Physicochemical, antioxidant and antibacterial properties of fish gelatin-based edible films enriched with orange peel pectin: Wrapping application

The physicochemical, thermal and mechanical properties of blood orange peel pectin (BOPP) film blended with fish gelatin (F-G), at different ratios, were investigated. BOPP was first, tested for its antioxidant capacity, monitored through the beta-carotene bleaching, DPPH radical-scavenging and reducing power activities. BOPP and gelatin blending was found to reduce the wettability of the gelatin film, whereas it slightly reduced its transparency. F-G:BOPP film prepared with equal ratios (50:50) showed the highest glass transition temperature (Tg similar to 79 degrees C) and tensile strength (TS similar to 14 MPa). The structure analysis of the blend films showed their homogeneity and miscibility, as revealed by the infrared spectra, the differential scanning calorimetry and the microstructure results. Of particular interest, blend films showed high antioxidant and antibacterial capacities, compared to the gelatin-based film and the best results were recorded in the F-G:BOPP (50:50) among all the other films, reaching 0.96, 50.36% and 67.36% for the reducing power, the beta-carotene bleaching inhibition and the radical scavenging activity, respectively. Furthermore, the prepared films were used to wrap cheese in order to enhance their preservation. The results showed that the F-G:BOOP wrapping improved the physicochemical and the textural properties and the microbial stability of cheese during chilled storage. Thus, overall results encourage the further use of pectin-gelatin films as active packaging material.