Fish burger enriched by olive oil industrial by-product.

Oil industry produces large volume of waste, which represents a disposal and a potential environmental pollution problem. Nevertheless, they are also promising sources of compounds that can be recovered and used as valuable substances. The aim of this work is to exploit solid olive by-products, in particular dry olive paste flour (DOPF) coming from cultivar, to enrich fish burger and enhance the quality characteristics. In particular, the addition of olive by-products leads to an increase of the phenolic content and the antioxidant activity; however, it also provokes a deterioration of sensory quality. Therefore, to balance quality and sensory characteristics of fish burgers, three subsequent phases have been carried out: first, the quality of DOPF in terms of phenolic compounds content and antioxidant activity has been assessed; afterward, DOPF has been properly added to fish burgers and, finally, the formulation of the enriched fish burgers has been optimized in order to improve the sensory quality. Results suggested that the enriched burgers with 10% DOPF showed considerable amounts of polyphenols and antioxidant activity, even though they are not very acceptable from the sensory point of view. Pre-treating DOPF by hydration/extraction with milk, significantly improved the burger sensory quality by reducing the concentration of bitter components.