## 3 Results
### FT-IR Analysis of Enriched Oils  
FT-IR analysis was carried out first as a non-destructive testing approach for the intact oil. The ATR-FTIR spectra of the virgin avocado oil (C-VAO, C-AO) contained all the characteristic bands of the fatty acid chains (methylene groups, cis-cis, or cis-trans double bonds), carbonyl and acyl ester bonds, as well as hydrogen-bonded molecular networks of freshly produced oils. These features coincided with the respective FTIR spectral bands of fresh EVOO [33] and are discussed in the following paragraphs. A high degree of unsaturation could be deduced from the spectral data in the region between 2850 and 3010 cm\({}^{-1}\) based on earlier findings about the diagnostic importance of those bands [34; 35]. Similarly, the ATR-FTIR spectra of the fortified avocado oils were visually identical to those of the reference oils. After normalization with the Standard Normal Variate (SNV), greater intensity variance was easily observed in the regions 650-780 cm\({}^{-1}\), 1000-1250 cm\({}^{-1}\), and 2850-2960 cm\({}^{-1}\) (Figure S2). However, the patterns of variance according to the fortification agent and its addition level were visualized only after PCA, especially through the corresponding score and loading plots. To avoid overfitting, the data from the full spectral range were minimally processed (smoothed or averaged) before normalization and mean-centering. The dataset (10 oil samples \(\times\) 1738 spectral points) resulted in four principal components (PCs) explaining 99% of the total variance. The major part (94.4%) could be described only by the first two PCs, indicating that the third and fourth PC carry systematic but minor differences among the spectra.  
Visualization of the scattered t1/t2 scores over the first two PCs (Figure S3) revealed that most of the fortified oils were clouded close to zero. It is striking though that the PC1 and PC2 axes were formed mainly due to the differences between the base AO and those fortified with the lowest amount of leaf material, OL and AL (5% _w/w_), respectively. The p2 loading values (_p_ > 0.05) signified that variance in three spectral regions--mainly at 2920-2960 cm\({}^{-1}\), along with those at 1730-1740 cm\({}^{-1}\), and less importantly at around 3450 cm\({}^{-1}\)--accounted for the scattering across PC2. On the other hand, distinct patternsof variance at around 720, 1140-1160, along with 2850-2860, 2910, and 1740-1750 cm\({}^{-1}\) were revealed from the lowest/highest p1 loadings. These results imply that methylene and carbonyl bond-stretching vibrations are the major contributors to the exposed pattern. The variance at 3450 cm\({}^{-1}\) also indicates a role of N-H bonds (as in amide groups), while that at 2910 cm\({}^{-1}\) could arise from alkane residues attached to other hetero-atoms [35]. One can speculate that AO fortification with the lowest dose of leaf material provoked changes in the content and configuration of unsaturated bonds of lipid and/or protein molecules that were not replicated with higher doses. Exploration of the lower PCs in the modeled spectral data did not add any further information regarding the possible physicochemical changes due to fortification with OP. Further analyses were thus carried out to enrich our understanding of those phenomena.