## 3 Results and Discussion
### Colour Parameters of Extracts in the CIEL\"a*b* System
 } & \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 & 0.177 \(\pm\) 0.110 & 0.074 \(\pm\) 0.070 & 0.198 \(\pm\) 0.007 & 1.207 \(\pm\) 0.150 & 19.444 \(\pm\) 1.250 & 0.035 \(\pm\) 0.090 \\ \cline{2-8}  & Gala & 0.169 \(\pm\) 0.015 & 0.074 \(\pm\) 0.090 & 0.224 \(\pm\) 0.100 & 1.078 \(\pm\) 0.015 & 17.616 \(\pm\) 2.  
colour had the greatest influence on the colour saturation of the tested extracts. Indeed, the extracts prepared using the SSE method had the most intense colour, and the extracts prepared using the ASE method had the least intense colour. The h\({}^{\text{o}}\) parameter for the latter had the highest value (102.2\({}^{\circ}\)), which indicates that their colour was visibly yellow-green, while the extracts made using the UAE and SSE methods were yellow. Also, in the case of extracts obtained from different cultivars of apple leaves, the extracts were characterised by high brightness. The values of the L\({}^{*}\) colour parameter were significantly the highest (93) in extracts obtained from the leaves of the Ligol cultivar (Figure 6). The colour parameter a\({}^{*}\), in the case of all cultivars of apple leaves, had negative values, so the colour of the extracts tended to be green. Extracts obtained from the leaves of the Ligol cultivar were significantly the greenest (\(-\)4.1), while extracts obtained from the leaves of the Gala cultivar were significantly the least green (\(-\)1.3). The b\({}^{*}\) parameter had positive values, so the colour of all extracts tended to be yellow. The extracts obtained from the Gala cultivar were significantly yellowest (52.4) and were characterised by the significantly highest colour intensity. Extracts obtained from leaves of the Gloster cultivar (49) were significantly less yellow but much more yellow than extracts made from the leaves of the Ligol cultivar (43.3). Also, the colour intensity of extracts from the leaves of the Gloster cultivar was significantly higher than that of the extracts from the leaves of the Ligol cultivar. The significantly highest value of the h\({}^{\text{o}}\) parameter was recorded for extracts from the leaves of the Ligol cultivar (98.2\({}^{\circ}\)). Extracts from all leaf cultivars were described by this parameter as yellow, but there were significant differences between them, and leaf extracts from the Ligol cultivar tended to be yellow-green. Figure 5: Values of colour parameters in extracts made using various extraction methods. Also, in the case of extracts made using various solvents, high values of the L* colour parameter were obtained. Water extracts had the significantly highest brightness (93.5), while water-ethanol extracts had the significantly lowest brightness (90.9) (Figure 7). The colour parameter a*, in the case of water and water-methanol extracts, had negative values, so their colour tended to be green. In fact, the extracts were the greenest water-methanol extracts (\(-\)8.7), while water extracts were significantly less green (\(-\)1.3). The value of the a* parameter for water-ethanol extracts was 1.7, which means that the colour of these extracts tends to be red. Also, the values of the colour parameters b* and C* in water-ethanol extracts had the significantly highest values (61.5 and 61.6), so they were characterised by the highest yellow intensity. Significantly, the lowest intensity of yellow colour was recorded in water and methanol extracts. The values of the h\({}^{\text{o}}\) parameter differed significantly between extracts made using different solvents. All extracts can be described as yellow; however, the water-methanol extracts are definitely more yellow-green and the water-ethanol extracts yellow-red. The differences in the colour of extracts obtained using different solvents were probably mainly influenced by coloured compounds soluble in a given extractant.