## 3 Results and Discussion
### Aluminum Content in the Tea Infusions  
Table 4 shows the results of determining the aluminum content in infusions of various teas without additives and infusions with juices and citric acid solutions. In infusions without additives, the aluminum content ranged from 1.08 to 6.46 mg/L, and the teas can be ranked with increasing aluminum content in the infusion as follows: pu-erh < white tea < black leaf tea < green tea <granulated black tea. Many factors influence the aluminum content in tea infusions, mainly the age of the leaves at the time of harvest, the genetic aspects of the plant, soil and atmospheric conditions, and the method of preparing the infusion. Based on numerous studies aimed at determining the aluminum content in tea extract, despite differences in extraction conditions, the determinations are similar and oscillate in the range of 1-6 mg/L [43]. The addition of quince juice did not cause a statistically significant increase in the aluminum content in the infusion in the case of pu-erh \begin{table}
\begin{tabular}{l c c c c c} \hline  & **White Tea** & **Black Granulated Tea** & **Black Leaf Tea** & **Pu-Erh** & **Green Tea** \\ \hline pH of infusions & & 5.6 \(\pm\) 0.02 a & 5.01 \(\pm\) 0.01 a & 5.02 \(\pm\) 0.01 a & 5.65 \(\pm\) 0.02 a & 5.51 \(\pm\) 0.01 a \\ without additives & & & & & \\ \hline pH of infusions with & & & & & \\ quince juice & 5.21 \(\pm\) 0.02 c & 4.8 \(\pm\) 0.01 b & 4.82 \(\pm\) 0.02 c & 5.32 \(\pm\) 0.02 c & 5.18 \(\pm\) 0.01 c \\ \hline pH of infusions & & & & & \\ with citric acid & 5.35 \(\pm\) 0.02 b & 4.77 \(\pm\) 0.02 c & 4.91 \(\pm\) 0.02 b & 5.41 \(\pm\) 0.02 b & 5.21 \(\pm\) 0.02 b \\ solution (quince) & & & & & \\ \hline pH of infusions with & & & & & \\ lemon juice & 3.65 \(\pm\) 0.02 f & 3.55 \(\pm\) 0.02 f & 3.57 \(\pm\) 0.02 e & 3.47 \(\pm\) 0.02 f & 3.54 \(\pm\) 0.02 f \\ \hline pH of infusions & & & & & \\ with citric acid & 3.63 \(\pm\) 0.01 f & 3.48 \(\pm\) 0.02 g & 3.58 \(\pm\) 0.01 e & 3.4 \(\pm\) 0.02 g & 3.47 \(\pm\) 0.02 g \\ solution (lemon) & & & & & \\ \hline pH of infusions with & & & & & \\ Japanese quince juice & 3.83 \(\pm\) 0.01 e & 3.74 \(\pm\) 0.04 e & 3.61 \(\pm\) 0.04 e & 3.81 \(\pm\) 0.03 e & 3.76 \(\pm\) 0.02 e \\ \hline pH of infusions with & & & & & \\ citric acid solution & 3.99 \(\pm\) 0.02 d & 4.03 \(\pm\) 0.01 d & 3.78 \(\pm\) 0.02 d & 3.91 \(\pm\) 0.02 d & 3.88 \(\pm\) 0.02 d \\ (Japanese quince) & & & & & \\ \hline \end{tabular}
\end{table} 
Table 3: Mean and SD pH values of tea infusions without additives and with additions of juices and citric acid solutions with the titratable acidity of the juices used. Values with different letters (a, b, c, etc.) in the same column are significantly different (\(p\) < 0.05), as determined using Duncan’s test. tea, black granulated tea, and loose-leaf tea. An increase in aluminum content was observed in white and green tea, 40.8% and 23.6%, respectively. The addition of citric acid with the acidity of quintee juice had a very similar effect on the aluminum content in the infusions. The main difference is the increase in aluminum content compared to infusions without the addition of 23.1% in the case of pu-erh tea and 70.4% in the case of white tea. It was also shown that there were no statistically significant differences between the aluminum content in the infusions of pu-erh tea, black loose leaf, and granulated tea and green tea with quintee juice and the corresponding citric acid solution. In the case of the influence of adding lemon and Japanese quintee juice and their corresponding citric acid solutions, significantly greater increases in aluminum content were found in the infusions of all types of teas compared to quintee juice. These increases ranged from 38.2% to 149.1% in relation to the initial aluminum content. It was also shown that there were no statistically significant differences in the aluminum content in infusions with these additions for white and green teas, and in the case of pu-erh and granulated black teas, these differences were minimal.