Bioactive-Loaded Zein Nanofiber Coatings for Improving Microbiological and Oxidative Quality, and Extending the Shelf...

In the present study, zein (ZN)-based nanofibers incorporating flaxseed oil (FSO), curcumin (CUR), and gallic acid (GA) were fabricated, systematically characterized, and investigated as active edible coatings for chicken meatballs stored under refrigerated conditions (4 ± 2 °C). Three different nanofiber formulations were developed: curcumin-loaded zein nanofibers (ZNC), zein nanofibers co-loaded with flaxseed oil and curcumin (ZNFC), and zein nanofibers simultaneously incorporating flaxseed oil, curcumin, and gallic acid (ZNFCG). The produced nanofibers exhibited uniform morphologies with average fiber diameters ranging from 135.93 to 338.55 nm and demonstrated high encapsulation efficiencies (97.13-98.03%). Antimicrobial activity against selected foodborne pathogens was confirmed, as evidenced by inhibition zone diameters of 14-16 mm and minimum inhibitory concentration values as low as 0.05 mg/mL. In addition, in vitro release profiles, total phenolic content, and antioxidant capacity assessed by the DPPH assay were evaluated. Following the application of nanofiber coatings, chicken meatballs were monitored throughout refrigerated storage until the total mesophilic aerobic bacteria (TMAB) count reached the microbiological acceptability threshold of 6 log CFU/g. Changes in microbiological quality, including TMAB, total psychrophilic bacteria, and total yeast and mold counts, as well as oxidative stability parameters such as thiobarbituric acid (TBA) values and protein carbonyl content, were systematically analyzed during storage. On the third day of storage, the TMAB count in the uncoated control samples reached 6.11 log CFU/g, whereas ZNFCG-coated samples maintained significantly lower levels (3.40 log CFU/g). Overall, the application of zein-based nanofiber coatings effectively suppressed microbial proliferation and oxidative degradation, with the ZNFCG formulation exhibiting the most pronounced protective effect. These results indicate that multibioactive zein nanofiber coatings, particularly the ZNFCG formulation, have promising potential as a laboratory-scale active coating system for improving the refrigerated storage stability of chicken meatballs. However, further food-contact safety, migration, mechanical integrity, adhesion, and refrigerated-release studies are required before practical or industrial application.