## 3 Results and Discussions
### Volatile Profile of the Mastic Gum Samples
#### 3.2.1 Monoterpenes
\\  & **Total** & **25.69** & **57.31** & & \\ \hline \multicolumn{9}{c}{**Volatile acid**} \\
31 & 1452 & \multicolumn{3}{l}{Acctic acid} & 4.53 \(\pm\) 0.26 & 60.3 \(\pm\) 0.67 & **\(\ast\)** & LRI, MS, std \\  & **Total** & **4.53** & **60.3** & & \\ \hline \multicolumn{9}{c}{**Aldehydes**} \\
32 & 1447 & \multicolumn{3}{l}{\(\alpha\)-Campolenal} & 1.63 \(\pm\) 0.15 & 69.95 \(\pm\) 1.23 & **\(\ast\)** & LRI, MS, tent. \\
33 & 1514 & \multicolumn{3}{l}{Isomeral} & 3.63 \(\pm\) 0.36 & 10.64 \(\pm\) 0.65 & **\(\ast\)** & LRI, MS, std \\  & **Total** & **5.26** & **80.59** & & \\ \hline \multicolumn{9}{c}{**Ketones**} \\
34 & 1341 & \multicolumn{3}{l}{Sulactone} & 1.98 \(\pm\) 0.18 & 3.66 \(\pm\) 0.19 & **\(\ast\)** & LRI, MS, tent. \\
35 & 1610 & \multicolumn{3}{l}{2-Undecanone} & nd & 5.07 \(\pm\) 0.1 & **\(\ast\)** & LRI, MS, tent. \\  & **Total** & **1.98** & **8.73** & & \\ \hline \multicolumn{9}{cAmong the terpenes, \(\alpha\)-pinene was present in the highest concentration in both gum samples (Table 2). Likewise, [PERSON] and [PERSON] [12] identified \(\alpha\)-pinene as the major compound in mastic gum and its oil originating from Chios Island, Greece. A literature review revealed a limited number of studies that directly examined the aroma profile of the mastic gum samples [11; 12; 26; 27]. In a study conducted by [PERSON] and [PERSON] [27], 26 and 34 compounds were determined in mastic gum and mastic oil, respectively, and \(\alpha\)-pinene was the main compound in both samples, followed by \(\beta\)-myrcene, \(\beta\)-pinene, limonene, and carophyllene. Similarly, [PERSON] et al. [11] analyzed the aroma and the AACs of mastic gums using GC-MS-O and found that \(\alpha\)-pinene was the dominant compound, with minor components such as \(\beta\)-myrcene, limonene, \(\beta\)-linalool, and perillene. [PERSON] et al. [26] also reported that \(\alpha\)-pinene was the major constituent in mastic gum while \(\beta\)-pinene, \(\beta\)-myrcene, limonene, and \(\beta\)-caryophyllene were present in smaller amounts. Some studies, however, focused on the aroma compounds of the volatile oil obtained through steam distillation from the mastic gum. [PERSON] et al. [18] carried out a study on mastic gum oil originating from the Cesme district of Izmir province, Turkiye, and reported \(\alpha\)-pinene as the most abundant monoterene. Similarly, \(\alpha\)-pinene was identified as the main compound in several studies on mastic gum oil [2; 17; 28]. Following \(\alpha\)-pinene, \(\beta\)-myrcene was the second most dominant monoterpene, with concentrations of 1448 and 1056 \(\mu\)g/kg in the MGT and MGG samples, respectively (Table 2). In several previous studies on the volatile oil of _P. lentiscus_ var. Chia mastic gum, similar to our findings, \(\alpha\)-pinene was the main compound, followed by \(\beta\)-myrcene and \(\beta\)-pinene [12; 27; 29; 30]. In another study on the aroma substances in various mastic gum volatile oils [2], the ratios of \(\alpha\)-pinene and \(\beta\)-myrcene were reported to range from 33.7-72.8% and 3.8-63.5%, respectively. The wide variation in these ratios was attributed to differences in the timing between the gum seeping from the tree trunk and its collection. Additionally, verbenone, \(\alpha\)-humulene, sabinene, and (\(E\))-anethole were detected in low amounts, similar to previous studies [2; 31]. In the literature, \(\beta\)-pinene, camphene, limonene, \(\beta\)-phellandrene, \(p\)-cymene, perillene, and verbenone were reported in mastic gum oil studies, similar to the findings of the present study [28; 31; 32; 33]. Finally, the citral compound was detected in the MGT sample but not in the MGG sample, marking the first identification of this constituent in _P. lentiscus_ var. Chia mastic gum. Some qualitative and quantitative differences determined in mastic gum and mastic oil have been attributed to factors such as geographical location, tree age, storage period, environmental conditions, soil physicochemical properties, and extraction method [7; 17; 18].