Influence of alginate emulsion-based films structure on its barrier properties and on the protection of microencapsulated aroma compound

In recent years the use of natural polymers coming from renewable sources has greatly increased due to the over-solid packaging waste and dwindling petroleum reserves. Biopolymer films, which contain both lipid and polysaccharide ingredients to form complex packaging enable us to obtain edible films with good mechanical and water barrier properties as emulsified alginate edible films. Moreover, these can be considered to encapsulate active molecules as flavours. The aim of this work is to better understand the influence of the composition and the structure of the film matrix on its barrier properties and thus on its capacity to protect encapsulated active substances. Granulometry, Differential Scanning Calorimetry (DSC) and Microscopy (MEB) characterizations of films with or without flavour and/or fat showed that the encapsulated n-hexanal compound modifies the film structure because of interactions with the alginate matrix. This interaction affects the studied barrier properties, oxygen permeability, aroma compound permeability, liquid aroma permeability and surface properties, of emulsified alginate films. This study brings new understanding on the role of emulsion-based edible films as a matrix and on its ability to protect encapsulated aroma compounds and on its barrier properties. (C) 2009 Elsevier Ltd. All rights reserved.