## 3 Results and Discussion
### The Changes in Bioactive Compounds and Antioxidant Activity
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Sample \({}^{\ast}\)**} & \multicolumn{8}{c}{**Time of Storage (Days)**} \\ \cline{2-7}  & **Unfermented** & **1** & **5** & **7** & **14** & **21** & **28** \\ \hline \multicolumn{7}{c}{L \({}^{\ast}\)} \\ CPC-15\% & 55.11 \(\pm\) 0.01 \({}^{\text{Aa}}\) & 55.65 \(\pm\) 0.01 \({}^{\text{Ba}}\) & 57.15 \(\pm\) 0.02 \({}^{\text{Ca}}\) & 56.51 \(\pm\) 0.03 \({}^{\text{Da}}\) & 56.60 \(\pm\) 0.01 \({}^{\text{Ba}}\) & 55.46 \(\pm\) 0.01 \({}^{\text{Fa}}\) & 55.27 \(\pm\) 0.01 \({}^{\text{Ca}}\) \\ \hline CPC-20\% & 53.32 \(\pm\) 0.00 \({}^{\text{Ab}}\) & 53.26 \(\pm\) 0.00 \({}^{\text{Bb}}\) & 51.07 \(\pm\) 0.01 \({}^{\text{Cb}}\) & 53.51 \(\pm\) 0.01 \({}^{\text{DB}}\) & 51.48 \(\pm\) 0.01 \({}^{\text{EB}}\) & 52.96 \(\pm\) 0.02 \({}^{\text{Bb}}\) & 52.47 \(\pm\) 0.01 \({}^{\text{CB}}\) \\ \hline \multicolumn{7}{c}{a \({}^{\ast}\)} \\ CPC-15\% & 7.74 \(\pm\) 0.01 \({}^{\text{Aa}}\) & 6.83 \(\pm\) 0.02 \({}^{\text{Ba}}\) & 6.81 \(\pm\) 0.01 \({}^{\text{Ba}}\) & 6.59 \(\pm\) 0.01 \({}^{\text{Ca}}\) & 6.59 \(\pm\) 0.01 \({}^{\text{Ca}}\) & 6.40 \(\pm\) 0.01 \({}^{\text{Da}}\) & 6.68 \(\pm\) 0.02 \({}^{\text{Ba}}\) \\ CPC-20\% & 8.07 \(\pm\) 0.01 \({}^{\text{Ab}}\) & 7.48 \(\pm\) 0.01 \({}^{\text{Bb}}\) & 7.11 \(\pm\) 0.01 \({}^{\text{Cb}}\) & 7.30 \(\pm\) 0.01 \({}^{\text{DB}}\) & 7.17 \(\pm\) 0.01 \({}^{\text{EB}}\) & 7.08 \(\pm\) 0.01 \({}^{\text{Pb}}\) & 7.49 \(\pm\) 0.01 \({}^{\text{Bb}}\) \\ \hline \multicolumn{7}{c}{b \({}^{\ast}\)} \\ CPC-15\% & 25.50 \(\pm\) 0.02 \({}^{\text{Aa}}\) & 25.61 \(\pm\) 0.03 \({}^{\text{Ba}}\) & 27.35 \(\pm\) 0.04 \({}^{\text{Ca}}\) & 24.44 \(\pm\) 0.01 \({}^{\text{Da}}\) & 26.30 \(\pm\) 0.03 \({}^{\text{Ba}}\) & 24.34 \(\pm\) 0.04 \({}^{\text{Fa}}\) & 25.41 \(\pm\) 0.02 \({}^{\text{Ca}}\) \\ CPC-20\% & 24.56 \(\pm\) 0.00 \({}^{\text{Ab}}\) & 24.16 \(\pm\) 0.01 \({}^{\text{Bb}}\) & 23.22 \(\pm\) 0.02 \({}^{\text{Cb}}\) & 24.90 \(\pm\) 0.04 \({}^{\text{DB}}\) & 23.61 \(\pm\) 0.03 \({}^{\text{EB}}\) & 24.35 \(\pm\) 0.01 \({}^{\text{Pb}}\) & 24.75 \(\pm\) 0.03 \({}^{\text{CB}}\) \\ \hline \multicolumn{7}{c}{\(\Delta\)E} \\ CPC-15\% & \
\begin{tabular}{c} Used as a standard \\ \end{tabular} & 1.00 \(\pm\) 0.01 \({}^{\text{Aa}}\) & 1.78 \(\pm\) 0.02 \({}^{\text{Ba}}\) & 2.08 \(\pm\) 0.10 \({}^{\text{Ca}}\) & 4.55 \(\pm\) 0.01 \({}^{\text{Da}}\) & 2.46 \(\pm\) 0.02 \({}^{\text{Ba}}\) & 1.11 \(\pm\) 0.01 \({}^{\text{Fa}}\) \\ CPC-20\% &
\begin{tabular}{c} Used as a standard \\ \end{tabular} & 0.87 \(\pm\) 0.01 \({}^{\text{Ab}}\) & 2.71 \(\pm\) 0.02 \({}^{\text{Rb}}\) & 0.54 \(\pm\) 0.04 \({}^{\text{Cb}}\) & 2.27 \(\pm\) 0.03 \({}^{\text{DB}}\) & 1.56 \(\pm\) 0.02 \({}^{\text{EB}}\) & 0.93 \(\pm\) 0.03 \({}^{\text{Pb}}\) \\ \hline \multicolumn{7}{c}{\({}^{\ast}\) CPC-15\%—sample with 15\% _(w/w)_ camelia press cake content, CPC-20\%—sample with 20% _(w/w)_ camelia press cake content; values are means \(\pm\) standard deviation of triplicate determinations. Means with different lowercase in the same column are significantly different at \(p<0.05\). Means with different uppercase in the same row are significantly different at \(p<0.05\). \\ \end{tabular}
\end{table} 
Table 2: Color parameters and total color difference (\(\Delta\)E) of samples during the storage time. Several studies reported good antioxidant activity of CPC extracts [3,7,10]. Performed tests revealed that, in general, antioxidant activity markedly increased as a result of fermentation (\(p<0.05\)). The highest activity against ABTS radical (59.03 \(\pm\) 4.27%) was noticed for sample CPC-20% on day 7, whereas the highest DPPH inhibition (62.59 \(\pm\) 5.33%) was found for sample CPC-15% on day 14. This observation is consistent with studies showing that fermented plant-based foods contained significantly more antioxidants than non-fermented raw materials [6,8,19,20]. Interestingly, only slight changes in DPPH radical scavenging activity after fermentation were observed for both variants (\(p<0.05\)).