Stable nisin food-grade electrospun fibers.

Most of antimicrobial peptides interact with food components decreasing their activity, which limit their successful incorporation into packaging material, functional foods and edible films. The aim of this work was to develop a nisin carrier. Nanofibers of amaranth protein and pullulan (50:50) loaded with nisin were obtained by electrospinning. The nanofibers morphology was determined by scanning electron microscopy and fluorescent microscopy. The molecular interactions were characterized by infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, and thermogravimetric analysis. The nisin loading efficiency as well as the antimicrobial activity against Leuconostoc mesenteroides were evaluated. The micrographs of the obtained materials exhibited smooth and continuous fibers with no defects characterized by diameters between 124 and 173 nm. The FTIR analysis showed intermolecular interactions mainly by hydrogen bonding. The electrospinning process improved the thermal properties of the polymeric mixture displacing the Tm peak to higher temperatures and increasing crystallinity. The antimicrobial activity of nisin in broth and agar against L. mesenteroides was maintained after incorporation into fibers. The results presented an outlook for the potential use of protein amaranth nanofibers when incorporating antimicrobials as a food preservation strategy.