Essential oil-incorporated pea protein films for salmon preservation

Active, sustainable films offer a promising alternative to petroleum-based packaging for extending food shelf life. To improve the packaging properties of pea protein isolate (PPI) films, 2 wt.% of essential oil (EO) from garlic, ginger, or cinnamon was individually incorporated as an active compound. The results indicated that garlic and ginger EOs significantly increased film hydrophobicity, decreasing moisture content (MC), total soluble matter (TSM), and water vapor permeability (WVP) values. The addition of EOs decreased tensile strength (TS) and elongation at break (EAB), with the extent of the reduction following the order: garlic EO < ginger EO < cinnamon EO. Scanning electron microscopy (SEM) images revealed that the distribution of EOs within the film matrix differed: garlic EO was mainly distributed within the internal structure, while ginger and cinnamon EOs were primarily on the surface. FTIR analysis confirmed the interactions between PPI and EOs. When applied to salmon, lipid hydroperoxide and thiobarbituric acid reactive substances (TBARS) results showed that cinnamon EO significantly delayed the lipid oxidation process while garlic or ginger EO promoted it. Aerobic plate count results indicated that pea protein films containing EOs did not inhibit bacterial growth, although they demonstrated remarkable antibacterial activity in vitro. Furthermore, the addition of EOs significantly altered the color and sensory acceptance of salmon. In summary, our findings suggest that incorporating EOs into protein films is a feasible approach to enhancing food shelf life, with the type of EO and the specific food system where the film is applied being key factors influencing its effectiveness.