## 3 Results and Discussion
### Antioxidant Properties of Fish Burgers  
Currently, much recent interest has been given to the considerable part of the enriched foods with bioactive substances, usually derived from plants, seaweeds and microalgae thanks to their safety and efficiency in the cure of different human disorders. In fact, the antioxidant activity of microalgae resulted from their abundance in enzymatic and non-enzymatic free radical scavengers. Thus, to estimate the input of _Spirulina_ to the burger antioxidant capacities, two different methods were used: the FRAP and the DPPH free radical-scavenging assays. The results of these methods are summarized in Table 6.  
Compared to the control burgers, the addition of _Spirulina_ in burgers increased significantly their antioxidant activities (\(p<0.001\)) as well as their chlorophyll (\(p<0.001\)), carotenoid (\(p<0.001\)) and phycocyanin (\(p<0.001\)) contents (Table 6). Furthermore, a positive correlation between antioxidant activity and pigment contents was clearly noticed. At a sample concentration of 10 mg/ml, carp and barbel burgers containing 1% of _Spirulina_ showed significantly higher DPPH scavenging activities (86.76 and 94.09%, respectively) than control burgers (56.28 and 40.09%) (\(p<0.001\)) (Table 6). Furthermore, a comparable trend was also noticed for FRAP. In fact, the ferric reducing activities for unfortified and fortified carp burgers with 1% of _Spirulina_, were equal to 0.31 and 0.651 (\(p<0.001\)) respectively, at a sample concentration of 10 mg/ml (Table 6). Similarly, significant differences (\(p<0.001\)) were also found for barbel formulations between 1% _Spirulina_-fortified samples and controls (Table 6). The rise in scavenging of free radicals may be attributed to the increase in the carotenoids [48; 49], chlorophylls [50], phycocyanin [51; 52] and polysaccharides [45] contents, which had an important role in the protection of the body's cells from oxidative stress and many other diseases. In this sense,  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Color Parameters** & **Fish Burger Types** & \multicolumn{2}{c}{**Burger Formulations**} \\ \hline  & & Control burger & 1\% _Spirulina_ fish burger \\ \hline \multirow{3}{*}{L*} & CB & 46.75 \(\pm\) 0.335 & 40.23 \(\pm\) 0.961 \({}^{\text{a}}\) \\ \cline{2-4}  & BB & 40.6 \(\pm\) 0.07 & 33.27 \(\pm\) 0.530 \({}^{\text{a}}\) \\ \hline \multirow{3}{*}{a*} & CB & 10.65 \(\pm\) 0.22 & 6.23 \(\pm\) 0.084 \({}^{\text{a}}\) \\ \cline{2-4}  & BB & 8.18 \(\pm\) 0.084 & 5.2 \(\pm\) 0.098 \({}^{\text{a}}\) \\ \hline \multirow{3}{*}{b*} & CB & 11.39 \(\pm\) 0.715 & 7.77 \(\pm\) 0.692 \({}^{\text{a}}\) \\ \cline{2-4}  & BB & 18.11 \(\pm\) 0.664 & 5.73 \(\pm\) 0.001 \({}^{\text{a}}\) \\ \hline \hline \end{tabular} CB: carp burgers; BB: barbel burgers; Control burgers rs _Spirulina_-fortified burgers: \({}^{\text{a}}\)\(p<0.001\).  
\end{table}
Table 5: Color analysis of control burgers and _Spirulina_-fortified burgers.  
the immunina polysaccharides from _Spirulina_ improve the enzymatic activity of the cell nucleus and synthesis of DNA repair, besides being a beneficial species for the immune system [53; 54]. Further, these polysaccharides were showed to have high scavenging activities against superoxide and hydroxyl radicals and moderate reductive power in a concentration-dependent manner [11; 46; 55]. These results also showed that fish burger processing did not have a negative effect on the antioxidant components.