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Thermal, structural and physico-chemical properties of different composite edible films based on alginate and pectin with the addition of citral essential oil (citral EO) as an agent to improve barrier properties, were investigated. The obtained films were clear and transparent, with a yellow hue that increased with citral EO addition. All the films displayed good thermal stability up to 160 °C, with a slight improvement observed by increasing the amount of citral EO in the composites. Gas transmission rate (GTR) strongly depended on the polymer structure, gas type and temperature, with improvement in barrier performance for composite samples. Also, citral EO did not exert any weakening action on the tensile behavior. On the contrary, an increase of the elastic modulus and of the tensile strength was observed. Lastly, water contact angle measurements demonstrated the dependence of the film wettability on the content of citral EO.

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Edible films with whey protein concentrate (WPC) with a lipid component, sunflower oil (O) or beeswax (W), to enhance barrier to water vapor were obtained. Brea gum was used as emulsifier and also as matrix component. In order to achieve emulsion with small and homogeneous droplet size, an ultrasonicator equipment was used after obtaining a pre-emulsion using a blender. The films were made by casting. Effects of lipid fraction on droplet size, zeta potential, mechanical properties, water vapor permeability (WVP), solubility, and optical properties were determined. The droplet size of emulsions with BG decreased when decreasing the lipid content in the formulation. The zeta potential was negative for all the formulations, since the pH was close to 6 for all of them and pI of BG is close to 2.5, and pI of ß-lactoglobulin and α-lactalbumin (main proteins in WPC) are 5.2 and 4.1, respectively. Increasing W or SO content in blended films reduced the tensile strength and puncture resistance significantly. BG and WPC films without lipid presented better mechanical properties. The presence of lipids decreased the WVP, as expected, and those films having BG improved this property. BG films were slightly amber as a result of the natural color of the gum. BG has shown to be a good polysaccharide for emulsifying the lipid fraction and improving the homogeneity and mechanical properties of the films with WPC and beeswax or oil.

Catalytic ceramic papers were developed by incorporating Pt-NaY zeolite to ceramic papers. The necessary mechanical strength was enhanced by the addition of natural borate compounds, which confer elasticity and resistance similar to those obtained using colloidal suspensions, which are the most commonly used binders. Pt-NaY zeolite was incorporated into ceramic papers either during the papermaking process or by spraying a zeolitic suspension on ceramic papers. The partial encapsulation of the faujasite by the sintering of the borate compound during the calcination step made catalytic ceramic papers less active toward the CO oxidation reaction than the corresponding traditional systems (Pt-NaY zeolite coated onto cordierite monoliths or the powder Pt-NaY faujasite). Light-off curves indicated that the activity of Pt-NaY zeolite was preserved when incorporating the zeolitic component by spray, in which case the CO oxidation reaction ran away at ca. 130 °C, and the total CO conversion was achieved at 150 °C, maintaining 100 % CO conversion for more than 90 h.