## 4 Conclusions  
The addition of _Spirulina_ seems to be a promising technological alternative for producing fish products, such as burgers made from carp and barbel, because the natural and healthy image of these products, by the consumers, could be improved. Besides its role as a nutritional component, _Spirulina_ serves as suitable source of beneficial natural antioxidant and coloring agents. Furthermore, _Spirulina_, rich in dietary fibers, plays a central role in the textural maintenance of the final fish products by improving their functional properties (water and oil holding capacities). According to these results, the addition of 1% of _Spirulina_ in fish burger canning can be recommended since _Spirulina_ is as a natural source of bioactive compounds noting (chlorophylls, carotenoids and phycocyanin). Therefore, the evaluated microalga might be an effective alternative to fortification with synthetic chemical supplements that can cause undesirable effects for consumers. The reasonable selection of _Spirulina_ as a fortifier agent in fish-based products seems to be substantial and it provides food that is both satisfying to the consumer and beneficial to their health.  
[PERSON], A.B.A., F.H. and M.D. carried out the production of fish burgers and their analysis. [PERSON] carried out the statistical analysis. [PERSON], I.F. and S.A. participated in the design of the study. [PERSON], I.F., M.A.A., P.M. and S.A. conceived the study, and participated in its design and coordination and helped to draft the manuscript. All authors read and approved the final manuscript.  
The study was supported by the Tunisian Ministry of Higher Education and Scientific Research. The funders had no role in study design, data collection and analysis, decision to publish and preparation of the manuscript.  
The authors confirm that they have no conflicts of interest with respect to the study described in this manuscript.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Color Parameters** & **Fish Burger Types** & **Burger Formulations** \\ \hline \hline \multirow{4}{*}{**Chlorophylls** (mg/100g DW)} & \multirow{2}{*}{CB} & 0 & 23.93 \(\pm\) 1.675 \({}^{\text{a}}\) \\ \cline{2-4}  & & BB & 0 & 20.05 \(\pm\) 1.97 \({}^{\text{a}}\) \\ \cline{2-4}  & & CB & 0 & 0.431 \(\pm\) 0.033 \({}^{\text{a}}\) \\ \cline{2-4}  & & BB & 0 & 0.446 \(\pm\) 0.199 \({}^{\text{a}}\) \\ \hline \multirow{4}{*}{**Carotenoids** (mg/100g DW)} & \multirow{2}{*}{CB} & 0 & 12.39 \(\pm\) 0.657 \({}^{\text{a}}\) \\ \cline{2-4}  & & BB & 0 & 14.06 \(\pm\) 0.848 \({}^{\text{a}}\) \\ \hline \multirow{4}{*}{**Scavenging activity (\%) \({}^{\text{*}}\)**} & \multirow{2}{*}{CB} & 56.28 & 86.76 \({}^{\text{a}}\) \\ \cline{2-4}  & & BB & 40.09 & 94.09 \({}^{\text{a}}\) \\ \hline \multirow{4}{*}{**Reducing power \({}^{\text{*}}\)**} & \multirow{2}{*}{CB} & 0.315 & 0.615 \({}^{\text{a}}\) \\ \cline{2-4}  & & BB & 0.410 & 0.584 \({}^{\text{a}}\) \\ \hline \hline \end{tabular} CB: carp burgers; BB: barbel burgers; Control burgers \({}^{\text{*}}\). _Spirulina_-fortified burgers: \({}^{\text{a}}\)\(p<\) 0.001; \({}^{\text{*}}\) The scavenging activity of DPPH free radicals (%) and the reducing power (absorbance at 700 nm) were determined at a samples concentration of 10 mg/ml.  
\end{table}
Table 6: Pigments content and antioxidant activities of control and 1% _Spirulina_-fortified burgers.