Preparation and characterization of sodium alginate-based edible film with antibacterial additive using lemongrass oil

Abstract

Sodium alginate films at various concentrations of glycerol (0.4, 0.6, and 0.8% v/v) were prepared and characterized. The thickness, water solubility (WS), water vapor transmission rate (WVTR), tensile strength (TS), elongation at break (EB) and Young’s Modulus (YM) of the films were affected by the amount of glycerol added. Among these films, the film containing lower glycerol (0.4 % v/v) presents better WS, WVTR, and the highest TS compared to other concentrations. Sodium alginate films containing lemongrass essential oil (LEO) were prepared to examine its antibacterial properties on four common foodborne pathogens: B. subtilis, S. aureus, E. coli, and P. aeruginosa using Disc-diffusion assay. The highest inhibition was shown by E. coli (21 mm/susceptible), B. subtilis (18 mm/intermediate), S. aureus (16 mm/intermediate), and P. aeruginosa (13.5 mm/resistant). The incorporation of lemongrass essential oil as a natural antibacterial agent in the film formulation has developed its potential to be used as an active packaging with improved physical properties, especially water barrier properties.