# Application of Cinnamon Essential Oil in Active Food Packaging: A Review
## 5 Chemical Composition of Cinnamon Essential Oil
### Antioxidant Activity  
During food storage, oxidation reactions occur, generating free radicals and reactive oxygen species (ROS) responsible for food rancidity and spoilage [54]. So far, the food industry has been using synthetic additives such as butylated hydroxyanisole (BHA) or butylated hydroxytoluene (BHT) to prevent the oxidation of fats and oils present in the food, thus extending the shelf life of products [55]. However, synthetic additives may have adverse health effects [56], so there is a growing interest in exploring natural sources of antioxidants [54]. In this regard, EOs can help extend the shelf life of food by preserving its quality and preventing lipid oxidation, while also avoiding or minimizing the use of synthetic additives.  
Numerous studies support the outstanding antioxidant power of cinnamon [57; 58; 59]. Often, this antioxidant effect of EOs is correlated with the presence of phenolic compounds, which neutralize free radicals and ROS, thus inhibiting their oxidative action [60]. The mechanism underlying this reaction involves the donation of protons to free radicals by phenolic compounds, inducing their own oxidation and subsequent stabilization of their polarity by electron dislocation [61]. In addition, several studies have highlighted the richness of phenolic compounds in cinnamon, positioning it as one of the spices with the highest phenolic content, along with clove [57; 62; 63].  
Likewise, differences in the antioxidant capacity of cinnamon EO have been observed depending on the part of the plant from which they are extracted. [PERSON] et al. [32] compared the antioxidant activity of cinnamon EOs extracted from leaves and bark, finding that the bark EO exhibited a higher percentage of oxidation inhibition than the leaves (61.34% vs. 59.17%).  
This antioxidant potential of cinnamon EO has been explored in different studies for the development of active packaging for food, allowing the stability of food products to be improved, extending their shelf life and maintaining freshness and nutritional value over time. Some polymers used to make these packaging materials may exhibit antioxidant activity, but the addition of cinnamon EO is able to enhance this activity [64]. [PERSON] and [PERSON] [65] developed Bombacaceae gum (BG) films to which cinnamon EO was added. BG naturally contains phenolic compounds; however, the combined films of BG and cinnamon EO showed a higher amount of these compounds. The amplified presence of phenolic compounds in BG and cinnamon films correlated with a significant increase in observed antioxidant capacity. Additionally, antioxidant activities increased in proportion to the increase in cinnamon EO concentration. On the other hand, in edible coatings for blueberries enriched with cinnamon EO, this oil favored the maintenance of high antioxidant potential in the fruit by reducing the capacity to form ROS. In uncoated blueberries, the ROS level increased eightfold compared to the initial value, while in the coated samples, it only increased slightly, thus minimizing the damage caused by ROS and maintaining quality fruit [66]. Edible coatings enriched with cinnamon EO also showed lower levels of lipid oxidation in pork meat [67].