# Application of Cinnamon Essential Oil in Active Food Packaging: A Review
## 5 Chemical Composition of Cinnamon Essential Oil  
As mentioned above, the composition of EOs, including cinnamon EO, varies depending on the species, geographical origin of the plant, method of extraction, and part of the plant from which it is extracted. Typically, cinnamon EO is extracted from the leaves or bark. Table 1 summarizes all of this information regarding the species _C. zeylanicum_ and _C. cassia_. Moreover, [PERSON] et al. [21] provide data for other species such as _C. verum_ and _C. burmannii_.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Species**} & \multirow{2}{*}{**Country**} & \multirow{2}{*}{**Part of Plant**} & \multirow{2}{*}{**Extraction Method \({}^{*}\)**} & \multicolumn{2}{c}{**No.**} & \multirow{2}{*}{**Compound**} & \multirow{2}{*}{**Ref.**} \\  & & & & & & \\ \hline \multirow{4}{*}{_C. zeylanicum_} & \multirow{4}{*}{Iran} & \multirow{4}{*}{Leaves} & \multirow{4}{*}{HD} & \multirow{4}{*}{24} & Cinnamaldehyde (62.06\%), & \multirow{4}{*}{[28]} \\  & & & & & (8.14\%), Eugenol (7.49\%), & \\ \cline{1-1} \cline{5-5}  & & & & & & \\ \cline{1-1} \cline{5-5}  & & & & & & (4.84\%) & \\ \hline \multirow{4}{*}{_C. zeylanicum_} & \multirow{4}{*}{India} & \multirow{4}{*}{Leaves} & \multirow{4}{*}{HD} & \multirow{4}{*}{24} & Cinnamaldehyde (33.0\%), linalool & \multirow{4}{*}{[29]} \\  & & & & & (16.85\%), eugenol (17.32\%), cinnamyl & \\ \cline{1-1} \cline{5-5}  & & & & & (1  
There are several studies that have investigated the composition of cinnamon EO and, although typically only between four and six compounds are found in quantities greater than 1% (both in bark and leaf EO), up to 47 volatile constituents have been reported from different chemical families including phenylpropanoids, terpenes, terpenoids, and esters [30].  
The main volatile component present in the EO extracted from the bark of _C. zeyalnicum_ and _C. cassia_ species is the phenylpropanoid cinnamaldehyde, which is responsible for the distinctive odor and flavor of cinnamon [38]. The different sources consulted agree that this compound is the one found in a higher percentage in the EO extracted from the bark, although the values obtained in different studies show differences ranging from 31% to 84.25% (Table 1). It appears that the extraction process significantly modifies the cinnamaldehyde content. [PERSON] et al. [37] investigated four extraction processes: steam distillation, ultrasound-assisted extraction, subcritical water extraction, and ultrasound-enhanced subcritical water extraction. The authors showed significant differences among  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  
the four methods, showing the highest cinnaldehyde content obtained with ultrasound-enhanced subcritical water extraction (71.3%) and the lowest with ultrasound-assisted extraction (46.3%). For their part, [PERSON] and [PERSON] [33] compared steam distillation and superheated water extraction, showing a higher cinnamaldehyde content with the latter method. Other compounds commonly found, although in smaller proportions, are linalool, eugenol, and benzyl benzoate [32; 33; 34; 36].  
No studies have been found analyzing the volatile profile of cinnamon EO extracted from the leaves of _C. cassia_, but there are studies available for _C. zeyalnicum_. In this case, three studies [28; 29; 32], similar to cinnamon EO extracted from bark, identify cinnamaldehyde as the major compound. In other works, benzyl benzoate [31; 32] and eugenol [30] were found in higher proportions, with cinnamaldehyde being undetectable in two of them [30; 32]. These findings highlight the remarkable variability in the volatile profile of EO extracted from cinnamon leaves.