## Results and Discussion
### Volatile components in fresh Jinchen fruit juice and peel oil
#### Gas chromatography-/olfactometry (GC-/O) analysis
Among them, ethyl butanoate, \(\beta\)-myrrene, octanal, linalool, and decanal decided the juice aroma because they are the strongest aroma active compounds perceived by all the panelists. Regarding the peel oil, 22 components appeared to contribute to the overall aroma. Linalool, \(\alpha\)-pinene, and decanal defined the aroma of the oil, because these compounds had the greatest aroma intensity. Twelve compounds were perceived by all the panelists in both juice and oil. Among them, five aromatic compounds present different odor intensity in both samples, such as \(\alpha\)-pinene, \(\beta\)-myrrene, octanal, (_trans, trans)_-2,4-decadienal, and valencene. The intensity of octanal, _trans, trans_-2, 4- decadienal, and valencene showed the significant difference (P\(<\)0.05) between the fruit juice and peel oil. Especially, valencene exhibited higher intensity in Jinchen fruit juice than in the peel oil, though valencene was not generally considered an important contributor to orange juice flavor in previously reports [20-23]. The different overall aroma between fruit juice and peel oil are attributed to the various composition of aroma active compounds [35]. The components which were perceived by all the panelists and only detected in the fruit juice or peel oil respectively may contribute to the aromatic differences. Among these, 19 components have been perceived only in the juice and 10 compounds were described as aromatic components of only the peel oil by the three panelists. Nineteen volatile components detected by the panelists only in fruit juice contribute to citrusy, green, and piney notes. The other ten volatile components described as aromatic components of only the peel oil impart a camphor, minty, green, fruity, and floral aroma. According to these results, not all of the components found in greatest concentration by GC-MS contributed to the aroma in orange juice. Limonene was present in highest amount versus other volatiles, but did not exhibit strongest aroma activity though it has orange odor in GC-O of fruit juice and peel oil. In contrast, ethyl 3-hydroxyhexanoate and nerol were not detected by GC-MS and found in low concentration, contributing to citrusy and lemon aroma of the fruit juice according to GC-O intensity data. Most odorant compounds characterized in Jinchen orange juice were also detected in some sweet orange juice[20-21], such as ethyl butyrate, myrcene, octanal, decanal, terpinen-4-ol, linalool, limonene, \(\alpha\)-pinene, and hexanal, but nonanal and _(E)_-2-nonenal was not found to be major aroma active compound in Jinchen juice. There were also some aroma active compounds detected in Jinchen juice not commonly reported in other orange juices, such as ethyl 3-hydroxyhexanoate, perillaldehyde, thymol, _trans,trans_-2,4-decadienal, \(\delta\)-amorphene. The aroma activities of these compounds in sweet orange flavor are not well documented. Most volatile compounds detected in Jinchen peel-oil were also found in many citrus oils, such as limonene, \(\alpha\)-pinene, myrcene, octanal, decanal, terpinen-4-ol, linalool, \(\gamma\)-terpinene, terpiolene, citronellal, neral, \(\alpha\)-copaene, valencene and nootkatone. These compounds were previously reported in other citrus oils but their aroma activities and contribution to citrus oil flavor were not described [9-11, 36-39]. \(\delta\)-Amorphene was the only compound found and identified tentatively in Jinchen peel-oil not previously reported in other citrus essential oils.