Performance of lipid-based edible moisture barriers in food products with intermediate water activity

Nine lipid-based barrier films (three chocolates, acetomonopalmitine, white beeswax, and four commercial blends: two acetoglycerides/beeswax blends, two hydrogenated and fractionated vegetable oils) were characterised using classical water-related and physical properties of edible barriers, such as water vapour permeability, moisture adsorption isotherm, moisture effective diffusivity, surface hydrophobicity, firmness and solid fat content (20 7C). Classifications based on these properties were established and compared to the barrier efficiency under real conditions of use, i.e. in a model food product (cereal-based component – intermediary aw gel). Moisture migrations were performed using self-supported barriers (300 mm) and fitted with a predictive model based on Fick’s Second Law. White beeswax and acetoglycerides enabled the best extensions of the dry-component shelf life from 2 h to between 100 and 330 h. Moisture effective diffusivity and calculated water vapour permeabilitycombined to a mechanical property evaluation of the barrier were more discriminating to assess the barrier efficiency in the model food than the moisture sorption and experimental water vapour permeability. The importance of combining both waterrelated and physical characteristics of the barrier and the advantages of an integrated approach through the simulation of the material behaviour under its real conditions of use with the model are highlighte