## 3 Results and Discussion
### Establishment of Molecule Aroma Wheel of RZT  
The aroma wheel served as a visual and intuitive tool for categorizing diverse types of flavor descriptions [61]. Currently, it is used in flavor research on beverages and conditions such as wine, coffee, and soy sauce [62; 63; 64]. The development of an aroma wheel can shed light on the chemical foundation of the distinctive aromatic qualities of RZT.  
Building upon the sensory aroma wheel and the findings of previous studies as references [7; 65], we refined the classification of key odorants according to their aroma types in order to more accurately define the aroma characteristics of RZT. The final RZT molecular aroma wheel is presented in Figure 6. The aroma quality of RZT was divided into seven groups using the molecular aroma wheel. Notably, the floral and sweet aroma type had the highest number of representative compounds, including linalool, gerani, (Z)-jasmone, \(\alpha\)-ionone, (E)-\(\beta\)-ionone, and indole. Typical compounds of the fruity and citrus and tropical categories include hexanoic acid methyl ester, 2-pentylfuran, 3,5-ocatadien-2-one, and \(\beta\)-cycloitral. Representative compounds of the green and minty category include methyl salicylate, heptanal, and hexanal. The aldehyde category includes octanal and nonanal, the earthy category contains 1-octen-3-ol, and the cheesy category comprises 2-heptanone. Through the integration of chemical composition and sensory descriptions, the molecular aroma wheel provides a comprehensive and consistent framework for evaluating RZT aromas, which can guide the creation of tea products with specific odor properties in future production.  
However, as previously noted, the aroma quality of tea is not solely attributed to the presence of a single volatile; instead, it is the result of the comprehensive actions of multiple volatiles with significant aroma contributions. Moreover, these volatiles interact with one  
Figure 6: The molecular aroma wheel of RZT.  
another through various mechanisms, including masking, additive, and synergistic effects. Therefore, the chestnut- and seaweed-like flavor characteristics of RZT do not suggest that the key odorants are confined to those that directly exhibit these flavors. Volatiles with floral, sweet, green, minty, aldehyde, and other odor types might also promote the perception of chestnut- and seaweed-like flavors in RZT. Consequently, future research on the flavor of RZT, including omission testing and other cutting-edge techniques, will be conducted to pinpoint the key odorants and ascertain their respective impacts.  
While this study has yielded significant findings, several limitations must be acknowledged. Firstly, commercially available tea samples were used in this study, which may affect result reliability due to the slight differences in the production process. Additionally, the precursors and the biochemical pathways leading to the formation of these key odorants remain obscure, as do the regulatory mechanisms under the specific conditions of high latitude and low temperature. To address these limitations, and to conduct a more comprehensive investigation into RZT's key odorants, future research should adopt a refined sampling strategy by processing the collected fresh tea leaves in a standardized technology. Moreover, sophisticated analysis technologies, including metabonomics and transcriptomics, will be essential to providing deeper insights into the underlying mechanisms.