## 5 Edible Films and Coatings Containing CEO  
One of the main limitations in using EOs as additives is their strong aroma and prominent flavour [50]. As evidenced in the previous section (Table 2), the direct application of CEO negatively influenced certain attributes related to the sensory perception evaluated in the different matrices of some studies [34; 40]. Likewise, clove is a photosensitive and thermolabile substance since it can easily decompose under normal environmental conditions [15]. In view of this problem, some authors investigated the EO through the implementation of edible films and coatings in order to minimise the adverse effects of its direct addition, thus increasing its activity and effectiveness against deterioration reactions and microbiological growth. The main objective of this barrier technology is to minimise contact between the product matrix and its environment, thereby inhibiting bacterial growth and slowing down oxidative and other degradation reactions. Regarding the quantification of studies, a total of 31 articles were obtained that analysed the EO through this form of application, of which 24 focused solely on the in vitro and in vivo antioxidant activity of the oil and some studied two activities. Biopolymers and their mixtures are widely used as a solid phase for film production in this case. Table 3 shows the studies in which the influence of CEO was analysed concerning the reduction in oxidative processes.  
The incorporation of CEO undoubtedly increased the antioxidant capacity of edible films and coatings compared to control treatments. However, it is difficult to directly compare the collected studies due to the variation in the composition between matrices, as well as the concentration of CEO used. The results (Table 3) showed that the incorporation of EO increased the total phenol content (TPC) and, therefore, the antioxidant activity of the films. [PERSON] et al. [36] suggested that this increase is due to the fact that at  
least a fraction of the EO is not strongly bound to the matrix, which allows its antioxidant properties to be maintained.  
[PERSON] et al. [49] evaluated the antioxidant activity of coatings containing CEO and eugenol and the effect on the quality and shelf life of beef. The comparison of the biofilms provides an understanding of the release rate of the active substances in these coatings and their influence on the free radical scavenging activity. The study concluded that the antioxidant activity in the coatings with the eugenol molecules was greater than in the biofilms with CEO because a faster release of active compounds occurred. [PERSON] et al. [64] explained how the release mechanism of the active compounds from an EO in a polymeric matrix occurs, which is based on two stages. The first stage, also known as the explosion stage, consists of the rapid release of the EO. This process occurs when the polymeric network comes into contact with an aqueous medium, which generates a volumetric expansion of the polymer where the molecules are released and diffused throughout the system. In the second stage, the activity of these molecules begins to decrease since undesirable products have developed in the food matrix due to the degradation of lipids and proteins, as well as pH alterations, which lead to a slower and decreasing diffusion until it becomes null. [PERSON] et al. [61] explained that the exposure stage is around the first 10 to 15 days of storage time. Likewise, the authors argued that the concentration of the EO is directly proportional to the release mechanism. Therefore, the coating containing a high concentration of CEO was the only treatment in which the analysis was performed in the evaluated time. After 10 days, a decrease in antioxidant activity was evident.