## 3 Results and Discussion
The biplot graphs, shown in Figure 5, represent (A) PC1\(\times\)PC2 and (B) PC1\(\times\)PC3, where the samples (scores) are represented by red triangles and the compounds (loadings) by blue squares. To improve the view of the compounds related to each sample, coloured regions were drawn for AZAC (blue), CASC (pink), ENIG (yellow), LORA (green), and ZAPP (grey). Regarding this result, a diversity of substances is related to the samples and, as expected, the complexity of compounds formed during hop metabolism. The distribution of compounds can be seen with the ZAPP hop related to the positive part of PC1, while ENIG is present in the negative part of PC2; moreover, AZAC is present in the positive part of PC1 and the negative part of PC2, while PC3 shows LORA in the positive section and CASC in the negative. Characterising some of the compounds, attention may be called to the unique compounds in each of the samples with the presence of clusters close to their respective red triangles shown in Figure 5. Characterising each hop variety, AZAC shows the influence of compounds hexanal (**1**), p-cymene (**33**), the sesquiterpene hydrocarbons \(\delta\)-cadinene (**124**), calamenene (**125**) and \(\alpha\)-calacorene (**130**), and the ketones 2-nonanone (**48**), 2-decanone (**65**), 2-undecanone (**79**), 2-dodecanone (**96**) and 2-tridecanone (**116**). This shows a significant connection between AZAC and the ketone formed in its metabolism. Regarding reports from the literature [55], the hop AZAC was studied by GC-MS and a method for the fraction of hydrodistilled essential oil followed by HS-SPME. This study also showed a high concentration of cryophyllene and a high percentage of humulene as reported by results in Table 3.  
For the hop CASC, the monoterpene hydrocarbons camphene (**14**) and perilene (**52**) and the oxygenated monoterpenes geraniol (**73**), _cis_-linaloid oxide (**44**), and _trans_-linaloid oxide (**47**) were related by PCA analysis. This shows that CASC has a relation with the auto-oxidation of myrcene [56; 57] by the formation of geraniol, an important floral odorant in the hop essential oil, as the presence of camphene and linaloid oxide in the two isomeric forms, related to the \"European hop aroma\" [17; 57]. The hop CASC is widely studied  
Figure 4: Compositional plots for the hop samples AZAC, CASC, ENIG, LORA, and ZAPP based on the classes of compounds expressed in area percentage (%), according to the SPME methodology employed. in the literature, as in the GC\(\times\)GC-TOFMS study from [PERSON] et al. (2018), and by GC-MS from other studies ([PERSON] et al., 2018). In the results of [PERSON] et al., the essential oil fraction of CASC was hydrodistilled and as a result also displayed the presence of geraniol and perilene, proving certain similarities. When compared to the composition of humulene (36.44%) and \(\beta\)-myrcene (5.93%) (noting limitations due to the SPME sampling), this paper shows a contrary behaviour compared to the literature ([PERSON] et al., 2018; [PERSON] et al., 2018; [PERSON] et al., 2018), where the concentration of \(\beta\)-myrcene is higher than humulene, which is explained as a distinct sample with a probable cause of low content of \(\beta\)-myrcene and high content of humulene related to the ripening period, more specifically an early harvest or a not-well-ripe hop ([PERSON] et al., 2018; [PERSON] et al., 2018). Regarding ENIG, three classes were significant: monoterpene hydrocarbons comprising \(\beta\)-myrcene (**22**), \(\beta\)-ocimene (**35**), and _trans_-\(\beta\)-ocimene (**36**), the two sesquiterpene hydrocarbons (\(E\))-\(\beta\)-farnesene (**107**) and \(\beta\)-eudesmene (**117**), and the esters isobutyl1 2-methylbutanoate (**25**) and 2-methylbutyl octanoate (**106**).