# Effects of Five Different Withering Methods on the Composition and Quality of Congou Black Tea
## 3 Results
### Impact of the Five Withering Methods on the Biochemical Components of Congou Black Tea  
Five different withering methods and their biochemical components are shown in Figure 1. Tea polyphenols is the general term for phenolic substances in tea leaves, and they are the key components with health benefits in tea [20]. Owing to their high content in water extracts, they have an important influence on the strength of tea infusion. The content of tea polyphenols in SNW was the highest at 17.22%, while the content in WAW was the lowest at 12.94%. There was no significant difference between SNW and SUW, but significant differences were observed among the other withering methods (\(p<0.05\)). Free amino acids are not only important factors in the quality of tea but also have excellent nutritional and medicinal functions. There are significant differences in the free amino acid content (\(p<0.05\)), with the highest content in the WAW treatment (3.67%) and the lowest in the SUW treatment (3.42%). Caffeine is an important characteristic substance in tea, with effects such as being refreshing, diuretic, and metabolism promotion. It mainly presents a bitter taste and can form hydrogen bonds with catechins to increase the freshness of the tea infusion and reduce its bitterness. Among the five types of withering methods, the WAM method had the highest caffeine content (5.16%), which was significantly different from that of the SUW and NAW methods (\(p<0.05\)). This may be related to the fresh and mellow taste of tea brewed via the WAM method. The total soluble sugars not only give the tea infusion a sweet and mellow taste [21] but are also related to the \"caramel aroma\" of the tea leaves. Among the five withering methods, there was a significant difference in the content of soluble sugars (\(p<0.05\)), with the highest content of 3.90% in the SUW treatment and the lowest content of 3.32% in the SHW treatment.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & **Appearance and Score** & **Liquor Color and Score** & **Aroma and Score** & **Taste and Score** & **Infused Leaf and Score** & \multirow{2}{*}{**Total Score**} \\  & **(25\%)** & **(10\%)** & **(25\%)** & **(30\%)** & **(10\%)** & \\ \hline \multirow{4}{*}{SHW} & The color of the tea is & & Floral and fruity, & & & \\  & dark brown with good & Red (\({}^{\ast}\)), bright & with a strong and & & & \\  & luster and golden hairs & 95.0 \(\pm\) 0.00 a & & persistent aroma & 95.9 \(\pm\) 0.92 a & 94.3 \(\pm\) 1.15 a \\  & 95.0 \(\pm\) 0.00 a & & & & & \\  & The color of the tea is & Orange-red, & Sweet aroma, & & & \\  & dark brown with luster & bright (\({}^{\ast}\)) & persistent (\({}^{\ast}\)) & bitterness (\({}^{\ast}\)) & & \\  & 94.0 \(\pm\) 0.00 ab & 94.3 \(\pm\) 0.66 ab & 91.4 \(\pm\) 0.42 b & 92.2 \(\pm\) 0.17 b & 93.7 \(\pm\) 1.15 a & \\  & The color of the tea is & & Sweet, floral (\({}^{\ast}\)), & & & \\  & dark brown with more & & & & \\  & golden hairs & 93.0 \(\pm\) 1.00 b & & & & \\  & 94.0 \(\pm\) 1.00 ab & & & & \\  & The color of the tea is & & & & & \\  & dark brown with luster & & & & \\  & and fewer golden hairs & 94.6 \(\pm\) 0.53 a & 91.8 \(\pm\) 0.59 b & 95.7 \(\pm\) 0.10 a & 93.7 \(\pm\) 1.15 a & \\  & The color of the tea is & & Sweet, floral (\({}^{\ast}\)), & & & \\  & dark brown with golden hairs & & & & \\  & 93.3 \(\pm\) 0.50 b & & & & \\  & 93.0 \(\pm\) 0.00 b & & & & \\ \hline \hline \end{tabular} Notes. The total score is 100 points: 25% represents the proportion of dry tea appearance; 10% represents the proportion of liquor color; 25% represents the proportion of aroma; 30% represents the proportion of taste; 10% represents the proportion of infused leaves. (\(-\)) means that this characteristic is present but slightly less intense; (\(+\)) means that this characteristic is present and slightly more intense; different letters for the same factor indicate a significant difference between groups (\(p<0.05\)).  
\end{table}
Table 1: Sensory evaluation results of black tea with different withering methods.