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Water barrier properties of various edible films: acetylated monoglycerides (AMG), dark chocolate (DC), and wheat gluten (WG) were evaluated through water sorption isotherm, diffusivity, and permeability measurements. Diffusivity and sorption isotherm were then used in a mathematical model for predicting moisture transfer evolution in composite foods. It was successfully validated in agar gel/sponge-cake systems with the studied films at the interface. Using model predictions and relevant permeability measurement comparisons, AMG appeared to be the most efficient water vapor barrier films. Acetylation of monoglycerides seemed to be favorable to improve their water vapor transfer resistance mainly by reducing water solubility and despite a slight increase of water vapor diffusivity.

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Several cultivars of apples (Malus domestica) were chosen for their variable concentrations and compositions in phenolic compounds. Cubed samples (1 cm3) were subjected to osmotic dehydration, and the effect of temperature was studied at 45 and 60 degrees C. Water loss, sucrose impregnation, and the evolution of some natural components of the product were followed to quantify mass transfer. Ascorbic acid and polyphenols were quantified by HPLC for several osmotic dehydration times and regardless of the quantity of impregnated sugar. Changes in antioxidant components differed as a function of the nature of molecules. Their concentrations decreased in line with temperature, and few differences were observed between cultivars. Processing at a lower temperature (45 degrees C) caused a total loss in ascorbic acid but allowed the retention of between 74 and 85% of initial polyphenols, depending on the cultivar. Cultivars containing highly polymerized procyanidins (such as Guillevic) experienced less loss. Hydroxycinnamic acids and monomeric catechins displayed the most marked changes. Leaching with water into the soaking solution was the principal mechanism retained to explain these losses.