## 3 Results
### Analysis of Aroma Activity (OAV)  
Odor characteristics play a key role in evaluating the flavor and quality of wine. It is generally accepted that only compounds with an odor activity value (OAV) higher than 1 can significantly influence the aroma characteristics of wine [37]. In this study, a total of 36 compounds with an OAV \(>\) 1 were identified (Figure 3). Among them, esters still accounted for the largest proportion of compounds, with a total of 19. Ethyl octanoate had the highest OAV (more than 23 in each producing area) among the esters, which contributed more to the wavy aroma. In particular, \(\beta\)-damascenone, \(\beta\)-ionone, and dodecanal were the key compounds with relatively high OAVs (mean 23.21-813.99), which were considered to be related to the aroma properties of flowers, fruits, and plants (Table 6). Generally, the OAV of aroma compounds in the HSP producing area are relatively higher, resulting in more pronounced aroma characteristics compared to other regions (Figure 3A). This characteristic is primarily manifested in the abundance of ester compounds and C\({}_{13}\)-norisoprene derivatives. Production practices have shown that increased light exposure can significantly enhance the levels of C\({}_{13}\)-norisoprene derivatives [43] and promote ester accumulation [44] in both grape berries and wine. Furthermore, while the number of compounds with an OAV > 1 in the QTX and YC producing areas is relatively similar, the overall contents of aromatic substances differ markedly. This discrepancy is likely influenced by factors such as the vineyard microclimate and other environmental variables [45]. Figure 3: Analysis of volatile compounds based on OAV > 1. (**A**) Heat map. (**B**) Intensity of different aroma categories. Detailed explanations of aroma category attributes can be found in Table 6. Different letters indicate that there are significant differences between different producing areas (\(p\) < 0.05). An aroma vector is defined as \"a sensory unit composed of one or more molecules with similar aroma descriptors, which are responsible for the specific sensory characteristics of a product\" [36]. By constructing an aroma vector, compounds with similar odor characteristics can be classified into an aroma series, which is determined by the sum of the OAVs of each compound [45]. In this research, six aromatic series were established, including floral, fruity, waxy, green, fatty, herbal, musk, and solvent fragrances (Table 6). As shown in Figure 3B and Table 6, \"floral\" and \"fruity\" are the most important aromatic series in wine, primarily due to the low odor thresholds of \(\beta\)-damascenone and \(\beta\)-ionone [70]. Studies have shown that the maturity of grapes has a significant impact on the fruity and floral intensities of wines [71]. Specifically, the fruit maturity of the HSP producing area was low (low TSS-TA ratio), and the aroma-active components showed the highest intensities of \"flower\" and \"fruit\" aromas. Moreover, studies have shown that wines produced from grapes harvested at the same time but with lower ripeness compared to those meeting maturity standards exhibit elevated levels of \(\beta\)-damascenone and \(\beta\)-ionone [72]. This finding suggests that harvesting grapes at a relatively lower maturity can enhance the retention of these desirable aromatic characteristics, further emphasizing the importance of ripeness in the overall aromatic profile of wine. This implies that lower maturity may contribute to the preservation of these aromatic features. The aroma of the \"green\" series was most prominent in the YN and QTX producing areas, which was attributed to the  
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