## 2 Aroma Volatile Composition and Their Biological Characteristic of Major Fruits
### Volatile Compounds and Their Biological Characteristic of Major Fruits
2-Heptanol, \(p\)-cymen-8-ol, 2-heptanone, 1-hexanol, \(\alpha\)-terpineol, pulegone, 1-octanol, isoborneol, myrtenol, 4-terpineol, carvone, elemicine, and nonanal have all been identified as the major volatiles [78]. In order to understand the aroma differences, the volatile compositions of \"Marion\" and \"Black Diamond\" was analyzed using stir bar sorptive extraction-gas chromatography-mass spectrometry (SBSE-GC-MS) and solid phase extraction (SPE)-microvial insert thermal desorption-GC-MS for two growing seasons. Although seasonal variations were present, the overall volatile profile in \"Marion\" and \"Black Diamond\" were very similar, but the concentrations of some aroma compounds varied greatly. Odour-activity value (OAV) indicated that furanel, linalool, \(\beta\)-ionone, and hexanal could be most important in \"Marion\", while in \"Black Diamond\", the most important compounds were linalool, \(\beta\)-ionone, furanel, and 2-heptanol. The major difference between the cultivars for aroma compounds was that \"Marion\" had higher OAV of furanel than \"Black Diamond\", while \"Black Diamond\" had higher OAV of linalool than \"Marion\". The chemical analysis results matched with the descriptive sensory evaluation that \"Marion\" had more berry, fruity, strawberry aroma while \"Black Diamond\" had more floral aroma [79]. A total of 42 volatiles were identified in four southern highbush blueberry (_Vaccinium sp._)cultivars (\"Primadonna\", \"Jewel\", \"Snowchaser\", and \"FL02-40\"), twelve of these volatiles are reported for the first time in highbush blueberries, with 10 being positively identified: (\(Z\))-3-hexenal, (\(E\),\(E\))-2,4-hexadienal, (\(E\),\(Z\))-2,6-nonadenal, (\(E\),\(E\))-2,4-nondeniend, methyl 2-methylbutanoate, butyl acetate, 2-methylbutyl acetate, and geranyl acetate. \"Primadonna\" was characterized by a large amount of esters and C\({}_{6}\) aldehydes. In contrast, fewer than four esters were found in \"FL02-40\" and \"Snowchaser\", respectively, but they produced more terpenids than \"Primadonna\" and \"Jewel\" [80]. More than 280 volatile compounds have been found in pineapple fruit (_Ananas comosus_ L. Merr.) [81]. Esters and hydrocarbons were the major constituents. Octenoic acid, methyl ester, hexanoic acid, octanoic acid and ethyl ester were the specific aromatic components of pineapple fruits. The relative content of volatiles showed significant variations during the fruit developmental period [82]. A total of 11 and 28 volatile compounds were identified in the Tainong No. 4 and No. 6 pineapples, respectively. According to the OAVs, four compounds were defined as the characteristic aroma compounds for the Tainong No. 4 pineapple, including furanel, 3-(methylthio) propanoic acid methyl ester, 3-(methylthio)propanoic acid ethyl ester and \(\delta\)-octalactone. The OAVs of five compounds including ethyl-2-methylbutyrate, methyl-2-methylbutyrate, 3-(methylthio) propanoic acid ethyl ester, ethyl hexanoate and decanal were considered to be the characteristic aroma compounds for the Tainong No. 6 pineapple [83]. The characteristic aroma compounds in the plug of cyaenne pineapple were ethyl 2-methylbutanoate, ethyl hexanoate, 2,5-dimethyl-4-hydroxy-3(2\(H\))-furanone (DMHF), decanal, ethyl 3-(methylthio) propionate, ethyl butanoate, and (\(E\))-3-ethyl hexenoate; while in core the main compounds were ethyl-2-methyl butanoate, ethyl hexanoate and DMHF. The highest odor units were found to correspond to ethyl 2-methyl butanoate, followed by ethyl hexanoate and DMHF [84]. More than 80 compounds related to fruit aroma have been identified in kiwifruit, with the major components being methyl and ethyl butanoate, (\(Z\))- and (\(E\))-2-hexenal, hexanal, (\(Z\))- and _(\(E\))_-3-hexenol, and methyl benzoate [17]. The volatile profile of eating-ripe \"Hort16A\" is dominated by ethyl esters and 3-(methylsulfanyl) ethyl propionate has been suggested to contribute to the tropical aroma of non-stored kiwifruit [85,86].