Physical properties and application of a red pepper seed meal protein composite film containing oregano oil

Red pepper seed meal protein (RMP) was extracted from the by-product of red pepper seed oil production. RMP composite films were prepared, and their physical properties were evaluated. The optimal concentration for the RMP composite film was suggested to be 4% RMP/1% gelatin, and the tensile strength (TS) and elongation at break (E) values of the RMP composite film were 20.14 MPa and 11.45%, respectively. In addition, RMP composite films containing oregano oil (OR) were prepared by incorporating different amounts (0, 0.1, 0.3, 0.5, 0.7, and 1%) of OR. OR affected the physical properties of the RMP composite film, and the composite film containing 0.5% OR had optimal physical properties: a TS of 8.71 MPa, a Young's modulus of 142.83 MPa, and an E of 75.32%. The antimicrobial and antioxidant activities of the RMP composite films with OR increased as the OR content increased. Wrapping fatty tuna meat with the RMP composite film containing 0.5% OR reduced the inoculated Listeria monocytogenes and Salmonella Typhimurium populations by 0.73 and 0.89 log CFU/mL, respectively, compared with the control sample after storage at 4 °C for 12 days. Moreover, the RMP composite film containing 0.5% OR decreased the degree of lipid oxidation in the fatty tuna meat during storage. Consequently, a RMP composite film containing OR can be useful in prolonging the shelf life of fatty tuna meat.