## 3 Results and Discussion
### General Multivariate Characterization of Samples using PCA  
Data were organized in a matrix and evaluated by principal component analysis (PCA) (with the data centered) to better elucidate the relationships between the composition of the samples and their storage conditions. The first three components explained 96% of the variability. Figure 3 shows the graph of the samples and variables together (biplot) for component 1 and 3.  
As shown in Figure 3, there are 11 main variables (oxidized phenolic compounds, non-oxidized phenolic compounds, total phenolic compounds, elenoic acid, tocopherols, DAODO (3,4-DHPEA-EDA, oxidized form), DALDO (_p-HPEA-EDA_, oxidized form), AOAHO (_3,4-DHPEA-EA-AH_, oxidized form), DAOD (3,4-DHPEA-EDA), DALD (_p-HPEA-EDA_), and AOAH (_3,4-DHPEA-EA-AH_) that allow for characterization of the samples according to their storage conditions. The samples from storage conditions C1 (\(-\)23 \({}^{\circ}\)C), C2, and C3 (room temperature) were differentiated from storage conditions C4 and C5 (30 and 40 \({}^{\circ}\)C,  
Figure 3: Multivariate general characterization of oil samples by PCA. Plots of samples and variables. Sample are labeled by storage conditions (C1: stored at \(-\)23 \(\pm\) 2 \({}^{\circ}\)C in darkness; C2: 23 \(\pm\) 2 \({}^{\circ}\)C, with light; C3: 23 \(\pm\) 2 \({}^{\circ}\)C in darkness; C4: 30 \(\pm\) 2 \({}^{\circ}\)C in darkness; C5: 40 \(\pm\) 2 \({}^{\circ}\)C in darkness); and storage time (from 1 to 12 months). Abbreviations: AOAH: 3,4-DHPEA-EA-AH; AOAHO: 3,4-DHPEA-EA-AH oxidized; DAOD: 3,4-DHPEA-EDA; DAOD: 3,4-DHPEA-EDA, oxidized; DALD: _p-HPEA-EDA_; DALD: _p-HPEA-EDA_, oxidized.  
respectively) through component 3; where the latter were associated with a higher quantity of oxidized phenolic compounds, elenoic acid, DAODO, DALDO, and AOAHO. This result further highlights the increased formation of these compounds under higher storage temperatures. Likewise, the higher content of these components in the oil is accentuated with storage time, as demonstrated for samples from the C4 and C5 conditions when stored for more than 10 and 3 months, respectively.  
Conversely, samples from C1, C2, and C3 conditions are associated with higher levels of non-oxidized phenolic compounds, DAOD, AOAH, and DALD, and suggests that lower storage temperatures favor stability and prevent oxidation of the oil components. Furthermore, with the exception of one month of storage, the C2 samples (room temperature with light) were grouped in the lower left quadrant directly associated with non-oxidized phenolic compounds, particularly those with shorter storage time (2 to 5 months). However, these samples are also inversely related to the content of \(\alpha\)-tocopherol (upper right quadrant) and highlights the antioxidant action of \(\alpha\)-tocopherol in photooxidation, with a dramatic drop throughout the storage period as discussed above. Importantly, the inverse relationship between oxidized phenols and the content of secoiridoids (DALD and DAOD) and \(\alpha\)-tocopherol is due to the production of oxidized phenols during oil degradation, which in turn causes a decrease in secoiridoids and tocopherols.