## 4 Discussion  
The gas chromatography/electron impact-mass spectrometry analysis of the EOs involved in this study is fully reported in [PERSON] et al. [20]. Briefly, in the _L. nobilis_ EO, the oxygenated monoterepnes 1,8-cineole (28.1%) and \(\alpha\)-terpinyl acetate (17.5%) were the most abundant components. In the _P. nigrum_ EO, over 60% of the composition was characterised by sesquiterpene hydrocarbons, including 45.7% of \(\beta\)-caryophyllene. The chemical compositions of both EOs align with those reported in the literature by other authors. Similarly to our accession, laurel EOs extracted from plants collected in Greece and Georgia contained 1,8-cineole (30.8 and 29.2%, respectively) and \(\alpha\)-terpinyl acetate (14.9 and 22.6%, respectively) as major components. In the Georgian EO, 8.1% of methyl eugenol was also found (7.3% in our sample) [36]. Regarding black pepper EOs, \(\beta\)-caryophyllene is often reported as their major component. Indeed, this sesquiterpene constituted 51.12% of the composition of a sample used by [PERSON] et al. [37] and 47.14-50.88% of one analysed by [PERSON] et al. [38]. Both EOs here employed have been evaluated before by a group of expert sensory analysts [20]. On a 0 to 9 scale, the _L. nobilis_ and _P. nigrum_ EOs simply diluted in ethanol received scores of 8.31 and 8.71, respectively, for their overall pleasantness. The former was associated with fresh and resinous notes while the latter was characterised by citrusy and floral scents. When added to the CH solution and applied on beef at 0.23 uL EO cm\({}^{-2}\) of treated surface (i.e., the same amount we used on our patties), the overall pleasantness was 7.52 for the _L. nobilis_ EO and 7.11 for the _P. nigrum_ EO [20]. The colour parameters of beef patties, which are crucial cues used by consumers to judge meat freshness through its appearance [39], were affected by our treatments and storage time. All the CH coatings resulted in a significant increase in lightness, which was more pronounced in the CH (+10.72%) and _L. nobilis_ EO-CH enriched (+7.58%) groups. This phenomenon is in accordance with [PERSON] et al. [20], which reported higher L* values in beef patties coated with different CH solutions after 4 and 7 days of storage at 4 \({}^{\circ}\)C. Furthermore, [PERSON] et al. [40] observed the same effect when adding CH oligomers to cooked pork sausage, [PERSON] et al. [41] when applying CH-thymme EO treatments on a ready-to-cook poultry preparation, and [PERSON] et al. [42] when dipping chicken breast fillets in CH and oregano EO-enriched CH. Therefore, CH itself likely creates a coating that increases the reflection of light, making the meat look brighter. A decreasing trend in \(\tt{a}^{\star}\), \(\tt{b}^{\star}\), and \(\tt{C}^{\star}\) values was observed from 0 to 4 days of storage in our study, together with a consequent \(\tt{H}^{\star}\) increase. Overall, these changes can be attributed to the gradual oxidation of myoglobin and the accumulation of metmyoglobin over time [43]. Lower \(\tt{a}^{\star}\) values were reported in pork patties containing roscamy compared to those with sage or soy proteins after 6 days of storage at 4 \({}^{\circ}\)C, despite the overall better effect of roscamy against lipid oxidation compared to the other natural additives [44]. Other studies reported an increase in redness and yellowness [40] or the absence of colour changes attributable to CH [42]. These discrepancies, in addition to pigment oxidation, might be due to the different meat types (e.g., beef, chicken, pork, lamb) and cut/preparation (e.g., steak, fillet, patty, sausage) used. The presence of secondary oxidation products increased over time in all the samples, but the _L. nobilis_ EO-enriched CH solution was able to maintain levels well below the minimum threshold for the rancidity perception [35]. Chitosan is already used by the food industry for its antioxidant properties [14], but according to our results, it appears that a specific EO with a positive synergy is required to actively protect the meat.