## 2 Results and Discussions
### Volatilomics and Molecular Networking Analysis
For example, aldehydes (2, 8, 45), alcohols (7, 10, 26), and straight-chain esters (89, 125, 158) are derived from fatty acids and amino acids. They have a fresh and fruity aroma and are formed during the ripening period associated with a climacteric increase in respiration [54]. In contrast, branched-chain esters (90, 145) are produced by isoleucine metabolism [55]. C6 and C9 aldehydes are formed via the lipoxygenase-hydroperoxide pathway, in which enzymes oxidize polyunsaturated fatty acids. Hexanal (45) is produced when the substrate is linoleic acid [56]. A study conducted by [PERSON] et al. [55] identified VOCs present in three varieties of apples during fruit development and found that hexanal (45) decreased as the fruits ripened. This decrease is related to ester biosynthesis, because alcohol dehydrogenase reduces aldehydes in the fatty acid and isoleucine degradation pathways to their corresponding alcohols, which are metabolized to esters by the action of alcohol acetyltransferaseases [57]. The wide variety of esters found in copoozu can be explained by the esterification of linear, branched, or aromatic alcohols with acyl-CoA, which is produced by the oxidative decarboxylation of  
Figure 4: Heatmap analysis of metabolite features associated with VOCs in copoozu. Variation and clustering of the three stages of fruit ripening according to the abundance of detected metabolites. The color spectrum ranging from red to blue indicates the range of high to low signal intensities for each metabolite. pyruvate, giving rise to acetyl-CoA. Acyl-CoA produces ethyl esters, whereas acetyl-CoA generates ethanoate esters [58]. Moreover, the molecular network analysis supports the differentiation of VOC profiles across ripening stages (Figure S9). It highlights distinct clustering patterns of VOCs, with some compounds unique to specific stages. For instance, 3-thujanone (117) and isothujol (152) were exclusive to the overripe stage, while 2,2-dimethylpentanoic acid (57) and 2-methylpropyl 2-methylbut-2-enoate (139) were found only in the ripe stage. The medium stage exhibited lower overall VOC concentrations but included compounds such as ethyl butanoate (46) at higher proportions than the other stages. The correlation between color due to carotenoids and variation in volatile terpen could be associated with the 2-c-methylerythriol 4-phosphate (MEP) pathway that produces both families of compounds [56]. In this case, the increase in the percentage of terpen in the ripening stage coincided with the results obtained in the ATR-FTIR spectro  
Figure 5: Molecular network from volatilomic profile of the copoazu in three ripening stages. In the molecular network, the biochemical correlation of the compound families is evidenced by the observation that the aldehydes butanal (2) and 3-methylbutanal (8) are precursors of the alcohols butan-1-ol (10) and 3-methylbutanol (26), and the esters resulting from metabolism, such as butyl ethanoate (38). In contrast, in the network dioxane/dioxane groups are formed by metabolites such as 2,4,5-trimethyl-1,3-dioxolane isomers (24, 28, 30) and 2,4-dimethyl-1,3-dioxane (41). According to [PERSON] et al. [59], this compound is formed by the condensation between acetaldehyde and 2,3-butanediol or ethanol. scopic analysis, in which spectral bands characteristic of carotenoids were found, in addition to the characterization of these compounds by HPLC. Furthermore, in the molecular network, a well-defined cluster of monoterpencoids (127, 129, 155, 101, etc.) and _trans_-linalo oxide (121) was observed, separated from the main cluster, possibly correlated with the increase in the ripening state of copoazu. The aromatic composition of fruits also depends on several factors, such as climatology, edaphology, time of harvest, pre- and post-harvest treatments, variety, phenological stage of the fruit [60], storage, fruit condition (whole, sliced, wet, dry), type of analysis (field or laboratory) [19], and VOC extraction technique.