Electrospun Nanofibers of Polyvinyl Alcohol Loaded With Carvacrol Nano-Emulsions Toward Antioxidant, Antimicrobial, and Controlled-Release Applications

Antibacterial composite films are commonly used in food packaging. However, most of these packaging materials are prepared from petroleum-based polymers and has generated grand challenges to the global environment due to the abuse of these non-biodegradable packaging materials. In this study, carvacrol (Car) was used to form highly stable nano-emulsions, followed by electrospinning with the polyvinyl alcohol (PVA) solution to prepare bio-functional nanofiber membranes (PVA-Car-NEs-NF). Meaningfully, the PVA-Car-NEs-NF can still maintain filamentary structure similar to the undoped PVA-NF membrane confirmed by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) further demonstrated the interfacial interaction between carvacrol and PVA molecules. As a consequence, the PVA-Car-NEs-NF demonstrated a modest release rate of carvacrol invitro with controlled release behavior. Moreover, the antioxidant capacity of PVA-Car-NEs-NF towards scavenging the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) progressively increased as the increasing carvacrol concentration, and the maximal clearance rate reached 52.56% +/- 2.50% at a carvacrol concentration of 2.0 mg/mL. Additionally, PVA-Car-NEs-NF also exhibited enhanced antimicrobial activity against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Candida albicans (C. albicans), while the inhibitory effect was positively dependent on the carvacrol content, thus greatly improving their utilization efficacy and provides the potential application of carvacrol for food, medicine, and cosmetic-related fields.