## 3 Results and Discussions
### Dynamic Changes in Different Compounds during Storage  
As indicated by the quantitative results, the contents of many volatile compounds varied greatly during the storage of RAPT. To visually illustrate the change patterns of  
Figure 1: Annotation of volatile compounds during RAPT storage: (**A**) upset diagram; (**B**) pie diagram. The proportion of different types of volatile compounds in RAPT: (**C**) total volatile compound content and classification. (**D**) Principal component analysis (PCA). (**E**) Hierarchical cluster analysis (HCA). volatile compounds in RAPT for different storage years, this study employed a heatmap analysis, as depicted in Figure 2.  
As illustrated in Figure 2, three distinct patterns of changes can be observed in the content of these compounds. The first pattern consists of a gradual decrease in content over time, the second pattern involves an increase in content with increasing storage time, and the third pattern exhibits an initial increase followed by a gradual decrease after 5 years. The first group of volatile compounds includes 1-octen-3-ol, 3,5,5-trimethy-2-hexene, (E)-2-octen-1-ol, 1-hexanol, 2-methl-butanoic acid, 3-methyl-butanoic acid, and 6,10-dimethyl-5,9-undecadien-2-one. These seven volatile compounds showed a tendency to decrease in content during storage, and their dominant aroma characteristics were described as mushroom-like, green, roasted, fatty, and cheese-like. It is worth noting that most of these compounds belong to the alcohol chemical class, which is an interesting finding. Alcohols have been found to be the main volatile compounds in RAPT and contribute significantly to its characteristic aroma [10]. Thus, it is hypothesized that tea with shorter storage times may have stronger grassy, roasted, and fatty aromas. In addition, the second group of compounds includes \(\alpha\)-pinene, D-limonene, 2-ethyl-1-hexanol, and DL-menthol. These volatile compounds are mainly associated with a woody and mint-like aroma. This finding explains the disappearance of green and roasted aroma, and the emergence of woody and mint-like aroma in RAPT. Furthermore, most of these compounds showed a pattern towards the third group of compounds (approximately 75%). For instance, benzaldehyde increased from 14.77 ug/100 g (stored for 0 years) to 46.78 ug/100 g (stored for 5 years) and then slowly decreased. Similarly, 2,4-Di-tert-butylphenol (16.86-35.94) increased from 16.86 to 35.94 (ug/100 g) initially and then slowly decreased. Here, benzaldehyde is produced through the deamination of amino acids by aminotransferase [28]. Interestingly, a majority  
Figure 2: Heat map of differential volatile compounds in the samples of RAPT at various storage time points. of the third group of volatile compounds decreased in 5 years of storage (T5), which is consistent with a previous study indicating that five years of storage is a significant turning point [29]. Moreover, most of the third group of volatile compounds contributes to the floral and fruity aroma. This result suggested that the green and roasted aromas diminish over time, while the floral and fruity aromas gradually become more prominent during the 0-5 years of storage. Figure S3 shows a decrease in the relative contents of 12 volatile compounds during storage. These compounds include 1-hexanol, 2,6-dimethyl-5-heptenal, 1-octen-3-ol, 2,3-octanedione, 2,6,6-trimethyl-1,3-cyclohexadiene-1-carboxaldehyde, 3,5,5-trimethyl-2-hexene, (E)-2-octen-1-ol, 2-methyl-butanoic acid, 1-ethyl-1H-pyrrole-2-carboxaldehyde, 6,10-dimethyl-5,9-undecadien-2-one, trans-\(\beta\)-ionone, and 6-undecanone. Specifically, they have predominantly green, fatty, floral, fruity, and roasted aroma. Moreover, the relative contents of some volatile compounds have been increased during storage, notably \(\alpha\)-ionone, isophorone, 1,2-dimethoxy-benzene, and 1,2,5,5-trimethyl-1,3-cyclopentadiene. These compounds contribute to violet-like, woody, fruity, vanilla, and phenolic-like aromas.