## 3 Results
### Chemometric Analysis  
Chemometric approaches, such as HCA, PCA, and PLS-DA, enable metabolite profiling datasets obtained from various food samples to be classified according to their geographical origin and processing methods [23; 24; 25]. In the present study, unsupervised PCA, HCA, and supervised PLS-DA were conducted to elucidate the influence of species, cultivar, cultivars, and cultivation year based on the volatile composition of white ginseng roots. Unsupervised PCA and HCA were performed using the volatile profiling data of the ginseng roots to reveal the same sample clustering pattern, provide an overview of the trend, and determine putative outliers. Different color groups reflect each of the Korean ginseng cultivars and American ginseng, and closer distances indicate similar volatile composition. As shown in Figure S1A, the PCA score plot showed well-separated clusters among American ginseng, \"Yunpoong,\" and \"Gumpoong\"/\"Cheonryang,\" while the age differences in cultivation were not clear. It is clear that the American and Korean ginseng groups were clustered separately. The first two principal components (PCs) represented 47.3% of the total variance (PC1 = 35.7% and PC2 = 11.6%). In addition, the influence of the Panax species and cultivars on each cultivation year based on volatile compound data was also analyzed by PCA and HCA (Figure 2) because the plot of all ginseng groups was ambiguous. The results indicated that four groups were clearly separated in the PCA score plot of 4- (PC1 = 46.9%, PC2 = 19.0%), 5- (PC1 = 41.6%, PC2 = 14.0%), and 6-year-old roots (PC1 = 42.4%, PC2 = 16.1%), except for 3-year-old roots (PC1 = 44.0, PC2 = 19.7%), with no significant sample outliers. Even though the volatile compositions of 3-year-old roots were well-distinguished between the Korean ginseng and American ginseng groups, \"Gumpoong\" was not completely separated from \"Cheonryang\". HCA was performed to elucidate the similarities and dissimilarities of the volatile profiles of different samples. The HCA dendrogram also indicated that the American ginseng group clustered with the Korean ginseng groups. However, the cultivation ages were not clustered on each ginseng root in the PCA score plot, which means the volatile composition of the ginseng roots were not affect by different cultivation ages (Figure S6). These results reflect the dissimilarity between American ginseng and Korean ginseng cultivars. Figure 1: Profiles of volatile compounds present in the four different white ginseng roots grown for 3–6 years. The concentrations of volatile compounds are relatively indicated as percentages based on the total peak area (100) in the 3-year-old ‘Cheonryang’ cultivar. Data are provided as mean values (\(n=3\) biological replicates). Supervised PLS-DA was conducted to calculate models that differentiate between groups and select the specific marker compounds responsible for the different ginseng group-dependent clustering based on VIP values above one. The PLS-DA score plot of all ginseng groups based on volatile compounds showed a distinct separation between Korean ginseng cultivars and American ginseng, although there was no clear clustering among Korean ginseng cultivars (Figure S1B). In the PLS-DA score plot of the ginseng samples for each cultivation year, the four different groups could be distinguished well (Figure S2). The PLS-DA loading plot revealed that the American ginseng group in 3-, 4-, 5-, and 6-year-old roots was positioned on the right side of the plot and was characterized by relatively high concentrations of 3-care, \(\beta\)-farmesene, \(\beta\)-sesquiphellandrene, octanal, and 2-nonenal (Figure 3). Monoterpenes such as \(\beta\)-pinene and \(\beta\)-myrcene appeared to be linked to \"Yunpoong\" cultivar. Most of the discriminative compositions in \"Cheonryang\" were characterized by the presence of 1-hexanol, 1-ocatanol and ethanol.