## 3 Results
### Analysis of Biochemical Compositions and Color Difference of the Tea Infusions  
In total, eight kinds of biochemical compounds, including polyphenols, free amino acids, caffeine, theaefflavins (TFs), thearubigins (TRs), theabrownins (TBs), flavonoids, and water-extractable substances, were quantified using different methods based on various National Standards of the Republic of China. All of the black tea samples were clustered into two kinds depending on their processing materials. In this way, the contents of these eight compounds were compared between JBT and FBT. Figure 2 shows this comparison for each compound type (the green column represents FBT, and the orange column represents JBT). The content of free amino acids and caffeine in FBT was extremely significantly higher than those in JBT (Figure 2B,C, respectively: \(p<0.01\) in both cases). Conversely, the content of theaefflavins (TFs, Figure 2D), thearubigins (TRs, Figure 2E), and flavonoids (Figure 2G) in JBT were extremely significantly higher (\(p<0.01\) in both cases). In addition, the content  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Tea Samples**} & \multicolumn{3}{c}{**Sensory Quality**} \\ \cline{2-4}  & **Liquor Color** & **Aroma** & **Taste** \\ \hline JBT 1 & Orange with yellow and bright & High and pure & Smooth \\ \hline JBT 2 & Orange with yellow and bright & \begin{tabular}{c} High and long-lasting \\ peach-like aroma \\ \end{tabular} & Smooth and mellow \\ \hline JBT 3 & Orange with yellow and bright & Pure with peach-like aroma & mellow \\ \hline JBT 4 & Orange with yellow and bright & \begin{tabular}{c} Sweet and pure but with aging \\ leaf odour \\ \end{tabular} & Mellow and fresh, after-taste \\ \hline JBT 5 & Orange with red and bright & \begin{tabular}{c} High and pure but with aging \\ leaf odour \\ \end{tabular} & \begin{tabular}{c} Thick and mellow with aging \\ leaf odour \\ \end{tabular} \\ \hline JBT 6 & Orange with red and bright & \begin{tabular}{c} High and long-lasting with \\ peach-like aroma \\ \end{tabular} & Mellow and fresh \\ \hline JBT 7 & Orange with red and bright & Aging lid odour & \
\begin{tabular}{c} Mellow but with aging \\ leaf odour \\ \end{tabular} \\ \hline JBT 8 & Orange with red and bright &
\begin{tabular}{c} High and significant \\ peach-like aroma \\ \end{tabular} & Astringent and green \\ \hline JBT 9 & Orange with red and bright & High and clean & Thick and fresh \\ \hline JBT 10 & Orange with red and bright & High and long-lasting & Thick and fresh \\ \hline FBT 1 & Red and bright & Significant caramel-like aroma & Mellow \\ \hline FBT 2 & Red and bright with a golden circle & Caramel-like with a floral aroma & Fresh and thick \\ \hline FBT 3 & Red and bright & Caramel-like and pure & Mellow and fresh \\ \hline \hline \end{tabular}
\end{table}
Table 2: Sensory quality of JBT and FBT samples.  
of theabrownins (TBs, Figure 2F \(p<0.05\)) in FBT was also significantly higher. These differences may influence the taste quality of both tea types in sensory evaluation.  
An evaluation of the coloration of both tea types was performed using color indexes L*, a*, and b*, which represent lightness (L*), red-green hue (a*), and yellow-blue hue (b*), respectively. The results are shown in Table S1. The values of L*, a*, and b* for JBT infusion imply that the color of this tea infusion was close to orange-red and brighter; the values of FBT indicate that the color of this tea infusion was red and bright, which also reflects the sensory evaluation results. Additionally, a difference analysis was also conducted between JBT and FBT; capital letters represent an extremely significant difference between the samples, while lowercase letters represent a significant difference between the samples.