# The Effect of Brewing Time on the Antioxidant Activity of Tea Infusions
## 3 Results
### Dpph  
A linear growth (\(p<0.05\)) of the capacity of DPPH to free radicals away with the extended brewing time was only found in green tea bags infusions (Figure 1e). In green leaf tea and black tea bag infusions, a significant increase in DPPH capacity to free radicals away was only recorded after 15 min of brewing. In the black leaf tea infusion, DPPH activity after ten minutes of brewing increased (\(p<0.05\)) more than after five minutes of brewing; however, after fifteen minutes, the capacity of DPPH to free radicals away significantly decreased compared to the level reported after five and ten minutes of brewing. In the red tea bags infusion, the DPPH capacity to free radicals away was significantly lower after fifteen minutes of brewing compared with that after five and ten minutes, but ten minute brewing time had no significant effect on DPPH capacity to free radicals away compared to five minutes. In the white tea bags and hibiscus flower tea infusions, the capacity of DPPH to free radicals away was significantly lower after 10 and 15 min of brewing compared with that after 5 min, but no difference (\(p<0.05\)) was identified between 10 and 15 min. No significant effect of brewing time on DPPH capacity to free radicals away was found in yerba mate, raspberry tea, butterfly pea flower tea and white lychee plum tea infusions. The Effect of Brewing Time of Particular Types of Tea on Changes in the Anti-oxidant Content of Tea Infusions  
Table 2 illustrates changes in the values of TPC, anthocyanins and flavonoids content and the capacity of ABTS and DPPH to free radicals away after ten minutes of brewing compared with five minutes, and after fifteen minutes of brewing compared with ten minutes. It should be noted that a positive effect of extended brewing time on the anti-oxidant activity (TPC, flavonoids and anthocyanins content, and capacity of ABTS and DPPH to free radicals away) of infusions was observed for green tea bags only. The best effects were noted down after 15 min of brewing. Also, the raspberry tea infusion showed the best effects after 15 min of brewing for TPC and anthocyanins content, and capacity of ABTS to free radicals away. Only for DPPH and anthocyanins, no effect of brewing time was reported. In the white lychee plum tea infusion, the TPC and the flavonoid content were the highest after 15 min of brewing, while the total antioxidant capacity of these teas (capacity of ABTS to free radicals away) and the anthocyanins content did not change after 15 min. Therefore, it should be assumed that 15 min is the best brewing time for white lychee plum tea. Similarly, results for yerba mate and white tea bags were the best after 15 min of brewing. The best brewing time for butterfly pea flower tea is 15 min because, after such an amount of time, the flavonoid content of the infusion increased and the content of other examined antioxidants did not change with longer brewing time. After 15 min of  
\begin{table}
\begin{tabular}{l c c c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**ATPC**} & \multicolumn{3}{c}{**\(\Delta\)Flavonoids**} & \multicolumn{3}{c}{**\(\Delta\)Anthocyanins**} & \multicolumn{3}{c}{**\(\Delta\)ABTS**} & \multicolumn{3}{c}{**\(\Delta\)DPPH**} \\ \cline{2-13}
**Tea** & **10 min** * & **15 min**  
brewing black tea bags, the flavonoid content and the capacity of DPPH to free radicals away in the infusion were the highest, whereas the content of other examined components did not change compared with the 10 min brewing time. Black leaf tea brewing time should also be 15 min, as this interval alters the flavonoid and anthocyanins levels of the infusion, although the capacity of DPPH to free radicals away simultaneously declines (by 21%) compared with the a 10 min brewing time. Green leaf tea infusion after 15 min of brewing revealed an increase in TPC and the capacity to sweep DPPH away, but also a decrease in the flavonoid content (by 113%) compared with the results after 10 min of brewing. Thus, ten minutes should be considered the optimum brewing time.