Active and smart biomass film containing cinnamon oil and curcumin for meat preservation and freshness indicator

Food safety issues caused by unrecognizable food spoilage threaten the health and lives of consumers. Simultaneously, petroleum-based plastic packaging films without degradability cause environmental pollution. Despite recent certain study progress in preparing biodegradable food packaging films, it is still significant and urgent to develop biomass food packaging films with favorable water resistance, mechanical strength, UV-barrier performance, antibacterial property, antioxidant activity and visual freshness indication performance at the same time. In this work, we fabricate an active and smart biomass composite film with favorable multifunctionality by incorporating the oxidized cellulose nanofiber (OCNF)-stabilized cinnamon oil (CNO) Pickering emulsion and curcumin (Cur) into gelatin/chitosan (GC) film matrix. The study results show that CNO Pickering emulsion droplets are uniformly distributed in the film matrix. Introducing Pickering emulsion reduces the film water absorption by 336.27% and promotes film antimicrobial activity. Moreover, the emulsion stabilizer OCNFs serve as nano-enhancers to increase film tensile strength by 1.4 MPa even if introducing CNO into the film matrix. Furthermore, Cur endows the film with colorimetric pH indication ability and increases the film antioxidant activity. The DPPH scavenging rates of film including Pickering emulsion and Cur maintain above 44% after 60-day storage, and its UV-barrier property increases by 65.5% at 400 nm compared with those of GC film. These results exhibit promising potential application of the prepared film in pork preservation and the visual pork freshness indicator by the film color changes. Thus, this work provides an attractive universal strategy to construct active and smart biomass composite film for meat packaging application.