Preservation effects of photodynamic inactivation-mediated antibacterial film on storage quality of salmon fillets: Insights into protein quality

[Display omitted] •Photodynamic inactivation-mediated film (PLA/ALA) killed bacteria on salmon.•The PLA/ALA film protected the muscle proteins from degradation in salmon.•Four main types of protein oxidations in salmon were inhibited by the novel film.•The flavor and essential amino acids in salmon were preserved by the novel film.•The PDI-mediated film can greatly preserve the storage quality of salmon. The preservation effects of a photodynamic inactivation (PDI)-mediated polylactic acid/5-aminolevulinic acid (PLA/ALA) film on the storage quality of salmon fillets were investigated. Results showed that the PDI-mediated PLA/ALA film could continuously generate reactive oxygen species by consuming oxygen to inactivate native pathogens and spoilage bacteria on salmon fillets. Meanwhile, the film maintained the content of muscle proteins and their secondary and tertiary structures, as well as the integrity of myosin by keeping the activity of Ca2+-ATPase, all of which protected the muscle proteins from degradation. Furthermore, the film retained the activity of total superoxide dismutase (T-SOD), suppressed the accumulation of lipid peroxides (e.g., MDA), which greatly inhibited four main types of protein oxidations. As a result, the content of flavor amino acids and essential amino acids in salmon fillets was preserved. Therefore, the PDI-mediated antimicrobial packaging film greatly preserves the storage quality of aquatic products by preserving the protein quality.