Production of zein-based electrospun nanofibers for preservation of Iranian traditional butter.

Microbial spoiling and oxidative rancidity pose serious problems for the shelf life of Iranian traditional butter. In order to preserve butter, this study created zein-based electrospun nanofibers (NFs) that contain thyme essential oil (TEO), grape leaf extract (GLE: 5-30 %), and zinc oxide nanoparticles (ZnONPs). The ideal formulation (Zein/ZnONPs/GLE30 %/TEO) demonstrated good antibacterial activity (11 mm and 16 mm inhibition zones against S. aureus and E. coli), high hydrophobicity (137.5° contact angle), uniform morphology (638 ± 164.69 nm diameter), and antioxidant capacity (34 % DPPH scavenging). The NFs successfully increased the shelf life of butter packaging by reducing oxidation (peroxide values were much lower than control), inhibiting microbial growth (lower yeast/mold counts), and preserving physicochemical stability over a 30-day storage period. The results show that the NFs have a great deal of potential to improve the preservation of conventional dairy products using active packaging technology.