## 3 Results
### Antioxidant Activity  
The antioxidant potential of the nalewkas measured by the DPPH, ABTS, FRAP, and CUPRAC methods are presented in Tables 1-4. All the tested nalewkas showed antioxidant activity. However, this parameter differed depending on the type of nalewkas and production year. The antioxidant activity measured with the DPPH method ranged from 2.814 \(\pm\) 0.062 mg Trolox\(\cdot\)g\({}^{-1}\) for plum nalewka prepared in 1997 to 4.005 \(\pm\) 0.014 mg Trolox\(\cdot\)g\({}^{-1}\) for cherry nalewka prepared in 2018 (Table 1). Figure 3 presents a comparison of the antioxidant activity of all nalewkas in individual years, expressed as free radical scavenging activity, in %. Taking into account the individual nalewka in each year, the ability to scavene free radicals varied depending on the fruit used. The ability to scavene free radicals was high and ranged from 66.47 \(\pm\) 1.39 for plum nalewka (the year 1997) to 93.33 \(\pm\) 0.32% for cherry nalewka (the year 2018) (Figure 3). In the case ABTS technique, the antioxidant potential ranged from 2.597 \(\pm\) 0.422 mg Trolox\(\cdot\)g\({}^{-1}\) for cherry nalewka prepared in the year 1997 to 17.249 \(\pm\) 0.151 mg Trolox\(\cdot\)g\({}^{-1}\) for cherry nalewka prepared in the 2018 year (Table 2). It should be added that for younger nalewkas higher antioxidant activity was found for cherry and plum nalewkas produced between 2016 and 2019, whereas for ratidia only for this produced in 2019. A similar trend was also observed for the FRAP method, in which the ability to reduce ferric ions ranged from 5.870 \(\pm\) 0.117 mg FeSO\({}_{4}\cdot\)g\({}^{-1}\) for cherry nalewka prepared in 1997 to 17.547 \(\pm\) 0.069 mg FeSO\({}_{4}\cdot\)g\({}^{-1}\) for cherry nalewka prepared in 2018. In general, the oldest nalewka, produced in 1997, showed a \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Year of Production** & **Ratafia** & **Cherry** & **Plum** \\ \hline
1997 & 3.145 \(\pm\) 0.015 a & 2.974 \(\pm\) 0.012 a & 2.814 \(\pm\) 0.062 a \\
2013 & 3.484 \(\pm\) 0.162 b & 3.126 \(\pm\) 0.188 a,b & 3.677 \(\pm\) 0.080 d,e \\
2014 & 3.257 \(\pm\) 0.013 a & 3.329 \(\pm\) 0.044 b & 3.353 \(\pm\) 0.052 b \\
2015 & 3.248 \(\pm\) 0.040 a & 3.270 \(\pm\) 0.093 b & 3.518 \(\pm\) 0.053 c \\
2016 & 3.189 \(\pm\) 0.085 a & 3.024 \(\pm\) 0.021 a & 3.527 \(\pm\) 0.041 c,d \\
2017 & 3.791 \(\pm\) 0.016 c & 3.684 \(\pm\) 0.007 c & 3.751 \(\pm\) 0.012 f \\
2018 & 3.816 \(\pm\) 0.039 c & 4.005 \(\pm\) 0.014 d & 3.706 \(\pm\) 0.010 f \\
2019 & 3.878 \(\pm\) 0.017 c & 4.004 \(\pm\) 0.009 d & 3.772 \(\pm\) 0.071 f \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The antioxidant activity of nalewkas was measured by the DPPH method (mean \(\pm\) SD, n = 3). Different letters indicate significant differences between the individual years. The result was expressed in mg Trolox:g\({}^{-1}\) of nalewka. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Year of Production** & **Ratafia** & **Cherry** & **Plum** \\ \hline
1997 & 9.342 \(\pm\) 0.139 a & 2.597 \(\pm\) 0.422 a & 2.560 \(\pm\) 0.549 a \\
2013 & 11.672 \(\pm\) 1.308 a & 7.550 \(\pm\) 0.705 b & 5.270 \(\pm\) 0.433 a \\
2014 & 9.912 \(\pm\) 0.122 a & 6.806 \(\pm\) 0.817 c & 3.122 \(\pm\) 0.102 a \\
2015 & 10.578 \(\pm\) 0.381 a & 5.275 \(\pm\) 1.220 b,c & 14.231 \(\pm\) 0.340 c \\
2016 & 9.771 \(\pm\) 0.274 a & 15.725 \(\pm\) 0.374 d,e & 11.598 \(\pm\) 0.508 b \\
2017 & 12.486 \(\pm\) 0.359 a & 16.554 \(\pm\) 0.335 de & 17.293 \(\pm\) 0.084 d \\
2018 & 11.850 \(\pm\) 0.155 a & 17.249 \(\pm\) 0.151 e & 16.406 \(\pm\) 0.378 d \\
2019 & 16.420 \(\pm\) 4.226 b & 15.474 \(\pm\) 0.090 d & 17.093 \(\pm\) 0.371 d \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The antioxidant activity of nalewkas was measured by the ABTS method (mean \(\pm\) SD, n = 3). Different letters indicate significant differences between the individual years. The result was expressed in mg Trolox:g\({}^{-1}\) of nalewka.