Electrospinning of gelatin/chitosan nanofibers incorporated with tannic acid and chitooligosaccharides on polylactic acid film: Characteristics and bioactivities

Electrospinning of gelatin/chitosan solutions incorporated with tannic acid (TA) and chitooligosaccharides (COS) at varying levels was performed on polylactic acid (PLA) films at a constant voltage of 20 kV with a feed rate of 0.5 mL/h. Nanofibers of gelatin/chitosan were incorporated with TA and COS as the sources of antioxidant and antimicrobial agents. SEM images revealed that the gelatin/chitosan nanofibers (GC-NF) had diverse morphologies and diameters. The concentration of TA and COS had prominent effect on the morphology of the nanofibers. Bead-free and smooth nanofibers were formed at higher TA and COS levels. PLA films coated with GC-NF showed high antioxidant activity, especially at higher levels of TA and COS incorporated. The films also exhibited antibacterial activity against both gram positive and gram negative bacteria. Selected GC-NF coated PLA films, having high antioxidant and antibacterial activities, were studied for mechanical and barrier properties. Water vapor permeability (WVP), tensile strength and elongation at break (EAB) of GC-NF coated PLA films were found to be improved when compared to PLA film. Moreover, light transmission of GC-NF coated PLA films was reduced and the films were cloudy in appearance. Characteristic peaks of functional groups in gelatin and chitosan were identified in the GC-NF coated PLA films using Fourier transform infrared (FTIR) spectroscopy. Overall, PLA film coated with GC-NF incorporated with TA and COS, could be a potential active packaging alternative for food applications.