## 2 Results
### Effect of drying Temperature on the Non-Volatile Components of LBT  
During the drying process, various transformations occur in the tea constituents, including the thermal degradation of catechin and its oxidation products, the Maillard reaction involving amino acids and sugars, caramelization, as well as pigment degradation [19; 20]. All of these reactions exert diverse effects on the sensory quality of the tea. Table 2 shows the effect of different drying temperatures on the chemical composition of the LBT. The presence of soluble sugar in the tea infusion plays an important role in mitigating the bitter taste resulting from tea polyphenols and caffeine [21]. In the present \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & **Appearance** & **Infusion Color** & **Aroma** & **Taste** & **Infused Leaf** & \\  & **(25\%)** & **(10\%)** & **(25\%)** & **(30\%)** & **(10\%)** & **Total Score** \\ \hline
70 \({}^{\circ}\)C & 86.16 \(\pm\) 0.06 \({}^{\circ}\) & 90.55 \(\pm\) 0.07 \({}^{\mathrm{b}}\) & 90.75 \(\pm\) 0.35 \({}^{\mathrm{c}}\) & 90.77 \(\pm\) 0.25 \({}^{\mathrm{c}}\) & 88.25 \(\pm\) 0.35 \({}^{\mathrm{a}}\) & 89.34 \(\pm\) 0.20 \({}^{\mathrm{c}}\) \\
80 \({}^{\circ}\)C & 86.56 \(\pm\) 0.08 \({}^{\mathrm{b}}\) & 91.00 \(\pm\) 0.00 \({}^{\mathrm{a}}\) & 92.05 \(\pm\) 0.07 \({}^{\mathrm{b}}\) & 92.20 \(\pm\) 0.26 \({}^{\mathrm{a}}\) & 88.25 \(\pm\) 0.35 \({}^{\mathrm{a}}\) & 90.24 \(\pm\) 0.12 \({}^{\mathrm{ab}}\) \\
90 \({}^{\circ}\)C & 86.88 \(\pm\) 0.11 \({}^{\mathrm{a}}\) & 91.00 \(\pm\) 0.00 \({}^{\mathrm{a}}\) & 92.55 \(\pm\) 0.07 \({}^{\mathrm{a}}\) & 92.43 \(\pm\) 0.12 \({}^{\mathrm{a}}\) & 87.15 \(\pm\) 0.21 \({}^{\mathrm{b}}\) & 90.40 \(\pm\) 0.04 \({}^{\mathrm{a}}\) \\
100 \({}^{\circ}\)C & 86.54 \(\pm\) 0.03 \({}^{\mathrm{b}}\) & 90.65 \(\pm\) 0.21 \({}^{\mathrm{b}}\) & 92.55 \(\pm\) 0.07 \({}^{\mathrm{a}}\) & 92.20 \(\pm\) 0.26 \({}^{\mathrm{a}}\) & 86.25 \(\pm\) 0.35 \({}^{\mathrm{bc}}\) & 90.12 \(\pm\) 0.12 \({}^{\mathrm{ab}}\) \\
110 \({}^{\circ}\)C & 86.63 \(\pm\) 0.04 \({}^{\mathrm{b}}\) & 91.00 \(\pm\) 0.00 \({}^{\mathrm{a}}\) & 92.15 \(\pm\) 0.21 \({}^{\mathrm{ab}}\) & 91.77 \(\pm\) 0.25 \({}^{\mathrm{b}}\) & 86.25 \(\pm\) 0.35 \({}^{\mathrm{c}}\) & 89.95 \(\pm\) 0.16 \({}^{\mathrm{b}}\) \\
120 \({}^{\circ}\)C & 86.07 \(\pm\) 0.10 \({}^{\mathrm{c}}\) & 91.00 \(\pm\) 0.00 \({}^{\mathrm{a}}\) & 89.25 \(\pm\) 0.35 \({}^{\mathrm{d}}\) & 88.77 \(\pm\) 0.25 \({}^{\mathrm{d}}\) & 85.65 \(\pm\) 0.21 \({}^{\mathrm{d}}\) & 88.13 \(\pm\) 0.19 \({}^{\mathrm{d}}\) \\
130 \({}^{\circ}\)C & 85.61 \(\pm\) 0.07 \({}^{\mathrm{d}}\) & 90.10 \(\pm\) 0.14 \({}^{\mathrm{c}}\) & 88.25 \(\pm\) 0.35 \({}^{\mathrm{e}}\) & 87.17 \(\pm\) 0.29 \({}^{\mathrm{e}}\) & 85.25 \(\pm\) 0.35 \({}^{\mathrm{d}}\) & 87.15 \(\pm\) 0.23 \({}^{\mathrm{e}}\) \\ \hline \hline \end{tabular} Different lowercase letters in the same column indicate significant differences at \(p\) < 0.05.  
\end{table} 
Table 1: Effect of different drying temperatures on the sensory quality of Lithuan black tea. Figure 1: QDA radar chart of the aroma (**A**) and taste (**B**) of LBT at different drying temperatures. study, the content of soluble sugar was significantly higher in the low-temperature-dried samples versus the high-temperature-dried samples, with 110 \({}^{\circ}\)C observed as an inflection point. This may explain the reason for the decline in the sweetness scores during the sensory evaluation from 110 \({}^{\circ}\)C onwards. Free amino acids are the primary contributors to the umami taste of tea [22], and are significant in the umami taste of tea infusions. Soluble sugars and free amino acids contribute to the sweet and umami taste of tea infusions, respectively, playing a crucial role in the flavor profile of black tea. However, under high-temperature conditions, they undergo the Maillard reaction and then are degraded by Strecker degradation to form aldehydes, pyrazines, pyrroles, and melanin [19].