## 3 Results
### Impact of Plant-Based Coatings on \"Rocha\" Pear Physiology during Storage
#### 3.3.3 Volatile Metabolites Analysis  
In order to make a more comprehensive analysis of the evolution of the volatile compounds profile emitted by coated pears during the assay, a subsequent HCA was performed with the complete dataset comprising the 57 compounds identified (Table 1) for both NA (Figure 7) and DCA (Figure 8). This attempts to evaluate the impact of plant-based coatings on potential aroma and/or ripening status related compounds on \"Rocha\" pears throughout the storage. Regarding NA (Figure 7), HCA shows that over the storage period, a clear clustering of any coating condition is not observed. Replicates of each condition are dispersed and a clear distinction between them is not observed.  
In the DCA storage (Figure 8), clustering formation along storage is more evident. At nine days, no clustering is observed and each condition samples are dispersed. However, at 32 days, two main branches are formed, one corresponding to CTR samples, and the other containing the coated conditions clustered according to the type of coating. The distinction of these two branches is further increased at 134 days through a higher Euclidean distance. Additionally, from day 32 to 134, coated samples became more similar among them from day 32 to day 134, although no clustering according to the type of coating is observed. The relative content of chemical families between CTR and coated conditions has a similar behavior to the NA storage, however, is more evident in this case. Coated samples have a lower content of esters and sesquiterpenes, while monoterpenes contents appear to be increased as compared with CTR.  
The content of specific volatile compounds (\(\alpha\)-farnesene and MHO) associated with oxidative processes, namely SC, between coating conditions at day 134, is presented in Figure 9. For NA, although no significant differences are observed in \(\alpha\)-farnesene content (Figure 9a) between the four coating conditions, the MHO content (Figure 9b) is significantly increased in all coated conditions as compared with the control. In DCA, the only coating that presents a lower \(\alpha\)-farnesene content (Figure 9c) is CT2 as compared with the control. In this kind of storage, MHO content (Figure 9d) only differs between CT1 and CT2 where the latter is inferior.  
Figure 7: HCA heatmap visualization of the 57 selected compounds at 9, 32, and 134 days in NA (normal atmosphere) storage conditions. Euclidean distances are included on the dendrogram Y-axis. The relative content of each compound, illustrated through a chromatic scale (from low (dark blue) to high chromatographic area (dark red black)), corresponds to its peak area normalized by autocalling. CTR (control). PCT (pectin). CT1 (coating 1). CT2 (coating 2).  
Figure 8: HCA heatmap visualization of the 57 selected compounds at 9, 32, and 134 days in DCA (dynamic controlled atmosphere) storage conditions. Euclidean distances are included on the dendrogram Y-axis. The relative content of each compound, illustrated through a chromatic scale (from low (dark blue) to high chromatographic area (dark red black)), corresponds to its peak area normalized by autoscaling. \(\blacksquare\) CTR (control); \(\blacksquare\) PCT (pectin); \(\blacksquare\) CT1 (coating 1); \(\blacksquare\) CT2 (coating 2).