methylbutyrate & 68032-6 & Fruity, apple & 20.83 & 1330/1327 & 43.17 (0–108.70) \\ E23 & Heyl propanoate & 2445-76-3 & Fruity, sweet & 21.14 & 1347/1344 & 180.82 (0–1404.90) \\ E24 & Heyl isobutyrate & 2349-07-7 & Fruity, sweet & 21.18 & 1350/1353 & 14.55 (0–262.64) \\ E25 & Heppt acetate & 112-06-1 & Fruity, orange & 22.09 & 1386/1366 & 0.30 (0–9.40) \\ E26 & Butyl caporate & 626-82-4 & Fruity, acid, racid & 23.17 & 1410/1414 & 433.62 (0–70)-1607.26) \\ E27 & Heyl butyrate & 2639-63-6 & Fruity, green, sweet & 23.23 & 1423/1244 & 72.12 (3-627.209) \\ E28 & Heyl 2-methylbutyrate & 10032-15-2 & Fruity, green & 23.53 & 1438/1438 & 3085.20 (106.76-10087.55) \\ E29 & Ethyl octanoate & 106-32-1 & Sweet, flora, pear & 23.72 & 1445/1445 & 2.51 (0–44.50) \\ E30 & 2-Methylbutyl hexanoate & 2601-13-0 & Fruity & 24.36 & 1467/1468 & 49.51 (0–291.37) \\ E31 & trans-2-Heewyl valerate & 5692-74-8 & Fruity & 24.94 & 1478/1478 & 5.12 (0–57.99) \\ E32 & Amyl caporate & 540-07-8 & Fruity & 25.73 & 1508/1509 & 69.62 (0–364.73) \\ E33 & Cely hexanoate & 4887-30-3 & Fruity & 25.75 & 1512/1512 & 12.29 (0–219.39) \\ E34 & Healy valerate & 1117-59-5 & Fruity & 25.77 & 1516/1516 & 8.48 (0–402.46) \\ E35 & Butyl heptanoate & 5454-28-4 & Fruity & 25.78 & 1518/1518 & 34.24 (0–363.05) \\ E36 & Propy1 octanoate & 624-13-5 & Fruity & 25.93 & 1525/1525 & 7.68 (0–83.56) \\ E37 & Hepptyl valerate & 5451-80-9 & Fruity & 26.10 & 1529/1530 & 4.72 (0–143.09) \\ E38 & Hepptj 2-methylbutyrate & 50862-12-9 & Fruity & 26.12 & 1530/1533 & 19.23 (0–111.43) \\ E39 & 3-methylbur-2-enyl & 76649-22-4 & Fruity & 27.53 & 1578/1575 & 0.37 (0–8.60) \\ E40 & Heyl hexanoate & 6378-65-0 & Fruity, wine & 28.07 & 1593/1993 & 1444/76.38 (0–5688.01) \\ E41 & Butyl capylate & 589-75-3 & Slightly fruity & 28.16 & 1603/1601 & 288.67 (0–2611.76) \\ E42 & Heyl figlate & 16930-96-4 & Fruity & 28.46 & 1631/1631 & 45.39 (0–233.71) \\ E43 & Butylolactone & 96-48-0 & Fruity & 28.76 & 1638/1640 & 0.44 (0–74.72) \\ E44 & 2-Perpul circanoate & 5913-30-1 & Fruity & 29.11 & 1647/1645 & 12.12 (0–245.97) \\ E45 & 2-Methylbutyl octanoate & 67121-39-5 & Fruity & 29.13 & 1648/1648 & 53.73 (0–302.66) \\ E46 & Heyl capylate & 1117-55-1 & Fruity & 31.82 & 1759/1760 & 114.96 (0–653.28) \\ E47 & Buyl caprate & 30673-36-0 & Fruity & 31.93 & 1765/1765 & 9.25 (0–163.04) \\ \hline Aldehydes & & & & & & \\ A1 & Hexanal & 66-25-1 & Green, sweet & 13.76 & 1090/1089 & 241.24 (0–29.1050.38) \\ A2 & 2-Methyl+1-pent & 5187-71-3 & Green & 15.42 & 1156/1155 & 7.8 (0–10.13.3) \\ A3 & (Z)-3-Hexanal & 6789-80-6 & Grass & 15.60 & 1161/1158 & 8.11 Aroma is a complex mixture of many volatile compounds, and the amount and content of aroma substances showed different patterns among various apple cultivars [18; 23].