Effect of essential oil and surfactant on the physical and antimicrobial properties of corn and wheat starch films.

The present study describes the microstructure, physical (tensile strength, elongation at break, water-vapor permeability, optical characteristics) and antimicrobial properties of biodegradable films prepared by incorporating different concentrations of lemon essential oil (LO) and surfactants (Span 80, Tween 80) into corn and wheat (CW) starch film. Results showed that the incorporation of LO provoked a decrease in water content, transparency, whiteness index (WI), water vapor permeability (WVP), solubility and tensile strength properties. Higher b*, elongation and haze values were observed in CW-LO composite films. Films with LO, especially at higher concentrations, were more effective against all tested bacteria than the control films. The films' surface and cross-section morphology was different depending on the LO contents. Compared with the CW-1LO film, the addition of surfactants significantly increased antimicrobial activity, solubility, haze, surface coarseness and porosity; remarkably decreased tensile strength and transparency. The film containing only Tween 80 showed higher b*, water content, solubility and WVP, lower WI and elongation when compared with the film containing only Span 80. These properties with some good physical and antimicrobial characteristics suggest applications for CW-LO-T/S film in a wide range of food products.