Development of Biodegradable and Antimicrobial Electrospun Zein Fibers for Food Packaging

There is an urgent need to develop biodegradable and nontoxic materials from biopolymers and nature-derived antimicrobials to enhance food safety and quality. In this study, electrospinning was used as a one-step, scalable, green synthesis approach to engineer antimicrobial fibers from zein using nontoxic organic solvents and a cocktail of nature-derived antimicrobials which are all FDA-classified Generally Recognized as Safe (GRAS) for food use. Morphological and physicochemical properties of fibers, as well as the dissolution kinetics of antimicrobials were assessed along with their antimicrobial efficacy using state of the art analytical and microbiological methods. A cocktail of nature-derived antimicrobials was developed and included thyme oil, citric acid, and nisin. Its ability to inactivate a broad-spectrum of with food-related pathogens was demonstrated. Morphological characterization of the electrospun antimicrobial fibers revealed bead-free fibers with a small average diameter of 165 nm, whereas physicochemical characterization showed high surface area-to-volume ratio (specific surface area:21.91 m2/g) and presence of antimicrobial analytes in the fibers. The antimicrobials exhibited initial rapid release from the fibers in 2 h into various food simulants. Furthermore, the antimicrobial fibers effectively reduced E. coli and L. innocua populations by ∼5 logs for after 24 h and 1 h of exposure, respectively. More importantly, due to the small diameter and high surface area-to-volume ratio of the fibers, only miniscule quantities of fiber mass and antimicrobials per surface area (2.50 mg/cm2 of fibers) are needed for pathogen inactivation. The scalability of this fiber synthesis process was also demonstrated using a multineedle injector with production yield up to 1 g/h. This study shows the potential of using nature-derived biopolymers and antimicrobials to synthesize fibers for sustainable food packaging materials.