## 3 Results and Discussion
According to the studies by other authors, during the aging process of garlic, the profile of organosulphuric metabolites changes significantly with regard to their share and mutual proportions. Allicin, unstable at high temperatures and responsible for the sharp, typical taste of garlic, is converted into other organosulphuric metabolites, giving black garlic the unique taste and aroma [110]. The content of volatile compounds responsible for the unpleasant taste and aroma of garlic is significantly reduced. In addition, other metabolites (not detected in fresh garlic) are formed, in particular furfural derivatives, such as 2-acetylfuran or 5-methylfurfural, which contribute to the characteristic sweet taste of black garlic and eliminate its sharp and unpleasant taste [108; 109; 110]. In the literature the increase in the antioxidant capacity of black garlic is also explained by the increasing level of the Maillard reactions products formed during the heat treatment process. These products determine the characteristic black colour of garlic [68; 78; 79; 95; 111; 112]. Therefore, in this study an instrumental measurements of the colour of white (unprocessed) and black garlic from both conventional and organic cultivation systems were performed. Colour parameters in \(L^{*}a^{*}b^{*}\) and RGB space obtained using the instrumental method (\"electronic eye\") in white and black, conventional and organic garlic are shown in Table 3.  
Significant differences (\(p<0.05\)) were found between the colour of both white and black garlic (subjected to long-term heat treatment), both organic and conventional. The samples differed in colour parameters taking into account both the \(L^{*}a^{*}b^{*}\) and RGB colour space. When comparing the colour of white vs. black garlic samples, significant differences (\(p<0.05\)) can be noticed, especially in the case of the \(L^{*}\) parameter. The white garlic samples (83.85 \(\pm\) 0.31 for G and 82.25 \(\pm\) 2.04 for EG samples) had much higher \(L^{*}\) values, which means that the samples were much lighter than the black ones (25.42 \(\pm\) 0.03 for BG and 18.92 \(\pm\) 1.03 for EBG samples). The \(a^{*}\) and \(b^{*}\) colour parameters in the \(L^{*}a^{*}b^{*}\) system, referring to the tones of red and yellow were characterised with significant differences (\(p<0.05\)) in white and black garlic samples. The \(b^{*}\) parameter values determined for white garlic samples (6.43 \(\pm\) 0.12 and 7.36 \(\pm\) 0.88 respectively for conventional and organic samples) were also significantly (\(p<0.05\)) higher compared to black one (5.04 \(\pm\) 0.89 \begin{table}
\begin{tabular}{c c c c c} \hline
**Colour Parameters** & **G** & **EG** & **BG** & **EBG** \\ \hline \(L^{*}\) (lightness) the line & \multirow{2}{*}{83.85 \(\pm\) 0.31 d  } & 81.25 \(\pm\) 2.04 c  & 25.42 \(\pm\) 0.03 b  & 18.92 \(\pm\) 1.03 a  \\ \hline \(a^{*}\) (redness) & 3.52 \(\pm\) 0.36 a  & 3.58 \(\pm\) 0.05 a  & 6.15 \(\pm\) 0.71 b  & 6.26 \(\pm\) 0.08 b  \\ \hline \(b^{*}\) (yellowness) & 6.43 \(\pm\) 0.12 c  & 7.36 \(\pm\) 0.88 c  & 5.04 \(\pm\) 0.89 b  & 2.86 \(\pm\) 0.02 a  \\ \hline R (redness) & 219.72 \(\pm\) 1.59 c  & 213.05 \(\pm\) 6.13 c  & 69.84 \(\pm\) 4.52 b  & 58.52 \(\pm\) 4.86 a  \\ \hline G (greenness) & 206.64 \(\pm\) 0.61 d  & 199.41 \(\pm\) 5.61 c  & 57.38 \(\pm\) 1.10 b  & 42.60 \(\pm\) 2.20 a  \\ \hline B (blueness) & 197.19 \(\pm\) 0.63 c  & 188.32 \(\pm\) 3.92 c  & 52.13 \(\pm\) 8.08 b  & 42.91 \(\pm\) 3.02 a  \\ \hline \end{tabular}
\end{table} 
Table 3: Colour parameters in \(L^{*}a^{*}b^{*}\) and RGB space obtained using the instrumental method (“electronic eye”) in white and black, conventional and organic garlic. and 2.86 \(\pm\) 0.02, respectively, for conventional and organic samples), which means the white garlic samples had a greater colour shift towards yellow. The values of parameter \(a^{*}\) determined for black garlic (about 6.20 for G and EG samples) were significant (\(p\) < 0.05) higher compared to the white one (about 3.5).