## 2 Results and Discussion
### Analysis of Cinnamon Volatiles by SPME/GC-MS
#### 2.1.1 Aldehydes/Ethers  
Cinnamon bark is well known for its richness in aldehydes, i.e., (_E_)-cinnamaldehyde or also called (_E_)-cinnamaldehyde, accounting for 65-76% of its essential oil composition [3]. Chiefly, (_E_)-cinnamaldehyde contributed up to 80% of total aldehydes, to which most of the health-promoting benefits of cinnamon are attributed [13].  
The results showed that aldehydes/others possessed the fourth place regarding the number of detected peaks, with 21 peaks after alcohols, sesquiterpene hydrocarbon, and ester. Nevertheless, they contributed with the highest relative abundance reaching up to 72% in the case of CVM. Aldehydes showed large quantitative differences as in the case of authenticated cinnamon samples accounting for 7.9% in CA versus 72.1% in CVM, and likewise in commercial products warranting that they are used for QC measures of cinnamon considering their health benefits and food value. Major aldehydes included (_E_)-cinnamaldehyde (P28), ranging from 4.2 in CA--60.9% in CVM (Table S1). The lowest content of (_E_)-cinnamaldehyde was detected in CA and in agreement with previous literature that contained 13.0-56.9 mg/g, i.e., approx. 1.3-5.7% [26]. However, [27] reported that (_E_)-cinnamaldehyde was determined at 79.4% in essential oil derived from _C. cassia_ from Hexin Tang, China, suggesting a geographical origin impact.  
With regards to commercial preparations, aldehyde/ether content showed large variation ranging from 10.1% to 68.2% in CP-1 and CP-2, respectively. (_E_)-cinnamaldehyde accounted for 6.3-64.6% of the total volatile peaks, with the highest level at 64.6% in CP-2 and the lowest in CP-1 (6.3%). CP-3 also showed a lower (_E_)-cinnamaldehyde level at 22.0%, while CP-4 showed relatively higher content at ca. 48.0%, Table S1. These findings suggested that CP-1 and CP-3 were closer to that of CA, whereas CP-2 and CP-4 mimicked more that of CV/CVM based on (_E_)-cinnamaldehyde relative levels.  
Next to (_E_)-cinnamaldehyde, other major aldehydes detected included \(O\)-methoxy cinnamaldehyde (P77), which reached 8.5 and 9.6% in CV and CVM, respectively. Ben  
Figure 2: Volatile classes percentile levels in investigated cinnamon products. The sample codes are listed in Table 1.  
zaldehyde (P7) was also detected at 0.35-1.22% in authenticated samples, comparable with previous reports in cinnamon bark (\(\mathbb{C}\). _verum_) essential oil at 0.23-0.31% [28]. Interestingly, commercial products showed the opposite pattern with higher benzaldehyde levels than in authenticated samples at 0.93-2.66% versus lower \(O\)-methoxy cinnamaldehyde levels at (0.2-2.17%), Table S1.  
Regarding ethers, eugenol (P41) was identified as the major ether in all accessions accounting for 0.02% in CVM to reach 4.7% in CI at its highest level. In contrast to cinnamon leaves, eugenol in cinnamon bark was detected at small levels and in agreement with previous reports ranging from 5.0 and 10.0% [3]. Interestingly, eugenol was reported in another study as the main VOC in \(\mathbb{C}\). _verum_ J. Presl essential oil at 80%, while (\(E\))-cinamaldehyde reached 16.3% [29]. This oil was derived from leaves collected from Xishuangbanna Tropical Botanical Garden, China, warranting analysis from several other origins to be conclusive.