Improvement of water barrier properties of starch films by lipid nanolamination

Abstract

A nanolaminate consists of two or more layers of material with nanometric dimensions that are physically or chemically bonded to each other. Starch based edible films present suitable characteristics for food protection, but their functional properties are affected by film water content. Nanolaminated films were formulated by coating the starch film with lipid nanolayers in order to improve their water resistance and barrier properties. Lipid nanolayer presence was confirmed by SEM images and contact angle measurements. Sorption isotherms of nanolaminated films showed an important reduction in film water adsorption through all the aw range studied. The effect on permeability of the driving force (aw difference) and the aw values at each side of the film, were analysed. Water vapour transport was controlled by water diffusion through hydrophobic nanolayers. Nanolamination of edible films improved the water barrier properties of hydrophilic films by combining starch with lipids materials at nanometric scale.