Bioactive potential and structural characterization of sulfated polysaccharides from Bullet tuna (Auxis Rochei) by-products.

The present study deals with the isolation of sulfated polysaccharides (Ps) from the Bullet tuna by-products (head, skin and bones). Results of chemical characterization revealed that Ps-bones showed the highest total sugar, uronic acid and sulfate group contents. Tuna extracted-Ps contained a mixture of neutral sugars, with high amounts of glucuronic and galacturonic acids and presented different molecular weights. The presence of sulfate groups in different Ps was confirmed by FTIR analysis. Interestingly, Ps-bones showed the highest antioxidant activity among all the extracted Ps. Moreover, results revealed that all polysaccharides displayed varying degrees of antibacterial activity. Ps-bones exhibited high and wide spectrum of activities, inhibiting the growth of all bacteria tested. Ps-bones incorporated during fillet cooking offered an excellent protection of fish fillet by avoiding pH change, color loss, lipid oxidation and spoilage. Overall, the results demonstrated that Ps could be potentially used as natural antioxidant and antibacterial agents.