## 4 Discussion  
For the purpose of describing the preliminary flavor of JBT, the sensory evaluation and biochemical compositions were conducted. As for the biochemical compositions of both two types of black tea samples, the content of free amino acids and caffeine in FBT were extremely significantly higher, while the content of theaflavins (TFs), thearubigins (TRs), and flavonoids in JBT was extremely significantly higher, which finally influenced the results of the sensory evaluation. Additionally, the index of tea infusion color was also measured. More specifically, the higher content of free amino acids and caffeine would contribute to the fresh and mellow taste of tea flavor, which is close to the sensory evaluation results of FBT; the higher content of theaflavins and thearubigins would both contribute to the taste of JBT and the bright color of the tea infusion, while the higher content of theabrownins would lead to the darker color of the FBT tea infusion. The comparison results between the aroma quality of both two types of black tea samples show that JBT has a higher and more significant floral and fruity fragrance, especially in terms of a peach-like aroma, which did not exist in FBT. The reason may be due to the difference in processing methods, but initially, the cultivated varieties, which would be the preliminary factor [32]. The detail of this factor was also further explored by other previous studies. For example, Jinxuan and other five kinds of tea cultivars were manufactured into black tea; subsequently, the detection results showed that the tea samples made from Jinxuan possessed a higher floral aroma, which is in concert with the previous finding that this tea cultivar is also suitable for floral-aroma type black tea processing [34]. It has been found that the floral odorants in different varieties of fresh tea leaves impact the aroma quality of processed tea as well as assist the assessment of cultivar processing- suitability [35]. It is undeniable that the process methods of tea also lead to the difference in aroma quality, most in the type and the content of aroma components. Take \(\delta\)-decalactone as an example, \(\delta\)-decalactone has been identified as an important aromatic compound in peach fruits [36], milk products [37; 38], and some specific tea samples. However, this compound has received less attention than other volatile compounds, such as genaniol or linalool. In our study, we surprisingly found that \(\delta\)-decalactone was the AAC of innovative JBT, and we suspected that the differences between tea processing methods should be taken into account. For example, previous studies showed that \(\delta\)-decalactone was also determined in Wuyi Rock tea, but due to the baking method, this kind of volatile was not approved as AAC [33]. Furthermore, a previous study found that \(\delta\)-decalactone and jasmine lactone were both identified in traditional JBT, but just jasmine lactone was characterized as AAC that contributes to the fruity aroma [39]. Contrarily, in our study, \(\delta\)-decalactone was characterized as AAC of peach-like JBT while jasmine lactone was not. It could be speculated that different processing methods led to this result. In our research, we selected the innovative JBT as samples, which integrate the turning-over method during production and consequently have a more significant peach-like aroma. A previous study found that fatty acids and its derivative are the important precursors supplied for fruity aroma volatile, which belong to straight chain aliphatic alcohols, aldehydes, ketones, and esters [40]. Apart from these, it has also been found that turning-over could facilitate the formation and accumulation of aroma volatile, especially the fatty acids, which contribute to fruity aroma during the processing period of oolong tea [41, 42]. Therefore, the processing methods play an indispensable role in the formation of tea aroma quality.