## 3 Results and Discussion
### Analysis of Volatile Arorna Components  
As presented in Table S2, a total of 156 volatile aroma substances belonging to 13 categories were identified in the four groups of aroma samples. These included 26 alcohols, 26 alkanes, 25 esters, 24 ketones, 15 aldehydes, 10 alkenes, 9 phenols, 7 aromatic hydrocarbons, 5 heterocyclic compounds, 4 acids, 2 ethers, 2 amines, and 1 halogenated hydrocarbon. The aroma components in the four groups of Liupao tea samples, which underwent different fermentation methods, exhibited variations in their categories. The content and percentage of different categories of aroma compounds in each group of samples were further analyzed, with the results presented in Figure 2a. It is evident that the different aroma compounds exhibited significant changes in their total amount and percentage. The relative total content of aroma components in the Cl group was higher in aldehydes, ketones, esters, and heterocyclic compounds, with values of 125.21 \(\mathrm{\SIUnitSymbolMicro g}\)/kg, 104.75 \(\mathrm{\SIUnitSymbolMicro g}\)/kg, 66.84 \(\mathrm{\SIUnitSymbolMicro g}\)/kg, and 57.27 \(\mathrm{\SIUnitSymbolMicro g}\)/kg, respectively, accounting for 21.32-26.08%, 18.96-21.24%, 11.91-13.77%, and 9.72-11.86% of the total content of aroma components. Similarly, the relative total content of aroma components in the CMI group was also higher in ketones, heterocyclic compounds, esters, and aldehydes, albeit with variations in content and proportion. The highest content and proportion were observed for ketones and heterocyclic compounds, with values of 78.98 \(\mathrm{\SIUnitSymbolMicro g}\)/kg and 63.74 \(\mathrm{\SIUnitSymbolMicro g}\)/kg, respectively, accounting for 19.71-22.31% and 15.41-18.41% of the total content of aroma components. The categories with higher average relative content of aroma components in the DI group differed significantly from those in the Cl and CMI groups. The relative contents of alkenes and alcohols were 101.97 \(\mathrm{\SIUnitSymbolMicro g}\)/kg  
Figure 1: Aroma profile of different Liupao teas by QDA. (**a**) Electronic nose odor fingerprints of different Liupao tea (**b**). and 81.66 \(\mathrm{\SIUnitSymbolMicro g}\)/kg, respectively, accounting for 18.54-23.9% and 16.13-17.87% of the total aroma components. Ketones, alcohols, esters, and heterocyclic compounds were relatively higher in the DMI group, with values of 194.33 \(\mathrm{\SIUnitSymbolMicro g}\)/kg, 181.68 \(\mathrm{\SIUnitSymbolMicro g}\)/kg, 120.67 \(\mathrm{\SIUnitSymbolMicro g}\)/kg, and 114.28 \(\mathrm{\SIUnitSymbolMicro g}\)/kg, respectively, accounting for 23.3-23.94%, 23.13-21.05%, 14.55-14.77%, and 13.67-14.11% of the total content of aroma components. The total amount and classification of aroma components in the four groups of Liupao tea subjected to different fermentation methods were significantly different, as shown in Figure 2b,c. The total amount of aroma components in the four groups followed the order of DMI (822.97 \(\pm\) 19.66 \(\mathrm{\SIUnitSymbolMicro g}\)/kg) > Cl (523.08 \(\pm\) 50.47 \(\mathrm{\SIUnitSymbolMicro g}\)/kg) > DI (480.53 \(\pm\) 2.39 \(\mathrm{\SIUnitSymbolMicro g}\)/kg) > CMI (375.55 \(\pm\) 49.50 \(\mathrm{\SIUnitSymbolMicro g}\)/kg). Significant differences were observed among the four groups in terms of the total amount of various aroma components (Figure 2d). The DMI group exhibited significantly higher levels of ketones and heterocyclic compounds compared to the other groups, with the total amount of aroma components in multiple categories being higher than in the other three groups. In addition to the high content of halogenated hydrocarbons and alkenes in the DI and CMI groups, the total amount of other aroma components remained relatively low. While the DMI group had the highest total amount of aroma components and high levels of each type of aroma component, this alone could not fully explain its aroma quality characteristics.