Application of electrospun zein/polyvinyl alcohol nanofibers incorporating thymoquinone and electrosprayed resveratrol nanoparticles on the shelf life of fresh rainbow trout fillet and inoculated Escherichia coli O157:H7

This study aimed to fabricate electrospun zein/polyvinyl alcohol (ZN/PVA) nanofiber, as well as ZN/PVA nanofiber containing 4% thymoquinone (TQ), and electrosprayed with ZN nanoparticles containing 2% resveratrol (RS) (ZN/PVA-TQ-RS). The effects of these nanofibers on the bacterial, oxidative, and sensory qualities, as well as the microbial safety (following inoculation with Escherichia coli O157:H7), of rainbow trout fillets during 12-day storage period at 4 °C were evaluated. According to the results of scanning electron microscope analysis, the average diameters of the ZN/PVA nanofibers, ZN/PVA nanofibers containing 4% TQ, and ZN nanoparticles containing 2% RS were measured at 207.5, 275.6, and 255.5 nm, respectively. Fish fillets wrapped with ZN/PVA-TQ-RS nanofibers exhibited significantly lower total viable counts (7.6 log10 CFU/g), psychrotrophic bacteria counts (7.1 log10 CFU/g), peroxide values (0.95 meq/kg lipid), thiobarbituric acid reactive substances values (0.62 mg MDA/kg sample), E. coli O157:H7 counts (5.7 log10 CFU/g), and demonstrated better sensory characteristics (overall acceptability: 4.8) compared to the other experimental groups (P ≤ 0.05). Thus, the ZN/PVA-TQ-RS treatment was able to extend the shelf life of fish fillets by at least 3 days, as determined by acceptable microbial, oxidative, and sensory thresholds. The present findings suggest that ZN/PVA-TQ-RS can be employed as an active packaging material containing natural preservatives to prolong the shelf life and enhance the microbial safety of refrigerated fish fillets in the packaging industry.