Gelatin nanofibers with black elderberry, Au nanoparticles and SnO2 as intelligent packaging layer used for monitoring freshness of Hake fish.

The electrospun gelatin nanofibers containing black elderberry (BE) extract, Au nanoparticles (AuNPs) and SnO₂ were fabricated as intelligent packaging layer for Hake fish (Merluccius merluccius) fillets. Image analysis confirmed the formation of continuous ultrafine fibers. Differences between nanofibers were evaluated in terms of thermal stability, and chemical composition during storage. Fourier transform infrared spectrums indicated strong bonding interactions between gelatin and other compounds. Thermal analysis results showed that the addition of AuNPs contributed to the thermal stabilization of the gelatin chain. L, a, and b values of nanofibers were also measured. A rapid color change occurred after exposure to volatiles with the highest difference in L (52.29 %) of the sample containing gelatin, BE, SnO₂ and AuNPs (p < 0.05). This study showed that the absorption of volatiles on nanofibers can be detected from color changes of nanofibers. The outcomes of this study can be applied for intelligent packaging layer in seafood products.