Pokeweed and black cumin in a polysaccharide-protein matrix as a means of extending the storage life of catfish (Clarias gariepinus)

In recent years, biopolymers have proved to be an excellent solution to preserve the shelf life of fish products, which are very susceptible to oxidation due to their high content of unsaturated fatty acids. The aim of this study was to evaluate the efficacy of biopolymers based on polysaccharides and proteins associated with plant substances (pokeweed and black cumin), to preserve the qualitative characteristics and extend the shelf life of catfish fillets. The fillets were packaged in biopolymers based on furcellan gel with the addition of substances such as pokeweed and black cumin protein. After that, the packaged fillets were stored at 4°C for 10 days, during which physicochemical (pH, color, storage loss), microbiological and sensory analyses were carried out to evaluate the evolution of the quality characteristics. The results showed that the use of biopolymers can preserve color and sensory aspect in the first days of storage. Significant differences were found between the control and coated samples that were shown to have a better odor, less surface patina formation, and less color change due to lipid oxidation. Films with pokeweed have released a purplish color on the fillets, due to the presence of anthocyanins, which has been positively evaluated. In addition, there were significant differences between the control and the coated samples that lost more water during storage. In fact, a disadvantage of biopolymers is the high solubility that absorbs a lot of water from the fillets. In addition, water makes it easier for biopolymers to grow microbially on the surface and decompose.