Physical and chemical properties of edible films containing nisin and their action against Listeria monocytogenes

The effects of hydrophobicity/hydrophilicity of edible films against Listeria monocytogenes strain V7 by various nisin concentrations (4.0-160 IU/film disk) and pH values ranging from 2.0 to 8.0 were determined and the mechanical properties and water vapor permeability of films prepared with or without nisin were compared. Surface hydrophobicities (446, 282, 232 and 142, respectively) of whey protein isolates, soy protein isolates, egg albumen and wheat gluten were determined. As the nisin concentration increased, the amount of inhibition progressively increased in all tested films. Using nisin, edible films with higher hydrophobicity values of 280 to 450 units under an acidic environment exerted a greater inhibitory effect against L. monocytogenes. Different interactions of nisin with the proteins of the different films resulted in variation in the mechanical properties and water vapor permeabilities of the films tested.