a b s t r a c tChitosan packaging films containing different bioactive compounds (a peptide fraction from whey protein concentrate (WPC) hydrolysate, glycomacropeptide (GMP) and lactoferrin) were produced and their mechanical and barrier properties were evaluated. The molecular weight of protein-based compounds was determined using SDS-PAGE. The addition of GMP and lactoferrin to chitosan film caused a significant reduction of tensile strength and the elongation-at-break significantly increased with the incorporation of lactoferrin. The addition of protein-based compounds also affected gas permeability: a significant decrease in water vapor permeability was observed with the incorporation of lactoferrin; oxygen permeability significantly decreased with the addition of GMP and lactoferrin and carbon dioxide permeability significantly decreased with the incorporation of all of the protein-based compounds. Such results were related with film's hydrophilicity and crystallinity.This manuscript contributes to the establishment of an approach to optimize edible films performance based on physico-chemical properties, aiming at a higher benefit for the consumer.

Nanolaminates have been reported to have applications in different areas, such as the preparation of multilayer films, coating biomedical appliances or multilayer edible coatings with enhanced properties for applications in the food industry. This work aims at characterizing the surface properties, water vapor permeability, and thermal and mechanical properties of a nanolayered film. The film was produced using two polysaccharides with opposite charges, chitosan and sodium alginate deposited on to aminolyzed/charged PET. Contact angle measurements showed differences in the films with a successively higher number of layers. SEM images allowed the measurement of the thickness of the layers. The nanolayered film had a water vapor permeability of (0.85 ± 0.04) × 10 −11 g m −1 s −1 Pa −1 and a hardness increase of 0.245 ± 0.06 GPa. DSC and TG analyses of the nanolayered film showed increases of 39.2% in the melting energy when compared with the PET film used as support, and a decrease in the decomposition temperature from 386 to 331 • C.

Sucrose solutions, with concentrations near or superior to saturation, present high potentialities for the candy and pastry industries.Creep measurements under small stresses were done to obtain the rheological properties of highly concentrated sucrose solutions, since such solutions could be in a metastable state and tend to crystallise. The viscosities of these solutions, from 70.0% to 85.2% (w/w), were determined experimentally at different temperatures, from 0 to 90°C. The temperature dependence of viscosity was studied using experimental and published data for, respectively, high and low concentrations (<70% (w/w)). Results showed that the Arrhenius model describes better the temperature dependence of viscosity for concentrations under saturation and in the high concentration regime the WLF model had a better predicting ability. The effect of concentration on viscosity was observed and included in the Arrhenius and WLF modelsÕ parameters. The proposed models were able to successfully describe the data in the corresponding concentration range. These results can be used in predicting the viscosities of syrups for either process design or new products formulation.