Shelf life extension of refrigerated breaded hake medallions packed into active edible fish gelatin films

Abstract

Fish consumption has increased in recent years. However, fish meat is highly perishable, which demonstrates the need for technologies to preserve its quality. Edible films might provide an alternative to extend the shelf life of fish. The goal of this study was to evaluate the efficiency of edible fish gelatin films added with carvacrol (blended: FG-0.6CRV and grafted: FG/CRV-g-FG) on the quality retention of commercially available prefried breaded hake medallions (BHMs). Samples of BHM were wrapped into films, heat sealed, and stored at −4 ± 1 °C for 49 days. Free carvacrol gelatin films and the unwrapped medallions were used as controls. After predetermined periods of time, samples were analysed in terms of microbiological and physicochemical properties. Overall the storage period, the total volatile basic nitrogen value (TVBN) and the total psychrotrophic bacteria counts (TPC) were significantly lesser in BHM wrapped in FG-0.6CRV than in the other samples. The total oxidation index (TOI), peroxide value (PV), and p-anisidine value (AV) were reduced by 18%, 30%, and 16%, respectively, compared with controls. FG/CRV-g-FG film was not efficient to reduce the microbial spoilage or the oxidation, probably due to the retention of CRV into the matrix avoiding its migration towards the foodstuff, proving the importance of checking the films functionality in real food systems. Sensory evaluation of fried samples wrapped in FG-0.6CRV was also performed. The results indicate that the medallions can be directly cooked and consumed without removing the packaging with a good acceptance by the consumer.