## 3 Results and Discussion
### Chemical Composition
#### 3.1.3 Chemical Composition of Propolis
Among the contaminants, nickel was identified in the market propolis samples at 1.71 ppm, and cadmium at 0.24 ppm in the own hive propolis sample and 0.55 pp from the market, and lead was not detected in any sample studied. The propolis's tincture studied had a moisture content of 96.79%, an acidity of 15.87 mg/g, a pH of 2.925, and an impurity percentage of 0.09% (Table 5). Calcium was the best represented macroelement at 437.36 mg, followed by sodium 84.63 mg, magnesium 58.26 mg, potassium 17.85 mg, and phosphorus 7.88 mg. Zinc was the major microelement in the propolis's tincture that we analyzed, with a content of 4.14 mg, followed by manganese 2.74 mg, copper 2.22 mg, and iron 2.03 mg. Of the heavy metals analyzed, cadmium was identified at a concentration of 0.62 ppm, and nickel and lead were below the detection limit. The studies carried out so far have shown that there are correlations between the chemical composition of propolis and the plants used by bees for its production [17]. The type of soil and its parameters, the botanical origin of the samples, the geographical area, and the climatic conditions can determine differences in the mineral profile of propolis from different areas [49]. The mineral contents of the propolis's samples evaluated have values close to those reported by [PERSON] et al. [50] in the case of propolis's from Croatia, and [PERSON] et al. [49] for propolis's from Serbia, the order of macrominerals being Ca > K > Mg > P \begin{table}
\begin{tabular}{c c c c} \hline  & \multicolumn{2}{c}{**Fresh Propolis**} & \multicolumn{2}{c}{**Tincture of Propolis**} \\  & **Market** & **Own Apiary** & \\  & **Mean \(\pm\) SD** & **Mean \(\pm\) SD** & **Mean \(\pm\) SD** \\ \hline Water content (\%) & 0.66 \(\pm\) 0.010 a & 0.35 \(\pm\) 0.010 b & 96.79 \(\pm\) 0.188 b \\ \hline DM (\%) & 99.15 \(\pm\) 0.175 a & 98.47 \(\pm\) 1.051 a & 3.14 \(\pm\) 0.173 b \\ \hline Acidity & 5.95 \(\pm\) 0.010 a & 3.97 \(\pm\) 0.015 b & 15.87 \(\pm\) 0.031 b \\ \hline pH & 3.55 \(\pm\) 0.136 a & 3.92 \(\pm\) 0.020 b & 2.95 \(\pm\) 0.025 b \\ \hline Impurities (\%) & 12.40 \(\pm\) 0.791 a & 5.74 \(\pm\) 0.393 b & 0.09 \(\pm\) 0.015 b \\ \hline Ash (\%) & 0.94 \(\pm\) 0.010 a & 0.98 \(\pm\) 0.025 a & 0.93 \(\pm\) 0.015 a \\ \hline \multicolumn{4}{c}{Macroelements} \\ \hline Na & 103.29 \(\pm\) 7.636 a & 110.33 \(\pm\) 6.648 a & 84.63 \(\pm\) 4.956 a \\ \hline Ca & 840.40 \(\pm\) 12.537 a & 587.05 \(\pm\) 63.01 b & 437.36 \(\pm\) 18.915 a \\ \hline K & 97.34 \(\pm\) 26.467 a & 128.79 \(\pm\) 44.491 a & 17.85 \(\pm\) 3.068 a \\ \hline Mg & 144.24 \(\pm\) 15.711 a & 148.99 \(\pm\) 0.084 a & 58.26 \(\pm\) 4.617 b \\ \hline P & 132.00 \(\pm\) 46.669 a & 152.63 \(\pm\) 31.99 a & 7.88 \(\pm\) 3.005 b \\ \hline \multicolumn{4}{c}{Microelements} \\ \hline Fe & 54.58 \(\pm\) 19.183 a & 41.97 \(\pm\) 0.883 a & 2.03 \(\pm\) 0.473 b \\ \hline Mn & 4.91 \(\pm\) 0.650 a & 5.67 \(\pm\) 0.926 a & 2.74 \(\pm\) 0.176 b \\ \hline Cu & 3.13 \(\pm\) 1.506 a & 2.32 \(\pm\) 0.120 a & 2.22 \(\pm\) 0.148 a \\ \hline Zn & 15.85 \(\pm\) 6.533 a & 42.73 \(\pm\) 10.868 a & 4.14 \(\pm\) 2.418 a \\ \hline Cr & Undetectable & Undetectable & 0.49 \(\pm\) 0.692 \\ \hline \multicolumn{4}{c}{Contaminants} \\ \hline Ni & 1.71 \(\pm\) 0.876 a & Undetectable & Undetectable \\ \hline Cd & 0.55 \(\pm\) 0.212 a & 0.24 \(\pm\) 0.091 a & 0.62 \(\pm\) 0.176 a \\ \hline Pb & Undetectable & Undetectable & Undetectable \\ \hline \end{tabular} Results are expressed as the two-determination mean \(\pm\) standard deviation (SD). Different letters indicate statistically significant differences between samples in a row (\(p\) < 0.05) according to the Tukey test.  
\end{table} 
Table 5: Chemical composition of fresh propolis and tincture. \(>\) Na, while in the case of microelements, the largest share is occupied by iron, followed by zinc.