## 3 Results and Discussions
### Aroma Characteristics of RAPT during Storage  
The odor activity value (OAV) is a quantitative measure used to assess the odor potency of a compound or mixture and is typically determined by measuring the concentration of a volatile compound in a sample and by comparing it to a corresponding odor threshold. Based on the OAV, the contribution of each volatile compound can be evaluated, and the correlation between the quantified volatile compounds and the aroma can be determined. In general, aroma compounds with OAV greater than or equal to one are considered as active aromatic compounds and are believed to significantly contribute to the overall aroma profile of tea [6; 30]. It is also important to consider the relative contribution of the components in a mixture, in addition to assessing the contribution of individual compounds. Therefore, the contribution of the mixed compounds to the aroma was further analyzed by calculating the aroma contribution index (ACI). Based on an OAV of \(\geq\)1, forty-three volatile compounds were identified as potential aroma compounds (Table S2). Figure 3 shows the change in these 43 volatile compounds during storage. Interestingly, most of the OVAs had their highest values at T3 and T4, and T4 had 22. In addition, according to their different aroma characteristics, the 43 volatiles were classified into nine groups: green, fruity, floral, roasted, fatty, chemical, cheese-like, stale, and woody. These aroma attributes have been previously used to describe the aroma characteristics of RAPT in other studies.  
Table S2 shows that the aroma compounds in RAPT decreased with increasing storage time, including 1-octen-3-ol, 2-methyl-butanoic acid, and 1-ethyl-1H-pyrrole. These compounds are related to green and roasted aroma attributes. On the one hand, linalool (OAV = 8040.2) and 1-octanol (OAV = 620.8) exhibited the highest OAVs at T3 (3 years of storage). (E,E)-2,4-heptadien (OAV = 5892) and octanal (OAV = 4131.4) had the highest OAVs at T4 (4 years of storage). On the other hand, DL-menthol (OAV = 1.8) reached its maximum value at T10 (10 years of storage) and was characterized by a peppermint and woody aroma. This could explain the formation of woody and mint-like aroma in RAPT after 10 years of storage. Moreover, (Z)-3,7-dimethyl-2,6-octadien-1-ol was found to contribute to the aroma profile of RAPT during storage. Its OAVs gradually increase from 2.7 at T0 to a peak value (6.2) at T3, before slowly decreasing with increasing storage time to 2.7 at T10. Furthermore, it is interesting to note that \(\alpha\)-ionone (OAV = 562.5) and linalool (OAV = 8040.2) have violet-like, citrus-like, and flowery aroma characteristics, reaching their peak levels at T3. Meantime, geraniol (OAV = 258.3), octanal (OAV = 4131.4), and \(\alpha\)-terpineol (OAV = 491.5) reached the highest at T4, displaying rose-like, citrus-like, and flowery aroma characteristics. This suggests that the storage of RAPT for about 3 to 4 years results in an abundance of floral and fruity aroma. Moreover, the contribution of aroma compounds in the mixture was compared using the aroma contribution index (ACI). Five  
volatile compounds were screened based on their high OAVs (\(\geq\)100) and ACIs (\(\geq\)1). These compounds include linalool (OAV: 2691.1-8040.2, ACI: 0.72-8.28), (E,E)-2-4-heptadienal (OAV: 3248.6-5892, ACI: 0.55-7.76), (Z)-3-hexen-1-ol (OAV: 0-151,243.8, ACI: 0-40.33), 2,6,10,10-tetramethyl-1-oxaspiro [4.5]dec-6-ene (OAV: 0-345,510, ACI: 0-76.48), and octanal (OAV: 1320.7-4131.4, ACI: 0.25-3.52).