## 3 Results and Discussion
### Colour Parameters of Extracts in the CIEL\"a*b* System  
Both the extraction method, the cultivar of apple leaves and the type of solvent used had a significant impact on the values of the colour parameters (L*, a*, b*, C*, h\({}^{\circ}\)) of extracts prepared from freeze-dried apple leaves. The L* parameter in the tested extracts had high values, from 91 to 94.5, so the extracts were definitely light. The brightest were the extracts obtained using the accelerated extraction method using a solvent (ASE), while the extracts obtained using the SSE method, by shaking them with a solvent, had the significantly lowest brightness (Figure 5). The colour parameter a*, in the case of all extraction methods, had negative values, so the colour of the extracts tended to be green. Extracts obtained using the ASE method were significantly the greenest (\(-5\)), while extracts obtained using ultrasound-assisted extraction (UAE) were significantly the least green (\(-0.9\)). The b* parameter had positive values, so the colour of all extracts tended to be yellow. Extracts obtained using the SSE method were significantly the yellowest (66.3), and extracts obtained using the UAE method (56.2) were significantly less yellow, but much more yellow than extracts were obtained using the ASE method (22.3). The colour parameter C* had almost the same values as the b* parameter and was almost one hundred percent correlated with it (r = 0.9999), so the yellow \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{\begin{tabular}{c} **Type of** \\ **Solvent** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Apple** \\ **Cultivar** \\ \end{tabular} } & \multicolumn{6}{c}{**Content of Phenolic Compounds in Extracts (mg/1 g of DW)**} \\ \cline{3-8}  & & **Epicatechin** & **Rutin** & **Hyperoside** & **Isoquercitrin** & **Phloridin** & **Phloricin** \\ \hline \multirow{3}{*}{Water} & Ligol & 0.129 \(\pm\) 0.030 & 0.077 \(\pm\) 0.090 & 0.205 \(\pm\) 0.009 & 0.971 \(\pm\) 0.030 & 1.636 \(\pm\) 0.040 & 0.030 \(\pm\) 0.010 \\ \cline{2-8}  & Gala & 0.100 \(\pm\) 0.009 & 0.075 \(\pm\) 0.070 & 0.180 \(\pm\) 0.090 & 0.806 \(\pm\) 0.020 & ND & ND \\ \cline{2-8}  & Gloster & 0.122 \(\pm\) 0.009 & 0.080 \(\pm\) 0.009 & 0.195 \(\pm\) 0.080 & 0.665 \(\pm\) 0.040 & 0.320 \(\pm\) 0.045 & 0.005 \(\pm\) 0.000 \\ \hline \multirow{3}{*}{\
\begin{tabular}{c} Water- \\ methanol (20:80, \(v/v\)) \\ \end{tabular} } & Ligol & 0.680 \(\pm\) 0.009 & 0.082 \(\pm\) 0.009 & 0.271 \(\pm\) 0.090 & 2.588 \(\pm\) 0.080 & 105.00 \(\pm\) 2.500 & 3.149 \(\pm\) 0.090 \\ \cline{2-8}  & Gala & 0.511 \(\pm\) 0.009 & 0.085 \(\pm\) 0.007 & 0.305 \(\pm\) 0.009 & 2.886 \(\pm\) 0.090 & 87.867\(\pm\) 0.900 & 1.167 \(\pm\) 0.090 \\ \cline{2-8}  & Gloster & 0.480 \(\pm\) 0.200 & 0.077 \(\pm\) 0.010 & 0.286 \(\pm\) 0.090 & 2.596 \(\pm\) 0.150 & 72.002 \(\pm\) 0.700 & 1.939 \(\pm\) 0.070 \\ \hline \multirow{3}{*}{
\begin{tabular}{c} Water- \\ ethanol (60:40, \(v/v\)) \\ \end{tabular} } & Ligol & 0.275 \(\pm\) 0.110 & 0.079 \(\pm\) 0.009 & 0.280 \(\pm\) 0.090 & 2.493 \(\pm\) 0.120 & 51.979 \(\pm\) 0.500 & 1.995 \(\pm\) 0.090 \\ \cline{2-8}  & Gala & 0.332 \(\pm\) 0.090 & 0.069 \(\pm\) 0.040 & 0.272 \(\pm\) 0.010 & 2.745 \(\pm\) 0.090 & 26.222 \(\pm\) 0.300 & 0.550 \(\pm\) 0.110 \\ \cline{2-8}  & Gloster & 0.145 \(\pm\) 0.120 & 0.078 \(\pm\) 0.009 & 0.284 \(\pm\) 0.009 & 2.505 \(\pm\) 0.200 & 28.290 \(\pm\) 0.250 & 1.104 \(\pm\) 0.070 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Content of polyphenolic compounds identified with HPLC in apple leaf extracts obtained using UAE. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{\ \begin{tabular}{c} **Type of** \\ **Solvent** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Apple** \\ **Cultivar** \\ \end{tabular}