Revestimentos de gelatina extraídos de pele da tilápia (Oreochromis niloticus) enriquecidos com ácido ferúlico na qualidade de filés de atum (Thunnus albacares)

Abstract

The large population growth around the globe leads to a greater global demand for quality food supply, which aims to serve increasingly demanding consumers. This factor ends up putting pressure on food industries to constantly seek to develop new procedures, both to process, package, and market your products. The use of coatings can be an alternative for this market, as it helps extend the fish shelf life. In this context, the objective of the study was to develop edible coatings based on gelatin from tilapia (Oreochromis niloticus) skin, incorporating ferulic acid as an antioxidant substance and evaluating the shelf life of tuna fillets (Thunnus albacares) refrigerated at 1°C±0.4, regarding oxidative and microbiological aspects. The gelatin was extracted, characterized as to proximate composition, pH, gel strength, color, extraction yield, differential scanning calorimetry (DSC), thermogravimetry (TGA), infrared spectroscopy (FTIR) and contact angle, aiming at a better solution for coating fish, and subsequently applied in a concentration of 1.0% gelatin adding glycerol and 0.50% ferulic acid. The physicochemical analyzes of coated fillets showed a significant difference (p < 0.5) when compared to uncoated samples, for total volatile base nitrogen (N-BVT), trimethylamine nitrogen (N-TMA), reactive substances to thiobarbituric acid (SRAT), hydrogenion potential (PH), in the color parameter there was a tendency towards darkening of the fillets, but there was no significant difference between the treatments. Microbiological analyzes of the coated fillets showed positive results for the control of Escherichia coli, Staphylococcus aureus, Salmonella, histamine-producing bacteria and psychrotrophic bacteria counts remained at acceptable levels until the fifteenth day of storage. It was concluded that this gelatin coating with ferulic acid can be used to increase the shelf life of refrigerated tuna up to the fifteenth day, given the potential of its antioxidant and antibacterial properties observed in vitro in the present study.