## 3 Results and Discussion  
### Aroma Compounds  
A total of 64 aroma compounds were identified and quantified in Cabernet Sauvignon and Marselan dry red wine (Table 2). The aroma activity value (OAV) of each compound is calculated according to the threshold value, the ratio of the aroma compound threshold value, and the concentration of the compound. When the OAV of the aroma compound in wine is greater than 1, the compound is considered to have an important contribution to the overall aroma of wine [13,14]. As shown in Table 2, a total of 18 aroma compounds had OAVs greater than 1 identified in both 2 varieties of wines, including ethyl acetate, ethyl butanoate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, ethyl 2-methylbutanoate, ethyl 3-methylbutanoate, ethyl cinnamate, isoamyl acetate, isoamyl alcohol, 2-phenylethyl alcohol, methionol, isovaleric acid, octanoic acid, \(\beta\)-damascenone, \(\beta\)-ionone, and (\(Z\))-oaklactone. \(\gamma\)-Butyrolactone displayed OAVs greater than one only in Cabernet Sauvignon wines. The paired \(t\)-test was carried out to identify the differences in aroma compounds between the two varieties of wines. It was shown that twelve volatile compounds, mainly terpenoids, higher alcohols, and aliphatic lactones, were significantly different according to the grape variety. Among the aroma compounds, three terpenoids (linalool, terpinen-4-ol, and \(\alpha\)-terpineol), three lactones (\(\gamma\)-butyrolactone, \(\delta\)-octanolactone, and \(\gamma\)-undecalactone), three higher alcohols (isoamyl alcohol, 2-phenylethyll alcohol, and methionol), isoamyl hexanoate, ethyl hexadecanoate, and isovaleric acid showed significant differences in concentration (Table 2). It is well known that grape-derived aroma compounds contribute to the typicity aromas of a specific grape variety and could be considered the marker chemicals responsible for the differentiation from other varieties. Among the different aroma compounds between the two varieties, terpenoids, and aliphatic lactones were two important categories of grape-derived aroma compounds. In this study, the total concentration of terpenoids was approximately 1.5-fold higher in the Marselan wines than in Cabernet Sauvignon, with a value of 21.79 \(\mu\)g/L, which was mainly dominated by linalool, terpinen-4-ol, and \(\alpha\)-terpineol (Table 2). The results were consistent with our previous study, which found higher concentrations of monoterenes in young Marselan wine compared with neutral grape varieties [6]. To our knowledge, these compounds are considered varietal aroma compounds, which are important contributors to the aroma of wines made from Muscat varieties (e.g., Muscat of Alexandria and Muscat Blanc a Petit Grain) and correlate with the floral aroma in wines [15]. The differences between the wines of the two varieties were anticipated due to the genetic differences affecting the final content of the aroma compounds in wine. However, both Cabernet Sauvignon and Grenache, the parents of the Marselan grape, are considered neutral varieties, characterized by their relatively low content of terpen [16]. Interestingly, previous research reported that Grenache wine showed maximum flavor dilution values in the case of terpenes in a comparative GC-olfactometry (GC-O) study between young wines made from Merlot, Cabernet Sauvignon, and Grenache grape varieties [17]. Therefore, it seemed that the levels of terpenes in Marselan wines could be associated with the character inheritance from the Grenache grape, which required confirmation by further studies. From the perspective of aroma contribution, the relatively high concentration of terpenes could be related to the intense floral note in young Marselan wine. For instance, the average concentration of linalool (mean average con. 7.82 \(\mu\)g/L) in Marselan wines could reach half of its odor threshold (15 \(\mu\)g/L in water/ethanol solution) [18] and might contribute to wine with flowery and muscat notes.